China Bets on Thorium Reactors

According to the South China Morning Post (hattip Next Big Future),

The deadline to develop a new design of nuclear power plant has been brought forward by 15 years as the central government tries to reduce the nation’s reliance on smog-producing coal-fired power stations.  A team of scientists in Shanghai had originally been given 25 years to try to develop the world’s first nuclear plant using the radioactive element thorium as fuel rather than uranium, but they have now been told they have 10, the researchers said.

I have to admit, I feel a little envious when I read things like that.  The Chinese government is showing exactly the kind of leadership that’s necessary to guide the development of nuclear power along rational channels, and it’s a style of leadership of which our own government no longer seems capable.

What do I mean by “rational channels?”  Among other things, I mean acting as a responsible steward of our nuclear resources, instead of blindly wasting them , as we are doing now.  How are we wasting them?  By simply throwing away the lion’s share of the energy content of every pound of uranium we mine.

Contrary to the Morning Post article, thorium is not a nuclear fuel.  The only naturally occurring nuclear fuel is uranium 235 (U235).  It is the only naturally occurring isotope that can be used directly to fuel a nuclear reactor.  It makes up only a tiny share – about 0.7% – of mined uranium.  The other 99.3% is mostly uranium 238 (U238).  What’s the difference?  When a neutron happens along and hits the nucleus of an atom of U235, it usually fissions.  When a neutron happens along and hits the nucleus of an atom of U238, unless its going very fast, it commonly just gets absorbed.  There’s more to the story than that, though.  When it gets absorbed, the result is an atom of U239, which eventually decays to an isotope of plutonium – plutonium 239 (Pu239).  Like U235, Pu239 actually is a nuclear fuel.  When a neutron hits its nucleus, it too will usually fission.  The term “fissile” is used to describe such isotopes.

In other words, while only 0.7% of naturally occurring uranium can be used directly to produce energy, the rest could potentially be transmuted into Pu239 and burned as well.  All that’s necessary for this to happen is to supply enough extra neutrons to convert the U238.  As it happens, that’s quite possible, using so-called breeder reactors.  And that’s where thorium comes in.  Like U238, the naturally occurring isotope thorium 232 (Th232) absorbs neutrons, yielding the isotope Th233, which eventually decays to U233, which is also fissile.  In other words, useful fuel can be “bred” from Th232 just as it can from U238.  Thorium is about three times as abundant as uranium, and China happens to have large reserves of the element.  According to current estimates, reserves in the U.S. are much larger, and India’s are the biggest on earth.

What actually happens in almost all of our currently operational nuclear reactors is a bit different.  They just burn up that 0.7% of U235 in naturally occurring uranium, and a fraction of the Pu239 that gets bred in the process, and then throw what’s left away.  “What’s left” includes large amounts of U238 and various isotopes of plutonium as well as a brew of highly radioactive reaction products left over from the split atoms of uranium and plutonium.  Perhaps worst of all, “what’s left” also includes transuranic actinides such as americium and curium as well as plutonium.  These can remain highly radioactive and dangerous for thousands of years, and account for much of the long-term radioactive hazard of spent nuclear fuel.  As it happens, these actinides, as well as some of the more dangerous and long lived fission products, could potentially be destroyed during the normal operation of just the sort of molten salt reactors the crash Chinese program seeks to develop.  As a result, the residual radioactivity from operating such a plant for, say, 40 years, could potentially be less than that of the original uranium ore after a few hundreds of years instead of many thousands.  The radioactive hazard of such plants would actually be much less than that of burning coal, because coal contains small amounts of both uranium and thorium.  Coal plants spew tons of these radioactive elements, potentially deadly if inhaled, into the atmosphere every year.

Why on earth are we blindly wasting our potential nuclear energy resources in such a dangerous fashion?  Because it’s profitable.  For the time being, at least, uranium is still cheap.  Breeder reactors would be more expensive to build than current generation light water reactors (LWRs).  To even start one, you’d have to spend about a decade, give or take, negotiating the highly costly and byzantine Nuclear Regulatory Commission licensing process.  You could count on years of even more costly litigation after that.  No reprocessing is necessary in LWRs.  Just quick and dirty storage of the highly radioactive leftovers, leaving them to future generations to deal with.  You can’t blame the power companies.  They’re in the business to make a profit, and can’t continue to operate otherwise.  In other words, to develop nuclear power rationally, you need something else in the mix – government leadership.

We lack that leadership.  Apparently the Chinese don’t.

 

Thorium metal
Thorium metal

Kerry, the Democrats, and the Demagoguing of Global Warming

Secretary of State John Kerry appeared quite concerned about global warming during a recent visit to Indonesia, telling students,

The bottom line is this: it is the same thing with climate change. In a sense, climate change can now be considered another weapon of mass destruction, perhaps even the worlds most fearsome weapon of mass destruction.

A bit later, Harry Reid and his fellow Democrat senators pulled an all-night talkathon to sound the climate change alarm.  According to Reid, climate change is “the worst problem facing the world today.”  All this left reporter Susan Davis at USA Today scratching her head:

The Democratic effort is cause for some confusion because these senators are calling for action in a chamber they control but without any specific legislation to offer up for a vote, or any timetable for action this year.

As noted at Hot Air, the talkathon and Kerry’s bloviations were nothing but PR stunts:

In other words, this is nothing but a stunt — and transparently so. Senate Democrats control all of the Senate committees, and what comes to the Senate floor. Boxer herself is the chair of the committee on environmental affairs, and could push through legislation any time she wants to the floor.

In other words, it’s business as usual when it comes to environmental activism.  The pose is everything, and the reality is nothing.  The reality is that Kerry, Reid, and the rest are transparently indifferent to the problem of climate change, except as it serves them as a political tool.  If they really cared about it, they would have put a stop to illegal immigration long ago.  The carbon foot print per capita of the United States is four times that of Mexico, and the ratio is much greater for most of the other countries of origin.  If they really cared, they would put a stop to Nuclear Regulatory Commission stonewalling of innovative nuclear plant designs, not to mention grossly excessive litigation hurdles for plant construction.  If they really cared, they would get behind the shale-energy revolution which has cut 300 million tons of US greenhouse gas emissions by replacing heavily polluting coal with natural gas, a contribution greater than that of all the worlds solar and wind power installations combined.  In other words, they don’t care.

It’s sad, because climate change actually is a potentially serious problem.  Kerry is just blowing hot air himself when he makes statements like,

We should not allow a tiny minority of shoddy scientists and science and extreme ideologues to compete with scientific fact.

The idea that someone like Kerry could distinguish “shoddy scientists” from “scientific fact” when it comes to climate change is beyond ludicrous.  What qualifies him to even make such a statement?  Certainly not the faintest understanding of current climate models.  The most powerful computers on earth couldn’t even come close to achieving a deterministic solution of the problem.  It involves billions of degrees of freedom in atmospheric and ocean conditions, and the necessary initial conditions are mostly either unknown or of limited accuracy.  The only way we can even begin to address the problem is with serious (and potentially inaccurate) data interpolation, and probabilistic computer models, the equivalent of “throwing dice” on a vast scale to see which numbers come up.  The statistical noise alone in such models renders it impossible to speak of “scientific facts” when it comes to climate change, but only a range of possible outcomes.  In other words, Kerry’s crude “alarmism” is an easy mark for the climate “denialism” on the other end of the ideological spectrum.  That’s too bad, because denying that any problem exists is just as bad as demagoguing it.

We may not be able to speak of “scientific facts” when it comes to climate change.  We do know, however, that solar radiation passing through a simplified model of the atmosphere and striking an “average” patch of the earth’s surface will raise the temperature of that atmosphere in proportion to the concentration of greenhouse gases.  The best computer models we have are not perfect, but they’re not useless either, and they predict that significant warming will occur over the coming decades.  In other words, we can’t speak of “facts” or certainty here, but we can say that there is a substantial risk that significant human-induced climate change will occur.  The effects might be benign, outweighed by the same factors that have driven variations in the earth’s climate throughout its history.  They might also be disastrous.  Given that earth is the only planet we have to live on at the moment, it seems foolhardy to rock the boat.

Under the circumstances, Kerry, Reid, and the rest might want to think twice about the value of crying “wolf” to score cheap political points, when it’s clear that they have no intention of seriously addressing the problem.  Particularly at the end of a 15 year pause in the rate of increase of global temperatures, the result, already much in evidence, will be an increase in cynicism and skepticism that the problem is real.  The resulting reluctance to sacrifice other priorities to address it may come back to haunt the alarmists if, as the boy in the story discovered, the “wolf” turns out to be real.

What to do?  Some of the most effective solutions are precisely what the alarmists who bray the loudest don’t want to do.  End significant immigration to countries with the most emissions per capita, for one.  Lead in the introduction and adoption of more efficient and safer nuclear technologies and the expansion of nuclear capacity instead of blocking it for another.   Instead, the wildly misnomered “Greens” in Germany are shutting down the nuclear plants in that country, with the entirely predictable result that Germany is currently planning to build 26 new, heavily polluting, coal-fired power plants to replace them.  Divert heavy subsidies for existing solar and wind technologies to investment in green technology research and development.  As those famously “green” Germans discovered once again, taxing the poor to finance the solar energy hobbies of the rich in a cloudy country whose capital lies above the 52nd parallel of latitude is a dubious proposition.  The cost of electricity there after years of massive subsidies to solar and a nuclear shutdown is now twice as high as in heavily nuclear France.  As noted in an article in the Frankfurter Allgemeine Zeitung, the burden of these skyrocketing costs is falling disproportionately on the backs of those least able to afford them.

Beyond that, we might want to get serious about finding another habitable planet, and developing the technology to get there.  We’ve been doing a lot of rocking the boat lately.  It would behoove us to have an alternative in case it eventually tips over, and the sooner the better.

coal-power-plant

 

 

 

The United States’ Nuclear Future

There are lots of great ideas out there for improving the way we do nuclear power.  For instance, Transatomic Power recently proposed a novel type of molten salt reactor (MSR).  The Next Generation Nuclear Plant (NGNP) Industry Alliance, with support from the U.S. Department of Energy, has chosen a high temperature gas reactor (HTGR) as its reactor of the future candidate.  Small modular reactors (SMRs) are all the rage, and a plethora of designs have been proposed.  Unlike the others, Terrapower’s traveling wave reactor (TWR), which is backed by Bill Gates, actually has a fighting chance to be built in the foreseeable future – in China.  With the possible exception of SMR’s, which have strong military support, the chances of any of them being built in the United States in the foreseeable future are slim.  Government, the courts, and a nightmarish regulatory process stand in the way as an almost insuperable barrier.

It wasn’t always this way.  A lot of today’s “novel” concepts are based on ideas that were proposed many decades ago.  We know they work, because demonstration reactors were built to try them out.  More than a dozen were built at Oak Ridge National Laboratory in Tennessee.  No less than 53 were built at Idaho National Laboratory!  Virtually all of them were completed more than half a century ago.  There are few historical precedents that can match the sudden collapse from the vitality of those early years to the lethargy and malaise prevailing in the nuclear industry today.  It’s sad, really, because the nuclear plants that actually are on line and/or under construction are artifacts of a grossly wasteful, potentially dangerous, and obsolete technology.

The light water reactors (LWRs) currently producing energy in this country use only a tiny fraction of the energy available in their uranium fuel, producing dangerous transuranic actinides that can remain highly radioactive for millennia in the process.  Many of the new designs are capable of extracting dozens of times more energy from a given quantity of fuel than LWRs.  Molten salt reactors would operate far more efficiently, could not melt down, and would consume dangerous actinides in the process, leaving such a small quantity of waste after several decades of operation that it would be less radioactive than the original ore used to fuel the reactor after a few hundred years rather than many millennia.  Besides also being immune to meltdown, HTGRs, because of their much higher operating temperatures, could enable such things as highly efficient electrolysis of water to produce hydrogen fuel and greatly improved extraction techniques for oil and natural gas from shale and sand.  Why, then, aren’t we building these improved designs?

It’s highly unlikely that the necessary initiative will come from industry.  Why would they care?  They’re in the business to make a profit, and LWRs can be built and operated more cheaply than the alternatives.  Why should they worry about efficiency?  There’s plenty of cheap uranium around, and it’s unlikely there will be major shortages for decades to come.  Ask any industry spokesman, and he’ll assure you that transuranic radioactive waste and the potential proliferation issues due to the plutonium content of spent LWR fuel are mere red herrings.  I’m not so sure.

In other words, strong government leadership would be needed to turn things around.  Unfortunately, that commodity is in short supply.  The current reality is that government is a highly effective deterrent to new reactor technology.  Take the Nuclear Regulatory Commission (NRC) for example.  Read Kafka’s The Trial and you’ll have a pretty good idea of how it operates.  So you want to license a new reactor design, do you?  Well, most of the current regulations apply specifically to LWRs, so you’ll have to give them time to come up with new ones.  Then you’ll need to spend at least a decade and millions of dollars explaining your new technology to the NRC bureaucrats.  Then you can expect an endless stream of requests for additional information, analysis of all the threat and failure scenarios they can dream up, etc., which will likely take a good number of additional years.  After all, they have to justify their existence, don’t they?  If you ever manage to get past the NRC, the court system will take things up where they left  off.

What to do?  I don’t know.  It really doesn’t upset me when reactors built with legacy technology are pulled off line, and replaced with fossil fueled plants.  They just waste most of their fuel, throwing away energy that future generations might sorely miss once they’ve finally burned through all the coal and oil on the planet.  Maybe the best thing to do would be to just buy up all the available uranium around and wait.  We might also stop the incredibly block-headed practice of converting all of our “depleted” uranium into ammunition.  The Lone Ranger’s silver bullets were cheap by comparison.  Future generations are likely to wonder what on earth we were thinking.

Things were a lot better in the “apathetic” 50’s, but the novelist Thomas Wolfe had it right.  You can’t go home again.

 

New Reactors in the UK and the Future of Nuclear Power

A consortium led by France’s EDF Energy, including Chinese investors, has agreed with the government of the UK on terms for building a pair of new nuclear reactors at Hinkley Point in the southwest of the country, not far from Bristol.  If a final investment decision is made some time next year, and the plants are actually built, they will probably be big (about 1600 Megawatts) pressurized water reactors (PWR’s) based on the French company Areva’s EPR design.  These are supposed to be  (and probably are) safer, more efficient, and more environmentally friendly than earlier designs.  In general, I tend to be pro-nuclear.  I would certainly feel a lot safer living next to a nuclear plant than a coal plant.  However, I’m a bit ambivalent about these new starts.  I think we could be a lot smarter in the way we implement nuclear power programs.

Reactors of the type proposed will burn uranium.  Natural uranium consists mostly of two isotopes, U235 and U238, and only U235 can be burnt directly in a nuclear reactor.  Why?  The answer to that question depends on something called “the binding energy of the last neutron.”  Think of a neutron as a bowling ball, and the nucleus of a uranium atom as a deep well.  If the bowling ball happens to roll into the well, it will drop over the edge, eventually smacking into the bottom, and releasing the energy it acquired due to the acceleration of gravity in the process.  The analogous force in the nucleus of a uranium atom is the nuclear force, incomparably greater than the force of gravity, but it acts in much the same way.  The neutron doesn’t notice this very short range force until it gets very close to the nucleus, or “lip of the well,” but when it does, it “falls in” and releases the energy acquired in the process in much the same way.  This energy is what I’ve referred to above as “the binding energy of the last neutron.”

When this binding energy is released in the nucleus, it causes it to wiggle and vibrate, something like a big drop of water falling through the air.  In the case of U235, the energy is sufficient to cause this “liquid drop” to actually break in two, or “fission.”  Such isotopes are referred to as “fissile.”  In U238, the binding energy of the last neutron alone is not sufficient to cause fission, but the isotope can still actually fission if the neutron happens to be moving very fast when it hits the nucleus, bringing some of its own energy to the mix.  Such isotopes, while not “fissile,” are referred to as “fissionable.”  Unfortunately, the isotope U235 is only 0.7 percent of natural uranium.  Once it’s burnt, the remaining U238 is no longer useful for starting a nuclear chain reaction on its own.

That would be the end of the story as far as conventional reactors are concerned, except for the fact that something interesting happens to the U238 when it absorbs a neutron.  As mentioned above, it doesn’t fission unless the neutron is going very fast to begin with.  Instead, with the extra neutron, it becomes U239.  However, U239 is unstable, and decays into neptunium 239, which further decays into plutonium 239, or Pu239.  In Pu239 the binding energy of the last neutron IS enough to cause it to fission.  Thus, conventional reactors burn not only U235, but also some of the Pu239 that is produced in this way.  Unfortunately, they don’t produce enough extra plutonium to keep the reactor going, so only a few percent of the U238 is “burnt” in addition to the U235 before the fuel has to be replaced and the old fuel either reprocessed or stored as radioactive waste.  Even though a lot of energy is locked up in the remaining U238, it is usually just discarded or used in such applications as the production of heavy armor or armor piercing munitions.  In other words, the process is something like throwing a log on your fireplace, then fishing it out and throwing it away when only a small fraction of it has been burnt.

Can anything be done about it?  It turns out that it can.  The key is neutrons.  They not only cause the U235 and Pu239 to fission, but also produce Pu239 via absorption in U238.  What if there were more of them around?  If there were enough, then enough new Pu239 could be produced to replace the U235 and old Pu239 lost to fission, and a much greater fraction of the U238 could be converted into useful energy.  A much bigger piece of the “log” could be burnt.

As a matter of fact, what I’ve described has actually been done, in so-called breeder reactors.  To answer the question “How?” it’s necessary to understand where all those neutrons come from to begin with.  In fact, they come from the fission process itself.  When an atom of uranium or plutonium fissions, it releases an average of something between 2 and 3 neutrons in the process.  These, in turn, can cause other fissions, keeping the nuclear chain reaction going.  The chances that they actually will cause another fission depends, among other things, on how fast they are going.  In general, the slower the neutron, the greater the probability that it will cause another fission.  For that reason, the neutrons in nuclear reactors are usually “moderated” to slower speeds by allowing them to collide with lighter elements, such as hydrogen.  Think of billiard balls.  If one of them hits another straight on, it will stop, transferring its energy to the second ball.  Much the same thing happens in neutron “moderation.”

However, more neutrons will be produced in each fission if the neutrons aren’t heavily moderated, but remain “fast.”  In fact, enough can be produced, not only to keep the chain reaction going, but to convert more U238 into useful fuel via neutron absorption than is consumed.  That is the principle of the so-called fast breeder reactor.  Another way to do the same thing is to replace the U238 with the more plentiful naturally occurring element thorium 232.  When it absorbs a neutron, it eventually decays into U233, which, like U235, is fissile.  There are actually many potential advantages to this thorium breeding cycle, such as potentially greater resistance to nuclear weapons proliferation, the ability to run the process at slower average neutron speeds, allowing smaller reactor size and easier control, less production of dangerous, long-lived transuranic actinides, such as plutonium and americium, etc.  In fact, if enough neutrons are flying around, they will fission and eliminate these actinides.  It turns out that’s very important, because they’re the nastiest components of nuclear waste.  If they could be recycled and burned, the amount of residual radiation from the waste produced by operating a nuclear plant for 30 or 40 years could be reduced to a level below that of the original uranium or thorium ore in a matter of only a few hundred years, rather than the many thousands that would otherwise be necessary.

So breeders can use almost all the potential energy in uranium or thorium instead of just a small fraction, while at the same time minimizing problems with radioactive waste.  What’s not to like?  Why aren’t we doing this?  The answer is profit.  As things now stand, power from breeder reactors of the type I’ve just described would be significantly more expensive than that from conventional reactors like EPR.  EPR’s would use enriched natural uranium, which is still relatively cheap and plentiful.  They would require no expensive reprocessing step.  Ask an industry spokesman, and they will generally assure you (and quite possibly believe themselves, because self-interest has always had a strong delusional effect) that we will never run out of natural uranium, that the radioactive danger from conventional reactor waste has been grossly exaggerated, and there is no long-term proliferation danger from simply discarding plutonium-laced waste somewhere and letting it decay for several thousand years.  I’m not so sure.

Now, I have no problem with profit, and I find Hollywood’s obsession with the evils of large corporations tiresome, but I really do think this is one area in which government might actually do something useful.  It might involve some mix of increased investment in research and development of advanced reactor technology, including the building of small demonstration reactors, continued robust support for the nuclear Navy, and eliminating subsidies on new conventional reactors.  Somehow, we managed to build scores of research reactors back in the 50’s, 60’s and 70’s.  It would be nice if we could continue building a few more now and then, not only for research into breeder technology, but as test beds for new corrosion and radiation resistant materials and fuels, exploration of high temperature gas-cooled reactors that could not only produce electricity but facilitate the production of hydrogen from water and synthetic natural gas from carbon dioxide and coal, both processes that are potentially much more efficient at high temperatures, and even fusion-fission hybrids if we can ever get fusion to work.

We aren’t going to run out of energy any time soon, but there are now over 7 billion people on the planet.  Eventually we will run out of fossil fuels, and depending entirely on wind, solar and other renewables to take up the slack seems a little risky to me.  Wasting potential fuel for the reactors of the future doesn’t seem like such a good idea either.  Under the circumstances, keeping breeder technology on the table as a viable alternative doesn’t seem like a bad idea.

Fusion Follies at Der Spiegel

Who says there’s no such thing as German humor?  Take, for example, some of the comments left by Teutonic wags after an article about the recent fusion “breakthrough” reported by scientists at Lawrence Livermore National Laboratory working on the National Ignition Facility (NIF).  One of the first was left by one of Germany’s famous “Greens,” who was worried about the long term effects of fusion energy.  Very long term.  Here’s what he had to say:

So nuclear fusion is green energy, is it?  The opposite is true.  Nuclear fusion is the form of energy that guarantees that any form of Green will be forever out of the question.  In comparison, Chernobyl is a short-lived joke!  Why?  Have you ever actually considered what will be “burned” with fusion energy?  Hydrogen, one of the two components of water, (and a material without which life is simply impossible)!  Nuclear fusion?  I can already see the wars over water coming.  And, by the way, the process is irreversible.  Once hydrogen is fused, it’s gone forever.  Nothing and no one will ever be able to make water out of it ever again!

I’m not kidding!  The guy was dead serious.  Of course, this drew a multitude of comments from typical German Besserwisser (better knowers), such as, “If you don’t have a clue, you should shut your trap.”  However, some of the other commenters were more light-hearted.  for example,

No, no, no.  What eu-fan (the first commenter) doesn’t seem to understand is that this should be seen as a measure against the rise in sea level that will result from global warming.  Less hydrogen -> less water -> reduced sea level -> everything will be OK.

Another hopeful commenter adds,

…if it ever actually does succeed, this green fusion, can we have our old-fashioned light bulbs back?

Noting that the fusion of hydrogen produces helium, another commenter chimes in,

So, in other words, if a fusion reactor blows up, the result will be a global bird cage:  The helium released will make us all talk like Mickey Mouse!

In all seriousness, the article in Der Spiegel about the “breakthrough” wasn’t at all bad.  The author actually bothered to ask a local fusion expert, Sibylle Günter, Scientific Director of the Max Planck Institute for Plasma Physics, about Livermore’s “breakthrough.”  She replied,

The success of our colleagues (at Livermore) is remarkable, and I don’t want to belittle it.  However, when one speaks of a “breakeven point” in the classical sense, in which the fusion energy out equals the total energy in, they still have a long way to go.

That, of course, is entirely true.  The only way one can speak of a “breakthough” in the recent NIF experiments is by dumbing down the accepted definition of “ignition” from “fusion energy out equals laser energy in” to “fusion energy out equals energy absorbed by the target,” a much lower amount.  That didn’t deter many writers of English-language reports, who couldn’t be troubled to fact check Livermore’s claims with the likes of Dr. Günter.  In some cases the level of fusion wowserism was extreme.  For example, according to the account at Yahoo News,

After fifty years of research, scientists at the National Ignition Facility (NIF) in Livermore, have made a breakthrough in harnessing and controlling fusion.

and,

According to the BBC, NIF conducted an experiment where the amount of energy released through the fusion reaction was more than the amount of energy being absorbed by it. This process is known as “ignition” and is the first time it has successfully been done anywhere in the world.

I’m afraid not.  The definition of “ignition” that has been explicitly accepted by scientists at Livermore is “fusion energy out equals laser energy in.”  That definition puts them on a level playing field with their magnetic fusion competitors.  It’s hardly out of the question that the NIF will reach that goal, but it isn’t there yet.  Not by a long shot.

 

Another Fusion Tease?

It has always seemed plausible to me that some clever scientist(s) might find a shortcut to fusion that would finally usher in the age of fusion energy, rendering the two “mainstream” approaches, inertial confinement fusion (ICF) and magnetic fusion, obsolete in the process.  It would be nice if it happened sooner rather than later, if only to put a stop to the ITER madness.  For those unfamiliar with the field, the International Thermonuclear Experimental Reactor, or ITER, is a gigantic, hopeless, and incredibly expensive white elephant and welfare project for fusion scientists currently being built in France.  In terms of pure, unabashed wastefulness, think of it as a clone of the International Space Station.  It has always been peddled as a future source of inexhaustible energy.  Trust me, nothing like ITER will ever be economically competitive with alternative energy sources.  Forget all your platitudes about naysayers and “they said it couldn’t be done.”  If you don’t believe me, leave a note to your descendants to fact check me 200 years from now.  They can write a gloating refutation to my blog if I’m wrong, but I doubt that it will be necessary.

In any case, candidates for the hoped for end run around magnetic and ICF keep turning up, all decked out in the appropriate hype.  So far, at least, none of them has ever panned out.  Enter two stage laser fusion, the latest pretender, introduced over at NextBigFuture with the assurance that it can achieve “10x higher fusion output than using the laser directly and thousands of times better output than hitting a solid target with a laser.”  Not only that, but it actually achieved the fusion of boron and normal hydrogen nuclei, which produces only stable helium atoms.  That’s much harder to achieve than the usual deuterium-tritium fusion between two heavy isotopes of hydrogen, one of which, tritium, is radioactive and found only in tiny traces in nature.  That means it wouldn’t be necessary to breed tritium from the fusion reactions just to keep them going, one of the reasons that ITER will never be practical.

Well, I’d love to believe this is finally the ONE, but I’m not so sure.  The paper describing the results NBF refers to was published by the journal Nature Communications.  Even if you don’t subscribe, you can click on the figures in the abstract and get the gist of what’s going on.  In the first place, one of the lasers has to accelerate protons to high enough energies to overcome the Coulomb repulsion of the stripped (of electrons) boron nuclei produced by the other laser.  Such laser particle accelerators are certainly practical, but they only work at extremely high power levels.  In other words, they require what’s known in the business as petawatt lasers, capable of achieving powers in excess of a quadrillion (10 to the 15th power) watts.  Power comes in units of energy per unit time, and such lasers generally reach the petawatt threshold by producing a lot of energy in a very, very short time.  Often, we’re talking picoseconds (trillionths of a second).

Now, you can do really, really cool things with petawatt lasers, such as pulling electron positron pairs right out of the vacuum.  However, their practicality as drivers for fusion power plants, at least in their current incarnation, is virtually nil.  The few currently available, for example, at the University of Rochester’s Laboratory for Laser Energetics, the University of Texas at Austin, the University of Nevada at Reno, etc., are glass lasers.  There’s no way they could achieve the “rep rates” (shot frequency) necessary for useful energy generation.  Achieving lots of fusions, but only for a few picoseconds, isn’t going to solve the world’s energy problems.

As it happens, conventional accelerators can also be used for fusion.  As a matter of fact, it’s a common way of generating neutrons for such purposes as neutron radiography.  Unfortunately, none of the many fancy accelerator-driven schemes for producing energy that people have come up with over the years has ever worked.  There’s a good physical reason for that.  Instead of using their energy to overcome the Coulomb repulsion of other nuclei (like charges repel, and atomic nuclei are all positively charged), and fuse with them, the accelerated particles prefer to uselessly dump that energy into the electrons surrounding those nuclei.  As a result, it has always taken more energy to drive the accelerators than could be generated in the fusion reactions.  That’s where the “clever” part of this scheme comes in.  In theory, at least, all those pesky electrons are gone, swept away by the second laser.  However, that, too, is an energy drain.  So the question becomes, can both lasers be run efficiently enough and with high enough rep rates and with enough energy output to strip enough boron atoms to get enough of energy out to be worth bothering about, in amounts greater than that needed to drive the lasers?  I don’t think so.  Still, it was a very cool experiment.

Accelerator-Driven Thorium Reactors, or An Easy Way to Eliminate Surplus Population

The Daily Telegraph has just taken thorium wowserism to a whole new level.  According to the title of an article penned by International Business Editor Ambrose Evans-Pritchard, Obama could kill fossil fuels overnight with a nuclear dash for thorium.  Continuing in the same vein, the byline assures us that,

If Barack Obama were to marshal America’s vast scientific and strategic resources behind a new Manhattan Project, he might reasonably hope to reinvent the global energy landscape and sketch an end to our dependence on fossil fuels within three to five years.

And how is this prodigious feat to be accomplished?  Via none other than Nobel laureate Dr. Carlo Rubbia’s  really bad idea for building accelerator-driven thorium reactors.  It would seem that Dr. Rubbia has assured the credulous Telegraph editor that, “a tonne of the silvery metal produces as much energy as 200 tonnes of uranium.”  This egregious whopper is based on nothing more complicated than a comparison of apples and oranges.  Thorium by itself cannot power a nuclear reactor.  It must first be converted into the isotope uranium 233 via absorption of a neutron.  Natural uranium, on the other hand, can be used directly in reactors, because 0.7 percent of it consists of the fissile isotope uranium 235.  In other words, Rubbia is comparing the energy potential of thorium after it has been converted to U233 with the energy potential of only the U235 in natural uranium.  The obvious objection to this absurd comparison is that the rest of natural uranium is made up mostly of the isotope U238, which can also absorb a neutron to produce plutonium 239, which, like U233, can power nuclear reactors.  In other words, if we compare apples to apples, that is, thorium after it has been converted to U233 with U238 after it has been converted to Pu239, the potential energy content of thorium and uranium is about equal.

As it happens, the really bad news in the Telegraph article is that,

The Norwegian group Aker Solutions has bought Dr. Rubbia’s patent for an accelerator-driven sub-critical reactor, and is working on his design for a thorium version at its UK operation.

In fact, Aker has already completed a conceptual design for a power plant.  According to Aker project manager Victoria Ashley, the group needs a paltry $3 million, give or take, to build the first one, and another $150 million for the test phase to follow.  Why is that disturbing news?  Because the U233 produced in these wonderful new reactors will be ideal for producing nuclear weapons.

In fact, it will be even better than the “traditional” bomb materials; highly enriched uranium (HEU) and weapons grade plutonium.  The explosion of a nuclear device is produced by assembling a highly supercritical mass of fissile material, and then introducing a source of neutrons at just the right moment, setting off a runaway chain reaction.  The problem with plutonium is that it has the bad habit of occasionally fissioning spontaneously.  This releases neutrons.  If such a stray neutron were to happen along just as the bomb material became critical, it would set off a premature chain reaction, causing the device to “fizzle.”  As a result, plutonium weapons must rely on a complicated implosion process to achieve supercriticality before the stray neutrons can do their dirty work.  Implosion weapons are much more technologically challenging to build than the gun-assembled types that can be used with HEU.  In these, one subcritical mass is simply shot into another.  However, the required mass of HEU is much larger than the amount of plutonium needed in an implosion-assembled weapon.  As it happens, the amount of U233 sufficient to build a nuclear device is about the same as the amount of plutonium, but spontaneous fission is not a problem in U233.  In other words, it combines the plutonium advantage of requiring a much smaller amount of material, and the HEU advantage of being usable in gun-assembled weapons.

Why, then, you might ask, are we even giving Rubbia’s idea a second thought?  Because of people like Professor Egil Lillestol, who, Evans-Pritchard helpfully informs us, is “a world authority on the thorium fuel cycle at CERN.”  According to Lillestol,

It is almost impossible to make nuclear weapons out of thorium because it is too difficult to handle.  It wouldn’t be worth trying.

Rubbia has made similar statements, based on the same “logic.”  The rationalization for the claim that U233 is “too difficult to handle” is the supposed presence of U232, an isotope of uranium with a half-life of about 69 years, one of whose daughters (elements in its decay chain) emits a highly energetic and penetrating, and hence deadly, gamma ray.  In fact, avoiding the production of U232 in accelerator-driven reactors would be a piece of cake.  Rubbia and Lillestol must know this, making it all the more incomprehensible that they dare to foist such whoppers on unsuspecting newspaper editors.

Only one neutron absorption is needed for the production of U233 from naturally occurring Th232.  Two are needed to produce U232.  Thus, one way to keep the level of U232 within manageable levels is to simply extract the U233 before much U232 has a chance to form.  However, there’s an even easier way.  Very energetic neutrons, with energies above a threshold of around 6 million electron volts, are necessary to produce U232.  Not many fission neutrons have that much energy, and slowing down the ones that do is simple.  Simply pass them through a “moderator” rich in hydrogen or some other light element.  Think of billiard balls.  If one of them going at a good clip hits another dead on, it stops, imparting its energy to the second ball.  Neutrons and the proton nuclei of hydrogen atoms have nearly the same mass, so the same thing can happen when they collide.  A fast neutron will typically lose a large fraction of its energy in such a collision.  In other words, the “secret” of avoiding the production of dangerous levels of U232 is as simple as passing the neutrons through a layer of hydrogen-rich material such as paraffin before allowing them to interact with the thorium.  All this should hardly come as a surprise to people like Rubbia and Lillestol.  It’s been old hat in the literature for a long time.  For a more detailed treatment, see, for example, U-232 and the Proliferation-Resistance of U-233 in Spent Fuel, a paper that appeared in the journal Science and Global Security back in 2001.

In other words, the idea that “it is almost impossible to make nuclear weapons out of thorium” is a pipe dream.  That does not necessarily mean that thorium technology should be rejected root and branch.  It will always be necessary to exercise extreme care to insure that U233 isn’t diverted for illicit purposes.  However, managing the risk will be considerably easier in “conventional” thorium breeders, which rely on assembling a critical mass to supply the necessary source of neutrons.  Such reactors have already been built and successfully operated for years.  The U233 they produce will always be mixed with highly radioactive fission products, and can also be “denatured” by mixing it with U238, from which it cannot be separated using simple chemistry.  Such reactors would produce few of the transuranic actinides that are the main culprits in nuclear waste, potentially requiring it to be stored securely for millennia.  They could also consume the actinides produced in the current generation of reactors, so that the remaining waste could potentially become less radioactive than the original uranium ore in a few hundred years, instead of many thousands.

If, on the other hand, the accelerators necessary to provide the neutron source for Dr. Rubbia’s subcritical facilities were to become readily available, they would be much easier to hide than conventional reactors, could be configured to produce U233 with almost no U232 contamination, and with much less radioactive fission product contamination.  In other words, they would constitute an unacceptable risk for the proliferation of nuclear weapons.  One must hope that the world will wake up in time to recognize the threat.

Fusion Update: The NIF Inches Closer to Ignition

In a recent press release, Lawrence Livermore National Laboratory (LLNL) announced that it had achieved a yield of 3 x 1015 neutrons in the latest round of experiments at its National Ignition Facility, a giant, 192-beam laser facility designed, as its name implies, to achieve fusion ignition.  That’s nowhere near “ignition,” but still encouraging as it’s three times better than results achieved in earlier experiments.

The easiest way to achieve fusion is with two heavy isotopes of hydrogen; deuterium, with a nucleus containing one proton and one neutron, and tritium, with a nucleus containing one proton and two neutrons.  Deuterium is not radioactive, and occurs naturally as about one atom to every 6400 atoms of “normal” hydrogen, with a nucleus containing only a single proton.  Tritium is radioactive, and occurs naturally only in tiny trace amounts.  It has a half-life (the time it takes for half of a given amount to undergo radioactive decay) of 12.3 years, and must be produced artificially.  When tritium and deuterium fuse, they release a neutron, a helium nucleus, or alpha particle, and lots of energy (17.6 million electron volts).

Fortunately (because otherwise it would be too easy to blow up the planet), or unfortunately (if you want to convert the energy into electricity), fusion is hard.  The two atoms don’t like to get too close, because their positively charged nuclei repel each other.  Somehow, a way must be found to make the heavy hydrogen fuel material very hot, causing the thermal motion of the atoms to become very large.  Once they start moving fast enough, they can smash into each other with enough momentum to overcome the repulsion of the positive nuclei, allowing them to fuse.  However, the amount of energy needed per atom is huge, and when atoms get that hot, the last thing they want to do is stay close to each other (think of what happens in the detonation of high explosive.)  There are two mainstream approaches to solving this problem; magnetic fusion, in which the atoms are held in place by powerful magnetic fields while they are heated (the approach being pursued at ITER, the International Thermonuclear Experimental Reactor, currently under construction in France), and inertial confinement fusion (ICF), where the idea is to dump energy into the fuel material so fast that its own inertia holds it in place long enough for fusion to occur.  The NIF is an ICF facility.

There are various definitions of ICF “ignition,” but, in order to avoid comparisons of apples and oranges between ICF and magnetic fusion experiments, LLNL has explicitly accepted the point at which the fusion energy out equals the laser energy in as the definition of ignition.  In the experiment referred to above, the total fusion energy release was about 10,000 joules, give or take.  Since the laser energy in was around 1.7 million joules, that’s only a little over one half of one percent of what’s needed for ignition.  Paltry, you say?  Not really.  To understand why, you have to know a little about how ICF experiments work.

Recall that the idea is to heat the fuel material up so fast that its own inertia holds it in place long enough for fusion to occur.  The “obvious” way to do that would be to simply dump in enough laser energy to heat all the fuel material to fusion temperatures at once.  Unfortunately, this “volumetric heating” approach wouldn’t work.  The energy required would be orders of magnitude more than what’s available on the NIF.  What to do?   Apply lots and lots of finesse.  It turns out that if a very small volume or “hot spot” in the fuel material can be brought to fusion conditions, the alpha particles released in the fusion reactions might carry enough energy to heat up the nearby fuel to fusion conditions as well.  Ideally, the result would be an alpha “burn wave,” moving out through the fuel, and consuming it all.  But wait, it ain’t that easy!  An efficient burn wave will occur only if the alphas are slammed to a stop and forced to dump their energy after traveling only a very short distance in the cold fuel material around the hot spot.  Their range is too large unless the fuel is first compressed to a tiny fraction of its original volume, causing its density to increase by orders of magnitude.

In other words, to get the fuel to fuse, we need to make it very hot, but we also need to compress it to very high density, which can be done much more easily and efficiently if the material is cold!  Somehow, we need to keep the fuel “cold” during the compression process, and then, just at the right moment, suddenly heat up a small volume to fusion conditions.  It turns out that shocks are the answer to the problem.  If a train of four shocks can be set off in the fuel material as it is being compressed, or “imploded,” by the lasers, precisely timed so that they will all converge at just the right moment, it should be possible, in theory at least, to generate a hot spot.  If the nice, spherical symmetry of the fuel target could be maintained during the implosion process, everything should work just fine.  The NIF would have more than enough energy to achieve ignition.  But there’s the rub. Maintaining the necessary symmetry has turned out to be inordinately hard.  Tiny imperfections in the target surface finish, small asymmetries in the laser beams, etc., lead to big deviations from perfect symmetry in the dense, imploded fuel.  These asymmetries have been the main reason the NIF has not been able to achieve its ignition goal to date.

And that’s why the results of the latest round of experiments haven’t been as “paltry” as they seem.  As noted in the LLNL press release,

Early calculations show that fusion reactions in the hot plasma started to self-heat the burning core and enhanced the yield by nearly 50 percent, pushing close to the margins of alpha burn, where the fusion reactions dominate the process.

“The yield was significantly greater than the energy deposited in the hot spot by the implosion,” said Ed Moses, principle associate director for NIF and Photon Science. “This represents an important advance in establishing a self-sustaining burning target, the next critical step on the path to fusion ignition on NIF.”

That’s not just hype.  If the self-heating can be increased in future experiments, it may be possible to reach a threshold at which the alpha heating sets off a burn wave through the rest of the cold fuel, as described above.  In other words, ignition is hardly a given, but the guys at LLNL still have a fighting chance.  Their main challenge may be to stem the gradual evaporation of political support for NIF while the experiments are underway.  Their own Senator, Diane Feinstein, is anything but an avid supporter.  She recently turned down appeals to halt NIF budget cuts, and says the project needs to be “reassessed” in light of the failure to achieve ignition.

Such a “reassessment” would be a big mistake.  The NIF was never funded as an energy project.  Its support comes from the National Nuclear Security Administration (NNSA), a semi-autonomous arm of the Department of Energy charged with maintaining the safety and reliability of the nation’s nuclear arsenal.  As a tool for achieving that end, the NIF is without peer in any other country.  It has delivered on all of its performance design goals, including laser energy, illumination symmetry, shot rate, the precision and accuracy of its diagnostic instrumentation, etc.  The facility is of exceptional value to the weapons program even if ignition is never achieved.  It can still generate experimental conditions approaching those present in an exploding nuclear device, and, along with the rest of our suite of “above-ground experimental facilities,” or AGEX, it gives us a major leg up over the competition in maintaining our arsenal and avoiding technological surprise in the post-testing era.

Why is that important?  Because the alternative is a return to nuclear testing.  Do you think no one at NNSA wants to return to testing, and that the weapon designers at the National Weapons Laboratories wouldn’t jump at the chance?  If so, you’re dreaming.  It seems to me we should be doing our best to keep the nuclear genie in the bottle, not let it out.  Mothballing the NIF would be an excellent start at pulling the cork!

I understand why the guys at LLNL are hyping the NIF’s potential as a source of energy.  It’s a lot easier to generate political support for lots of electricity with very little radioactive waste and no greenhouse gases than for maintaining our aging arsenal of nuclear weapons.  However, IMHO, ICF is hopeless as a source of electricity, at least for the next few hundred years.  I know many excellent scientists will disagree, but many excellent scientists are also prone to extreme wishful thinking when it comes to rationalizing a technology they’ve devoted their careers to.  Regardless, energy hype isn’t needed to justify the NIF.  It and facilities like it will insure our technological superiority over potential nuclear rivals for years to come, and at the same time provide a potent argument against the resumption of nuclear testing.

German “Greens” and the Poisoning of Eastern Europe

A while back in an online discussion with a German “Green,” I pointed out that, if Germany shut down its nuclear plants, coal plants would have to remain in operation to take up the slack.  He was stunned that I could be so obtuse.  Didn’t I realize that the lost nuclear capacity would all be replaced by benign “green” energy technology?  Well, it turns out things didn’t quite work out that way.  In fact, the lost generating capacity is being replaced by – coal.

Germany is building new coal-fired power plants hand over fist, with 26 of them planned for the immediate future.  According to Der Spiegel, the German news magazine that never misses a trick when it comes to bashing nuclear, that’s a feature, not a bug.  A recent triumphant headline reads, “Export Boom:  German Coal Electricity Floods Europe.”  Expect more of the same from the home of Europe’s most pious environmentalists.  Germany has also been rapidly expanding its solar and wind capacity recently thanks to heavy state subsidies, but the wind doesn’t always blow and the sun doesn’t always shine, especially in Germany.  Coal plants are required to fill in the gaps – lots of them.  Of course, it would be unprofitable to let them sit idle when wind and solar are available, so they are kept going full blast.  When the power isn’t needed in Germany, it is sold abroad, serving as a useful prop to Germany’s export fueled economy.

Remember the grotesque self-righteousness of Der Spiegel and the German “Greens” during the Kyoto Treaty debates at the end of the Clinton administration?  Complying with the Kyoto provisions cost the Germans nothing.  They had just shut down the heavily polluting and grossly unprofitable industries in the former East Germany, had brought large numbers of new gas-fired plants on line thanks to increasing gas supplies from the North Sea fields, and had topped it off with a lame economy in the 90’s compared to the booming U.S.  Their greenhouse gas emissions had dropped accordingly.  Achieving similar reductions in the U.S. wouldn’t have been a similar “freebie.”  It would have cost tens of thousands of jobs.  The German “Greens” didn’t have the slightest problem with this.  They weren’t interested in achieving a fair agreement that would benefit all.  They were only interested in striking pious poses.

Well, guess what?  Times have changed.  Last year U.S. carbon emissions were at their lowest level since 1994, and down 3.7% from 2011.  Our emissions are down 7.7% since 2006, the largest drop among major industrial states on the planet.  German emissions were up at least 1.5% last year, and probably more like 2%.  Mention this to a German “Green,” and he’s likely to mumble something about Germany still being within the Kyoto limits.  That’s quite true.  Germany is still riding the shutdown of what news magazine Focus calls “dilapidated, filthy, communist East German industry after the fall of the Berlin Wall,” to maintain the facade of environmental “purity.”

That’s small comfort to her eastern European neighbors.  Downwind from Germany’s coal-fired plants, their “benefit” from her “green” policies is acid rain, nitrous oxide laced smog, deadly particulates that kill and sicken thousands and, last but not least, a rich harvest of radioactive fallout.  That’s right, Germany didn’t decrease the radioactive hazard to her neighbors by shutting down her nuclear plants.  She vastly increased it.  Coal contains several parts per million each of radioactive uranium and thorium.  These elements are harmless enough – if kept outside the body.  The energetic alpha particles they emit are easily stopped by a normal layer of skin.  When that happens, they dump the energy they carry in a very short distance, but, since skin is dead, it doesn’t matter.  It’s an entirely different matter when they dump those several million electron volts of energy into a living cell – such as a lung cell.  Among other things, that can easily derange the reproductive equipment of the cell, causing cancer.  How can they reach the lungs?  Very easily if the uranium and thorium that emit them are carried in the ash from a coal-fired plant.  A typical coal-fired plant releases about 5 tons of uranium and 12 tons of thorium every year.  The German “Greens” have no problem with this, even though they’re constantly bitching about the relatively miniscule release of uranium from U.S. depleted uranium munitions.  Think scrubber technology helps?  Guess again!  The uranium and thorium are concentrated in the ash, whether it ends up in the air or not.  They can easily leach into surrounding cropland and water supplies.

The last time there was an attempt to move radioactive waste to the Gorleben storage facility within Germany, the “Greens” could be found striking heroic poses as saviors of the environment all along the line, demonstrating, tearing up tracks, and setting police vehicles on fire.  Their “heroic” actions forced the shutdown of Germany’s nuclear plants.  The “gift” (German for “poison”) of their “heroic” actions to Germany’s neighbors came in the form of acid rain, smog, and airborne radiation.  By any reasonable standard, coal-fired plants are vastly more dangerous and damaging to the environment than the nuclear facilities they replaced.

It doesn’t matter to Germany’s “Greens.”  The acid rain, the radiation, the danger of global warming they always pretend to be so concerned about?  It doesn’t matter.  For them, as for the vast majority of other environmental zealots worldwide, the pose is everything.  The reality is nothing.

coal-power-plant

Nuclear Energy and the “Too Cheap to Meter” Lie

According to a German proverb, “Lügen haben kurze Beine” – Lies have short legs.  That’s not always true.  Some lies have very long ones.  One of the most notorious is the assertion, long a staple of anti-nuclear propaganda, that the nuclear industry ever claimed that nuclear power would be “Too cheap to meter.”  In fact, according to the New York Times, the phrase did occur in a speech delivered to the National Association of Science Writers by Lewis L. Strauss, then Chairman of the Atomic Energy Commission, in September 1954.  Here is the quote, as reported in the NYT on September 17, 1954:

“Our children will enjoy in their homes electrical energy too cheap to meter,” he declared.   …    “It is not too much to expect that our children will know of great periodic regional famines in the world only as matters of history, will travel effortlessly over the seas and under them and through the air with a minimum of danger and at great speeds, and will experience a lifespan far longer than ours, as disease yields and man comes to understand what causes him to age.”

Note that nowhere in the quote is there any direct reference to nuclear power, or for that matter, to fusion power, although the anti-nuclear Luddites have often attributed it to proponents of that technology as well.  According to Wikipedia, Strauss was “really” referring to the latter, but I know of no evidence to that effect.  In any case, Strauss had no academic or professional background that would qualify him as an expert in nuclear energy.  He was addressing the science writers as a government official, and hardly as a “spokesman” for the nuclear industry.  The sort of utopian hyperbole reflected in the above quote is just what one would expect in a talk delivered to such an audience in the era of scientific and technological hubris that followed World War II.  There is an excellent and detailed deconstruction of the infamous “Too cheap to meter” lie on the website of the Canadian Nuclear Society.  Some lies, however, are just too good to ignore, and anti-nuclear zealots continue to use this one on a regular basis, as, for example, here, here and here.  The last link points to a paper by long-time anti-nukers Arjun Makhijani and Scott Saleska.  They obviously knew very well the provenance of the quote and the context in which it was given.  For example, quoting from the paper:

In 1954, Lewis Strauss, Chairman of the U.S. Atomic Energy Commission, proclaimed that the development of nuclear energy would herald a new age. “It is not too much to expect that our children will enjoy in their homes electrical energy too cheap to meter,” he declared to a science writers’ convention.  The speech gave the nuclear power industry a memorable phrase to be identified with, but also it saddled it with a promise that was essentially impossible to fulfill.

In other words, it didn’t matter that they knew very well that Strauss had no intention of “giving the nuclear power industry a memorable phrase to be identified with.”  They used the quote in spite of the fact that they knew that claim was a lie.  I all fairness, it can be safely assumed that most of those who pass along the “too cheap to meter” lie are not similarly culpable.  They are merely ignorant.