Fukushima
units Nos .3 (left) and 4 on 24 March 2011, looking seaward.
No.3
is in meltdown. No. 4's 90 metric tons of fuel rod
assemblies (about 60 tons of uranium oxide and isotopes) had joined 130
tons of older "pins" in the 5th floor spent fuel pool during
reactor maintenance. A hydraulic cement pumping
truck (red
pipe) is trying to replace the boiled off water in the pool.
At
1200 deg C, the fuel rods oxidize directly with the remaining
water's oxygen, leaving hydrogen gas explosions to
cause the
visible damage. It is believed that most of the hydrogen came
from the failure of the primary containment vessels of the three
reactors that went into meltdown, not the boiling pools. Unmanned
aerial drone photo released by Air
Photo
Service.
Bottom & links.
WRONG TECHNOLOGY
Why the global reactor
fleet must go.
J. I. Nelson, June 2011
neutrons.notlong.com
Rev 30Nov2011-Sec VIII
70
years ago, before the first reactor was ever built, we chose a reactor
design optimized to produce radioactive waste, because among the
isotopes was the plutonium for Nagasaki and the 60,000 warheads which
followed . . . and we won the Cold War. Now civic society
wants
electric power. It is time for this industry to turn the
page.
If it has water in it, don't build it.
PREFACE
Why couldn't the
Fukushima reactors turn off? Why did the spent
fuel pools boil away? High school classmates wrote back
saying my
explanations were helpful and again there was kidding for being a class
brain. Most touching was one man's hope that people out there
with such understanding would bring a safer nuclear future for
all. I'm old enough to accept my inconsequentiality, so I had
two
choices: send out more e-mails to explain that we are
powerless and I can't help, or share knowledge with everyone, knowing
that people united are more powerful than any ruling elite.
My
choice was obvious, and here is the paper that tells you what you need
to know. Your efforts to follow this sometimes strange
material
will be a great comfort to me. We roar through a lot of biology
and physics in this teaching paper, and younger people you know might
also enjoy the ride in order to see all the science. If you visit
a lot of physics and some of the history of WWII, you see that the
reactors generating power today should never have been built, and the
road to sustainable nuclear technology is obvious -- all we have to do
is stop the global nuclear establishment dead in its tracks. So
this unconventional teaching paper is also neither conventionally pro-
nor anti-nuke.
Corrections & comments:
jerry-va RemoveThisTextAt speakeasy.net
PAPER's
PREVIEW
We review first the
biology of DNA, because DNA is the link between
radiation and radiation sickness, as well as cancer. Then we
turn
to the operating principles of nuclear power reactors to see what makes
the trash coming out so much more radioactive than the fuel going in.
Atoms have outer
electrons going around an inner nucleus. The electrons make chemical bonds, the nucleus makes trouble. An energized
or unstable nucleus emits radiation ("nuclear radiation", "atomic
radiation" from "radioactive decay") and is "radioactive".
The
nuclear-based nature of radioactivity makes it inherently more powerful
than the electron-based nature of chemical bonds.
When
nuclear radiation meets chemical bonds -- when physics meets chemistry
-- nuclear radiation wins nearly every time, and chemical bonds
break. Radioactivity able to break chemical bonds
is called
"ionizing radiation", after the fact that electrons are knocked clear
out of orbit, leaving the molecule out of electrical balance; i.e.,
charged or ionized. What matters about ionizing radiation is
not
that something gets ionized, but that molecules are left in pieces or
bent and broken.
The bonds you don't want
to break are the ones that hold your body's
DNA together. A look at the role of DNA in the life
of
every cell in our bodies explains why we so quickly see nausea (and
worse) in workers exposed to a lot of radiation, but cancer rates rise
only years later . . . and keep rising for decades.
These are bedrock
principles of cellular reproduction, heredity,
cancer. There will always be more to learn, but the basics
remain
true. Knowing the basics makes clear to us all when talk
about
the effect or lack of effect of radiation -- and any settlement of damages that does not
indemnify the listener for life -- is fraudulent. A public
exposed to radiation without a public health program is a public that has been betrayed by those in
power. If one corporation makes you sick and another treats
you,
both can make money.
Is radiation that
bad? There are research papers purporting to show benefits
from small amounts of radiation. There are papers purporting
to convey documentation of damage
from small amounts of radiation, and still more papers that claim the
others are flawed and the documentation is invalid. Such arguments will
not be reviewed and settled here, and I advocate no political group. We are both tasked instead
with
laying out an understanding that makes ignorance, evasion, and outright
lying easy to detect, an understanding that remains valid to the limits
of human knowledge.
Our main job after
biology is reactor physics: what goes in, what comes out, what happens
inside.
A modern nuclear reactor
(1,100 megawatts) is loaded with 130 metric
tons of fuel rod assemblies or about 78 tons of pure uranium dioxide
pellets. 96% of this uranium is the garden-variety U-238
isotope,
and about 4% is enriched U-235. These pellets, hardly larger
than
a pencil eraser, can be dropped by hand into the long, hollow metal
tubes (the "fuel rods" or "pins"), wearing only latex gloves for
protection against dust. (In practice, machines load most
pins.) Packs of fuel rods (49, 64, more) make a "fuel
assembly". When a gantry crane hauls the fuel assemblies out
of
the reactor two years later on their way to the spent fuel pool, they
are radioactive enough to kill a person in one second. Under
four
percent of the fuel has been burned ("fissioned") and 96% has not. But that 96% is now laced with
a zoo of radioactive isotopes, some not seen on Earth for billions of
years. Producing 78 tons of hot trash every few years is not
the
result of choosing how to operate the reactor; it is the result of the
reactor design we have chosen. We will examine how the choice
was
made to (1) split uranium and (2) use slow neutrons to do it.
The
choice between two things you may never have heard of -- "slow
neutrons" and "fast neutrons" -- was the choice that sealed our fate.
These basic reactor design choices were made before the first
reactor had ever been built. A design to maximize the
production
of radioactive waste was chosen because, among the radioactive isotopes was the
man-made element plutonium needed for the second atomic bomb dropped on Japan, and the
60, 000 others which followed, none of them a repeat of the first-and-only
all-uranium bomb, the one dropped on Hiroshima. Plutonium saved
that
day and won the Cold War too. Seventy years later, our needs have
changed but the reactors have not. It is time for this
industry
to turn the page.
Basic
physics makes it obvious that "clean, efficient nuclear power" is
deceptive, because only 4% of the fuel is fissioned (not efficient),
while 96% is laced with insanely radioactive elements that did not
exist before, that never went into the reactor (not clean).
These reactors never burn most of what we put in them. "Spent fuel"
is deceptive because 96% of the fuel was never consumed and is not spent;
rather, it has been activated, it has been made much more radioactive than it was. The activated, unspent fuel is declared
"waste", a form of waste that will be dangerous to life for
geologically long periods of time. We still "reprocess" the
fuel,
even though we don't want the plutonium from it and the rest is never
returned to service.
The phrases "spent fuel"
from "clean, efficient nuclear power" were
lies when they were first coined, they are lies today, and our
understanding of the universe around us -- bedrock principles of
physics -- tells us they will be lies forever. You and I are tasked
now, in the essay which follows, with mastering enough physics to see
why these phrases are lies, enough to be able to explain it to
others. Other reactor designs greatly reduce waste production
and
storage problems. These designs are called "fast-neutron
reactors". You may be opposed to all nuclear power, while I
am
not. That's OK. My advocacy goes only as far as asking you to
resolve with me to work for the abolition of the current global reactor
fleet. The nuclear power industry must start over. It is now
up
to the public to know more nuclear physics than the nuclear power
industry. We must teach the industry itself that they were
dealt
a bad hand for today's needs, and there are better
choices.
Why is our situation as a people, as a great nation, so seemingly
ridiculous?
However
we got there, we found a rut and stayed in it until we had
built an
industry powerful enough to buy self-perpetuation.
An
industry powerful enough to buy self-perpetuation uses money to corrupt
institutions that work for public health, uses money to corrupt
financial and legislative processes, uses money to corrupt institutions
that work for reliable technological superiority and honorable behavior
in the industry itself. Ultimately, the problems we face are
social: problems that multiply and won't go away in an increasingly
corrupt and dysfunctional society. Election cycles come and
go.
So do democracies, nations, empires, civilizations, species.
But
here, we will expend effort mostly on what lasts: knowledge
of
biology (especially the operating principles of DNA) and physics
(especially neutron bombardment -- slow or fast -- of uranium and other
big atomic nuclei). The water-moderated, slow-neutron reactors of the
global fleet must be decommissioned. It was the wrong choice.
There are other choices and, speaking for myself, the industry is free
to invest in them, and start over. I thank the industry for
working so hard to do so well with such terrible technology.
Now
it is time to relax and apply those heroic skills to something happier,
something different that can be what this nuclear industry will never
be: sustainable. Slow neutrons? Wrong technology.
Water inside? Don't build it.
You can get through
this; just take aspirin and try again in the
morning. Yes, you're unqualified, but it's not hopeless.
My
Ph.D. is in psychology, so I'm unqualified too. I gratefully
accepted help from one physicist friend who led some of the
design work on the Large Hadron Collider's largest detector at CERN,
Geneva and another who once designed thermonuclear bombs with Edward
Teller, and they said they were not reactor physicists and were
unqualified too, so let's all just push on. Qualified people
who
want to fix oversimplifications and misconceptions may write to me at
jerry-va RemoveThisTextAt speakeasy.net Qualified people too
angry to write can send links for us to look at.
--jerry
J. I.
Nelson, Ph.D.
IEEE
Optical
Society of America
Society for
Neuroscience
CONTENTS
I.
ATOMS, MOLECULES, PROTEINS and the GENETIC CODE
It is not that hard to
set out the basics of cellular biology, physics
and chemistry. If only in self-defense, we will do all three,
because the attack on public health and on the cells of our bodies with
atomic reactors is an attack on chemistry by physics. It is a
clash of two very different worlds. Chemistry plays out in atoms'
electron orbits as they bump into one another, while physics plays out
in the nucleus. Both electron orbits and nuclei play by
similar
rules: you can pump either up to higher energy levels, and they'll give
it back later. Normally, though, nothing ever reaches the
nucleus -- unless you have an "atom smasher", or bombs and
reactors, which hit the nucleus with neutrons.
And normally, nothing
is ever heard from the nucleus -- except in bombs, reactors and
radioactivity, when energy pours out of disturbed nuclei.
Inherent differences in these energy sources (outer electrons, inner nucleus) brings inherent
differences in their intensity. It's a stacked deck: nuclear
radiation breaks chemical bonds, damaging molecules. When
physics
attacks chemistry, physics wins.
ATOMS
AND THEIR ORBITING ELECTRONS
An atom has a nucleus of
neutrons (no electric charge) and protons (one
positive charge each) whose net positivity attracts electrons
(negative)-- most happily one per proton. I got through most
of
my life thinking of electrons as orbiting the nucleus in tight little
patterns (not necessarily all circular) which got bigger when you pump
energy into the atom, until you put in too much energy and the
outermost electrons fly away altogether. An atom with one or
more
electrons knocked out is charged or "ionized". "Ions" can be
charged either way, since electrons missing one place can wind up as
extras in another.
Actually the orbits are
not tight at all. If a simple atom
(hydrogen; one proton, no neutrons) were a football field, the nucleus
would be an ant. It's nearly all empty space. In a childhood
science fiction thriller, the
protagonist figured out a way to align the nuclei with those vast,
empty spaces, walk through walls, rob banks, and astound
everyone. But in reality you can't get through.
When atoms
meet, the electron orbitals -- electrons in a whirling cloud that is
everywhere at once, a giant beach ball -- bounce off one
another.
Like charges repel. In our world of regular stuff, objects rub
their electron shells with one another, and electrons are always
rubbing off,
sometimes with shocking results after you slide across a car seat.
It may be mostly empty space, but, in everyday life, powerful
electromagnetic forces keep us out of it
SHARED
ORBITS IN
CHEMICAL BONDS. In high school I learned that
not every orbit is possible; some were preferred and others,
forbidden. There were preferred numbers of electrons for any
orbital that was permitted. These preferences were so strong
that
atoms would put their nuclei beside one another and share their
electrons to get the preferred orbits stocked with the preferred, full
complement of electrons. Atoms that share electrons in
orbits around their nuclei are "chemically bonded"; all
chemically-bonded atoms, whether only a pair of atoms or thousands, are
called molecules. Every molecule has vastly different
properties
from its constituent atoms because it now bounces off the rest of the
world with a totally different electron cloud. When there's a single
nucleus inside, people speak of the "electron orbital levels" or
"electron shells"; when there's more than one nucleus inside, people
speak of the "chemical bonds". Because electron orbits aren't all
circular, chemical bonds have preferred angles, and molecules have
particular shapes.
We live in a world where
nuclear radiation from radioactive decay meets chemical bonds and the
radiation wins. How come?
Radiation trumps
chemical bonds because the energy saved by forming a
bond is not very great. So applying not much energy back
again
will break the bond. For example, most molecules we know can be
destroyed by heat energy (think of fires). You don't need an
A-bomb, just a match. What luck that chemical bonds are weak
--
we constantly break and remake them: batteries are charged and
discharged, plants build up carbohydrates and we animals digest them back down
again, we store energy as starch and fats and hopefully exercise enough
to re-bond most of those same atoms as sugar molecules, burn them, and
piss it away.
QUANTUM LEVELS WE LIKE
OR CAN'T HAVE. I passed my high school
chemistry and so did the years. The magic of childhood faded
a
little. Atoms didn't really "prefer" certain orbital levels
filled
with certain numbers of electrons; rather, those configurations just
had lower energies, so atoms weren't necessarily any happier to find
them. They might have just been walking backwards at the time
and
fallen into them. There were preferences everywhere, but the
magic shared in Mrs. Walsh's chemistry class was gone. Today, even
the nucleus has preferred and forbidden energy levels just as the
electrons do. Since the nucleus can't orbit anything, its
energy
levels were seen at first as the vibrations of a
suspended water droplet. In atomic bombs and reactors, the
droplets vibrate too much and shatter (we split the nucleus; we get
smaller droplets). Now physicists realize the neutrons and protons
don't touch one another, packed like red and green tennis balls in a
Science Fair model. The soft touch of indistinct edges leaves a lot of
freedom for movement somewhat like orbitals after all.
Unhappy
nuclei can spend an awfully long time before settling into something
preferable for them because of its lower energy level. We get the
energy the nucleus doesn't need anymore as a radioactive emission.
The conceptual framework
developed to bring order to the
occurrence everywhere of preferred and forbidden levels of energy is
quantum mechanics,
the product of the most famous people (Einstein
& company) in the most famous century (the last one) in
physics. For the smallest units of matter, physicists want to
describe everything as waves. If we accept waves, we get quantum
mechanics. We can't
expect energy to rise to levels they say are forbidden, any more than
we can expect a guitar string to play a note to which it is not
tuned. You like it? I went into biology. If you want to
pursue
quantum
mechanics further, I must warn you that the next thing physicists ask
for is to treat matter the same way as energy (E=mc^2).
Regarding solid matter as "waves" may lead
to the lost magic you were looking for, but for the rest of us, what
matters is that anything you do in an atomic bomb or a nuclear reactor
to beat the crap out a nucleus will raise it to energy levels it does
not prefer, and it will give that energy back to you.
Sooner or later, the nucleus will find a lower energy state for
itself, and hand nuclear radiation out to you.
NUCLEI WE LIKE OR CAN'T
HAVE. Radioactivity is not just rearranging the
furniture you already have. Any nucleus has powerful
preferences
for how many constituent neutrons and protons it cares to unite into a
single structure. If a nucleus bent on reorganizing itself changes its
number of protons, then the (matched) number of electrons changes (you
can always find one somewhere), the chemistry changes, and the name
changes ("nickel" minus a proton is "cobalt"). A change to
the
neutron count matters more to the nucleus than it does to us.
The
atom retains its chemistry, we keep the name (17 protons is chlorine),
and some specialists speak of the "Cl-37 isotope" of chlorine, which is
mostly (75%) chlorine-35. Both isotopes are stable, but Cl-36
isn't. Only the neutron count has changed when we go from
isotope
to isotope. Proton changes change the associated electron
cloud,
the chemistry, and the name of the element.
Nuclear reactors throw neutrons at
atoms, a lot of them acquire an extra neutron, and none of them like
it. We return to these extra-neutron isotopes when we
return to the unstable nuclei
that pour out of our nuclear power plants. Now it's time to
make
big molecules, not big atomic nuclei, because that is the road from
chemistry to biology. Biology goes to enormous lengths to
preserve a place for itself on this planet. Radiation must
always
bring disorder to Life, and will always be wedded to cancer.
UPWARD
TO CELLULAR BIOLOGY
SIMPLE, REPEATING CHAINS
OF MOLECULES ARE POLYMERS. If you make a molecule of
20 or 30 atoms and pick mostly carbon and hydrogen, you often find
configurations that can connect together head-to-tail in long
chains. The chains are thin, can bend a lot, and get into
tangled
mats with one another (that can still slide past one another and bend a
lot). Chaining the identical molecules together into one
really
big molecule is called "polymerization", the tangled mat is "plastic"
and, if you spend too much time at this, you're a hydrocarbon
industrial chemist. These polymer chains can go on for a
million
molecules, each link a dead repeat of the one before.
Plastics
are wonderful, but biochemistry -- and, ultimately, life -- is going to need something less
monotonous.
CHOOSING INDIVIDUAL
LINKS, NOT REPEATING THEM. In living cells,
the polymer chain's individual links (the small molecules of 20, 30 or so atoms
each) are not identical. We draw links from a set of 21
different
molecules, with more shapes and ways of connecting together.
We'll still make a chain, but, when it's done, the many attractions of
the 21 different shapes used as links will cause the chain (now
one single, larger molecule) to fold up into a particular shape. We
need only 400, maybe 600 smaller molecules (the links) for the
chain, but the problem is, we need to know which of the 21
building blocks to choose for each next link, and we need to stop at
some exact chain length.
The set of 21 molecules
are the amino acids we make or eat, and then
circulate all over our body. The chain, after it folds up into a shape
that does something wonderful, is one of the proteins that cells make
as they grow; and the instructions for which one of 21 amino acids to
link up next is the genetic code stored in our DNA. Every
cell
has a copy of the code; how about the amino acids? Animals
have
lost the instructions for making 9 of the 21 amino acids, so we have to
eat plants (or other animals) to get them. These 9 are the
"essential amino acids". Chained together, only one or two dozen
amino acids makes a useful protein (e.g., the small, agile peptides,
used for signaling), but let's look at a really big protein.
FIGURE
CAPTION: Muscular Contraction.
With
two proteins, we can create muscle fibers that contract. The size and
complexity of actin and myosin carry us into the realm of
micromachinery. Celebrate how much of this you already understand. On
the lower left, a "ribbon diagram" represents the long chain of amino
acids out of which myosin (or any protein) is built. You know that
chains like this are built (linked up or "polymerized") under DNA
control. The DNA dictates a particular choice of amino acid for each
new link. Given abrupt changes in amino acid choices, you half-expected
these abrupt turns and changes in the ribbon diagram. You were warned
of the tangle we might get once we switched the chain's links from the
simple building blocks of plastics to amino acids, because they attract
each other laterally, causing the chain to "fold". The colorful helices
(corkscrews) so common in the ribbon diagram are a common "protein
folding" pattern. Each turn of such a helix is formed by about 3.6
successive amino acids. Thus, each turn is the polymer that 3 or so
successive instructions of DNA ordered the cell to synthesize. Admit to
yourself that you have a start-to-finish grasp of what a ribbon diagram
for any protein molecule is, and how it got there. Down to the atomic
level. Yes, there will always be more to add, but perhaps this is a
painful admission -- is it? Because if it was so easy to get this far,
you could go anywhere if you wanted to . . .
A better
guide to how one protein fits alongside and interacts with another is a
"volume diagram" of the molecule's surface, and most of the figure uses
them, not ribbon diagrams. Chemical bonds can form if atoms get close,
and proteins vary their shapes to control fitting and bonding.
Muscles
can change their length much more than a molecular spring can, and hold
the new length steadily with great force. Myosin fibers (pink) achieve
muscular contraction with their numerous protruding ratchet arms that
engage (make light chemical bonds with) actin fibers lying alongside
them. The ratchet arm moves, and so actin fibers are pulled past myosin
fibers. The change in tilt of the ratchet arm is a change in the
preferred angle of chemical bonds when energy supplied by the body is
consumed, an event marked by the absorption of the body's small,
ubiquitous energy carrier ("ATP" in the diagram), and its eventual
ejection -- now spent -- as "ADP". The helical springs so obvious in
the ribbon diagram actually add some "spring" to the ratcheting action.
Finally,
the ribbon diagram on the lower right is one unit of actin. This single
actin "monomer" is the DNA-dictated chain of amino acids specified by
the cell's actin-making instructions (this actin's "gene"). Multiple
copies of these monomers are chained together -- top to bottom -- to
make the actin filaments seen in the rest of the diagram (blue). Chains
of chains? Yes; it is an added layer of complexity, but it brings
magic. The monomers can be chained or unchained as the cell supplies or
withholds energy for the reaction, in accord with signals from the
world outside. Such polymerization and de-polymerization of
"scaffolding" enables cells to migrate and move (using actin alone --
no big investment in muscle formation here). We are beyond plastics;
this is responsive, alive. Using what is already a chain of amino acids
for each link of actin makes it possible, as with everyday ropes, to
create actin in the form of two intertwined strands for extra strength.
The
stunning revelation of molecular micromachines like this one for
muscular contraction inspired man to try his own hand at it, and the
field of nanotechnology was born. Nothing, no single technology, can
reveal what is portrayed here. The arguments and detective work are
driven by genomic and protein sequencing, by clever preparations
subjected to X-ray crystallography or electron microscopy, and by
experiments to see what breaks the machine or makes it run. Love life.
It is a marvelous gift.
(Adapted in part from
Garrett
& Grisham "Biochemistry".
)
THE INSTRUCTION
MANUAL. DNA instructs cells which amino acid to
choose next (and when to stop) to make the string of amino acids that
constitute a particular protein. Proteins are the body's most
specially-shaped molecules. Some are small and travel far, where their
unique shape acts as a unique signal; others are among the body's
largest molecules. These molecules combine into sheets of
muscle
tissue (figure above), or cartilage, or scaffolding rods inside cells
to give them
shape and the ability to move themselves or their internal stuff
around. Proteins create lock-and-key communication systems
that
enable only a particular hormone or neurotransmitter to fit into the
matching receptor on a distant target cell and thus command a nerve
cell to fire, or a distant blood vessel to contract, or the target to
secrete or release a needed growth factor / histamine / sugar. Proteins evolved to make tubes of just the right size
to
let only calcium or only sodium ions through, then added a
lid or other devices to open or close the tube, then a remote control
system for the lid. Not to
be
a protein chauvinist, but the rest of the body is just water,
teeth
and fat droplets as far as I'm concerned.
The instructions for the
the body's estimated 100,000 different
proteins are all strung together, which, with a lot of "junk" DNA left
over from Earth's 3+ billion years of cellular evolution, makes a chain
1 meter long -- too long to handle as one piece, given the fragility of
a thread only a few atoms across. For convenience and safety, the DNA
strand is broken up -- in humans, into 22 pieces plus the X and Y
pieces. Wound up so tightly that they appear dark under the
microscope, these pieces or "chromosomes" are collected together and
held by a thin bag with holes in it to form the prominent nucleus
of
nearly every cell in your body. The nucleus holds the
Instruction
Manual for the total, unique you. With few exceptions, every cell
has one copy of the complete Instruction Manual. Physics and
biology chose the same word because the atomic nucleus (one atom) and
the cellular nucleus (billions and billions of atoms) are both central,
and important, in their respective worlds.
As mentioned, not every cell in your body has a copy of the Manual for making You. Red blood cells are
special. Red blood cells are modified after formation to remove the
chromosomes and other organelles, stripping the cell down to an oxygen
carrying unit small enough to travel through the smallest capillary
beds. Deprived of a nucleus -- all the instructions -- red
blood
cells can only die, never reproduce, and so must get cranked out in a
red blood cell factory someplace else. This turns out to be
the
bone marrow. Special exceptions like that aside,
plants,
animals and even bacteria have agreed: a cell nucleus is a
great
place to put the Instruction Manual. Each cell in
every
one of these life forms has a nucleus (the cells are
"eukaryotic"). Anyone from Homeland Security who swabs the
inside
of your cheek gets the whole Instruction Manual too. If we
ever
get as far as mail order clones and you want a spare copy of yourself,
you won't have to enclose anything in the envelope but your check. Just
lick the envelope and mail it.
RADIATION
DAMAGE OF PERFECT COPIES
Except when a lot of
body needs to be built (embryonic months, early
childhood), most cells never read more than a page or two of the
Instruction Manual. Cellular roles are fixed, and narrow.
(Bone
marrow and the new "adult stem cells" are exciting exceptions.) So,
does this mean that damage to instructions that never get read doesn't
matter? It doesn't, until the cell needs to duplicate itself.
A
copy is a copy of everything: the cytoplasm, the organelles in it, and,
not least of all, the three billion "code letters" in the meter-long
DNA.
Only perfect copies will
do. Anything less is the end of "heredity".
A single
damaged
molecule will have important consequences if the
molecule was the set of DNA instructions your new child is about to
inherit from you. (The kid
only gets a single copy, no spares; indeed,
only a single half-copy from one of you, in the successful sperm,
completed with a complementary half-copy from your mate, in the
fertilized egg -- the two strands of the famous "double-stranded helix"
that is DNA.) Fortunately, the body detects and rejects most
cases of DNA damage, and we experience "reproductive problems"
(sterility) from radiation damage. But sometimes there are
stillbirths, and sometimes all barriers are passed. Survivors
of
the Chernobyl meltdown had live-birth children that later developed
leukemia (or other cancers) and died. If you even get a live
birth after germ cell damage, save for cancer bills, not just
college. A government's responsibility for the health of its
people extends to two generations from a nuclear accident.
"Germ cells" (egg and
sperm, the "gametes") are most vulnerable to damage from
radiation. These cells have already copied, split the double helix, and
are waiting, forever for many, for The Big Moment. Until
pairing,
there will be no copying and no copy corrections. Before a
dental
X-ray, the lead blanket goes over your pelvis. Unborn children should also
recognize and do something about the special vulnerability of their
mothers. Women
are more vulnerable to ionizing radiation than men, as they enter
maturity with all the eggs for childbearing they will ever have.
Women are the sole source of their offspring's mitochondrial
DNA,
which lacks the repair mechanisms of nuclear DNA.
The
mitochondrial organelle
has performed many regulatory roles --
most famously, making energy available from metabolism -- so
well
since a big bacterium ate a little one 3.7 billion years ago and thus
acquired the first one, that the once-ingested organelle wasn't
digested, and every plant and animal cell in the
world decided ever since to keep the mitochondrial organelle and its
own, brief DNA. No other DNA exists outside
the
nucleus. The mitochondrial DNA has no sexual recombinations,
no shuffling of the deck. Mitochondrial DNA is passed down from mothers
to all offspring. Mitochondrial DNA's odd maternal-only inheritance -- and lack of deck-shuffling -- has made it a tool for tracing the races of man, his spread across the planet.
Gametes aside, copying goes on
forever
for most of the body's 10 trillion
"somatic" (non-germ) cells. This constant copying of cells is the key to the
link
between radiation, "radiation sickness", and cancer.
THE DNA
POLICE. Radiation breaks molecules, yet all my life I
have heard people say this or that level or source of radiation was
"safe". How was I to know if it was true? Then we
discovered repair mechanisms for DNA, and control points during cell
reproduction to stop the copy if repairs were impossible.
Perhaps
up to some point, the body can
repair any radiation damage to DNA (or completely kill off the damaged cell line). Yet the research is now
piling up that very small differences in amount of radiation make a
difference in a particular individual's chances of getting cancer, and
make a difference (tens of thousands of people) in the cancer rate for
a nation's population as a whole.
If we have repair
mechanisms for DNA that can fix a few errors, why are
we seeing data that document a cancer rise for any rise in radiation?
For most of the body's
somatic cells, the copy-error rate on the
1-meter long DNA strand of three billion code letters is one in a
billion. That's three mutations for the DNA police to set
straight
every time a cell replicates itself. There are more errors down stream
("What'd you bring me that for? I said the protein's next
amino
acid was tryptophan"), but let's stick to DNA replication.
You
are walking around today with 10 billion cells you didn't have
yesterday. Some say we are not properly estimating the bone marrow's
generation of blood cells, and the number is at least double that.
Ten billion cells arrive
daily when you are not healing from surgery,
when you are no longer a vulnerable, growing child, when you are not
pregnant, when you are only replacing daily wear and tear. That's 30
billion mutations for the DNA police. It now appears that
research can document increases in cancer rates for very low increases
in radiation because the body's DNA repair mechanisms are matched to,
and have their hands full with, the 30 billion mutations that they
catch and repair every day.
CANCER vs.
AGING. One reason we are all more likely to develop
cancer the older we get is that the DNA police don't catch all the
copying mistakes (mutations) that occur naturally, and, the faithful
copying machine of heredity being what it is, each mutation is inherited forever. The mutations
accumulate. If so, then
- any additional radiation-induced
mutations move up our date with cancer, and
- anyone who talks about a
safe level of radiation is wrong.
Declaring any increased
level of radiation "safe" is
unacceptable. I would settle for "acceptable level of
radiation
for low-risk adults". If there is no cancer in your family,
maybe
you don't care if your date with cancer is moved up from age 110 to 95.
CANCER'S SLOW
EMERGENCE. Reactors don't need iodine to run, and
nobody puts any in, but iodine comes out. The body
concentrates
iodine in the thyroid gland. Although I-131 has a half-life
of 8
days, today, 25 years after Chernobyl, the National Institutes of
Health states that the rate at which new thyroid cancers are being
reported is still increasing. In Japan, the number of new cancer cases
per annum, especially leukemia, will peak 10 years from now in the
younger school children of Fukushima Prefecture. Here is why the
appearance of cancer is delayed.
A cell with a
radiation-induced DNA error that doesn't
get caught --
that overwhelms the body's ability to fix errors and let only perfect
copies through -- that cell becomes a grandfather cell at the head of a
growing
population of equally-corrupted daughter cells (traditional terms;
nothing do to with grandpas and girls). The grandfather cell
itself was a failed copy, but now the DNA police can only insure that
each daughter cell is an accurate copy of grandpa. If the probability
of cancer increases for all of us as "natural" copying errors
accumulate with age, then these people have a head start on developing
cancer, but need time to express it. It takes the
passing
of years of body maintenance, of replacing old cells with new, to
slowly cover the body with damaged daughter cells, just as weeds appear
and cover a
lawn. The larger the patch of damaged daughter cells, the more
likely
that additional copying errors among them will add new errors to the
original
one. Without adding more radiation, you eventually cross your own
personal threshold to cancer, and you will cross it sooner if you got a
head start years ago.
With ingested or inhaled radioactivity, the errors pile up faster. When
that nuclear "event" happened upwind from where you live, did
you
shower and drive away after exposure, or stay put? From
the cancer's point of
view,
the beauty of a plutonium dust speck lodged in the bronchia or lungs is
that only a small daughter cell population need line up
around a tiny area
to receive the next hit of ionizing radiation, and the next. The
tissue sits, an enthralled audience around the inhaled particle,
watching the dazzling show. That tissue sums genetic errors to
cross the line to cancer. There's
no waiting for the weeds to cover the lawn, no waiting for the
daughters of childhood's forgotten exposure to sum with adulthood's
occasional failures of DNA replication.
Cancer
is delayed
because we are alive. We have to grow and
propagate changed daughter cell lines (mutated cell lines) that never
should been
initiated in the first place. The more daughter cells, the more chance
new genetic errors will be added to the old, inherited one.
Children grow faster and we can see what we have
done
to them sooner.
RADIATION SICKNESS
APPEARS FAST. Radiation sickness doesn't arrive insidiously,
as cancer does. Why so fast?
The DNA police only
check the Instruction Manual (the DNA) when it's
time to copy. Cells discovered to have errors make
hasty
repairs, or are "set" to commit suicide ("apoptosis"). There
are
places in the body where cells normally get copied (replaced) very
often. The lining of the gut turns over completely every
couple
of weeks; platelets important for blood clotting last only 10 days.
Hair follicle roots push out 0.2mm of hair a day, and twice that for
beards. If you are exposed to high radiation levels, these
are
the areas of the body that will show the damage first (cancer patients
undergoing radiotherapy go bald), these are the areas where the body
itself will first detect that much is terribly wrong. Since
radiation is crude and mangles the double helix itself rather than
merely slipping the wrong code letter into it (a normal copying
error), cell reproduction will typically fail entirely and the cell will be killed
("apoptosis") when an irradiated cell tries to reproduce itself.
After intense radiation
exposure, so much of your intestinal lining
will die that you will feel nauseous and vomit within hours. Within
weeks, when your hair is falling out, you will get infections and
bloody stools because your blood doesn't clot, the immune system (where
white blood cells also turn over a lot) is shot, and your gut lining
can't heal. To look at treatments, run a search on "DTPA,
KI, Prussian blue".
Remember to write down the number of hours between your exposure and
first vomit. The doctor can estimate your dose from the
delay;
beyond a certain dose, you cannot be saved.
RADIOTHERAPY.
Cancer cells turn over a lot also -- they have
escaped many of the body's regulations that foster our common good, and
instead they pursue only self-advancement. Cancer cells use
the
body's food and oxygen supply, the body's waste removal
systems,
but contribute only blight to the ordered tissues of the body where
they claim membership. Eventually they learn to influence the
body's decision
making, and then command blood vessels to proliferate toward them
("angiogenesis"),
so that the tumor can grow and command still more
resources. Fortunately, cancer cells preoccupied with copying their own
perverted DNA are, like the gut lining, disproportionately sensitive to
radiation. Cancers try to copy often, and the DNA police
come to check the copy. By itself, the copy will pass inspection.
Radiation treatment in oncology adds enough damage
to
the DNA that the DNA police can recognize it. Apoptosis ensues.
The cancer
itself
attracts little attention because its instructions, while altered, are
perfectly readable, whereas radiation shatters them.
Cancer evolves as a
disease of the genes to escape the body's controls. A pre-cancerous
cell line that begins to escape local controls on copying makes too
many cells that forget to read the Instruction Manual for advice on how to specialize. This
bunch
of perennially immature cells are "dysplastic". When they finally learn
to read the Instruction Manual, it will be the wrong page (the wrong
genes are "expressed"). The cancerous cells can mature somewhat and organize
into a neoplasm
or tumor that doesn't fit with what their neighbors are
doing. Errors in the DNA accumulate, rules are not followed, and the
tissue becomes disordered as increasingly sloppy copies are made. The
cancer makes so many copies that it doesn't care if some cells fail,
doesn't care if some can't even metabolize food for energy. What
counts
is the chance for the cancer to discover and turn on genes -- pages in
the Instruction Manual long ago closed when the cancer's parent cells
became matured and specialized. What counts, as reproduction gets
sloppier and faster, is the chance to discover signaling proteins that
turn on the body's angiogenesis (beckon blood vessels hither, we're
hungry), that signal the body to deliver hormones or growth factors,
that trick the immune system into not attacking. It is
Darwinian
-- whatever works by chance grows, and soon there are millions. You
want to catch cancer fast, not because it will be more to remove later,
but because it will become a different, smarter enemy. A
cancerous cell line that escapes all apoptosis mechanisms (the suicide
commands) achieves immortality. Now these cells will never be
flagged down by the DNA police. Radiation therapy will lose its efficacy. Metastasis requires cells to learn another particular
skill set for budding and spreading. Metastatic cells that are also immortal can spread with
youthful vigor forever. Your body's concept of government for the common good is now history.
Cancer is a combination
of disorganization (of growth, of genetic
regulation, of assigned roles and contributions to the common good) and cunning (the
discovery of genes that one's specialized neighbors do not
express). It is clear that ionizing radiation leads to mutant
cell lines and cumulative genetic damage that will eventually trigger this disease and perhaps speed its progression.
FREE RADICALS.
What if you only knock a few atoms out of the
body's ordinary molecules (not the germ cells, not the DNA of somatic
cells). Violent changes to the molecule breaks up the
electron
cloud that had wrapped round and resonated across that molecule -- the
bonds that made the molecule in the first place. What do the broken
pieces do?
An atom you knock out is
likely to be positively charged, having failed
to take all its electrons with it. The two pieces of
a
broken molecule are likely to wind up electron-rich -- negatively charged
for one piece -- and electron-poor for the other. A charged
atom or
(piece of) molecule is called an ion, so the beam or particle of
radiation that committed molecular mayhem was "ionizing
radiation".
Unimportant technical differences distinguish an ionized piece of
broken molecule from a "free radical" -- they both have energy and
charge, they attract stuff to them, they are chemically reactive with
what they attract. Free radicals can react with (clog or bend and
break) DNA, so we are back where we started. More likely, the
pieces will just be digested, but the reactivity can make the metabolic
breakdown tough on the enzyme attempting to do it.
The body routinely
creates several types (families) of molecules as
free radicals and routinely makes use of their reactivity to signal
that something needs to be done. At least some naturally-occurring free radicals are useful. When ionizing radiation
creates free radicals, what
molecule acquires free-radical activation and where
it is activated are unnatural. As a class, free
radicals
are implicated in aging as well as DNA damage.
Anti-oxidant-rich
foods neutralize some of them.
THE
"DEBATE" OVER LOW-LEVEL RADIATION
In the world outside you
will be told that such-and-such a level of
radiation is safe, or maybe it isn't safe, but you would get more
dosage if you flew across the country at 35,000 feet (less atmosphere
between you and cosmic rays), so stop complaining.
Please turn away and
consider instead these items as a starting point
for arriving at your own approach to the conflict between public health
and private nuclear power.
1. When ionizing radiation is
absorbed, it ionizes something.
Was DNA never hit? If by magic DNA molecules were missed every time,
we'd
both like to know this. What has been done to screen for genetic
damage? For many decades, we have been able to look for gross
chromosomal abnormalities in response to radiation, changes visible in
any pathology lab light microscope. It is not expensive. Have you run any checks even for gross chromosomal
abnormalities? Today we have gene chips to detect changes as
small as a single code letter in the 3 billion letter-long human
genome. Have you surveyed SNPs (Single Nucleotide
Polymorphisms)
in the population? Ultraviolet-induced genetic damage begins
with
the signature damage of fused thiamine code letters in the DNA wherever
they happen to occur in adjacent positions. What have you
done to
detect and characterize analogous genetic signatures for nuclear
radiation damage? If it is safe, then DNA was not
changed.
Perhaps you should have a look.
2. If the situation is safe,
cover my health insurance.
It will cost you nothing. A nation with a nuclear power
program
and no national health insurance has not kept its date with destiny,
but, after a radiation event, all of us surely will.
3. What have you done to improve
normative data for baseline cancer rates?
If you don't want to pay my health insurance, just insure the public
for any cancer elevation over baseline rates for the next 2
generations. At present, only Connecticut has historically
deep,
population-wide data with granularity fine enough to distinguish a
useful number of different cancer types. Once you have to pay
for increases above baseline cancer rates, you will want to rely on good cancer rate data, not hide increases
behind gross population averages.
4. I cannot accept any settlement
because I won't know the damages until decades from now.
We turn from cellular
biology to nuclear physics and nuclear reactors.
II. PHYSICS: POWERFUL RADIATION BREAKS MOLECULES
I remember how attractive she was, a former staff member for Newt Gingrich. She
put the coffee into the microwave, saying she would "nuke it" for me.
Actually, she was using electromagnetic energy, and had probably never
met nuclear energy in her life, since it could have killed her.
There's certainly a lot
of nuclear energy out there. Throughout
the cosmos, unstable nuclei abound, born anew in the violence of
stellar collapse and sorted out to the inner rocky planet orbits at
protoplanetary birth. But on one small, blue, inner-orbit
planet,
radioactivity has largely faded in 4.5 billion years of charmed
existence. We have a nice rocky planet, in a quiet
neighborhood,
with an iron core like most of them, but ours is still molten, and ours
is still rotating, and therefore ours still holds up a magnetic shield.
Yes, some cosmic rays do still penetrate this shield and keep up a
little background radioactivity, but you can't say a few inter-galactic
cosmic rays spoil the whole neighborhood.
Atomic weapons and
nuclear
reactors destroy what only time can heal.
Physics is physics. If the decay time was 1.5 million years
at
the creation (e.g., for zirconium-93, common in spent fuel), then it is
still 1.5 million years. If we now look at what goes into a
nuclear reactor, what happens inside, and what comes out, the absurdity
of our choices becomes clear. Just as clear is an
alternative
path to a sustainable nuclear energy industry, the path we have not chosen. A lot of
people
will lie to you about our situation and earn a comfortable living doing so. Our
goal
is to understand what is inherent in the physics, in our reactor designs. Here we will learn what
can never change on this planet, in this galaxy, in this universe --
from
here to the limits of human knowledge.
THE STRONG AND WEAK
NUCLEAR FORCES. Let's go back to that coffee, she says it's hot
now. The forces we experience in daily life are only two in
number: gravity, and electromagnetism (light waves, radio waves, other
waves, or electricity by itself and magnetism by itself).
Electromagnetism (radio waves) heated the coffee by shaking the water
molecules and leaving them still vibrating. We experience the
motion of their vibration as heat.
These
forces are not nuclear. Nuclear forces are very short-range
-- they are designed for the nucleus, and that's where they usually
stay. We seldom experience nuclear forces directly
in daily life, and their names are unfamiliar to most of us.
The
"weak force" changes one element to another and leads to the emission
of particles and radiation strong enough to kill us (thanks).
Calling that a weak force is enough to make you think physicists
actually have a
sense of humor, until you meet the strong force. The strong force
creates and
obliterates the known universe. Fortunately for human
curiosity,
a little strong force leaks from the interior of neutrons and protons
(which the strong force is responsible for creating) and out into the
larger nucleus as a whole, where we can play with it by setting off
atomic bombs to see what happens.
Both nuclear forces, the
weak force and the strong force, don't do
anything without calling for -- or giving back -- enormous amounts of
energy. Nothing new here: as we saw with the force
that
makes chemical bonds, some energy levels are preferred, some are
forbidden, it takes energy to go up a level and you get it back when
you come back down. Only now the smallest steps between adjacent
levels of
energy happen to be enormous. The
suggested opening poker chip in the nuclear research game is a $10
billion particle accelerator. That particle accelerator sits in
Europe. We would have had a better one, but we quit because it would
have cost us $11B.
"...
the US was arguably the mecca for physics from 1950 to 2000, with the
most Nobel Prizes, the biggest accelerators, and the leading journals."
--Michael S. Turner
Distinguished Service Professor at the University of Chicago
Not anymore. We tried, and you can't say we have nothing to show for it. There's a big hole in the ground in Texas, and no way to get back the $2B in 1993 dollars we spent digging it.
Since energy from
nuclear forces is often put into electromagnetic form when sent out into our
everyday world, it is worth having a closer look at the nature of
electromagnetism. The nuclear energy from radioactive decay
which
we receive in electromagnetic form arrives as "gamma rays".
There
are only three kinds of radioactivity, and gamma rays are the most
penetrating. Of all electromagnetic waves (radio stations,
radar
systems, the microwaves that heated the cup of coffee), gamma ray waves
are at the highest possible energy levels. How do they behave?
ELECTROMAGNETIC WAVES:
FROM BASICS TO GAMMA RAYS. Electromagnetic
waves -- of whatever energy -- cover distance at 186,210 miles per
second. If you divide the number on your car radio (e.g.,
100.3
MHz, 100.3 million full cycles per second) into this speed, you get
almost a car length for just one of those many cycles. This
is
the distance the wave went in that fraction of a second, and, according
to the radio dial, this is the distance it takes to trace out exactly a
single, full cycle of the radio station you have selected. One
"cycle" or "wavelength" is the "up" and then the "down", a
plus-to-minus voltage swing, and back again; or, for magnetism, a
north- to south-pole swing, and back again. If the station sounds
terrible, roll forward half a car length, and take yourself from a
trough to the next peak of the radio wavelength, then stop.
The
speed never changes (186,210 miles/second, the speed of light; or,
better, the speed of any electromagnetic radiation), so making faster
frequencies means making shorter cycles. Short cycles have to be little
-- the faster the wave changes direction (a growing positive electrical
potential reverses; a growing North Pole magnetism stops and reverses),
the less far it can go up before it has to come down again. So
the
higher the frequency, the more "forward" and the less up-and-down
"sideways" it goes. The electromagnetic whatever-it-is (radio, light,
gamma rays) will be "more arrow and less feathers" (more particle-like)
if it is higher frequency.
As one might imagine, it
takes more energy to get any physical system
swinging back and forth more times per second. Higher
frequencies
(shorter wavelengths) deliver inherently higher energies from one
physical system to another. The highest-of-all-energy gamma rays that
radioactive isotopes emit act like particles that bounce from one
collision to another before eventually disappearing.
Nevertheless, despite these particle-like properties, the fact
that there's no big-mass object here is reflected in the
ability of gamma rays, like
X-rays and most radio waves, to penetrate deeply into objects. Stepping out for a suntan will clarify all this.
ENERGY LEVELS vs.
SUNSCREEN. Beyond the color violet (in
frequency) lies Ultra-Violet, which tans, and far ultraviolet, which is
dangerous. Our treatment as a society of sun tanning is an
interesting contrast to our society's ability to deal with nuclear
power.
The violet just beyond
the visible is UV Band A ("UV-A"); the more
energetic bands are UV-B and UV-C. The bonds of DNA cannot be
broken by UV-A, but other molecules' chemical bonds have energy levels
low enough to match the energy deliverable at UV-A's
frequencies.
These molecules' bonds are
broken. The molecules, mostly
smaller
ones, are ionized, and the ions, sometimes after basically minor
rearrangements (a bend here, a twist there) can act as free
radicals. So, in nuclear power industry terms, UV-A is only
very
weakly ionizing radiation; indeed, when climbing the electromagnetic
spectrum to ever-higher energies, UV-A is the first radiation scientists see
that can do any ionizing at all. Period. UV-A usually can't ionize or damage
any DNA. Again, in nuclear power industry terms, any level of
UV-A radiation is safe because science has established that UV-A
radiation does not break DNA bonds.
Let us turn from what we
imagine
the US Nuclear Regulatory Commission and United Nations health and
atomic
energy organizations might say, to look instead at the Food and Drug
Administration. The rest of the UV-A data now come into view. This UV-A radiation ionizes part of the
body's molecules, creating free radicals. The free radicals damage DNA.
Indeed, 92% of malignant human melanomas are caused by such an indirect
attack on the integrity of DNA by free radicals produced in turn by ionizing
radiation. Therefore, beginning in 2012, the Food and Drug
Administration will require drugstore sunscreen products to protect
from UV-A or else provide a consumer warning on the label that they do
not offer any protection. For the FDA, DNA damage defines
public
health. Radiation too weak to ionize DNA directly requires
protection and warnings if we can show that this weak radiation (here,
sunshine) can still do damage to DNA indirectly.
Ionizing radiation in
the form of gamma rays enters our environment in
any reactor incident and accompanies every spent fuel rod.
Gamma
rays are the most energetic from of electromagnetic radiation; the
wavelengths are so short, the wiggles have so little time to depart
from a straight-line arrow, that the radiation moves and acts like a
hurled particle. The ionizing gamma radiation of atomic power
plants is not two or three times more ionizing than UV-A or UV-B
radiation, it is 300,000 times more ionizing. Penetration is
measured not in millimeters of epidermal collagen, but in inches of
concrete. The energy level is so high, the electromagnetic wave, acting
like a particle, bounces off the first atom with enough energy left to
ionize another atom somewhere else.
- What sunscreen does the FDA recommend for
power plant radiation?
- What label reminding you of non-protection is
required on each nuclear power plant?
- What is it about
"300,000
times as powerful" that those entrusted with protecting us do not understand?
Paper's
PREVIEW
I. Atoms, Molecules, Proteins
and the Genetic Code
II.
Physics:
Powerful Radiation Breaks Molecules
III.
Let's
Build a Reactor.
IV. The Fateful Decision: Uranium and Slow Neutrons
V. The
Spent Fuel Story - No Place to Put Anything
VI. The Big Picture: Uranium
& Our Universe
VII. Public
Policy -- We subsidize this
industry from cradle to grave.
VIII.
The Nuclear Renaissance: Fast Reactors Only - They don't make waste, and perform their own
burial.
III.
LET'S BUILD A REACTOR
The best way to learn
reactor basics is to build one. Let's start at
the core and work outwards.
FUEL RODS
("PINS"). Just as in the spent fuel pool, we'll immerse
the uranium in water to take the heat away. The heat energy
pours
out in such ridiculously large amounts that we must keep the uranium
down to a
thin sliver not much bigger than the diameter of a pencil. That
way, no uranium is more than a few millimeters away from water
cooling. To increase the amount of uranium to increase power
output, the only choice we have is to elongate this pencil, and so every
reactor winds up with those typical long, thin fuel rods: perhaps 3.6
meters (nearly 12 feet) of uranium pellets dropped into a tube whose
overall length is 4.5 meters (nearly 15 feet), but only 12.5 mm (1/2
inch) in diameter. It's already clear that, by the time we finish, our
reactor housing -- any reactor housing -- is going to be a long
structure, tubular like a big water boiler for strength against
pressure when the water boils. This housing or water boiler
is
the "reactor pressure vessel" which will have steel walls 7 or 8 inches
thick and run at 1000 psi (I am using gauge pressures, "psig", the
pressure above atmospheric by which we all measure our car tires).
In any reactor, the fuel rods are long
and delicate,
so we'll have to lower them up and down into the reactor with an
overhead gantry crane -- true, a lot of conventionally-fired boilers
are horizontal, but our reactor pressure vessel, like most of the
others,
will have stand vertically. (A wonderful exception is Canada's
innovative CANDU reactor.) Around the reactor pressure
vessel is
the larger steel "primary containment vessel". The steel walls of Fukushima's BWRs
(boiling water reactors) primary containment vessel are 3 cm thick,
nearly 1 1/8". PWR
(pressurized water
reactors), operate at higher pressures with thicker containments.
As with a kitchen
pressure
cooker, higher pressure means higher temperatures, which brings a
couple percent
greater efficiency to overall steam turbine operation -- as they have
grown to larger sizes as well as higher temperatures and pressures,
nuclear power plants have grown from efficiencies in the lower to
mid-thirty percents, closer to the 40% achieved by the best oil- and
coal-fired plants.
FUEL
ROD ASSEMBLIES. Our main energy source is fission (splitting)
of
individual uranium atoms when they are struck by neutrons.
Our
metal rods are made of a zirconium metal alloy ("Zircalloy") that lets
neutrons pass through easily, if only we had some neutrons!
Neutrons are found
in the nucleus of most atoms, but don't like to leave without an
act of
violent persuasion. For getting neutrons loose,
smashing atoms together or splitting nuclei apart are both effective.
Reactors use the second method. One of our uranium atoms
somewhere will spontaneously split, releasing perhaps two neutrons
which we want to hit other uranium atoms, but which instead promptly
escape the
thin fuel rod we have to use because of the heat, and hit
nothing. The obvious solution is to put more fuel rods around
the
first one so that neutrons escaping from from one rod will hit a
uranium atom in another. A few hundred rods would do, but for
760
megawatts of electrical power (Fukushima reactors Nos. 2, 3, 4, and 5,
Model BWR-4), we'll go for 34,524 rods. For control purposes, a small,
scattered minority of rods will be filled with substances other than
uranium, or sometimes with sensors. The main control "rods"
have
a plus-sign cross section, and slide in between four fuel rod assembly
baskets. In a meltdown, all of this makes quite a mess at the
bottom of the reactor pressure vessel.
Fuel rods are delicate
and heavy. Uranium weighs half again as
much as lead, bringing fuel rods to between 3 and 7 lbs each in most
reactor designs. Besides being stainless (corrosion
resistant),
stainless steel is a good neutron reflector, so we'll build stainless
steel carrier baskets for groups of 7 x 7 fuel rods (and larger numbers in
larger reactors). These "fuel rod assemblies" are what the
overhead gantry crane takes back and forth to the spent fuel pool when
we take the lid off the primary containment vessel and the reactor
pressure vessel inside to empty the entire
reactor for maintenance, or to replace fuel rods that are "spent" after
18 to 24 months. Because stainless steel is a good neutron
reflector, it's also a good idea to line the primary containment vessel
with it; neutron reflection is a well-engineered issue within the
reactor pressure vessel itself.
In the 1970s Model BWR-4
machines like Fukushima's Nos. 2,3,4, and 5
reactors, the 548 fuel rod assemblies -- stainless steel, Zircalloy
tubes, uranium pellets -- weigh 90,000 kg. Approximately 66%
of
the fuel assembly weight (60 tons) is the actual uranium dioxide fuel;
press reports often confuse the two weights. New reactor designs are
twice this size.
click photo to enlarge
Figure caption: Nuclear power plant basics, from steam generation in reactor to cool
water returning from condensers to be boiled again. The neutrons
flying everywhere inside reactors make water radioactive; some oxygen
temporarily becomes a radioactive isotope of nitrogen (before
returning to an O in H2O again). Because the radioactivity in
steam released from Stack "S" normally comes just from such N-16,
with a half-life of only 7 seconds, an increase in cancer rates has so
far been demonstrated only for very young children (5 years and under)
living very close (5 km and under) to such stacks. When a reactor
overheats and its fuel rods crack, the fuel spills into the water and
the steam is deadly. Maine Yankee plant, completed in 1972 for
$231M ($1.1B in 2005 dollars). Shut in 1997 and
decommissioned by 2005 at a cost of $508M (1998 estimate).
During its lifetime, the 810MW plant (810 million watts) generated 119 billion
kilowatt-hours of power with a retail value of $12 to $24 billion.
(Drawing by David Fierstein, http://www.davidiad.com/ ).
REACTOR
PROBLEMS. This completes the sketch of heating elements
inside the reactor pressure vessel (boiler) and its primary
containment vessel (also steel, or steel-lined concrete). We are ready to boil some
water. There
is a secondary containment structure which truly is a only a
containment barrier with concrete walls, not a boiler. The
secondary containment structure is meant to contain the pressure if the
reactor explodes its boiler. The thick reinforced concrete
walls,
preferably lined with stainless steel, make secondary containment
vessels (buildings) expensive. There are controversies over
whether companies build them large enough for an explosion to expand a
lot and drop its pressure to something that actually can
be contained. Sometimes there are scandals surrounding
thinning
from corrosion of the innermost reactor vessel itself
(Davis Besse reactor, Ohio, 2002).
I expect to see boilers
explode here in the USA, because corrosion thins the steel, neutron
bombardment makes the steel brittle, our reactors are old, the licenses
are routinely extended, the Nuclear Regulatory Commission
relaxes
safety standards instead of maintaining (enforcing) them as the
installations age, and policy has shifted from 40 to 60 year lifespans
for
all nuclear plants. Building a reactor without water inside
eliminates explosion problems, leaving only the issue of heat control.
The reactors that have no water to make explosions of steam or hydrogen
are molten-metal or gas designs used to keep the neutrons "fast"
instead of
"moderating" them with water, as we shall see in concluding section VIII, The Nuclear Renaissance: Fast Reactors Only.
A
reactor pressure vessel without water is a nuclear power plant in
meltdown. Getting water into the reactor to save the day always
means releasing radioactivity into the neighborhood. Here is why.
In
order to pump
emergency water into the reactor pressure vessel with ordinary
electric-motor
pumps, the pressure must be dropped from ca. 1000 psi to 350 psi by
releasing radioactive steam into the atmosphere. In normal
operation at 1000 psi, only pumps
run by the steam pressure itself can force water back into the reactor
pressure vessel to keep it going. These pumps are in a big steam loop
that must
be shut
down in any emergency. The shut-down must be fast. All AC power
generators run in perfect
synchrony with the
electric grid, or not at all, so fluctuations at the reactor are
intolerable. If there is a fluctuation at the reactor, the
generator must be shut off at once, and then there is no use for all
the steam. The loop with the turbogenerator and
steam condensers is shut down. We
have a hot reactor and plenty of
steam,
but no place to put it and no way to pull out the energy and return the
steam to water. We have steam to drive the
steam-driven pumps, but there is no water in the pipes. So, to
get
cooling water into the reactor vessel, the plant can only use other
water
moved by electric pumps that only work at lower pressure levels.
To pump this water with lower
pressure
electric pumps, the reactor's steam pressure must be dumped,
and
the steam is radioactive, at least briefly.
No one is happy to release radioactivity into the environment,
but that is what nuclear power plants are designed to do.
Nearly
all the world's power plant reactors have water inside, and all the
water becomes radioactive -- some oxygen atoms turn into an
unstable nitrogen isotope. The radioactive nitrogen-16
arising from neutron bombardment of the oxygen-16 in water has
a half-life of only 7.1 seconds. Much equipment and attention is expended to condense this
steam
quickly back to water (somewhere else, not in the main condensers), to
minimize what is released back into the
atmosphere, to delay the release so the radioactivity can die down. So
then are we perfectly safe
because
it's only water, only 7 seconds? We would like to think the
water
is perfectly pure, and it is indeed demineralized continuously as
metal
from pipes and valves leach into it, and as corrosion builds up.
But
the public never thinks to ask about water purity, and we are not
taught that cobalt (natural Co-59) and nickel (natural Ni-58) used to
make most steel alloys become Co-60 and Co-59. Cobalt-60 is
responsible for most of the radioactivity that makes
decommissioning any nuclear plant difficult. Steam release is not
just an N-16 story, and it would be nice to know completely what's
being discharged. But, in a serious
accident, it will not matter that the public never demanded to
know how pure the
water once was, when operations were normal. The fuel itself
falls into the water and contaminates it with a zoo of radioactive
isotopes.
When cooling fails and
the path to meltdown begins, the Zircalloy rods
balloon at 900 deg C and may crack. Cracks will give the
water circulating through the reactor water more
radioactivity, because neutron
bombardment of reactor fuel (which starts as only uranium, or only a
uranium-plutonium mixture) creates radioactive versions of many new
elements. Some of these are water-soluble, and out the cracks they go. The cesium and the iodine that
unite chemically to form cesium iodide from the I-131, I-132, Cs-134
and Cs-137 isotopes are a deadly example. Fukushima reactors No. 1, 2,
and 3 surpassed this temperature and the cooling water which they
subsequently boiled away into the atmosphere became sharply more
radioactive on the first weekend after the Friday, March 11 tsunami and
power failure. How much was released? We do not know, but all four isotopes were seen in Seattle 7 days
later.
Reactors
with water inside can explode unless steam pressure is released, and
the steam carries dissolved radioactivity into the environment.
At 1200 deg C, the zirconium of the
Zircalloy fuel
rod tubes oxidizes directly with the oxygen in the remaining water,
leaving hydrogen gas which explodes, as we saw in Japan. At
1800
deg C the fuel rods rupture and the fuel inside falls to the bottom of
the reactor vessel. The fuel pellets -- the uranium dioxide itself
-- are often referred to as "ceramic", which sounds sealed and
stronger, but the iodine gets out and the pellets crumble.
The
industry calls the collapse of fuel rods and the spilling of the fuel
inside "rubbelization". Rubbelized fuel which
reaches 2700 to 2800 deg C melts and runs together. Fukushima
reactor #1 reached this temperature first. Since the neutrons
now
find more uranium atoms close by to split, temperatures can rise even
more to melt through steel and boil the damp earth and groundwater
underneath the building. Some newer reactor designs call for
a
large, thick pad of concrete under the reactor as a drip catcher for
reactors that pass from the meltdown to the melt-through
stage.
Fukushima reactors Nos. 1, 2, and 3 are now (late June, 2011) said to
be in the melt-through stage. The fuel rod assembly weights
in Fukushima Reactors Nos. 1, 2, and 3 are
70, 90, and 90 metric tons respectively, representing about 150 tons of uranium
dioxide in all (now partially transmuted into other elements).
All
the fuel rod assemblies of Fukushima reactor No. 4
(90
tons) were in the spent fuel pool (during reactor maintenance), along
with about 130 tons of other,
older spent fuel rod assemblies, all 5 stories above ground, so there
is no steel reactor pressure vessel or steel primary containment vessel
for protection. When the lights went out and the circulation
stopped, all the water boiled directly into the atmosphere.
GOING
CRITICAL: LET'S START OUR REACTOR. Not to be discouraged by
unlikely problems with reactors, let's start ours. Our
reactor,
like the global reactor fleet, has to be stopped, not
started. It
starts itself, so all we have to do is stop stopping it. We
do
this as Enrico Fermi did it with the very first atomic reactor on 2
December 1942: we pull out special rods loaded with neutron-stopping
elements, not fuel (silver, indium, hafnium, boron as boron carbide;
Fermi's control rods were coated with cadmium). Fermi had the control
rods pulled out a foot at a time, saw the radioactivity rise gently,
and took a break for lunch. After lunch, he pulled the last
control rod out all the way, and the radiation level abruptly jumped as
the reactor "went critical": it had crossed the dividing line between
(on average) losing neutrons and gaining them with each successive
fission. It is a dividing line, a balance. Once there is any small probability that more
neutrons
will be released by splitting new nuclei
than disappeared crashing into the old ones, then the number of
fresh neutron released will grow. Fermi shut the reactor down
after 28 minutes. There was no radiation shielding, no
cooling
system of any kind, three million people living where the reactor had
been built, and no problems with Enrico Fermi's prior calculations.
Please -- there will never be another Enrico Fermi, don't try it.
The goal of any reactor
is to split (fission) large nuclei, because that releases
the energy we're after, 10 to 100 times the nuclear energy released by
most single radioactive decays (they are very variable), and tens of
millions of times the chemical energy released by burning in
oxygen one atom of
carbon (coal, oil, natural gas). Any large nucleus will do, all
of them can be
split, although some have to be hit harder to do it than others.
The way
every reactor gets the splitting done is neutrons. Neutrons can split
the nuclei they crash into. An intense neutron flux is the
key to
reactor operation; so, we must create a space, the core of the reactor,
that becomes a cacophony of hurtling neutrons. There must be
neutrons
everywhere, going in every directions, bouncing off the walls and
hurtling into the fuel. But you don't
see
free neutrons very often. Most neutrons are bound up tightly and not
going anywhere; they are inside a nucleus, the ant at the center of the
football field. Key decisions were made very early about
where to
get neutrons and how to groom or "moderate" them for fissioning nuclei.
Paper's
PREVIEW
I. Atoms, Molecules, Proteins
and the Genetic Code
II.
Physics:
Powerful Radiation Breaks Molecules
III.
Let's
Build a Reactor.
IV. The Fateful Decision: Uranium and Slow Neutrons
V. The
Spent Fuel Story - No Place to Put Anything
VI. The Big Picture: Uranium
& Our Universe
VII. Public
Policy -- We subsidize this
industry from cradle to grave.
VIII.
The Nuclear Renaissance: Fast Reactors Only - They don't make waste, and perform their own
burial.
IV.
THE FATEFUL DECISION: URANIUM & SLOW NEUTRONS
We split U-235 with slow
neutrons to boil water for atomic power in
nearly every one of the world's 400+ nuclear reactors and the 65 more
additional reactors now under construction in 16 countries around the
world. Water inside the reactor containment vessel itself is used to slow the neutrons down.
Why do we use
slow-neutron reactor designs that maximize the number of
radioactive isotopes generated? Why do we start with uranium,
when thorium works also, and is three times more plentiful? I
cannot find the answer. We seem to be trapped in an accident of
history.
ELECTRIFYING
NEWS. Fission with neutron bombardment was
discovered at the end of 1938 in Germany, and confirmed at Columbia
University on 25 January 1939. The confirmation data suggested that
traces of U-235 within the natural uranium sample were doing most of
the splitting. The advantage of slow over fast neutrons for
getting atomic reactions was known since Enrico Fermi's work in 1934,
and U-235 also proved to split best with slow neutrons.
The physics community
was electrified. It was known by all that
splitting one atom released about 200 million electron volts of energy
(vs. an electron volt or two per chemical bond in burning), and
that the
accompanying neutron release meant chain reactions of many splitting
atoms could ignite either atomic reactors or atomic bombs. One ton
bombs would become megaton bombs, and bombs certainly excite the human
imagination. By
July of the same year, a parade of Hungarians anxious over Hitler's
advances had trooped out to Albert Einstein's summer cottage on Long
Island. Leo Szilard wrote multiple drafts, Einstein signed a longer
version dated 2 August 1939, and on 11 October the hand-delivered
letter that eventually launched the Manhattan Project lay on
Roosevelt's desk. The race to an atom bombs was on, on both
sides of
the Atlantic. The reactors and bombs of the impending Atomic Age would
use the "235" isotope of uranium, and reactors would split it with slow
neutrons, just as reactors do today.
It soon emerged that
even-numbered U-238 (99.3% of Earth's uranium),
like other even-numbered, big-nucleus isotopes, fissioned spontaneously
enough to give reactors their kick-starting neutrons (good), but made bombs explode prematurely. U-235
(0.7%
of the Earth's uranium), like other odd-numbered, big-nucleus
isotopes,
didn't fission much spontaneously (good for bombs), but was easy to fission
with neutron bombardment, provided the neutrons were slow enough to
stick.
Sticking of course makes the U-235 nucleus not only greatly
disturbed from the collision, but even-numbered, and thus in possession
of easier paths to splitting. And it does. Before the first
atomic reactor
had
been built, we were heading towards uranium fission with slow neutrons
using
tons of natural U-238 fuel (the reactor starts all by itself), enriched
with some added U-235 (sustains the chain reaction after startup).
Fuel choice and neutron moderation: seventy
years later, nothing has changed in these, the most fundamental choices
of atomic reactor design.
1. What fuel will we
load?
Natural uranium-238 enriched with some U-235.
2. What level of neutron
energy -- fast or slow -- will we use to split the fuel?
Slow. As slow as possible -- no broad spectrum of energies.
A third question is, How
will we kick-start the reactor? The
first confirmation of fission on US soil used a particle accelerator to
get the uranium to fission
and release its own neutrons. We
can
kick-start any reactor with a particle accelerator, but we marched off
behind Enrico Fermi to reactors filled with a mixture of an
even-numbered isotope to emit kick-starting neutrons (but they won't
fission under slow neutron bombardment), and a fissionable odd-numbered
isotope that needs other
neutrons to get it started. For 70 years, these three choices
have given us reactors filled with some uranium-235 and over 90% of
U-238 that absorbs neutrons but does not split. Let's say this
again: nearly the whole show -- all the power release -- is run by a
small amount of U-235 that is only about 0.7% of the world's uranium
deposits and thus requires uranium enrichment plants (big buildings
full of centrifuges) to be built all around the world. The vast
bulk of the "fuel" isn't fuel at all, but provides a steady level of
neutrons that makes it easy to start the reactor, but impossible to
turn it fully off in an accident or any routine maintenance. This
vast bulk of non-fuel becomes the mountain of radioactive trash
generated by the reactor. Neutrons don't split it, but they do
make it more radioactive.
After years
of
neutron bombardment, tons of U-238 emerge, containing a zoo
of
new
radioactive isotopes that did not exist before, that were created from
U-238 that never split. Although -- in rough terms -- only 5% of all the
U-238
atoms have changed, their radioactivity will kill you in seconds if
you go near freshly irradiated fuel as it is pulled from a
reactor. Radioactivity declines but is persistent.
Two
hundred tons or more of old reactor fuel rods
per hectare (about 2 1/2 acres) are expected to keep an underground
spent fuel repository above the boiling point of water for 10,000 yrs.
You may read elsewhere
that our water-moderated reactors have to be
refueled so often and need spent fuel pools so close by because "the
uranium is gone in the spent fuel rods but they are still
radioactive." This person is wasting your time.
Atomic reactors were
wedded to atomic weapons from the start, and this
influenced their design. With few exceptions, the
design of
the
world's reactors is moderation with graphite (Hanford, WA or Chernobyl,
USSR/Ukraine) or water (91% of the global fleet) to produce slow
neutrons, and the fuel is a
little U-235 added to natural uranium, which is U-238.
PLUTONIUM FOR
BOMBS. Before the world's first atomic reactor had
ever been built or run on 2 December 1942, it was realized that getting
tons of U-235 for bombs might be impossibly difficult. It
was. The United States has only built and exploded a single
A-bomb based completely on U-235 (6 August 1945, Hiroshima). The
rest (Trinity 16 July 1945, Nagasaki 9 August 1945, and 60,000
warheads more) use
plutonium-239. The critical mass to make a plutonium bomb is
a
third that of U-235, and this minimum can be reduced further with
superior implosion explosives and neutron reflectors (e.g., beryllium)
to concentrate more plutonium and plutonium-splitting neutrons together
in the same place at the same time . . . before the device itself
vaporizes. Unlike trying to shut down a reactor, the
vaporization
of the bomb scatters everything and the atomic reaction stops suddenly
and completely -- a clear advantage of bombs over reactors.
Plutonium means smaller
bombs than uranium, and small bombs mean more
per B-52, more bombs per missile warhead. The desirability of
Pu-239 is clinched by the easier-to-stop radioactivity it emits (alpha
particles, few gamma rays). Now we could build not only warheads with
Multiply Independently-targeted Re-Entry Vehicles (MIRVs) inside each
nose cone, but sailors could safely sleep next to those missiles on
nuclear
submarines. Everything from small tactical nuclear weapons and
"bunker
busters" to the largest H-bombs use plutonium-based A-bombs to get
started. In the
H-bombs, the plutonium-based A-bomb sets off the fusion-based
"enhancement". All bombs throw in some uranium-238 casings -- it's
cheap, and there are always enough neutrons around once the "real" bomb
goes off, to split some of it, enhancing the explosive yield. The
U-238 splits because the neutrons are fast, they have extra energy --
there is no water inside the bomb to slow them.
Victory in the grand pageant of human conflict was at hand. There was only one
problem: no plutonium anywhere on Earth.
Our planet didn't have any. It might have had it once, but, since every
plutonium isotope is radioactive, they all decayed long ago and the Earth was quiet.
Man made
plutonium. By the 1960s, nine atomic reactors were
operating on the Hanford campus in Washington State, not to produce
electricity, but to produce plutonium. (The Savannah River
site
in South Carolina was also a plutonium producer.) Plutonium
is
created by changing something else into it. Changing one
element
into another is "transmutation". In general, we transmute
elements by adding neutrons to them in a reactor.
Plutonium-239
is made in the intense neutron flux of reactors filled with
garden-variety uranium-238. Some neutrons stick to U-238
atoms
making a new uranium isotope, U-239. Like nearly all isotopes
created by the addition of a neutron, the nucleus finds the addition unwelcome and
the isotope is unstable. Radioactive decay changes first one
neutron to a proton (half-life delay of 23.45 minutes), and then
another (2.4 day delay). With the first new proton, uranium-239 becomes
Neptunium-239, and the next proton changes the Neptunium to
Plutonium-239, which sticks around (half-life 24,110 years).
The
Hanford reactors existed to make lots of radioactive isotopes, many
rare or absent in nature. The Hanford reactors existed to
produce
"spent fuel", not electricity.
The spent fuel was processed
chemically (the start of today's fuel "reprocessing"), and the
reprocessing separated the radioisotopes, removing only
plutonium. Now all the natural U-238 taken out
of mines had a bigger purpose than kick-starting the U-235.
Now
all the insanely radioactive isotopes that ensued had a
purpose: bomb production. Neutron bombardment and
absorption
moved tons of U-238 up a notch on the Periodic Table of the Elements to
a highly desired, radioactive,
trans-uranic isotope, plutonium-239.
Plutonium production
locked the United States and then the world into these most fundamental
of reactor design choices:
1.What fuel will we load?
U-238
with 4% U-235. For decades, if a nation wanted a nuclear
power
program, their reactors would not run without the approval of the USSR
or the USA, the only nations with uranium enrichment programs large
enough to provide the U-235.
2 What level of neutron energy
-- fast or slow -- will we use to split the fuel?
Slow
neutrons; splits only the U-235 (through neutron-induced fission).
Makes many intensely radioactive isotopes out of the U-238,
plutonium-239 among them. Alas, 1% of the U-235 never gets split,
because many of the isotopes absorb the neutrons even more than the
U-238 did -- they are "reactor poisons".
3. How will we kick-start the
reactor?
With neutrons from the
spontaneous fission of the 96% U-238 atoms,
instead of with a short blast from a neutron particle accelerator,
which we then unplug.
These choices gave us
plentiful plutonium-239. As far as I know,
nobody ever asked what to change for making electricity instead of
plutonium. Secrecy surrounded military efforts at Savannah,
Hanford, Los Alamos. Secrecy became the civilian culture as
well.
Secrecy delayed civic society from asking, Why are
we doing
it
this way? We left it to the experts, and the experts didn't just answer incorrectly, they never asked the question.
MODERATION MAKES
SLOW NEUTRONS. Any reactor with water inside
is a slow neutron reactor. It will split U-235 and make
radioactive waste out of the U-238. Water moderates the
neutrons, and the moderated, slow neutrons stick to the U-238
without
splitting it. The slow neutrons can't reduce the radioactive
daughter nuclei of the fissioned U-235 either, and some of these
(cesium, iodine) are particularly damaging biologically.
"Fast"
and "slow" neutrons are seldom discussed, but
neutron moderation to make them slow is easily understood.
"Moderating" (slowing) a
neutron's velocity (lowering its energy level)
occurs after neutron emission from one nucleus splitting event while
the neutron is on its way to the next nucleus splitting
event.
Moderation is done by bouncing the neutron around. The thin
Zircalloy walls of the fuel rods are transparent; the metal atoms of
the stainless steel in the fuel assembly cages are so large that most
neutrons bounce off them like a racquet ball off the wall -- going as
fast as ever. But the water is different. The water
we use
to carry heat off on the way to making electricity also plays a fundamental role in the reactor's
physics: it is the moderator that slows neutrons
down.
Atoms of water, especially the hydrogens, are about equally heavy as
the neutrons themselves. After an ideal, head-on collision,
the
neutron would be at a near-standstill, while what it struck would fly off
with all its original velocity, just like the ball bearings in the
"Newton's cradle" desktop toy illustrated above. In the real world of glancing
hits, figure that both parties fly apart on average at
about equal velocities: the water's hydrogen takes away half the
neutron's energy (and gets warmer). After two dozen
collisions,
the neutrons are moving with whatever slow velocity represents the
ambient temperature (stopping them entirely would require a temperature
of absolute zero, -273 deg C). Such "slow neutrons" are said
to
be "thermalized" or to be "thermal neutrons". With thermalization, we have dropped a couple million
electron
volts of energy down to only a fraction of an electron volt
(at room temperature, 1/40th eV). Could we have used that
energy
for something else? Reactors using molten metals for cooling
(lead,
sodium, something that melts easily) keep their neutrons
fast.
Neutrons that bounce around in water between uranium collisions become
slow.
SWIFT. History
was swift. The United States tumbled into
uranium fuel and slow neutron reactors in part because we were
developing a technology to make plutonium for bombs. It was a
technology that celebrated radioactive waste production, not a
technology to make electricity. I know of no National Academy
of
Sciences review or any other national forum which asked, How should we
generate electricity for civic society from nuclear power?
The
pioneers asked, Can we do it? And they did it. And
now it's
done. Each of us is left to ask, Is this what we wanted?
I understand that
another generation in a prior century had to beat
Hitler to uranium fission bombs. I'm thankful they
succeeded. I'm thankful that neutron bombardment to produce
plutonium weapons gave us Mutual Assured
Destruction to hold the USSR at bay (and they, us) until their empire
collapsed (not ours),
even if we still have enough radioactive trash to render Hanford,
Washington a wasteland for human eternity. Now we want to
generate electricity instead of plutonium. Uranium, slow neutrons, and
tons of waste
are not what we need, but the nuclear power industry never turned the
page.
I see no way to change
the physics that says slow neutron reactors are
the wrong choice for generating the world's electric power.
Water-moderated nuclear power reactors take more from society than they
give. The nuclear power industry must reach financially the
same
bankruptcy it so fully enjoys socially and technologically.
If
there's water inside it, don't build it.
Paper's
PREVIEW
I. Atoms, Molecules, Proteins
and the Genetic Code
II.
Physics:
Powerful Radiation Breaks Molecules
III.
Let's
Build a Reactor.
IV. The Fateful Decision: Uranium and Slow Neutrons
V. The
Spent Fuel Story - No Place to Put Anything
VI. The Big Picture: Uranium
& Our Universe
VII. Public
Policy -- We subsidize this
industry from cradle to grave.
VIII.
The Nuclear Renaissance: Fast Reactors Only - They don't make waste, and perform their own
burial.
V. THE SPENT
FUEL STORY: NO PLACE TO PUT ANYTHING
History
handed us a reactor technology that celebrates waste production, a
technology intended to produce radioactive isotopes, among them
one ideal in
many ways for nuclear bomb production. Nature had handed us a
planet with little U-235 and no plutonium at all. Our nuclear
power industry embraced a technology chosen to correct the
planet's lack of radioactive isotopes.
There
was a time when Earth had so much uranium-235 that atomic reactors
formed in hillsides and became active when it rained (water is the
moderator of choice for U-235). The natural reactors in
Gabon,
West Africa, ran for hundreds of thousands of years, but ours run out
of fuel in 18 to 24 months. What happened?
Gabon's
natural reactors occurred 2 billion years ago. Today, the
earth
still has enough radioactivity to keep our deep rocks in
meltdown. This moves the continents and refreshes the
scenery ("continental drift").
Radioactive potassium, plentiful thorium, and
uranium
heat and melt the rocks, but today this uranium is almost entirely the
238 isotope (durable,
with a half-life 4.46 billion years), while the U-235 isotope (three
fewer neutrons, same 92 protons, still called "uranium") is more
radioactive (half-life 704 million years), and is all but gone. At a
non-abundance of 0.7% in all ore bodies, nations go to great lengths to
achieve uranium-235 enrichment for bombs, and to produce some for power
plants.
The
Manhattan Project enriched uranium from nature's 0.7% to 88% for the Hiroshima "Little
Boy" bomb.(the bomb had 64 kg
total fuel: 50 kg at 88% and 14 kg at 50%). Other less-enriched uranium started nuclear
reactors
to create plutonium for the superior bombs which followed. We
never stopped making reactors that run on U-235 -- that today run on 4%
of the fuel and stop running 24 months later.
Any
nuclear engineer can increase plutonium production simply by wrapping
the neutron inferno of his reactor core in a blanket of cheap
uranium-238 and extracting the plutonium after the next refueling. This
is how India created a "peaceful atomic explosion" on 18 May 1974.
Plutonium complicates dealing with spent fuel. Political as well as
health problems are released into our environment whenever a
water-moderated reactor is refueled.
What has the world done
to bury reactor waste and separate out the plutonium?
YUCCA
MOUNTAIN FIASCO. Tunnel boring machines able to drive a 7.6
meter
diameter hole 30 meters daily, straight into a rock face, began the
nation's first "geological repository" for nuclear waste in
1994.
The 1982 Nuclear Waste Policy Act had authorized a capacity of 70,000
metric tons. $25 billion and 25 years later, the Yucca
Mountain
repository was still unfinished, but the Department of Energy wanted to
double its authorized size. Why are we not surprised?
Our
global fleet of 430+ reactors requires 67,000 metric tons of uranium
each
year (data for 2007) to be processed into fuel. Out of the global
reactor fleet come over 10,000 tons of spent fuel annually --
another Yucca Mountain every seven years. 84,000 metric tons of
radioactive, useless, spent fuel rods will slide out of the nuclear
power plants already running in the United States alone by the time
they
reach the end of their licensed operating life (40 years each, but now
routinely extended). Another Yucca Mountain. A
nuclear
Renaissance to triple nuclear capacity using current "once-through"
fuel cycles leave us wanting a 70,000 ton capacity Yucca Mountain
every 2 years. But we don't have any Yucca
Mountains. We
canceled the first one in May, 2009.
From fuel costs alone,
there is no pressure for change. There is no end in sight for
global uranium ore reserves mined at $130/kg and adding 0.3 cents to
each kWh produced at a total wholesale cost of about 6 cents/kWh, and
sold at retail for 10 to 20 cents. Enrichment to 4.4% U-235
adds
only 0.25 cents. Half-cent uranium costs could double with little
economic effect
on the industry we have today, a global industry locked into
water-moderated reactors that split their 4% of U-235 and throw the
rest away. As long as financial risks and costs associated
with
building plants and cleaning up after them can be passed off onto
others, the market dictates that nuclear power reactors will be
built to convert everything but U-235 to radioactive garbage, dump it
on the road to nowhere every 18 to 24 months, and reload. The
market always works: we pay to distort the market, and receive
what we paid for. This is
not a free market -- state control has distorted it. The few
benefit
financially by hurting the many and running away from responsibility
for their own choices.
What does the nuclear
power industry itself think should be done with their waste?
THE
REPROCESSING FIASCO. A Fukushima model BWR-4 reactor is
loaded
with 90 metric tons of fuel rod assemblies (ca. 60 metric tons of
uranium dioxide fuel). Eighteen to 24 months later, a remote-controlled
crane lifts assemblies of fuel rods, now radioactive enough to kill a
person in seconds, into the spent fuel holding pool. When the
fuel's radioactivity has died down enough to make handling easier (1 to
10 years), the nuclear power industry suggests "reprocessing" the fuel
in the rods.
"Reprocessing"
means separating the isotopes that have been created, not getting rid
of anything, least of all any radioactivity. What got
separated out was the plutonium, so that the nuclear powers could make
bombs. What gets separated out now is the plutonium, so that
no
one else can make bombs. One 1,000 megawatt nuclear power reactor
makes enough plutonium for 30 nuclear bombs every year.
(Three-year fuel cycle yields 1/3 of 99 tons fuel per year; 4%
plutonium generation, 50% recovery, 610 kg Pt, about 20kg/bomb --
nearly twice the critical mass -- because amateurs can't get down
to the 5 or 6kgs of our sophisticated missile warheads.)
Separation
methods vary, but share the key step of dissolving the fuel in acid
(e.g., nitric). Once we have a large vat of highly
radioactive
acid, relatively simple chemistry can retrieve desired components
(usually plutonium). "Reactor poisons"
(an element that absorbs neutrons, as a control rod does) that
stopped the reactor before the 4%
enriched uranium could be all split are usually not removed. (One
reactor poison is samarium-149, which is stable, not
radioactive, and does not go
away. There are perhaps a dozen others.) Reactor poisons
are not removed because it is
cheaper to mine new uranium. Reprocessing does not retrieve,
restore or return the original uranium-238 fuel for re-use.
Calling
it
for what it is -- separation -- would raise the question of what is
done with what is separated. The answer is:
nothing. The
radiation is not decreased, and some decay times go beyond a million
years (technetium Tc-99, half-life 211,100 years; neptunium Np-237 and
cesium CS-135, half-lives of 2.144 and 2.3 million years). If
you
do not want to store radioactive isotopes for a million years, do not
make them in the first place. If you can't avoid their
appearance
in a reactor's neutron bombardment, use neutrons strong enough to
destroy them after they appear. Use a reactor that can smash its
own trash.
How are our fuel
separation ("reprocessing") programs doing?
THE
HANFORD, WASHINGTON FIASCO. The Department of Energy (DOE)
wound
up holding approximately 100 million gallons of radioactive acid waste
stored in 243 large underground tanks in 4 states. At Hanford, WA, one basin
leaked
millions of gallons of contaminated waste into the ground. The next 3
largest leaks of high-level radioactive waste are estimated at 115,000, 70,000 and
55,000 gallons. The Hanford site runs for 50 miles along the
Columbia River.
Photo (Dept of Energy/Boeing):
One of five atomic reactor fuel-reprocessing canyons in Hanford,
WA. At Hanford, the government made over half the plutonium for
our atomic bombs (the Savannah River Site in Aiken, SC, did the
rest). Plutonium is man-made; it does not occur naturally.
Plutonium is one of many intensely radioactive isotopes created in
atomic reactors whenever their uranium fuel -- not very radioactive to
begin with -- experiences a reactor's intense neutron
bombardments. Hanford ran up to 9 reactors day and night, threw
away the energy from all but one, eagerly brought the spent fuel to
this reprocessing canyon and four others, and reloaded the reactors for
more. Our atomic power plants today have the same short,
once-through fuel cycle.
Separation of small percentages of plutonium was achieved by dissolving
all the tons of spent fuel pouring out of all the 9 reactors.
Into vats of
concentrated acid it went. The acid was then passed down the canyon
through the ca. 174 tanks you see in this photo, and the plutonium was
concentrated, step-by-step. Remotely operated cranes and other
machinery pursued the processing because the radioactivity levels in
the canyon were
lethal. The workers above have left the lids on every tank, and
they are wearing disposable clothing as they poke devices through
little holes to get information on what's inside.
Separating out ("reprocessing") only the plutonium left so many other
isotopes in the acid that it became thermally hot. Some
unapproachable vats of radioactive acid that no one approached
became unapproachable vats of boiling-hot
radioactive acid with accelerated corrosion and poison gas
problems. Later, therefore, some
reprocessing was done to separate out the cesium and strontium as well
as the plutonium. Spent fuel pools were built to hold the cesium
and strontium underwater until someone could think of what to do
next. Since the cancellation of the Yucca Mountain waste
repository in Nevada, there has been more thinking in Hanford,
Washington.
The acid tanks in all 5 canyons were constantly refreshed. Where
did the old acid go? 177 dump tanks were built outside the
canyons to hold the old acid until someone could figure out how to deal
with it -- 55 million gallons, all intensely radioactive.
Meanwhile, the acid dump tanks rotted, and "a hellish mixture of
liquids, gases, peanut-butter-like sludges and rocklike 'salt cake' "
began to leak out. "Although they were intended to hold some
radioactive products with half-lives of thousands of years, the tanks
were designed to last only 25 years -- and were built without any means
for draining the waste." --Glenn Zorpette, Scientific American, 1996.
The first tanks were finished in 1944. By 1959, weapons officials
at the Atomic Energy Commission (today, the Department of Energy) knew
that some of them had leaked. When a tank started to leak,
contents were shifted around among the 177 tanks. Today, nobody knows
what's in each tank.
"Yet they kept building them until 1964 and kept introducing waste into
them until 1980. It's hard to explain this history in a rational
way." --Andrew P. Caputo, Natural Resources Defense Council
For you and for me, these canyons and their leaking external tanks establish the level of
care given by the most nuclear-savvy U.S. government agency we have, to
55 million gallons of the highest-level nuclear waste there is.
What was done with low-level waste? It is believed that 343
billion gallons of liquid waste and contaminated effluents were
directly pumped into Hanford's soil.
We do not leave children alone with gasoline and matches. We
cannot leave the government alone with atomic power. The adult
supervision these people so desperately need is called
"democracy". Secrecy kills democracy.
That
was then: we had a World War to win. Today we know
better.
The liquid can be evaporated, the acid sludge dried and converted to
oxides, and, before any dust gets airborne (to induce bronchial or
lung cancer from the alpha radiation of a single particle lodged in the
airways, as described above), these oxides can be mixed with borosilicates and other
minerals, heated until it all melts, and cast as glass logs
("vitrification"). Radioactive chemicals sealed in glass are less
likely to leach into groundwater. Some things (cesium oxide) tend to
crystallize out, thorium and aluminum don't like to dissolve, but, with
$12 billion for Hanford's vitrification plant, you can solve a lot of
problems.
High-level
waste requires disposal in a geologic repository. In today's
world, 30 and 55 gallon drums with plutonium and radioactinides stored
directly on the dirt (Colorado's Rocky Flats facility) or cardboard and
wooden boxes (Idaho's "National Engineering and Environmental
Laboratory," a site larger than the state of Rhode Island) simply don't
cut it. Vitrification will make 3 meter long glass logs 66 cm
(26
inches) in diameter -- 10,000 to 60,000 of them, about 1.5 tons
each. President Obama canceled the waste repository at Yucca
Mountain, NV, before Nevada Senator Harry Reid's re-election campaign,
so, if we make the logs, there will be no place to put them.
Hanford's
cleanup, launched in 1989, was to be completed a generation
later. In 2009, deadlines for eliminating sludge and saltcake
from acids used to dissolve fuel rods were extended another generation
to 2040. After we complete the generations needed to finish
reprocessing this fuel, we can begin waiting the millennia needed for
the radioactivity to cease being a hazard to ground water and the food
chain.
But
at least we get the plutonium. Thousands of gallons of
radioactive acid is worth it because we can remove the plutonium and
send it to a peaceful power plant before the terrorists get
it.
Are you sure?
Nine
hundred and forty tons of plutonium are already on the market from
nuclear power plants. Any developing country that can make shaped
explosive charges for an armor-penetrating roadside bomb (Iran;
smuggled into Iraq) is close to making an A-bomb with 10 or 11 kg of
plutonium
(it takes the military to miniaturize it). Their yield will
be
crummy compared to how many kilotons the government guys could get, but
that's 94,000 idiot-grade atomic bombs from the power plants alone.
I am sure the nuclear power industry degrades their plutonium or guards
it well, and
I'm sure the reprocessing plants never lose any. But can we ever use it
and make it go away?
STUCK
WITH PLUTONIUM THE PLANET NEVER HAD BEFORE. Our reactor
design
choices were chosen for plutonium production. The US and USSR
military's ca 100 tons and 160 tons respectively of plutonium are
starting to come out of decommissioned weapons, adding to the 940 tons
already separated out from commercial reactors, which generate about 30
nuclear bombs worth of plutonium per reactor per year (1,000 megawatt
level; e.g.,
Fukushima No. 6). A good idea would be a reactor design that
did
not produce plutonium (load the reactor with thorium fuel), or
fissioned whatever plutonium appeared (fast neutrons). The
current idea is to reprocess the fuel just as the military
did.
Reprocessing plants like Rokkasho, Japan -- $25 billion so far and
opening date pushed back to October, 2012 -- separate out the
plutonium, which is fed back into the reactors we have. Fukushima
reactor No. 3 went into meltdown loaded in part with plutonium oxide
fuel, called Metal Oxide or MOX fuel, to avoid the acronym "POX".
There
is good news and there is bad news for Pu-239. The
odd-numbered
isotope splits easily just as U-235 does. The bad news is that it is a
much better neutron absorber than U-235. In our reactors,
some
splits, but neutron absorption turns much of the rest into isotopes
that won't split. We put it in, it doesn't burn.
Meanwhile, the U-238 that
comprises the
bulk of the fuel is absorbing neutrons too, and
generating fresh
plutonium.
Some say our reactors only break even on the plutonium, and
then
it's off to the spent fuel
pool all over again -- the public is getting a good story, we are
getting nowhere. The companies getting $25 billion in
contracts to build
a
new reprocessing plant will tell a different story.
Whatever story you like best, burning
plutonium is slow going. France tried. France’s
nuclear
conglomerate Areva bravely maintains that their early-generation
fast-neutron reactors (not moderated by water) will ultimately fission
all the plutonium building up in France’s water-moderated reactors, but
both the Phenix and the Superphenix fast-neutron reactors have been
disconnected from the grid.
OUR
REPROCESSING INDUSTRY. Separating fuel into components we
have no
place to store and no reactors designed to split ("reprocessing")
remains the goal of the world's nuclear power industry. This
industry has piled up 290,000 tons of used fuel, but managed to
separate ("reprocess") less than a third of it. Send
consolation
cards to the World Nuclear Association for the 400,000 tons of new
waste their nuclear Renaissance will bring by 2030 (their estimate).
Taking
stock, we the people of the United States have no reprocessing plants
nor any geological nuclear waste repositories for radioactive nuclear
garbage. Yet our stated national intention is to build more
water-moderated, slow-neutron nuclear power plants, using the people's
money (the Federal budget) to subsidize private industry with loan
guarantees. Doubtless someone will get rich, but is this what
the
rest of us need?
Failed
national leadership is not the path to national greatness.
Getting nothing accomplished -- going nowhere -- is bad enough, but
setting the wrong
priorities takes you to the wrong destinations. Backing out
of a
place you don't want to be is harder than going forward. The
global nuclear power industry has taken us to a place we do not want to
be.
THE
REFUELING MERRY-GO-ROUND. In reactors we run today and have
proposed for tomorrow, everything stops when the U-235 runs low.
The fuel alone weighs 78 tons (e.g., Fukushima No. 6, a General
Electric BWR-5); with all the stainless steel fuel assembly cages it is
130 tons, but only about 4% is the U-235 enrichment. As the
U-235 runs low, the only thing the slow neutrons might have split is
gone, and the reactor lacks more powerful, faster neutrons to split
much else. Intensely radioactive isotopes generated from the U-238
undergo further cycles of neutron absorption--radioactive decay--more
absorption. The isotopes -- as well as the fission products
from U-235 atoms that did
split -- suck up neutrons, make chain
reactions
die, and make refueling urgent even before the 4% U-235 enrichment has
been fully consumed. In 18 to 24 months, it is reloading time
in
today's nuclear power fleet.
We
load our reactors with tons of U-238, little of which is split. Back
out of these "clean energy" machines come tons of "spent"
(neutron-activated) fuel, now endowed with a zoo of radioactive
elements. Neutron absorption, not nucleus splitting for energy release,
turns some of the easily handled U-238 into intensely radioactive
isotopes, all of them bad for health, and some also poisons for the
reactor, where their neutron absorption shuts down chain reactions. The
reactors, never designed to split more than the 4% of rare U-235
artificially added to the natural U-238, are described as "efficient"
and the newly activated fuel rods still full of uranium that come back out of them are described as
"spent". "Reprocessing" or separation of the "spent" (activated) fuel
does not retrieve the U-238, which is cheaper to mine afresh.
"Reprocessing" does not reduce radioactivity. Separation begins by
dissolving the fuel in acid. A $12 billion government project
to
vitrify tanks of radioactive acid is not running yet. We have
no
existing geological repository for vitrified or other waste, but we do
have a demonstrated political will for canceling attempts to build one.
An
industry that deceives itself and lies to the public about "clean,
efficient nuclear power" cannot recognize or innovate a way out of its
own problems. These problems will bury us.
Paper's
PREVIEW
I. Atoms, Molecules, Proteins
and the Genetic Code
II.
Physics:
Powerful Radiation Breaks Molecules
III.
Let's
Build a Reactor.
IV. The Fateful Decision: Uranium and Slow Neutrons
V. The
Spent Fuel Story - No Place to Put Anything
VI. The Big Picture: Uranium
& Our Universe
VII. Public
Policy -- We subsidize this
industry from cradle to grave.
VIII.
The Nuclear Renaissance: Fast Reactors Only - They don't make waste, and perform their own
burial.
VI.
THE BIG PICTURE: URANIUM & OUR UNIVERSE
The
universe is 13.7 billion years old and had already chugged along for 9
billion years before our sun and planets formed. Good, direct
evidence (a microwave "glow" that radio telescopes see bathing the
cosmos everywhere) tells us that the universe started at a high energy
level (the
Big Bang). The essence of the Big Bang is the
conversion of
some of that energy into everyday matter. Nearly 5% of the
energy
became matter, but not in an everyday form. The initial
energy
levels were so high that
everything
would have been blown apart into sub-atomic particles, particles whose
interactions, on our small planet and in our time, demand the most
powerful atom smashers we can build in order to re-visit them.
These
particles present at the start of the universe were smaller than the
protons and neutrons we see now. Within the first second of
creation, the strong force
brought these particles together into
something bigger. That something was isolated neutrons
and
protons, a whole universe full of them, but it was momentous: matter as
we know it today had appeared. A little atom with only an
isolated proton for its nucleus is hydrogen. If the strong
force
played a key role at creation and the strong force is what puts protons
together -- creates them -- then of course our universe will start with
protons, with a
glut of hydrogen gas. A proton with an electron is what we call a
hydrogen gas atom, and you can always find an electron somewhere.
Our universe began with 76% hydrogen, the rest
helium
and not much else -- with very little else, without you, without your
planet, without your Milky Way galaxy.
This is still a fairy tail of magic, and nobody
likes to have the starry sky above and all of astronomy
created by magic. Will it ever get better? When we try to get from all the energy of
the
Big Bang to all the hydrogen of the early universe, the strong
force will tell us -- once we understand it better -- how the first
matter was organized. The first matter -- all that hydrogen -- set the stage
for the
formation of stars, galaxies, and us. Atom smashers of the small take
us to ultimate questions of the big.
But
we live on a heavy, rocky planet. Our sun is still running on
hydrogen from the Big Bang but we are not. Where does the
large-nucleus fuel that we put into our reactors come from in a
universe born mostly as hydrogen?
As
our sun or any star fuses pairs of ever-larger atoms into bigger ones,
atomic fusion's energy yield drops, and ceases altogether with nickel
and iron. A lot of suns older than ours came to a screeching halt at
nickel and iron, and the universe is full of it -- meteorites fall from
the sky made of it, and below our planet's rocky crust-and-mantle lies
more.
After
iron, it takes very special, very rare events to make the other 66
heavier elements, culminating in the heaviest of all, uranium. (Earth
has traces of plutonium-244, heavier still, but that arises -- transiently -- only from
the uranium.) Any event that can make big-nucleus elements
has to
put energy into the
synthesis. When we split the large nucleus back down again (reactors, bombs), we get a
little of that energy back out.
In 1054 Chinese
astronomers recorded an explosion in the heavens that persists today as
the Crab Nebula (switch Google to image
search
for pictures so stunning nine centuries later that people use it for
computer wallpaper). During its first 10 seconds it is possible this
explosion gave off more energy than all the other stars and galaxies in
the rest of the visible universe combined -- more energy, 100 times
more, than our sun will ever produce in its entire 10 billion year
lifetime. It was a supernova explosion. This is
what it
takes to fill the periodic table, to make large nuclei like those we
put into our reactors, hoping to split them, hoping to see a little of
that energy come back out.
Long
before the 1054 supernova, in a younger, more violent time, many
other supernovas changed the universe, hurling unheard-of heavy elements
across space. Soon stars were forming in polluted neighborhoods like
ours, stars that now often had heavy, rocky planets in their inner
orbits. These planets had their own deposits of various heavy
elements. The time when our sun and planets formed was a time
closer to the creation of these heavy, trans-iron elements, many in
unstable isotopes. The early Earth was surely more
radioactive
then, but has had 4.6 billion years to get over it.
Today,
supernovas are less common and most stars lead non-explosive lives
unable ever to create large-nucleus elements beyond iron. But
the
search is on with large-field telescopes and fast computers surveying
the sky, to alert the global astronomical community whenever a
supernova goes off, even if, unlike the one in 1054, the supernova is
not in our own Milky Way galaxy. At these energy levels,
supernovas are bright enough to be seen out to the edge of
creation. Their flash of cataclysm takes so long to find us,
that
to see to the edge of creation is to observe back to the beginning of
time.
Back
in our solar system, in the quiet outskirts of the Milky Way galaxy,
it's a peaceful scene except at Earth's nuclear power plants and waste
dumps, where the strong and weak forces of unhappy nuclei are throwing
nuclear radiation at us. Nuclei disturbed by neutron bombardment in
reactors shift their arrangements, releasing energies in
species-specific amounts. These energy fingerprints (gamma ray spectra) of disturbed nuclei make elements released in
reactor
accidents identifiable all around the world, but the many energy levels
from strong- and weak-force-mediated nuclear changes are all high
enough to be lethal. It was easy to build reactors to get the
energy out that supernovas had put in. Now we must find
reactors
that do not take us back 4.5 billion years to radioactivity levels
incompatible with life. The wise bird does not sully his own nest.
Paper's
PREVIEW
I. Atoms, Molecules, Proteins
and the Genetic Code
II.
Physics:
Powerful Radiation Breaks Molecules
III.
Let's
Build a Reactor.
IV. The Fateful Decision: Uranium and Slow Neutrons
V. The
Spent Fuel Story - No Place to Put Anything
VI. The Big Picture: Uranium
& Our Universe
VII. Public
Policy -- We subsidize this
industry from cradle to grave.
VIII.
The Nuclear Renaissance: Fast Reactors Only - They don't make waste, and perform their own
burial.
VII. PUBLIC
POLICY
The present nuclear
power industry makes money; it is prosperous.
1.
All of us pay to help build the plant (proposed loan guarantees) and
insure it afterwards (Price-Anderson Nuclear Industries Indemnity Act
of 1957, and renewed perpetually thereafter).
2. All of
us pay to haul away the spent fuel and create places to put it.
3.
Old plants are sold to a smaller company that says it can't afford to
get rid of it. If we force it to honor its commitments, it
declares bankruptcy. All of us pay to reclaim the land.
4.
When accidents occur, all of us pay by turning our wealth into medical
care. There is no Price-Anderson Nuclear Indemnity Act for elevation of
cancer rates in the nation's population.
The
nuclear power industry has one clear responsibility which they
invariably honor: to collect the public's monthly payments for
electricity, and convert the margin over production costs into private
wealth with no claw-back.
Corporate
welfare subsidizes this industry from cradle to grave, and then they
have the nerve to ask us to pay for the electricity.
Nationalize
the nuclear power industry -- we've already paid for it.
Loan
guarantees to build more water-inside reactors are a brilliant way to
muzzle the public. Imagine construction of a loan-guaranteed
plant has started. A worker reports X-ray inspections on the
steel containment vessel were faked and we never hear from him
again. To avoid throwing construction off-schedule, there are
changes in the water pumps and the pressure relief valves.
The
new ones are "just as good". The 10 million people within a
50-mile radius who must evacuate in emergencies depend on the new
warning system's automatic alerts, but that system isn't installed
yet. Management says everything's new and working perfectly;
critics say the staff isn't trained because computer-simulator trainers
were cut from the budget. The power plant needs to sell its first
electricity this month or bond payments can't be met. This is your
moment, your credit default swap. Like American Insurance
Group
(AIG), you insured the loan's creditors against default. Now
choose: you can leave well enough alone, or you can get this fixed,
find out why the whistle-blower's car ran off the road and struck a
culvert, and pay your $8 billion. You pay, because you
drove the company into bankruptcy over issues which experts testified
did not matter. You guaranteed the loan; now you bought the
plant. At least you capture the revenue stream. But
wait. This industry is too big to fail (national brownouts,
power
grid collapse). In the bailout that follows, you pay the $8
billion, and they keep their company, their salaries, and the
plant. The flawed reactor goes to full power.
It is best not to
guarantee any loans.
Today,
we get the radiation and they get the indemnity. A national
health insurance policy on the consumer side, to match the national
nuclear industry's Indemnity Act on the corporate side, would make me
happier about nuclear power.
What
stake does the government have in public health? No
individual
dying of cancer will ever prove in court (rationally, by any science I
know) that his particular cancer was caused by a reactor incident years
earlier, yet group averages might show thousands of surplus cancer
fatalities in the population. When the Executive Branch goes to
Congress under the Price-Anderson Act, will their report of damage from
the latest "reactor incident" indemnify cancer bills 20 years down the
track? The record is bleak.
422
atomic bombs were exploded in the earth's atmosphere by the United
States (206) and the Soviet Union (216) before the Partial Test Ban
Treaty went into effect (1963). The six largest Soviet tests
totaled 136.9 megatons, the equivalent of Hiroshima plus Nagasaki
combined (35 kilotons) 4,000 times over. Radiation levels
around
the world rose -- radiation levels rose in the bones and teeth of humans alive at the time.
It
is accepted that at least 15,000 additional people died from the
radioactivity of atmospheric atomic testing. You can still
measure today the radioactive strontium-90 in baby teeth collected from
children in the 1960s. Bodies with more strontium at that time have
more cancers now (or at the time they died) of brain, bladder, colon,
connective and soft tissue, esophagus, rectum, and testicles, and more
leukemia, melanoma, and non-Hodgkin’s lymphoma.
Chernobyl's
flames drove many tons of reactor fuel into the air. The
United Nations says, apart from thyroid cancers, "there is no
scientific evidence of increases in overall cancer incidences or
mortality rates..." (UNSCEAR, the United Nations Scientific Committee
on the Effects of Atomic Radiation). A Russian compilation of
Russian health publications says that by 2004, 824,000 deaths resulted
worldwide from the released radioactivity.
Something
is obviously wrong with institutions in our society that go around
distributing white papers saying all is well without tripping over even
one corpse in 824,000. The Russian publication has been put
online by the New York Academy of Sciences, whose members since 1817
have included Thomas Jefferson, Thomas Edison, Charles Darwin and
today, a council of 23 Nobel Laureates to advise them on what work to
support and publish. To get your own copy of "Chernobyl:
Consequences of the Catastrophe for People and the Environment," go to janettesherman.com/books
for a $10 hardcopy with added index (I endorse the science Janet
Sherman does) or download a pdf file at http://www.strahlentelex.de/Yablokov%20Chernobyl%20book.pdf
To review your own government's treatment of
radioactivity-contaminated citizens from atom bomb-testing days, search
"downwinders".
Let
the nuclear power industry form an industry-wide consortium to
underwrite the medical insurance for us, the public. Don't
want
to guarantee payment for everyone's cancer therapy? Not a
problem. Write a policy to insure the public only for the
elevation in nationwide cancer rates compared to baseline.
We'll
take halfway between your scientist's number (zero, perhaps?) and the
numbers from scientists not supported by corporate money. If
the
plants are as safe as you say, you won't have to pay anything but the
salary of the office manager for the public insurance program you'll
never have to use.
The
failure to set up an industry-wide consortium for handling health costs
in an accident suggests to me that the industry is confident it can
escape accountability for its own actions and get others to pay the
consequences. This lack of responsibility for the consequences of their
own choices is a condemnation of the industry (for selfishness and
indifference toward others), it is a condemnation of our government
(for betrayal of its own people), and it is a condemnation of us for
letting it happen.
Set up the health
insurance syndicate and then we'll discuss guaranteeing the loans.
Paper's
PREVIEW
I. Atoms, Molecules, Proteins
and the Genetic Code
II.
Physics:
Powerful Radiation Breaks Molecules
III.
Let's
Build a Reactor.
IV. The Fateful Decision: Uranium and Slow Neutrons
V. The
Spent Fuel Story - No Place to Put Anything
VI. The Big Picture: Uranium
& Our Universe
VII. Public
Policy -- We subsidize this
industry from cradle to grave.
VIII.
The Nuclear Renaissance: Fast Reactors Only - They don't make waste, and perform their own
burial.
VIII. THE NUCLEAR RENAISSANCE: FAST REACTORS ONLY
We need fast neutron
reactors. All but one of the world's fleet of power plant
reactors is a slow-neutron machine. It is time to shut down our
simplistic reactors. "Safe or unsafe" debates will never take this nation
where it needs to go. Debating "safe or unsafe" will never give us the
technology we deserve because the first question we must ask is, "Fast or slow neutrons?"
Instead of minimizing waste production, the industry maximizes it
by using a once-through fuel cycle
-- after 18 - 24 months, the
uranium is pulled out of the reactor, never to be used again.
This is very expensive for civic society, which has spent
billions of dollars unsuccessfully seeking ways to dispose of the
trash. Yet civic society has yet to penalize corporations
for producing it. The global nuclear
industry continues to buy cheap uranium and turn it into
a million-year trash problem in mere months of time. This is the rational
choice for
corporate executives and their stockholders -- we as a society pay them
to do this.
THE TRASH PROBLEM
At
Hanford, 8 reactors ran day
and night to do nothing more than make radioactive trash (a ninth reactor made some electricity as well as trash). As soon
as
the natural uranium was laced with deadly isotopes, it
came out of the reactors to separate the plutonium from the rest of the
radioactive mess. Our nuclear power generators are not much
different
-- we run them until many deadly isotopes have been created, then
remove the fuel. It is here, at refueling time, that current nuclear reactor
designs and the industry itself have lost the way.
Nuclear Engineer (NE): "I'm ready to refuel this 1100 megawatt boiling water reactor. These BWR-5's don't run forever."
INNOCENT
BYSTANDER (IB):
"You just put in 78 tons of uranium dioxide fuel.
That was 764 fuel rod assemblies, 40,256 individual fuel rods,
130 tons counting all the steel & zirconium holders. You
must be kidding."
NE:
"It's staggered -- 26 tons every 12 months, not 78. 36 months are
up -- these 26 tons are ready for a trip to the spent fuel pool."
IB: "26 tons? Didn't you use any up?"
NE: "One thing just turns into another. It'll never weigh much less than 26 tons, even if you write E=mc2
on your T-shirt. A kilogram less, maybe two. Out of 78,000
kg who cares? We used about 4% of the 5% U-235 we put in there."
IB: "Why didn't you use all 5%?"
NE:
"The U-238 absorbs too many neutrons, it turns into transuranic isotopes.
If you get splits, the daughter nuclei can be almost anything.
Some are
worse neutron absorbers than the U-238 was to begin with -- the rare
earths are terrible, samarium-149 is a real killer. We can
never produce enough neutrons to finish off all the U-235 we paid for."
IB: "4%, that's a ton. What about the other 25 tons?"
NE:
"I told you, we don't split the U-238, it just absorbs neutrons. Some
turns into plutonium-239, we can split that, sometimes we get maybe a third of
our energy from breeding plutonium. We burn maybe half the 8% plutonium in there
before we have to pull everything out. We don't do anything with the
rest, and we hope nobody else does either -- there's enough in there to make 30 bombs
easy, if the radioactivity doesn't kill you trying to separate it out."
IB: "Now we're two tons down and 24 to go. What about them?"
NE:
"I keep telling you. Our neutrons get absorbed by the U-238 and get
absorbed even more by some of the things the uranium turns into. All 26 tons are trash as far as I'm concerned."
IB: "Why do you even put the U-238 into the reactor if you can't split it?"
NE:
"We breed plutonium out of it and burn some of that, but, yeah, we're
not breeders, we do U-235 and quit when that's done. The U-238 is sort
of traditional. It splits by itself, and we use those neutrons to
re-start the chain reaction if we ever have to shut down the reactor.
We tell people it's "spent" but we really
couldn't do anything much with it in the first place. We
tell them we "reprocess it", but we never use it again.
Believe me, for this machine, these 26 tons are useless.
Take it away."
IB: "What will I do with it?"
NE: "Find a mountain where it will be safe for geologically long periods of time and put it under the mountain."
IB: "At least you split 2 tons of it."
NE:
"I've got good news and I've got bad news. The good news is that the
split nuclei are smaller and won't be radioactive as long as the 24
tons of big unsplit nuclei will be. Neutron absorption really activates that stuff."
IB: "And the bad news?"
NE:
"The little ones won't be radioactive long because they are radioactive as hell -- it gets the
half-life over with in a hurry, they break down into something more stable at a furious rate,
but in the mean time, stay the hell away. Leave all 26 tons in the pool for 10 years before you go
on any trips to your mountain. Don't you love the way the water glows
blue in the darkness?"
IB: "Isn't there anything you can do?"
NE:
"Not in this
machine, not with slow neutrons. We make the isotopes, we don't break
them. Fresh uranium's cheap, I'm reloading -- 26 tons this
morning, the
whole set of 764 fuel rod assemblies every 3 years."
There
are 78 tons of useless, highly radioactive trash in this BWR-5
reactor, or 130 tons counting the
zirconium tubes and stainless steel racks, the "fuel assemblies"
that come up on the crane, that go into the spent fuel pools, that fill
the million-dollar, 100 metric ton cylinders for dry cask storage. Globally, 400 other
reactors run day and night producing similar output. What is the
alternative we seek as a nation today?
THE SOLUTION: SMASH THE TRASH REACTORS
Fuel
must stay in the reactor until nuclear reactions have smashed all the
trash. Smash the Trash reactors can solve every problem this
industry faces today.
1.
REDUCE WASTE: Smash the Trash reactors would split all large
nuclei, producing trash with only small nuclei. A small-nucleus
atom has fewer possible isotopes than a large-nucleus atom. It
therefore will make fewer radioactive transitions before finding a
stable configuration and ceasing all radioactivity. We say that,
in general, small-nucleus atoms have "shorter decay chains"
and shorter
half-lives. Smash the Trash reactor
designs are our best shot at reducing nuclear waste and eliminating the
need for geological storage -- special facilities intended to
remain stable and secure for geologically long spans of time.
We have no geological waste storage solutions to our trash
problems, only a track record of proven failure to obtain them.
Many fast-neutron reactors that can smash the trash have been
built, although mainly as pilot projects and research machines.
In aggregate, we have 400 years of
successful operational experience with powered-up, fast-neutron
reactors (World Nuclear Organization figures), even if they did not
become
the world's dominant reactor design. New, long-term-radioactive
"problem nuclei" can only be created in nuclear reactors, and only
in nuclear reactors can we move these nuclei on
to more benign forms of matter.
2.
ELIMINATE WEAPONS PROLIFERATION: Atomic reactors
are full of free neutrons flying into other atoms
everywhere, because that's how "atom smashing" for "atomic
power" gets done. Atoms that did not split into small
pieces just absorb the neutron and get a little bigger. The
bigger nucleus is almost always less stable; it almost always emits
radioactivity and eventually
changes into other elements. All reactors create one element out
of another -- that is how medical "tracers" are manufactured, that is
where the Americium-241 in smoke detectors comes from. The
creation of uranium atoms from
thorium fuel and the creation of plutonium atoms from uranium fuel
presents a weapons
proliferation problem. Smash the Trash reactors will eventually
split the large atoms we put in as fuel, and split any other large
atoms that are created ("bred") from them. Maybe sometimes
a neutron is absorbed (bad), but, if ever a neutron succeeds in
triggering atomic fission (good), the daughter fragments will never on
Earth go back together again. The Humpty Dumpty Principle
of Smash
the Trash reactors eliminates the nuclear proliferation problem for
atomic power; once it's broken, you can never go back.
Keep the door
closed and the fuel inside until the large nuclei have been split. The
problem is also the solution when we just keep the door shut:
all reactors "breed" new fuel, faster neutrons can breed some
things better, but, in time, faster neutrons can also split all things
better.
3. ELIMINATE REPROCESSING: We have
seen that fuel reprocessing is a fiction. Separating the
isotopes we created does not change their radioactivity or shorten
their half-lives. Sorting the trash does not bury the garbage. Further, the "reprocessed" uranium is never reused.
Reprocessing
is also expensive: it will take $100B in cleanup costs for the Hanford and Savannah
River reprocessing sites by 2008 estimates; it took $25B to build Japan's new
Rokkasho campus by Forbes 2011 estimate. "Smash the trash" means
split the large atoms, which eliminates the atoms from which bombs
could be made, which eliminates in turn the expensive fiction of
"reprocessing". Fuel
reprocessing is big-nucleus-isotope separation. So, if there are no
big-nucleus isotopes, there is nothing to separate. Let us destroy the
reprocessing
plants and make the 2011-style reactors that feed them illegal.
The reactors themselves must eat what they cook. Any nation which develops and preserves fuel
reprocessing know-how is a nation which desires to develop and preserve
the option of making nuclear weapons for itself, or for those who
helped pay for the facility.
4.
ELIMINATE FUEL POOLS AND
MILLION DOLLAR CASKS: Smash the Trash reactors do not stop
running when 4% of the fuel is gone. They keep going until every
big-atom nucleus is split. Because all large atoms are
fissioned in these reactors, one load of fuel lasts longer.
Designers today aim to
produce a reactor that can be run for 30 years without refueling, just
as nuclear submarines do.
Fuel rods may have to be shuffled from one position to another,
but they will not have to be removed -- spent fuel rod pools and
dry cask storage are postponed, reduced, and, as we shall see,
eliminated by new plant decommissioning practices.
5. ELIMINATE REFUELING: Today
we give up when the first new, heavy, radioactive elements appear, and
declare
the fuel "trash". Smash the Trash reactors keep
changing heavy nuclei until they get varieties that
are fissile, and then they split those. Just split it all: the continued
neutron flux from this continued fission will, over time, cleanse the
core of all less fissile -- but harmfully radioactive -- nuclei that
we do not want. The reactors, like US atomic submarines today,
will not have to be refueled for 30 years -- time enough for the
neutron
bombardment to finish its work on the fuel, time enough for the reactor
to be its own spent fuel pool and give the early fission products --
the smaller daughter nuclei -- a chance to die down while the reactor
captures their heat. While smashing the
trash, the reactor generates electricity and earns revenue.
Besides knowing how to take out their own trash, Smash the Trash
reactors can consume the "spent" fuel of today's nasty reactors, can
consume the weapons plutonium, can consume the 700,000 metric tons of
depleted uranium fluoride waiting at Paducah, KY and other government
sites after having the U-235 mostly taken out of it.
6. ELIMINATE THE TECHNICAL DIFFICULTY, COST, & DANGER OF DECOMMISSIONING
Decommissioning
a nuclear power plant is difficult because it must be cut up into
little pieces and buried. Nobody can do this because of the
radioactivity, so specialized, remotely-operated machines must be
brought in, sometimes from other countries because the US no longer has
the technology or the expertise. Owners are understandably eager
to prolong the license
of an increasingly old, leaky and risky plant rather than tear it
down at great expense. When the time comes for tear-down, owners
are understandably eager to transfer ownership -- and legal liability
-- to another company and move on. If the new, nominal holder
collapses financially, the burden of plant disposal falls to civic
society -- a final, graveside subsidy to this industry.
Our
projected Smash The Trash reactor will be modular, shippable (as a long
structure that fits onto a truck or rail car), installed by burying
it vertically in a concrete cylinder on-site, and capable of running three decades
without
refueling. Pioneering molten salt reactors have run 30 years
without refueling in the past, reactors run 30 years without refueling
on
submarines today, and Smash the Trash reactors will run 50 years
without refueling in the
future. A steady run of 50 years is possible as a steady
succession of new fissionable material is created in a succession
of fuel
rods, and is in turn split. Excess neutrons from regions of
fission activity cleanse materials in the rest of the core.
After breeding has occurred inside them, newly fertile fuel
rods may
have to be shuffled into the core region of early reactor designs. As reactor designs grow
more sophisticated, movable beryllium or stainless steel neutron
mirrors (reflectors) can force the region of fertile fuel rods
to migrate on its own as a traveling wave of fission moving down
the
reactor's extended core, a core that was pre-fueled with
uranium-238, thorium-232, or trash from the horrible nuclear age
of weapons and war that we linger in today.
When
the reactor stops, the fuel is truly spent; large-nucleus-based
radioactivity is gone.
Reactor
decommissioning problems disappear when smash-the-trash fuel cycles
reach
50 years. The reactor, heat exchanger and
other plumbing reach the
end of their useful life as the fuel itself comes to the end of its
ability to sustain criticality, even if aided by an external
neutron generator (see below). We can now design the reactor to
be self-decommissioning. Installed vertically in a concrete silo
at the start, cleared of long-lived isotopes at the finish, we just
disconnect the pipes, leave it where it is, and order the next one.
7. ELIMINATE GEOLOGICAL STORAGE : The
need for geological waste repositories is eliminated for modular,
Smash the Trash reactors. These reactors are installed in underground concrete
cylinders to begin with and simply left in place when the systems and
the fuel that drove them are both exhausted after decades
of
profitable use. The daughter nuclei of fissioned large-nucleus
atoms have half-lives mostly in the range of 10 to 30 years, not the
hundreds and thousands of years seen with the large-nucleus
atoms of the original fuel. If the fuel and the isotopes that
arose from it (were "bred" from it) are largely gone, the need for
geological waste repositories is largely over. It is stupid to
keep building reactors that make trash that nations find so difficult to transport or bury.
SUMMARY OF GOALS
The goals are clear:
- reduced waste -- reduced volume, reduced radioactivity, reduced half-lives
- nuclear proliferation eliminated -- no weapons-usable isotopes ever come out of the reactor
- isotope separation technology ("fuel reprocessing" capability) disappears from civic society
- reactor
refueling stops -- No heavy isotopes are
released; the reactor remains sealed and running until every large-nucleus atom is split. The
radiation for fully-fueled reactors that have not been turned on yet is
low enough for rail and truck shipment to any town
that wants one. The reactor is a 30- to 50-year battery that any
municipality can buy.
- spent fuel pools and dry cask storage disappear from nuclear power plant campuses
- decommissioning
costs are radically reduced -- modular reactors installed in
underground silos can be left there at the end of their useful life.
- "geological
time" repositories for waste disappear, as all long-time-active,
large-nucleus isotopes have been fissioned away in the reactors that made them in the first place.
GOLDILOCKS TECHNOLOGY: The choice is not this reactor or that, one fuel cycle (thorium) or another (uranium). Bringing
several lines of development together at
once gets us all the goals at
once. Small reactors with long fuel cycles driven by fast
neutrons are the Goldilocks combination. Long fuel cycles of fast
neutrons remove the worst waste, enabling a reactor to be buried to
begin with and decommissioned where it sits, not sawed into little
pieces and shipped in radiation-proof casks to a mountain repository
that we don't have yet. There are no fuel pools, casks, geological
repositories, separation
("reprocessing") or weapons-grade by-products. The reactors we need will have neutrons with enough
energy to smash all large nuclei, and will have a fuel cycle of 30
years or more that gives those energetic neutrons enough time to complete
their work. Let's take a closer look at what the rebirth of nuclear power must look like.
SMALL, MODULAR REACTORS, FAST NEUTRONS INSIDE.
THERMAL
ENERGY: Nuclear
power plants turn heat into electricity via steam. The overall
efficiency of such "thermal energy plants" increases with size,
and so,
inevitably, we make reactors bigger with each successive
generation. Centralized power generation has now reached a
staggering industrial scale.
We
have all boiled water by plugging in an electric teakettle.
An ice-cold Olympic swimming pool plugged into an 1100 megawatt
atomic power plant (Fukushima model BWR-5, reactor number 6) will boil
in 54 seconds. Only about a third of all the reactor's heat
energy gets turned into electricity. Running normally day and
night, the reactor itself is putting out enough raw heat energy
("thermal energy") to
completely boil away one Olympic swimming pool every 2 1/2 hours.
A nuclear
reactor cannot be switched off.
"Scrambling" a reactor does not stop it. Chain reactions
are broken, but neutrons still fly and nuclei are still split.
Radioactive decay without nuclear splits adds more energy and is
completely unstoppable. If our nuclear engineers shove in every control rod to "shut down
the reactor", they shut down chain-reaction growth, not
the radioactivity. We still need enough electricity, pumps, and
cooling capacity to deal with a machine that can boil an Olympic pool
worth of water every 35 hours (7% power level; it decays over ensuing
weeks).
There is danger here. To perfect new Smash the Trash
reactors, it would be best to start out small: 30, 40, 50
megawatts, the size of the natural gas generators so popular with electric utilities today.
SMALLER
REACTORS: Smaller reactors are nice. Nice reactors can be
packed with tons of scarcely radioactive natural thorium
or natural uranium. Nice reactors loaded and ready to go (but
not
yet ever started) can be shipped to remote towns to light up the
local economy as well as the power grid, neatly side-stepping a town's problems with highway or national grid access.
Prosaic reasons also favor small, modular reactors: they require
smaller investments that can be made by more agile, private-sector
investors. A municipal bond issue can pay under $100 million for
a municipal power plant reactor, but $9 billion is out of the question. A
municipality can plan around a 3 year assembly time to bolt fully
manufactured, modular components together after site work (e.g., Babcock & Wilcox's mPower plant), but not deal with an 8 year stretch of planning and financing (25 years' delay is the record). "Modular" reactors give any town that orders their first machine a way of getting the
right-sized machine without excessive engineering, test and
certification costs for each departure they might make from a one-size-fits-all machine. When it's time to go critical, approvals are more predictable with a cookie-cutter design.
Innovation is the real issue here: twenty smaller reactors at 50MW (megawatts, millions of watts) vs
yet another 1000MW plant give us 20 generations of successive innovation,
20 different teams to climb the learning curve, and a chance for a new
generation to see nuclear engineering as a workable career, as an
area of rapid change in which to start their own company
Nice
reactors can be fired up with a particle accelerator, as long advocated by Nobel physicist Carlo Rubbia with his ADSR, an Accelerator-Driven Subcritical Reactor. 30,000
accelerators have been built world-wide since 1950, growing to a 1000
machines a year -- an industry with $2 billion in annual revenues.
Neutron
accelerators
are lowered down oil wells to identify the stone types (neutron
activation analysis). We have the skills to create
kick-starters for reactors. We do not need excessive U-235 enrichment to
cold-start reactors. We do not need U-235 enrichment plants in
countries
around the world. Worried that natural thorium (Th-232) and
natural uranium (U-238) won't split? Bombard them with neutrons,
augmented by accelerators at first if necessary, until they turn into something
that will
split (uranium into Pu-239, 240; thorium into U-233). Worried
that plutonium-239 and uranium-233 could be used to make nuclear
weapons? Keep the door shut until they are gone.
The
reactor can't be buried in place unless the worst radioactivity is gone
(physics) and the investment is repaid (finance) when the music
stops. Both the physics and the finance require a long run to
smash the trash with no refueling, and to repay the investment.
In the neutron inferno all reactors create, neutron
absorption
turns once-quiet fuel into wildly radioactive isotopes with
thousand- and million-year decay chains. Our failure has
been to wed ourselves to reactor designs and fuel cycles that require
us to declare the
fuel "trash" and remove it when it is in its worst, most lethal state.
Bombardment for more time at a greater variety of neutron
velocity levels would have cleansed the
trash. Getting 30+ years of neutron flux to perform the cleansing
requires generating fuel
as you go, so you can keep going until the reactor eats everything it
cooked (until it fissions every activated isotope it made). Both
generating the fuel ("breeding"),
and then smashing what was bred, require reactors with a range of
neutron velocities that extends upward into higher energy levels we do
not have today.
THEY ALL BREED: "Breeder
reactors"
have a bad name because, in the bad old days of the cold
war, we used them only to breed plutonium for bombs.
"Breeding plutonium" is what we think a "breeder" does. But
every reactor breeds.
Our old breeders shifted neutron energies to shift the
proportions of isotopes in the trash, but the other isotopes are
still there. Cold war breeders bred all the same
isotopes that
our electric power industry creates today, the isotopes that $100
billion will never fully eliminate at either Savannah River SC or
Hanford WA. As cold warriors, we refueled quickly and rushed
to separate and extract
only the plutonium and dump the rest. Today, we rush to get the
radioactive trash out of the reactor (before
the reactor can fission anything away again), because the U-235
and the
neutron flux are fading away and we have no other choice. But the
same cold war isotopes are there. When it's running, you can't
tell
a reactor to
stop the neutron bombardment, and you can't tell it to just make
electricity. Any reactor will turn natural thorium into
bomb-type uranium, or natural uranium into
bomb-type plutonium (and a dozen other horrible isotopes). But,
idiots that we are, we surely can stop removing the fuel when those
bomb-type isotopes have appeared, and instead leave the reactor alone
and running until they disappear again.
Smash the Trash
reactors will stay active longer because we use neutron velocities that
will eventually push big-nucleus atoms into forms that fission easily.
New fuel appears. Until we get the designs perfected,
there will have to be some fuel rod shuffling over the years, to
bring the
"bred", "fertile"
fuel rods with their new fuel beside one another in the very
core, and put the other rods where they can irradiate
themselves in the lesser neutron flux at the periphery. In many
designs, movable beryllium or stainless steel reflectors will be used
to change the
focal point for neutron flux concentration. In the active core,
large atomic nuclei breed along from one thing to another, changing
from one similar-sized atom to another, until we hit a combination
of neutrons and protons that makes a fissile nucleus (splittable by
neutrons of almost any energy level).
Because some large nuclei are still not sure they want to split,
we
design and run a broad-spectrum reactor (many energy levels for our
neutrons) so that we can always provide neutrons with the appropriate
energy level to drive a particular big-nucleus atom across the
line to fission. Whether they change easily (fissile) or
with reluctance (fissionable but not simply fissile), we will
ultimately achieve the splits that get every large
nucleus down to something small enough to change the
radioactivity game for us and the reactor.
We will ultimately arrive at small-nucleus isotopes with short
decay chains and briefer half-lives. This is the 21st century.
We do not leave 96% of the fuel in big-nucleus form for anyone
else's future. It is already the 21st century. We are
already caught in the future.
BROADBAND
REACTORS - TIMING, POSITIONING, ENERGY LEVEL: How can we have it
both ways, the breeding and the cleansing? They seem
like opposite outcomes. The answer is timing: if something
won't split, it just absorbs a neutron and changes into something else,
eventually into something else that will split when in turn it
takes a neutron hit. So the bad stuff tends to build up in
reactors
early, and, with continued neutron flux, it fades away. In
the dominant designs of the day,
we remove the fuel early, and then complain that it is too
radioactive. Smash the Trash reactors leave the fuel inside (no
refueling, keep the door shut). Besides timing to get the
cleansing, there is also
layout: the intense
fission is very local, like the fire line in a forest fire, but the
radiant energy -- the neutron flux -- can be used to breed
"unsplittable" atoms
into a usable form, in fuel rods spread across the reactor core.
And finally, there is the neutron energy spectrum. Both the
probability of breeding and the probability you can split what breeding
hands you are a function of neutron velocity. We need broadband
reactors with a range of velocities. A
sophisticated broadband reactor with many neutron velocities gives
designers a chance to "have it all," to breed it all, and to fission
it all. A sophisticated broadband reactor gives designers a
chance to have 100% fuel efficiency. Why bother with perfect
fuel efficiency, you ask? Uranium is cheap, you say? But
it's not the money, stupid, it's the radioactive waste.
Today's
low tech, slow-only reactor designs are a one-trick pony. One or
two isotope species within the tons of fuel we load into them are the
chosen, splittable ones, and the rest -- unsplittable and worthless to
the nuclear power industry -- are trash. The trash is useless for
today's global reactor fleet because today's global reactor fleet is
the wrong technology.
INNOVATE FOR FAST NEUTRONS
Only fast-neutron designs can breed fuel to achieve 30+ year fuel cycles, and smash our trash, yet we use
slow-neutron machines almost exclusively. It is time to innovate.
Every
technology has a learning curve. Fast neutron reactors have been
built, but they need to be better. We need innovations in
- fast reactor coolants to replace the water we use today
- accelerators -- the ability to jump-start new fuel mixtures using particle accelerators, not enriched uranium
- reactor
core monitoring -- of the spectrum of available neutron energy levels
and the distribution of the evolving fuel during the machine's 30 to 50
year run-time
- the safety of Paradise Lost -- the better we can completely optimize the machine at all times, the more completely it will fall apart and shut down if anything changes.
Reactor
stability is more difficult when fast neutrons move the power level up
faster than you can shove control rods in to lower it. The
fast-moving neutron has hit the next fissile nucleus before you could
move the control rod. As for
coolants, reactors
have kept neutrons fast with everything from molten lead to helium gas.
A gas leaves the neutrons fast because there's
just not enough molecules to
hit very often, and the neutrons retain their speed. And
molten
metals? Neutrons hit lead so hard that they bounce off with
nearly full velocity, like a ball hitting the wall in a racquet ball
court. As with ball vs. wall, the difference in weight (one
neutron vs lead with 207 such nucleons) makes it impossible to share
velocity equally, makes it impossible for each partner to leave
the collision with half the original velocity (and opposite
directions), and half again after the next encounter. Instead,
the small neutron leaves with most of its original velocity and the
large nucleus has hardly budged. But there are issues.
Molten
salts, sodium, lead, lead-bismuth mixtures:
successful fast-neutron reactors have been built with all of
them, but
all have shortcomings that future research must overcome. The
molten solids are corrosive, but there is no pressure, no explosions,
no release of radioactive gases with every serious accident. A
gas like helium solves the corrosion problems and doesn't have even the
short-term radioactivity we saw with water (O-16 turning into
radioactive N-16), a breakthrough not lost on designers.
Turbogenerators directly driven by a helium-cooled fast-neutron
reactor do not turn into piles of radioactive metal. This
simplifies the entire plant tremendously, and gives us power plants we
can site anywhere -- no cooling towers, no seaside tsunamis, no
polluted rivers, no water, no dual plumbing loops meeting at the steam
generator, no steam at all. But we are back to explosive
pressures inside the key components.
DEAD-END SPECIALIZATION -- BARELY FISSIONS ANYTHING: Goldilocks
is in the fast lane: it takes several things to get a nuclear energy
program that is "just right": fast neutrons, a long fuel cycles,
and small modular reactors that can live and die in the same concrete
cylinder. Neutrons start fast. Neutrons coming out
of an atom splitting event have the velocity to be gained by falling
down a hill nearly 2 million electron volts high, which gets you up to
a velocity of 20,000 kilometers per second (same energy, different
units of measurement). Neutrons start fast, but
today's reactors "moderate" them down to only a few hundredths of
an electron
volt, an energy level insignificant for splitting most nuclei. The
only thing such neutrons can do is stick to a nucleus, join
it --
that's why the trash is so laced with radioactive isotopes, each one of
which started as a nucleus destabilized by an unwanted, stuck-on, extra
neutron.
Why do we get
any fission at all with our wrong-technology reactor design? Our
lowest-common-denominator reactors can easily split only the most
fissionable of nuclei, U-235 and Pu-239. Nearly any nucleus
resents an extra neutron and most express this resentment as
radioactivity. But U-235 and Pu-239 are special. An extra
neutron -- should it ever arrive -- makes proton and neutron numbers both even for both these large
nuclei. And then? For
reasons of quantum magic, "both even" is very special. Settling
suddenly down into their oh-so-different configuration, U-235+1 and
Pu-239+1 fall apart from their own
released energy,
not ours. Today, drowning in radioactive waste, we need to split
all the heavy nuclei, not just the magic ones. When plopping an
unwanted neutron into a nucleus other than U-235 is not enough to split
it, we need to supply the extra energy ourselves and force the issue.
That energy is the neutron velocity we moderated away in reactors
that are the wrong design. Since we must split all the heavy
nuclei, we must retain all the
velocities. If a reactor has water in it, don't build it.
Lowest-common-denominator reactors that are tuned to only the
two or three most fissile isotopes and then hand us back everything else as trash -- tons of uranium the machine poisoned
but cannot split
-- these reactor were the wrong choice. We have specialized
ourselves into a dead end with water moderation. We need
broadband reactors instead.
BUILDING IN STABILITY: Triumphs await innovators
in fast reactor designs. Reactor stability interacts with coolant choice and how the machine is fueled. The uranium-238 discarded today as trash can provide both fuel and stability tomorrow. Each big nucleus has its
own preferences ("resonances") for either absorbing a neutron or
getting fissioned by it. Coolants will typically shift the
range of neutron energies ("spectrum")
higher when hotter, and broaden it.
There is a particular, higher neutron energy -- available in our
broad-spectrum, fast-neutron reactors but not others -- at which the
reactor's tons of U-238 preferentially
absorb neutrons, enough neutrons to end further fissioning by
them. In an accident, the hotter coolant shifts more neutrons
into absorption; chain reactions die. The U-238's own resonance
for neutron absorption also broadens as temperatures rise. After
broadening, more neutrons in our reactor will "look acceptable"
to the U-238, and disappear by absorption before they can split
anything. A reactor that eats its neutrons shuts down. So
changes in coolant, fuel, and the spectrum of neutron energies
throughout the machine can be lined up to shut down runaway reactors.
Finally, fuel in metallic
but not ceramic form shows enough thermal expansion during thermal
runaway to make the reactor core less compact and less
neutron-efficient -- output drops.
Under
the right conditions, we have a fail-safe machine. In April
1986, Experimental Breeder Reactor II (EBR II), a 62.5 MW (raw
thermal output) fast neutron reactor at the Idaho National Laboratory,
had all its primary cooling pumps shut off. As at Chernobyl,
technicians had previously turned of key safety system because they
wanted to run a test. Temperatures rose quickly. As
temperatures rose, the chain reactions were broken, the reactor shut
down from full power in 300 seconds, and did not restart. That
was the test. The machine passed -- it had passive safety.
COMPUTER MODELING CHANGES EVERYTHING TODAY: It is a
long road from passive safety in1986 to knowing a new design is
fail-safe. We want to breed and burn all the fuel,
so the fuel is constantly changing, constantly transformed.
We have a spectrum of neutron velocities, not the same wimpy
(thermalized) neutrons everywhere. More so than in today's
reactors, that spectrum will be "harder"
(more higher velocities; faster) in some places than others, and we
need to know and exploit these differences so that every nucleus gets
what it loves best for breeding and burning. We want neutron
reflectors to be moved around optimally, we want gamma ray spectrum
data to tell us what the fuel has evolved into, year by year.
Today, we throw everything in the reactor out ("it's trash to me,
you take it") and start over
with fresh fuel -- we keep our primitive machines relatively uniform
inside -- relatively uniform fresh fuel, relatively uniform neutron
velocities. Tomorrow we will keep the door shut on a Smash the
Trash reactor for 30, even 50, years and a lot will change inside.
We have a lot of computer modeling to do, a lot to discover.
Spain has a network of teraflop computers,
starting with the 94 teraflop Mare Nostrum in Barcelona. It is
time to model
new reactors and run the modeled reactors through full fuel cycle
simulations. Go for it. Spain wants the business.
I
am eager to see the innovation begin, in dozens
of machines by different teams of innovators, not in
trillion-watt, multi-decade, multi-billion-dollar projects that
frustrate everyone who
works on them. Financially, these ponderous projects are
not viable without government loan guarantees, even in a financial
system willing to take risks that trillions of dollars in Federal Reserve and Troubled Asset Relief Program (TARP) funds did not fully cover.
INNOVATION IN THIS NATION -- LOVED or FEARED?
OPTICS:
Something
truly new attracts laughter. The laser became "a solution in
search of a
problem" for most of the 1960s. 60,000 high-power units are sold
today for materials processing (writing numbers onto parts, cutting,
drilling, welding),
they are sold for communications (fiber optics), read/write
optical disks, medicine,
research -- a $6 billion annual market. We celebrate innovators
like Gene Watson who saw what was coming, started one company
(Spectra-Physics) and founded another (Coherent Lasers) when his own
board of directors didn't share his vision of what high-power lasers
would someday do. His first one in the basement laundry room
(220VAC, running water) burned the garage door paint on a neighbor's
house across the street whom no one liked anyway, but many companies
liked the CO2 laser and ordered them.
COMPUTATION: Usually an innovation is pretty feeble at first, and ignored. In an open market, fat, comfortable, and lazy minicomputer companies (Digital Equipment Corporation, Data General) were
free to ignore computers-on-a-chip which were only 4-bit, only
8-bit, which had no general purpose operating system written for them,
which could therefore never become general purpose computers.
But 8 bits
grew to 16, 32 and 64; Gary Kildall's CP/M operating system became DOS,
Windows and Linux, and the entire Digital Equipment Corporation and its
PDP/VAX minicomputers are both gone.
COMMUNICATION:
At century's turn, the revolution in
communication brought a more disruptive crisis than the explosion
in computation. The nation struggled to change from an
analog national telecommunications infrastructure to a digital one,
from an electronics-based national backbone to photonics and
fiber, and from voice to data traffic. This transition rendered
$500 billion in central office voice switches obsolete.
It produced
single Atlantic fiber crossings with more capacity than all systems
built in telecom history since 1858 combined. It promised to
erase over 180 billion dollars in annual revenues for all long-distance
phone
companies. The new players offered more, better, and faster.
Companies enjoying dominance in their markets faced great change.
Innovation confronted the nation.
Dominance
takes time and, when dominance is achieved,
it will always be with yesterday's technology. Dominance
brings wealth and power. A free market forces the wealthy and
powerful to buy into the new technology and compete to bring it -- to
bring More, Better, Faster -- to the nation faster than can small
companies with great innovations but few resources. How did it
go? The telecommunications industry chose to corrupt the
marketplace, to buy influence in the Public
Utility Commissions of the 50 States, to buy influence in (to lobby)
Congress, to kill non-dominant competitors whose innovations
would have carried the nation rapidly from analog to digital, from
electronic to photonic, from voice to data. The result is
that this nation is not even among the top ten in the strength of our Internet, however you measure it: by speed, cost, or penetration (nor in 2006 or in 2008).
This is an odd societal outcome in the nation that first
created an Internet, that invented so many of the foundational
software protocols that define its functionality, so much of the
hardware that directs its traffic, so many of the solid
state semiconductor components that gain its bandwidth. We were
the first. We had the most. Yet something suppressed
our level of excellence. We were pushed so far down in the global
sweepstakes that we fell out of the top ten. We are not among the
top nations for providing Internet service to citizens, to the kids who
will walk out of their dorm rooms with the next great companies.
Where are we headed next with nuclear
power?
NUCLEAR ENERGY & TERRAPOWER: Reactors
unlike any we see now would overcome the problems we suffer from, but
first we must block a nuclear industry that had already overpowered governmental
agencies and deceived itself and the people. The nuclear power
industry must start over with fast neutrons, but it is entrenched with the wrong technology.
Nathan
Myhrvold and the man who once hired him at Microsoft (Bill Gates) have
been leading the financing, design and computer modeling of new-technology reactors at
their adopted company, Terrapower, Inc. (search on TED
Terrapower).
Terrapower has chosen all the Goldilocks features: fast-neutrons
and a long fuel cycle to smash the trash, a size and shape that can be
buried and stay that way at decommissioning time because the
large-nucleus isotopes are gone.
Terrapower may create the first Smash the Trash reactor before anyone
else does. It is an innovative company. As we have seen, there is
a lot of computer modeling to be done if we are to innovate our way out
of one-velocity, one-fuel, one-trick-pony reactors into Smash the Trash
technologies. This is one reason why we see the nation's
best innovation in nuclear engineering coming from former leaders in
the nation's most famous computer software company, and not from the
nuclear engineering departments of our universities, nor from the
nuclear power industry itself.
Myhrvold and Gates' Terrapower may be our most innovative nuclear power company, but our government
forced its backers to
travel overseas seeking financial and technical support, while the government itself tried
to sell the public on loan guarantees for more slow-neutron,
wrong-technology reactors from old players with the dominant
revenues. If we must indeed spend the people's money on yesterday's
technology, then let us spend it to
clean up the pools of unusable radioactive fuel rods (which does not
make private investors rich), lets spend to clean up the tanks of radioactive
reprocessing acid (which does not make private investors rich), or to
clean up the tons of bomb-grade plutonium (which does not make private
investors rich). No government loan guarantees should be used
to
build more water-moderated nuclear power reactors. If there
is
water inside it, don't build it.
IT CAN'T HAPPEN HERE: The nuclear industry talks a good game, but the reactors remain the same.
Fast-neutron research
has all but stopped, not because there was no way forward towards smash-the-trash solutions, but
because there was easier money to be made with the wrong
technology. There is plenty of money to
be made because, instead of a
free market, costs are off the books. The industry enjoys cradle-to-grave support from a society unable
even to get the industry to take out its own trash. Corporate welfare dampens the need to
innovate.
The
world’s reactors make 13.5% of all commercial electricity; they bring
in about
$220 billion a year in revenues. One old 110 MegaWatt Boiling Water Reactor Model 5 (110MW BWR-5)
brings in about $31 billion over a 50 year lifetime, if
you can
keep it up only three years out of every four. What
does it cost to play the game? The uranium costs 0.3 cents a
kilowatt-hour (kw-h).
Enrichment to 4.4% U-235 adds 0.25 cents per kw/h. So, if total
fuel
costs are 0.55 cents/kwh and homeowners can be billed 10 to 21
cents/kwh retail, then there is no free market incentive to make any
change in the fuel cycle. If that is your main cost, don't change a
thing. Evaluate the expected
returns on investment and behave rationally. Instead of research,
load up on cheap uranium. Invest the profits in corrupting the
government. Get the government to take out the trash.
See if the government will clean up the whole plant when
it's done. Get the government to pay for loan guarantees,
then load up the new machines
with more cheap uranium, and forget the trash they make -- it's all on
their balance sheet, not yours. Make it look like progress.
Call the new
plants "Generation Two", "Generation Three," but don't change a thing.
Whatever the critics want, say it's coming, it's Generation Four,
Generation Five, you're working on it. Talk a good game, but keep
everything the same.
The IEEE (Institute for Electrical and Electronic Engineers):
We asked the experts how to build a safer and stronger nuclear industry. Q:
Will the Fukushima accident cause companies to reevaluate their newest
reactor designs? Is there a new urgency to develop advanced,
Generation IV reactors?A:
The entire nuclear industry is evaluating the impact of the Fukushima
event on reactor designs. Westinghouse will incorporate
lessons learned into its AP1000 design ... There will be no significant
change in our direction and no new urgency to pursue development of
Generation IV designs. These Generation IV designs are typically
considered to be advanced reactors that use either gas or liquid metals
as reactor coolant instead of water. The commercialization of
these Generation IV reactors is not feasible in the near term, as many
technical challenges need to be addressed.
—Ed Cummins, vice president of new plant technology for Westinghouse Electric Co.
IEEE Spectrum, November 2011.
THANK YOU
Thank
you for the time you have put into this paper. We must all
push
for what is best to make our country strong, and not expect anyone who
appears to be in a position of leadership to show any. We must measure the radioactivity ourselves, document the dosage, and
insist on health care for elevations in cancer case rates above national
baselines. We should choose the right technology, abandon the
wrong technology, and oust a political system that cannot tell the
difference between the two. We are
--
you, me, all of us -- members of the most technologically advanced
civilization in history. We must either understand the
technology
or lose the civilization.
This
is one of history's great countries. We can build fast
neutron
reactors that smash atoms and don't stop smashing them until the job is
done and the radioactive dangers are largely past. When
everything becomes fuel and little remains as waste, there is power
enough to run reactors for 50 years with no refueling. And
then
just bury them. The reactor proper is small. Keep
the
plant, the electric and cooling towers, keep the huge generators and
turbines, keep the pipes that bring steam and water to them, and just
fire up the next 50-year reactor. It is time for new fuel
cycles
and new reactor designs. We can take fast-neutron reactors
from
pilot projects to 1,000 megawatts. We are a great
country.
We will do this.
ACKNOWLEDGEMENT
I thank my wife for
graciously giving me family time to teach others.
I
thank my reviewers, especially A.A., for urging me to explain the pros
and cons of Smash the Trash reactors and not merely be a cheerleader
for them.
top
home
page for this Website
Paper's
PREVIEW
I. Atoms, Molecules, Proteins
and the Genetic Code
II.
Physics:
Powerful Radiation Breaks Molecules
III.
Let's
Build a Reactor.
IV. The Fateful Decision: Uranium and Slow Neutrons
V. The
Spent Fuel Story - No Place to Put Anything
VI. The Big Picture: Uranium
& Our Universe
VII. Public
Policy -- We subsidize this
industry from cradle to grave.
VIII.
The Nuclear Renaissance: Fast Reactors Only - They don't make waste, and perform their own
burial.
GE BWR-5
boiling water reactor, Browns Ferry, Alabama, 1973.
This 1100 megaWatt unit is the same as Fukushima Unit 6. We
see the primary containment vessel with ca. 3 cm thick steel
walls. The smaller reactor pressure vessel goes inside and is
not visible. The lid (foreground) is removed every 18 - 24
months to pull fuel rods out the top. During the triple meltdown
at Fukushima, Japan in 2011, neither the smaller reactor pressure
vessels nor older versions of these enormous containment
structures (BWR-3's and BWR-4s) were able to contain the hydrogen gas
that blew the roofs off buildings Nos. 1, 3 and 4 when it exploded.
A muffled explosion was heard inside No. 2.
REVISIONS
26Jun2011,
5Jul full paper at neutrons.notlong.com,
9Jul 4figs: e-shells; gametes, somatic
DNA zipper, BrownsFerry
Radioactive steam release clarified.
Neutron moderation's ideal (head-on)
vs real elasticity of collisions
10Jul mitochondrial DNA;
29Jul Newton's Cradle figure illustrates neutron moderation.
16Aug BIO-actomyosin figure.
18Aug Big Bang
converted only 4.6% of energy to baryonic matter.
18Aug free radicals natural vs by ionization.; better wave-particle
duality for gamma radiation.
18Aug Better FDA sunscreen clarity.
28Aug BasicReactor figure added
5Sept Better reactor steam loop description;
3Nov Hanford reprocessing canyons figure added
5Nov link to big 24Aug2011 supernova in Pinwheel Galaxy
27Nov Revise opening and closing fig caps in accord w/IEEE postmortem on Fukushima disaster
4Nov - 2Dec Section VIII FastReactors conclusion rewritten / new
2Dec better breeder text
