Category: Nuclear energy

Nuclear Update: Molten Salt, Rugby Balls, and the Advanced Hydrodynamic Facility

I hear at 7th or 8th hand that the folks at DOE have been seriously scratching their heads about the possibility of building a demonstration molten salt reactor.  They come in various flavors, but the “default” version is a breeder, capable of extracting far more energy from a given quantity of fuel material than current reactors by converting thorium into fissile uranium 233.  As they would have a liquid core, the possibility of a meltdown would be eliminated.  The copious production of neutrons in such reactors would make it possible to destroy the transuranic actinides, such as americium and curium, and, potentially, also some of the most long-lived radioactive products produced in fission reactions.  As a result, the residual radioactivity from running such a reactor for, say, 30 years, would potentially be less than that of the ore from which the fuel was originally extracted in under 500 years, a far cry from the millions commonly cited by anti-nuke alarmists.  Such reactors would be particularly attractive for the United States, because we have the largest proven reserves of thorium on the planet.  Disadvantages include the fact that uranium 233 is a potential bomb material, and therefore a proliferation concern, and the highly corrosive nature of the fluoride and/or chloride “salts” in the reactor core.  More detailed discussions of the advantages and disadvantages may be found here and here.

The chances that the U.S. government will actually provide the funding necessary to build a molten salt or any other kind of advanced reactor are, unfortunately, slim and none.  We could do such things in the 50’s and 60’s with alacrity, but those days are long gone, and the country seems to have fallen victim to a form of technological palsy.  That’s too bad, because private industry won’t take up the slack.  To the extent they’re interested in nuclear at all, the profit motive rules.  At the moment, the most profitable way to generate nuclear energy is with reactors that simply burn naturally occurring uranium, wasting the lion’s share of the potential energy content, and generating copious amounts of long-lived radioactive waste for which no rational long term storage solution has yet been devised.  In theory, DOE’s national laboratories should be stepping in to take up the slack, doing the things that industry can’t or won’t do.  In reality what they do is generate massive stacks of paper studies and reports on advanced systems that have no chance of being built.  Enough must have accumulated since the last research reactor was actually built at any of the national labs to stretch back and forth to the moon several times.  Oh, well, we can take comfort in the knowledge that at least some people at DOE are thinking about the possibilities.

Moving right along, as most of my readers are aware, the National Ignition Facility, or NIF, did not live up to its name.  It failed to achieve inertial confinement fusion (ICF) ignition in the most recent round of experiments, missing that elusive goal by nearly two orders of magnitude.  The NIF is a giant, 192 beam laser system at Lawrence Livermore National Laboratory (LLNL) that focuses all of its 1.8 megajoules of laser energy on a tiny target containing deuterium and tritium, two heavy isotopes of hydrogen.  Instead of generating energy by splitting or “fissioning” heavy atoms, the goal is to get these light elements to “fuse,” releasing massive amounts of energy.

Actually, the beams don’t hit the target itself.  Instead they’re focused through two holes in the ends of a tiny cylinder, known as a hohlraum, that holds a “capsule” of fuel material mounted in its center.  It’s what’s known as the indirect drive approach to ICF, as opposed to direct drive, in which the beams are focused directly on a target containing the fuel material.  When the beams hit the inside walls of the cylinder they generate a burst of x-rays.  These are what actually illuminate the target, causing it to implode to extremely high densities.  At just the right moment a “hot spot” is created in the very center of this dense, imploded fuel material, where fusion ignition begins.  The fusion reactions create alpha particles, helium nuclei containing two neutrons and two protons, which then smash into the surrounding “cold” fuel material, causing it to ignite as well, resulting in a “burn wave,” which spreads outward, igniting the rest of the fuel.  For this to happen, everything has to be just right.  The most important thing is that the implosion be almost perfectly symmetric, so that the capsule isn’t squished into a “pancake,” or squashed into a “sausage,” but is very nearly spherical at the point of highest density.

Obviously, everything wasn’t just right in the recently concluded ignition experiments.  There are many potential reasons for this.  Material blowing off the hohlraum walls could expand into the interior in unforeseen ways, intercepting some of the laser light and/or x-rays, resulting in asymmetric illumination of the capsule.  So-called laser/plasma interactions with abstruse names like stimulated Raman scattering, stimulated Brillouin scattering, and two plasmon decay, could be more significant than expected, absorbing laser light so as to prevent symmetric illumination and at the same time generating hot electrons that could potentially preheat the fuel, making it much more difficult to implode and ignite.  There are several other potential failure mechanisms, all of which are extremely difficult to model on even the most powerful computers, especially in all three dimensions.

LLNL isn’t throwing in the towel, though.  In fact, there are several promising alternatives to indirect drive with cylindrical hohlraums.  One that recently showed promise in experiments on the much smaller OMEGA laser system at the University of Rochester’s Laboratory for Laser Energetics (LLE) is substitution of “rugby ball” shaped targets in place of the “traditional” cylinders.  According to the paper cited in the link, these “exhibit advantages over cylinders, in terms of temperature and of symmetry control of the capsule implosion.”  LLNL could also try hitting the targets with “green” laser light instead of the current “blue.”  The laser light is initially “red,” but is currently doubled and then tripled in frequency by passing it through slabs of a special crystal material, shortening its wavelength to the shorter “blue” wavelength, which is absorbed more efficiently.  However, each time the wavelength is shortened, energy is lost.  If “green” light were used, as much as 4 megajoules of energy could be focused on the target instead of the current maximum of around 1.8.  If “green” is absorbed well enough and doesn’t set off excessive laser/plasma interactions, the additional energy just might be enough to do the trick.  Other possible approaches include direct drive, hitting the fuel containing target directly with the laser beams, and “fast ignitor,” in which a separate laser beam is used to ignite a hot spot on the outside of the “cold,” imploded fuel material instead of relying on the complicated central hot spot approach.

Regardless of whether ignition is achieved on the NIF or not, it will remain an extremely valuable experimental facility.  The reason?  Even without ignition it can generate extreme material conditions that are relevant to those that exist in exploding nuclear weapons.  As a result, it gives us a significant leg up over other nuclear weapons states in an era of no nuclear testing by enabling us to field experiments relevant to the effects of aging on the weapons in our stockpile, and suggesting ways to insure they remain safe and reliable.  Which brings us to the final topic of this post, the Advanced Hydrodynamic Facility, or AHF.

The possibility of building such a beast was actively discussed and studied back in the 90’s, but Google it now and you’ll turn up very little.  It would behoove us to start thinking seriously about it again.  In modern nuclear weapons, conventional explosives are used to implode a “pit” of fissile material to supercritical conditions.  The implosion must be highly symmetric or the pit will “fizzle,” failing to produce enough energy to set off the thermonuclear “secondary” of the weapon that produces most of the yield.  The biggest uncertainty we face in maintaining the safety and reliability of our stockpile is the degree to which the possible deterioration of explosives, fusing systems, etc., will impair the implosion of the pit.  Basically, an AHF would be a system of massive particle accelerators capable of generating bursts of hard x-rays, or, alternatively, protons, powerful enough to image the implosion of the fission “pit” of a nuclear weapon at multiple points in time and in three dimensions.  Currently we have facilities such as the Dual-Axis Radiographic Hydrodynamic Test Facility (DARHT) at Los Alamos National Laboratory (LANL), but it only enables us study the implosion of small samples of surrogate pit material.  An AHF would be able to image the implosion of actual pits, with physically similar surrogate materials replacing the fissile material.

Obviously, such experiments could not be conducted in a conventional laboratory.  Ideally, the facility would be built at a place like the Nevada Test Site (NTS) north of Las Vegas.  Experiments would be fielded underground in the same way that actual nuclear tests were once conducted there.  That would have the advantage of keeping us prepared to conduct actual nuclear tests within a reasonably short time if we should ever be forced to do so, for example, by the resumption of testing by other nuclear powers.  With an AHF we could be virtually certain that the pits of the weapons in our arsenal will work for an indefinite time into the future.  If the pit works, we will also be virtually certain that the secondary will work as well, and the reliability of the weapons in our stockpile will be assured.

Isn’t the AHF just a weaponeer’s wet dream?  Why is it really necessary?  Mainly because it would remove once and for all any credible argument for the resumption of nuclear testing.  Resumption of testing would certainly increase the nuclear danger to mankind, and, IMHO, is to be avoided at all costs.  Not everyone in the military and weapons communities agrees.  Some are champing at the bit for a resumption of testing.  They argue that our stockpile cannot be a reliable deterrent if we are not even sure if our weapons will still work.  With an AHF, we can be sure.  It’s high time for us to dust off those old studies and give some serious thought to building it.

ICF

No Ignition at the National Ignition Facility: A Post Mortem

The National Ignition Facility, or NIF, at Lawrence Livermore National Laboratory (LLNL) in California was designed and built, as its name implies, to achieve fusion ignition.  The first experimental campaign intended to achieve that goal, the National Ignition Campaign, or NIC, ended in failure.  Scientists at LLNL recently published a paper in the journal Physics of Plasmas outlining, to the best of their knowledge to date, why the experiments failed.  Entitled “Radiation hydrodynamics modeling of the highest compression inertial confinement fusion ignition experiment from the National Ignition Campaign,” the paper concedes that,

The recently completed National Ignition Campaign (NIC) on the National Ignition Facility (NIF) showed significant discrepancies between post-shot simulations of implosion performance and experimentally measured performance, particularly in thermonuclear yield.

To understand what went wrong, it’s necessary to know some facts about the fusion process and the nature of scientific attempts to achieve fusion in the laboratory.  Here’s the short version:  The neutrons and protons in an atomic nucleus are held together by the strong force, which is about 100 times stronger than the electromagnetic force, and operates only over tiny distances measured in femtometers.  The average binding energy per nucleon (proton or neutron) due to the strong force is greatest for the elements in the middle of the periodic table, and gradually decreases in the directions of both the lighter and heavier elements.  That’s why energy is released by fissioning heavy atoms like uranium into lighter atoms, or fusing light atoms like hydrogen into heavier atoms.  Fusion of light elements isn’t easy.  Before the strong force that holds atomic nuclei together can take effect, two light nuclei must be brought very close to each other.  However, atomic nuclei are all positively charged, and like charges repel.  The closer they get, the stronger the repulsion becomes.  The sun solves the problem with its crushing gravitational force.  On earth, the energy of fission can also provide the necessary force in nuclear weapons.  However, concentrating enough energy to accomplish the same thing in the laboratory has proved a great deal more difficult.

The problem is to confine incredibly hot material at sufficiently high densities for a long enough time for significant fusion to take place.  At the moment there are two mainstream approaches to solving it:  magnetic fusion and inertial confinement fusion, or ICF.  In the former, confinement is achieved with powerful magnetic lines of force.  That’s the approach at the international ITER fusion reactor project currently under construction in France.  In ICF, the idea is to first implode a small target of fuel material to extremely high density, and then heat it to the necessary high temperature so quickly that its own inertia holds it in place long enough for fusion to happen.  That’s the approach being pursued at the NIF.

The NIF consists of 192 powerful laser beams, which can concentrate about 1.8 megajoules of light on a tiny spot, delivering all that energy in a time of only a few nanoseconds.  It is much larger than the next biggest similar facility, the OMEGA laser system at the Laboratory for Laser Energetics in Rochester, NY, which maxes out at about 40 kilojoules.  The NIC experiments were indirect drive experiments, meaning that the lasers weren’t aimed directly at the BB-sized, spherical target, or “capsule,” containing the fuel material (a mixture of deuterium and tritium, two heavy isotopes of hydrogen).  Instead, the target was mounted inside of a tiny, cylindrical enclosure known as a hohlraum with the aid of a thin, plastic “tent.”  The lasers were fired through holes on each end of the hohlraum, striking the walls of the cylinder, generating a pulse of x-rays.  These x-rays then struck the target, ablating material from its surface at high speed.  In a manner similar to a rocket exhaust, this drove the remaining target material inward, causing it to implode to extremely high densities, about 40 times heavier than the heaviest naturally occurring elements.  As it implodes, the material must be kept as “cold” as possible, because it’s easier to squeeze and compress things that are cold than those that are hot.  However, when it reaches maximum density, a way must be found to heat a small fraction of this “cold” material to the very high temperatures needed for significant fusion to occur.  This is accomplished by setting off a series of shocks during the implosion process that converge at the center of the target at just the right time, generating the necessary “hot spot.”  The resulting fusion reactions release highly energetic alpha particles, which spread out into the surrounding “cold” material, heating it and causing it to fuse as well, in a “burn wave” that propagates outward.  “Ignition” occurs when the amount of fusion energy released in this way is equal to the energy in the laser beams that drove the target.

As noted above, things didn’t go as planned.  The actual fusion yield achieved in the best experiment was less than that predicted by the best radiation hydrodynamics computer codes available at the time by a factor of about 50, give or take.  The LLNL paper in Physics of Plasmas discusses some of the reasons for this, and describes subsequent improvements to the codes that account for some, but not all, of the experimental discrepancies.  According to the paper,

Since these simulation studies were completed, experiments have continued on NIF and have identified several important effects – absent in the previous simulations – that have the potential to resolve at least some of the large discrepancies between simulated and experimental yields.  Briefly, these effects include larger than anticipated low-mode distortions of the imploded core – due primarily to asymmetries in the x-ray flux incident on the capsule, – a larger than anticipated perturbation to the implosion caused by the thin plastic membrane or “tent” used to support the capsule in the hohlraum prior to the shot, and the presence, in some cases, of larger than expected amounts of ablator material mixed into the hot spot.

In a later section, the LLNL scientists also note,

Since this study was undertaken, some evidence has also arisen suggesting an additional perturbation source other than the three specifically considered here.  That is, larger than anticipated fuel pre-heat due to energetic electrons produced from laser-plasma interactions in the hohlraum.

In simple terms, the first of these passages means that the implosions weren’t symmetric enough, and the second means that the fuel may not have been “cold” enough during the implosion process.  Any variation from perfectly spherical symmetry during the implosion can rob energy from the central hot spot, allow material to escape before fusion can occur, mix cold fuel material into the hot spot, quenching it, etc., potentially causing the experiment to fail.  The asymmetries in the x-ray flux mentioned in the paper mean that the target surface would have been pushed harder in some places than in others, resulting in asymmetries to the implosion itself.  A larger than anticipated perturbation due to the “tent” would have seeded instabilities, such as the Rayleigh-Taylor instability.  Imagine holding a straw filled with water upside down.  Atmospheric pressure will prevent the water from running out.  Now imagine filling a perfectly cylindrical bucket with water to the same depth.  If you hold it upside down, the atmospheric pressure over the surface of the water is the same.  Based on the straw experiment, the water should stay in the bucket, just as it did in the straw.  Nevertheless, the water comes pouring out.  As they say in the physics business, the straw experiment doesn’t “scale.”  The reason for this anomaly is the Rayleigh-Taylor instability.  Over such a large surface, small variations from perfect smoothness are gradually amplified, growing to the point that the surface becomes “unstable,” and the water comes splashing out.  Another, related instability, the Richtmeyer-Meshkov instability, leads to similar results in material where shocks are present, as in the NIF experiments.

Now, with the benefit of hindsight, it’s interesting to look back at some of the events leading up to the decision to build the NIF.  At the time, government used a “key decision” process to approve major proposed projects.  The first key decision, known as Key Decision 0, or KD0, was approval to go forward with conceptual design.  The second was KD1, approval of engineering design and acquisition.  There were more “key decisions” in the process, but after passing KD1, it could safely be assumed that most projects were “in the bag.”  In the early 90’s, a federal advisory committee, known as the Inertial Confinement Fusion Advisory Committee, or ICFAC, had been formed to advise the responsible agency, the Department of Energy (DOE), on matters relating to the national ICF program.  Among other things, its mandate including advising the government on whether it should proceed with key decisions on the NIF project.  The Committee’s advice was normally followed by DOE.

At the time, there were six major “program elements” in the national ICF program.  These included the three weapons laboratories, LLNL, Los Alamos National Laboratory (LANL), and Sandia National Laboratories (SNL).  The remaining three included the Laboratory for Laser Energetics at the University of Rochester (UR/LLE), the Naval Research Laboratory (NRL), and General Atomics (GA).  Spokespersons from all these “program elements” appeared before the ICFAC at a series of meetings in the early 90’s.  The critical meeting as far as approval of the decision to pass through KD1 is concerned took place in May 1994.  Prior to that time, extensive experimental programs at LLNL’s Nova laser, UR/LLE’s OMEGA, and a host of other facilities had been conducted to address potential uncertainties concerning whether the NIF could achieve ignition.  The best computer codes available at the time had modeled proposed ignition targets, and predicted that several different designs would ignite, typically producing “gains,” the ratio of the fusion energy out to the laser energy in, of from 1 to 10.  There was just one major fly in the ointment – a brilliant physicist named Steve Bodner, who directed the ICF program at NRL at the time.

Bodner told the ICFAC that the chances of achieving ignition on the NIF were minimal, providing his reasons in the form of a detailed physics analysis.  Among other things, he noted that there was no way of controlling the symmetry because of blow-off of material from the hohlraum wall, which could absorb both laser light and x-rays.  Ablated material from the capsule itself could also absorb laser and x-ray radiation, again destroying symmetry.  He pointed out that codes had raised the possibility of pressure perturbations on the capsule surface due to stagnation of the blow-off material on the hohlraum axis.  LLNL’s response was that these problems could be successfully addressed by filling the hohlraum with a gas such as helium, which would hold back the blow-off from the walls and target.  Bodner replied that such “solutions” had never really been tested because of the inability to do experiments on Nova with sufficient pulse length.  In other words, it was impossible to conduct experiments that would “scale” to the NIF on existing facilities.  In building the NIF, we might be passing from the “straw” to the “bucket.”  He noted several other areas of major uncertainty with NIF-scale targets, such as the possibility of unaccounted for reflection of the laser light, and the possibility of major perturbations due to so-called laser-plasma instabilities.

In light of these uncertainties, Bodner suggested delaying approval of KD1 for a year or two until these issues could be more carefully studied.  At that point, we may have gained the technological confidence to proceed.  However, I suspect he knew that two years would never be enough to resolve the issues he had raised.  What Bodner really wanted to do was build a much larger facility, known as the Laboratory Microfusion Facility, or LMF.  The LMF would have a driver energy of from 5 to 10 megajoules compared to the NIF’s 1.8.  It had been seriously discussed in the late 80’s and early 90’s.  Potentially, such a facility could be built with Bodner’s favored KrF laser drivers, the kind used on the Nike laser system at NRL, instead of the glass lasers that had been chosen for NIF.  It would be powerful enough to erase the physics uncertainties he had raised by “brute force.”  Bodner’s proposed approach was plausible and reasonable.  It was also a forlorn hope.

Funding for the ICF program had been cut in the early 90’s.  Chances of gaining approval for a beast as expensive as LMF were minimal.  As a result, it was now officially considered a “follow-on” facility to the NIF.  No one took this seriously at the time.  Everyone knew that, if NIF failed, there would be no “follow-on.”  Bodner knew this, the scientists at the other program elements knew it, and so did the members of the ICFAC.  The ICFAC was composed of brilliant scientists.  However, none of them had any real insight into the guts of the computer codes that were predicting ignition on the NIF.  Still, they had to choose between the results of the big codes, and Bodner’s physical insight bolstered by what were, in comparison, “back of the envelope” calculations.  They chose the big codes.  With the exception of Tim Coffey, then Director of NRL, they voted to approve passing through KD1 at the May meeting.

In retrospect, Bodner’s objections seem prophetic.  The NIC has failed, and he was not far off the mark concerning the reasons for the failure.  It’s easy to construe the whole affair as a morality tale, with Bodner playing the role of neglected Cassandra, and the LLNL scientists villains whose overweening technological hubris finally collided with the grim realities of physics.  Things aren’t that simple.  The LLNL people, not to mention the supporters of NIF from the other program elements, included many responsible and brilliant scientists.  They were not as pessimistic as Bodner, but none of them was 100% positive that the NIF would succeed.  They decided the risk was warranted, and they may well yet prove to be right.

In the first place, as noted above, chances that an LMF might be substituted for the NIF after another year or two of study were very slim.  The funding just wasn’t there.  Indeed, the number of laser beams on the NIF itself had been reduced from the originally proposed 240 to 192, at least in part, for that very reason.  It was basically a question of the NIF or nothing.  Studying the problem to death, now such a typical feature of the culture at our national research laboratories, would have led nowhere.  The NIF was never conceived as an energy project, although many scientists preferred to see it in that light.  Rather, it was built to serve the national nuclear weapons program.  It’s supporters were aware that it would be of great value to that program even if it didn’t achieve ignition.  In fact, it is, and is now providing us with a technological advantage that rival nuclear powers can’t match in this post-testing era.  Furthermore, LLNL and the other weapons laboratories were up against another problem – what you might call a demographic cliff.  The old, testing-era weapons designers were getting decidedly long in the tooth, and it was necessary to find some way to attract new talent.  A facility like the NIF, capable of exploring issues in inertial fusion energy, astrophysics, and other non-weapons-related areas of high energy density physics, would certainly help address that problem as well.

Finally, the results of the NIC in no way “proved” that ignition on the NIF is impossible.  There are alternatives to the current indirect drive approach with frequency-tripled “blue” laser beams.  Much more energy, up to around 4 megajoules, might be available if the known problems of using longer wavelength “green” light can be solved.  Thanks to theoretical and experimental work done by the ICF team at UR/LLE under the leadership of Dr. Robert McCrory, the possibility of direct drive experiments on the NIF, hitting the target directly instead of shooting the laser beams into a “hohlraum” can, was also left open, using a so-called “polar” illumination approach.  Another possibility is the “fast ignitor” approach to ICF, which would dispense with the need for complicated converging shocks to produce a central “hot spot.”  Instead, once the target had achieved maximum density, the hot spot would be created on the outer surface using a separate driver beam.

In other words, while the results of the NIC are disappointing, stay tuned.  Pace Dr. Bodner, the scientists at LLNL may yet pull a rabbit out of their hats.

ICF

Nuclear Power and the Anti-Science Ideology of the “Progressive” Left

The ideological Left is fond of accusing the Right of being “anti-science.”  The evidence often comes in the form of Exhibit A (climate denialism) and Exhibit B (Darwin denialism).  True, these maladies are encountered more frequently on the Right than on the Left.  As it happens, however, there are also scientific allergies on the Left, and there is little question that they have been a great deal more damaging than their conservative analogs.  The best example is probably the Blank Slate debacle.  In order to prop up leftist shibboleths, denial of the very existence of human nature was enforced for more than half a century.  The effect on the behavioral sciences, and with them the self-knowledge critical to our very survival, was devastating.  “Scientific” Marxism-Leninism is another obvious example.  However, when it comes to scientific allergies, the Left’s irrational and often fanatical opposition to nuclear power may turn out to be the most damaging of all.

Those who seek to alarm us about rising CO2 levels in the atmosphere, and yet reject the most effective technology for bringing them under control, are not serious.  They are mere poseurs.  Thanks to these anti-science attitudes on the Left, dozens of dirty, coal-fired power plants will be built in Germany alone to replace the baseload generating capacity once provided by nuclear reactors.  The situation is no better in the U.S.  Both countries have developed some of the most advanced, not to mention safest, nuclear technologies known to man, and yet both, hamstrung by opposition coming from the Left of the political spectrum, have abdicated the responsibility to apply that knowledge.  Instead, they are exporting it – to China.

As I write this, we are helping China to build a novel type of reactor that combines molten salt technology developed in the United States with a version of the “pebble” type fuel pioneered by the Germans.  Approved in 2011, the original target completion date of 2015 has now slipped to 2020, but both goals would be out of the question in the byzantine regulatory atmosphere of the 21st century United States.  U.S. knowhow will also be used to build the novel “traveling wave” reactor design favored by Bill Gates – also in China.  The Chinese are also actively pursuing the high temperature gas-cooled reactor (HTGR) technology that was proposed for the ill-fated Next Generation Nuclear Plant (NGNP), further development of which was recently cancelled in the United States.

I certainly have nothing against China building advanced reactors using technology that was developed elsewhere.  It’s good that the knowledge in question is being applied at least somewhere on the planet.  However, I find it unfortunate that we no longer have the leadership, vision, or political will to do so ourselves.  It was not always so.  The U.S. commissioned the world’s first nuclear powered submarine, the U.S.S. Nautilus, in 1954, little more than a decade after the successful demonstration of the first self-sustaining nuclear chain reaction at the University of Chicago.  More than 50 experimental nuclear reactors were built at what is now Idaho National Laboratory (INL) in a period of about two decades stretching from the 50’s to the mid-70’s.  None has been built since.  The situation is similar at Oak Ridge National Laboratory (ORNL), site of the world’s first molten salt reactor.  Instead of working, next generation reactors, INL, ORNL, and the rest of the U.S. national laboratories now turn out only paper studies – gigantic mounds of them – in quantities that would probably stretch to the moon and back by now.  The chances that any of them will ever be usefully applied in this country are slim and none.

The technologies in question are not mere incremental improvements over the conventional nuclear power plants that now produce almost all the world’s nuclear power.  They have the demonstrated capacity to extract more than an order of magnitude more energy out of a given quantity of mined fuel material than conventional designs.  They can burn the long-lived radioactive actinides and other hazardous isotopes produced in nuclear fission that represent the most dangerous types of radioactive waste, reducing the residual radioactivity from operation of a nuclear plant to a level less than that of the original uranium ore is less than 500 years – a far cry from the millions of years often cited by hysterical anti-nukers.  Under the circumstances, it is worth taking note of where the opposition that stopped the development and application of these technologies in the past, and continues to do so today, is coming from.

The regulatory nightmare that has brought the continued development of these technologies in the United States to a virtual standstill is primarily the legacy of the “progressive” Left.  The anti-nuclear zealots on that side of the political spectrum cling to bogus linear no-threshold models of radioactive hazard, grotesquely exaggerated horror stories about the supposed impossibility of dealing with nuclear waste, and a stubborn cluelessness about the dangers of the alternative coal and other fossil-fired technologies that their opposition to nuclear will inevitably continue to promote in spite of all their strident denials.  These are facts that it would be well to keep in mind the next time you hear the Left calling the Right “anti-science,” or, for that matter, the next time you hear them pontificating about their deep commitment to the fight against global warming.

Do We Really Need New Nukes?

If an article that just appeared in the LA Times is any indication, the agitation for jump-starting the nuclear weapons program at the Department of Energy (DOE) and the three nuclear weapons laboratories (Lawrence Livermore, Los Alamos, and Sandia National Laboratories) continues unabated. Entitled “New nuclear weapons needed, many experts say, pointing to aged arsenal,” it cites all the usual talking points of the weaponeers. For example,

Warheads in the nation’s stockpile are an average of 27 years old, which raises serious concerns about their reliability, they say. Provocative nuclear threats by Russian President Vladimir Putin have added to the pressure to not only design new weapons but conduct underground tests for the first time since 1992.

“It seems like common sense to me if you’re trying to keep an aging machine alive that’s well past its design life, then you’re treading on thin ice,” said Rep. Mac Thornberry (R-Texas), chairman-elect of the House Armed Services Committee. “Not to mention, we’re spending more and more to keep these things going.”

Thornbury also offered support for renewed testing, saying, “You don’t know how a car performs unless you turn the key over. Why would we accept anything less from a weapon that provides the foundation for which all our national security is based on?”

Such comments are entirely typical. They would make a lot of sense if the U.S. nuclear weapons program existed in a vacuum. However, it doesn’t. It exists in a world with several other major nuclear powers, and they all have the same problems. Under the circumstances, the fact that such problems exist and are shared by all the nuclear powers is less significant than the question of which nuclear power is best equipped to deal with them. The question of who will benefit by the building of new weapons and a resumption of nuclear testing depends on the answer to that question. If one country has a significant advantage over its rivals in dealing with a common problem as long as the status quo is maintained, then it would be very ill-advised to initiate a change to the status quo that would allow them to catch up.  At the moment, the United States is the country with an advantage. As noted in the article,

The U.S. has by far the greatest archive of test data, having conducted 1,032 nuclear tests. Russia conducted 715 and China only 45.

Beyond that, we have the ability to conduct tests with conventional explosives that mimic what goes on in the initial stages of a nuclear explosion, and superb diagnostics to extract a maximum of data from those tests. Perhaps more importantly, we have an unrivaled above ground experimental, or AGEX, capability. I refer to machines like Z at Sandia National Laboratories, or the NIF at Livermore, which are far more capable and powerful than similar facilities anywhere else in the world. Those who say they can’t access physical conditions relevant to those that occur in exploding nuclear weapons, or that they are useless for weapon effects or weapon physics experiments, either don’t know what they’re talking about or are attempting to deceive.

As far as the NIF is concerned, it is quite true that it has so far failed to achieve its fusion ignition milestone, but that by no means rules out the possibility that it ever will. More importantly, the NIF will remain a highly useful AGEX facility whether it achieves ignition or not. Indeed, before it was built, many of the weapons designers showed little interest in ignition. It would merely “muddy the waters,” making it more difficult for the diagnostics to precisely record the results of an experiment. The NIF could access weapons-relevant conditions without it. In fact, in spite of its failure to achieve ignition to date, the NIF has been a spectacular success as far as achieving its specifications are concerned. It is more than an order of magnitude more powerful than any previously existing laser system, its 192 laser beams are highly accurate, and its diagnostic suite is superb.

Another problem with the resumption of testing is that it will lead to the development of weapons that are much more likely to be used. Once the nuclear genie is out of the bottle, it will likely prove very difficult to put it back in. For example, again quoting the article,

John S. Foster Jr., former director of Lawrence Livermore National Laboratory and chief of Pentagon research during the Cold War, said the labs should design, develop and build prototype weapons that may be needed by the military in the future, including a very low-yield nuclear weapon that could be used with precision delivery systems, an electromagnetic pulse weapon that could destroy an enemy’s communications systems and a penetrating weapon to destroy deeply buried targets.

The commonly heard narrative at DOE goes something like this: “We need to develop small, precise, penetrating nuclear weapons because they will be a much better deterrent than the existing ones. Potential enemies are unlikely to believe that we would ever use one of the high yield weapons that are all that remain in the current arsenal. They would be far more likely to believe that we might use a small bunker buster that would minimize the possibility of significant collateral damage.” The problem with that narrative is that it’s true. We would be far more likely to use such a weapon than the ones in the current arsenal, and there would be no lack of voices within DOE and DoD calling for its use if an appropriate opportunity ever arose.

I can understand the agitation for a resumption of testing. It’s a lot sexier to make things that go boom than to serve as custodians for an aging pile of existing nukes. Unfortunately, the latter course is the wiser one. By resuming nuclear testing we would really be unilaterally surrendering a huge advantage, playing into the hands of our enemies and destabilizing the nuclear landscape at the same time.

Of Smug Germans and Sinful Australians: Global Warming Update

No doubt the outcome of the Nazi unpleasantness resulted in attitude adjustment in Germany on a rather large scale.  Clearly, however, it didn’t teach the Germans humility.  At a time when a secular mutation of Puritanism has become the dominant ideology in much of Europe and North America, the Germans take the cake for pathological piety.  Not that long ago the fashionable evil de jour was the United States, and anti-American hate mongering in the German media reached levels that would make your toes curl.  In the last years of the Clinton and the first years of the following Bush administrations it was often difficult to find anything about Germany on the home pages of popular German news magazines like Der Spiegel because the available space was taken up by furious rants against the United States for the latest failures to live up to German standards of virtue.  Eventually the anti-American jihad choked on its own excess, and other scapegoats were found. Clearly, however, German puritanism is still alive and well.  An amusing example just turned up in the Sydney Morning Herald under the headline, “Merkel adviser lashes Abbott’s ‘suicide strategy’ on coal.”  The advisor in question was one Hans Joachim Schellnhuber, Chancellor Merkel’s lead climate advisor.  A picture of him posing as the apotheosis of smugness accompanies the article, according to which he,

…attacked Australia’s complacency on global warming and described the Abbott government’s championing of the coal industry as an economic “suicide strategy”.

Alas, we learn that Schellnhuber’s anathemas also fell on our neighbor to the north.  The SMH quotes him as saying,

Similar to Canada, Australia for the time being is not part of the international community which is cooperating to achieve greenhouse gas emission reductions.

Tears run down our cheeks as Schellnhuber describes Australia’s fall from grace:

 …it had been disappointing to see Australia’s retreat on climate policy after it became “the darling of the world” when Kevin Rudd ratified the Kyoto Protocol in 2007.

As readers who were around at the time may recall, the Kyoto Protocol conformed perfectly to German standards of “fairness.”  It would have required states like The United States and Canada to meet exactly the same percentage reduction in emissions from the base year 1990 as the countries in the European Union, in spite of the fact that their economies had expanded at a faster rate than most of Europe’s during the period, they did not enjoy the same access to cheap, clean-burning natural gas as the Europeans in those pre-fracking days, and, “fairest” of all, they weren’t the beneficiaries of massive emission reductions from the closing of obsolete east European factories following the demise of Communism.  In other words, it was “fair” for the US and Canada to shed tens of thousands of manufacturing jobs in order to meet grossly disproportionate emissions standards while Germany and the rest of the Europeans cheered from the sidelines.

What is one to think of this latest instance of ostentatious German piety?  I don’t know whether to laugh or cry.  For one thing, the apparent concern about climate change in Germany is about 99% moralistic posing and 1% real.  Solzhenitsyn used a word in The First Circle that describes the phenomenon very well; sharashka.  Basically, it’s a lie so big that even those telling it eventually begin to believe it.  The German decision to shut down their nuclear power plants demonstrated quite clearly that they’re not serious about fighting global warming.  Base load sources of energy are needed for when renewables are unavailable because the wind isn’t blowing or the sun isn’t shining.  Practical alternatives for filling in the gaps include nuclear and fossil fuel.  Germany has rejected the former and chosen one of the dirtiest forms of the latter; coal-fired plants using her own sources of lignite.  She plans to build no less than 26 of them in the coming years!

It’s stunning, really.  These plants will pump millions of tons of CO2 and other greenhouse gases into the atmosphere that wouldn’t have been there if Germany had kept her nuclear plants on line.  Not only that, they represent a far greater radioactive danger than nuclear plants, because coal contains several parts per million of radioactive thorium and uranium.  The extent of German chutzpah is further demonstrated by a glance at recent emission numbers.  Germany is now the worst polluter in the EU.  Her CO2 emissions have risen substantially lately, due mainly to those new lignite plants beginning to come on line.  Coal-generated energy in Germany is now around 50% of the mix, the highest it’s been since 1990.  Even as the German government shook its collective head at the sinful Australians, telling them to mend their evil ways or bear the guilt for wars and revolution, not to mention the bleaching of the coral in the Great Barrier Reef, her own CO2 emission rose 1.5% in 2013 over the previous year, while Australia’s fell by 0.8% in the same period!

In a word, dear reader, for the German “Greens,” the pose is everything, and the reality nothing.

Comments on Some Comments on the National Ignition Facility

We live in a dauntingly complex world.  Progress in the world of science is relevant to all of us, yet it is extremely difficult, although certainly not impossible, for the intelligent layperson to gain a useful understanding of what is actually going on.  I say “not impossible” because I believe it’s possible for non-experts to gain enough knowledge to usefully contribute to the conversation about the technological and social relevance of a given scientific specialty, if not of its abstruse details, assuming they are willing to put in the effort.  Indeed, when it comes to social relevance it’s not out of the question for them to become more knowledgeable than the scientists themselves, narrowly focused as they often are on a particular specialty.

To illustrate my point, I invite my readers to take a look at a post that recently appeared on the blog LLNL – The True Story.  LLNL, or Lawrence Livermore National Laboratory, is one of the nation’s three major nuclear weapons research laboratories.  It is also home of the National Ignition Facility, which, as its name implies, was designed to achieve fusion “ignition” by focusing a giant assembly of 192 powerful laser beams on tiny targets containing a mixture of deuterium and tritium fuel.  The process itself is called inertial confinement fusion, or ICF.  Ignition is variously defined, but as far as the NIF is concerned LLNL officially accepted the definition as fusion energy out equal to total laser energy in, in the presence of members of a National Academy of Sciences oversight committee.  This is a definition that puts it on a level playing field with the competing magnetic confinement approach to fusion.

According to the blurb that appears on the home page of LLNL – The True Story, its purpose is “for LLNL present and past employees, friends of LLNL and anyone impacted by the privatization of the Lab to express their opinions and expose the waste, wrongdoing and any kind of injustice against employees and taxpayers by LLNS/DOE/NNSA.”  The post in question is entitled ICF Program is now Officially Owned by WCI (Weapons and Concepts Integration).  It’s certainly harmless enough as it stands, consisting only of the line,

ICF program is now officially owned by WCI.  A step forward or an attempt to bury it out of sight?

This is followed by an apparently broken link to the story referred to.  This gist can probably be found here.  Presumably the author suspects LLNL might want to “bury it out of sight” because the first attempt to achieve ignition, known as the National Ignition Campaign, or NIC, failed to achieve its goal.  What’s really of interest is not the post itself, but the comments following it.  The commenters are all listed as “anonymous,” but given the nature of the blog we can probably assume that most of them are scientists of one tribe or another.  Let’s take a look at what they have to say.  According to the first “anonymous,”

If (takeover of NIF by WCI) is an attempt to keep funding flowing by switching milestones from energy independence to weapons research.  “Contingency Plan B”.

Another “anonymous” writes in a similar vein:

Reading between the lines it is clear that the new energy source mission of the NIF is over and now it’s time to justify the unjustifiable costs by claiming it’s a great too for weapons research.

Perhaps the second commenter would have done better to read the lines as they stand rather than between them.  In that case he would have noticed that energy independence was never an official NIF milestone, not to mention its “mission.”  NIF was funded for the purpose of weapons research from the start.  This fact was never in any way a deep, dark secret, and has long been obvious to anyone willing to take the trouble to consult the relevant publicly accessible documents.  The Inertial Confinement Fusion Advisory Committee, a Federal Advisory Committee that met intermittently in the early to mid-90’s, and whose member included a bevy of heavyweights in plasma physics and related specialties, was certainly aware of the fact, and recommended funding of the facility with the single dissenting vote of Tim Coffey, then Director of the Naval Research Laboratory, based on that awareness.

Be that as it may, the claim that the technology could also end our dependence on fossil fuel, often made by the NIF’s defenders, is credible.  By “credible” I mean that many highly capable scientists have long held and continue to hold that opinion.  As it happens, I don’t.  Assuming we find a way to achieve ignition and high gain in the laboratory, it will certainly become scientifically feasible to generate energy with ICF power plants.  However, IMHO it will never be economically feasible, for reasons I have outline in earlier posts.  Regardless, from a public relations standpoint, it was obviously preferable to evoke the potential of the NIF as a clean source of energy rather than a weapons project designed to maintain the safety and reliability of our nuclear arsenal, as essential as that capability may actually be.  In spite of my own personal opinion on the subject, these claims were neither disingenuous nor mere “hype.”

Another “anonymous” writes,

What’s this user facility bullshit about?  Only Livermore uses the facility.  Cost recovery demands that a university would have to pay $1 million for a shot.  How can it be a user facility if it’s run by the weapons program?  This isn’t exactly SLAC we’re talking about.

Here, again, the commenter is simply wrong.  Livermore is not the only user of NIF, and it is, in fact, a user facility.  Users to date include a team from MIT headed by Prof. Richard Petrasso.  I’m not sure how the users are currently funded, but in the past funds for experiments on similar facilities were allocated through a proposal process, similar to that used to fund other government-funded academic research.  The commenter continues,

By the way, let’s assume NIF wants to be a “user facility” for stockpile stewardship.  Since ignition is impossible, the EOS (Equation of State, relevant to the physics of nuclear weapons, ed.) work is garbage, and the temperatures are not relevant to anything that goes bang, what use is this machine?

NIF does not “want to be a user facility for stockpile stewardship.”  Stress has always been on high energy density physics (HEDP), which has many other potential applications besides stockpile stewardship.  I was not surprised that NIF did not achieve ignition immediately.  In fact I predicted as much in a post on this blog two years before the facility became operational.  However, many highly competent scientists disagreed with me, and for credible scientific reasons.  The idea that ignition is “impossible” just because it wasn’t achieved in the first ignition campaign using the indirect drive approach is nonsense.  Several other credible approaches have not yet even been tried, including polar direct drive, fast ignitor, and hitting the targets with green (frequency doubled) rather than blue (frequency tripled) light.  The latter approach would enable a substantial increase in the available laser energy on target.  The EOS work is not garbage, as any competent weapons designer will confirm as long as they are not determined to force the resumption of nuclear testing by hook or by crook, and some of the best scientists at Livermore confirmed long ago that the temperatures  achievable on the NIF are indeed relevant to things that go bang, whether it achieves ignition or not.  In fact, the facility allows us to access physical conditions that can be approached in the laboratory nowhere else on earth, giving us a significant leg up over the international competition in maintaining a safe and reliable arsenal, as long as testing is not resumed.

Anonymous number 4 chimes in,

I love this quote (apparently from the linked article, ed.):

“the demonstration of laboratory ignition and its use to support the Stockpile Stewardship Program (SSP) is a major goal for this program”

Hey guys, this has already failed.  Why are we still spending money on this?  A lot of other laboratories could use the $$.  You’re done.

The quote this “anonymous” loves is a simple statement of fact.  For the reasons already cited, the idea that ignition on the NIF is hopeless is nonsense.  The (very good) reason we’re still spending money on the project is that NIF is and will continue into the foreseeable future to be one of the most capable and effective above ground experimental (AGEX) facilities in the world.  It can access physical conditions relevant to nuclear weapons regardless of whether it achieves ignition or not.  For that reason it is an invaluable tool for maintaining our arsenal unless one’s agenda happens to be the resumption of nuclear testing.  Hint:  The idea that no one in DOE, NNSA, or the national weapons laboratories wants to resume testing belongs in the realm of fantasy.  Consider, for example, what the next “anonymous” is actually suggesting:

Attempting to get funding for NIF and computations’s big machines was made easier by claiming dual purposes but I always felt that the real down and dirty main purpose was weapons research.  If you want to get support from the anti-weapon Feinstein/Boxer/Pelosi contingent you need to put the “energy” lipstick on the pig.  Or we could go back to testing.  Our cessation of testing doesn’t seem to have deterred North Korea and Iran that much.

Yes, Virginia, even scientists occasionally do have agendas of their own.  What can I say?  To begin, I suppose, that one should never be intimidated by the pontifications of scientists.  The specimens on display here clearly don’t have a clue what they’re talking about.  Any non-technical observer of middling intelligence could become more knowledgeable than they are on the topics they’re discussing by devoting a few hours to researching them on the web.  As to how the non-technical observer is to acquire enough knowledge to actually know that he knows more than the scientific specialists, I can offer no advice, other than to head to your local university and acquire a Ph.D.  I am, BTW, neither employed by nor connected in any other way with LLNL.

 

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.