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  • Fisking a Fusion Fata Morgana

    Posted on April 10th, 2018 Helian 2 comments

    Why is it that popular science articles about fusion energy are always so cringe-worthy? Is scientific illiteracy a prerequisite for writing them? Take the latest one to hit the streets, for example. Entitled Lockheed Martin Now Has a Patent For Its Potentially World Changing Fusion Reactor, it had all the familiar “unlimited energy is just around the corner” hubris we’ve come to expect in articles about fusion. When I finished reading it I wondered whether the author imagined all that nonsense on his own, or some devilish plasma physicist put him up to it as a practical joke. The fun starts in the first paragraph, where we are assured that,

    If this project has been progressing on schedule, the company could debut a prototype system that size of shipping container, but capable of powering a Nimitz-class aircraft carrier or 80,000 homes, sometime in the next year or so.

    Trust me, dear reader, barring divine intervention no such prototype system, capable of both generating electric energy and fitting within a volume anywhere near that of a shipping container, will debut in the next year, or the next five years, or the next ten years.  Reading on, we learn that,

    Unlike in nuclear fission, where atoms hit each other release energy, a fusion reaction involves heating up a gaseous fuel to the point where its atomic structure gets disrupted from the pressure and some of the particles fuse into a heavier nucleus.

    Well, not really.  Fission is caused by free neutrons, not by “atoms hitting each other.”  It would actually be more accurate to say that fusion takes place when “atoms hit each other,” although it’s really the atomic nuclei that “hit” each other.  Fusion doesn’t involve “atomic structure getting disrupted from pressure.” Rather, it happens when atoms acquire enough energy to overcome the Coulomb repulsion between two positively charged atomic nuclei (remember, like charges repel), and come within a sufficiently short distance of each other for the much greater strong nuclear force of attraction to take over. According to the author,

    But to do this you need to be able to hold the gas, which is eventually in a highly energized plasma state, for a protracted period of time at a temperature of hundreds of millions of degrees Fahrenheit.

    This is like claiming that a solid can be in a liquid state. A plasma is not a gas. It is a fourth state of matter quite unlike the three (solid, liquid, gas) that most of us are familiar with. Shortly thereafter we are assured that,

    Running on approximately 25 pounds of fuel – a mixture of hydrogen isotopes deuterium and tritium – Lockheed Martin estimated the notional reactor would be able to run for an entire year without stopping. The device would be able to generate a constant 100 megawatts of power during that period.

    25 pounds of fuel would include about 15 pounds of tritium, a radioactive isotope of hydrogen with a half-life of just over 12 years. In other words, its atoms decay about 2000 times faster than those of the plutonium 239 found in nuclear weapons.  It’s true that the beta particle (electron) emitted in tritium decay is quite low energy by nuclear standards but, as noted in Wiki, “Tritium is an isotope of hydrogen, which allows it to readily bind to hydroxyl radicals, forming tritiated water (HTO), and to carbon atoms. Since tritium is a low energy beta emitter, it is not dangerous externally (its beta particles are unable to penetrate the skin), but it can be a radiation hazard when inhaled, ingested via food or water, or absorbed through the skin.”  Obviously, water and many carbon compounds can be easily inhaled or ingested. Tritium is anything but benign if released into the environment. Here we will charitably assume that the author didn’t mean to say that 25 pounds of fuel would be available all at once, but would be bred gradually and then consumed as fuel in the reactor during operation.  The amount present at any given time would more appropriately be measured in grams than in pounds.  The article continues with rosy scenarios that might have been lifted from a “Back to the Future” movie:

    Those same benefits could apply to vehicles on land, ships at sea, or craft in space, providing nearly unlimited power in compact form allowing for operations across large areas, effectively eliminating the tyranny of distance in many cases. Again, for military applications, unmanned ground vehicles or ships could patrol indefinitely far removed from traditional logistics chains and satellites could conduct long-term, resource intensive activities without the need for large and potentially dangerous fission reactors.

    Great shades of “Dr. Fusion!” Let’s just say that “vehicles on land” is a bit of a stretch. I can only hope that no Lockheed engineer was mean-spirited enough to feed the author such nonsense. Moving right along, we read,

    Therein lies perhaps the biggest potential benefits of nuclear fusion over fission. It’s produces no emissions dangerous to the ozone layer and if the system fails it doesn’t pose nearly the same threat of a large scale radiological incident. Both deuterium and tritium are commonly found in a number of regular commercial applications and are relatively harmless in low doses.

    I have no idea what “emission” of the fission process the author thinks is “dangerous to the ozone layer.” Again, as noted above, tritium is anything but “relatively harmless” if ingested. Next we find perhaps the worst piece of disinformation of all:

    And since a fusion reactor doesn’t need refined fissile material, its much harder for it to serve as a starting place for a nuclear weapons program.

    Good grief, the highly energetic neutrons produced in a fusion reactor are not only capable of breeding tritium, but plutonium 239 and uranium 233 from naturally occurring uranium and thorium as well.  Both are superb explosive fuels for nuclear weapons.  And tritium?  It is used in a process known as “boosting” to improve the performance of nuclear weapons.  Finally, we run into what might be called the Achilles heel of all tritium-based fusion reactor designs:

    Fuel would also be abundant and relatively easy to source, since sea water provides a nearly unlimited source of deuterium, while there are ready sources of lithium to provide the starting place for scientists to “breed” tritium.

    I think not. Breeding tritium will be anything but a piece of cake.  The process will involve capturing the neutrons produced by the fusion reactions in a lithium blanket surrounding the reactor, doing so efficiently enough to generate more tritium from the resulting reactions than the reactor consumes as fuel, and then extracting the tritium and recycling it into the reactor without releasing any of the slippery stuff into the environment.  Do you think the same caliber of engineers who brought us Chernobyl, Fukushima, and Three Mile Island will be able to pull that rabbit out of their hats without a hitch?  If so, you’re more optimistic than I am.

    Hey, I like to be as optimistic about fusion as it’s reasonable to be. I think it’s certainly possible that some startup company with a bright idea will find the magic bullet that makes fusion reactors feasible, preferably involving fusion reactions that don’t involve tritium. It’s also quite possible that the guys at Lockheed will achieve breakeven, although getting a high enough gain of energy in versus energy out to enable efficient generation of electric power is another matter.  There’s a difference between optimism and scientifically illiterate hubris, though.  Is it too much to ask that people who write articles about fusion at least run them by somebody who actually knows something about the subject to see if they pass the “ho, ho” test before publishing?  What’s that you say?  What about me?  Please read the story about the Little Red Hen.

  • Whither Nuclear Power? A Few Comments on Thorium and the End of the “Nuclear Renaissance”

    Posted on September 2nd, 2017 Helian No comments

    About a decade ago there was much talk of a “nuclear renaissance” amid concerns about greenhouse gas emissions and the increasing cost of fossil fuel alternatives.  The Nuclear Regulatory Commission received applications to build no less than 31 new nuclear plants as the price of crude oil spiked to over $140 per barrel.  Now, however, with last month’s decision by SCANA Corp. to abandon the V. C. Summer project, a pair of nukes that had been under construction in South Carolina, nuclear’s future prospects look dim, at least in the United States.  Two plants remain under construction in Georgia but, like the ones abandoned in South Carolina, they are to be AP1000s, designed by Westinghouse.  Westinghouse filed for bankruptcy in March.  Delays and massive cost overruns similar to those that led to the demise of V. C. Summer also afflict the Georgia project, and its future seems doubtful at best.

    In short, the dream of a nuclear renaissance has evaporated.  For the time being, at least, nuclear in the U.S. is no match for more agile competitors like wind, solar, and natural gas.  However, there may be a silver lining to this cloud.  Plants like Westinghouse’s AP1000 waste most of the energy in their nuclear fuel, creating massive amounts of avoidable radioactive waste in the process.  To the extent that it makes sense to build nuclear plants at all, these are not the kind we should be building.  To understand why this is true it is first necessary to acquire some elementary knowledge about nuclear physics.

    The source of the energy produced in the core of nuclear reactors is a nuclear fission chain reaction.  Only one material that exists in significant quantities in nature can sustain such a chain reaction – uranium 235, or U235.  U235 is an isotope of uranium.  Isotopes of a given element consist of atoms with the same number of positively charged protons in their central core, or nucleus.  Like all other isotopes of uranium, U235 has 92.  There are also 143 neutrally charged neutrons, making a total of 235 “nucleons.”  Natural uranium consists of only about 0.7 percent U235.  Almost all the rest is a different isotope, U238, with a nucleus containing 146 neutrons instead of 143.

    When we say that U235 can sustain a nuclear chain reaction, we mean that if a free neutron happens to come within a very short distance of its nucleus, it may be captured, releasing enough energy in the process to cause the nucleus to split into two fragments.  When this happens, more free neutrons are released, that can then be captured by other uranium nuclei, which, in turn, fission, releasing yet more neutrons, and so on.  As noted above, U235 is the only naturally occurring isotope that can sustain such a nuclear chain reaction.  However, other isotopes can be created artificially that can do so as well.  The most important of these are U233 and plutonium 239, or Pu239.  They are important because it is possible to “breed” them in properly designed nuclear reactors, potentially producing more usable fuel than the reactor consumes.  U233 is produced by the reactions following absorption of a neutron by thorium 232, or Th232, and Pu239 by those following the absorption of a neutron by U238.  In other words, we know of three practical types of nuclear fuel; U235, U233 and Pu239.  The first occurs naturally, and the other two can be readily “bred” artificially in nuclear reactors.

    Let’s consider what this means in the case of conventional nuclear reactors like the Westinghouse AP1000.  These are powered by fuel elements that typically are enriched in U235 from the naturally occurring 0.7 percent to from three to five percent.  The remaining 95 to 97 percent of the uranium in these fuel elements is U238.  When the fission process starts, some of the neutrons released are captured by the U238, eventually resulting in the production of Pu239.  Some of this plutonium fissions along with the U235, contributing to the total energy produced by the fuel elements.  However, only a small fraction of the U238 is converted to Pu239 in this way before the fuel is consumed and it becomes necessary to replace the old fuel elements with fresh ones.  In addition to a great deal of U238, these spent fuel elements contain a significant amount of plutonium, as well as other transuranic elements such as americium and curium, which can remain dangerously radioactive for thousands of years.  The “waste” plutonium might even be used to produce a nuclear weapon.

    Obviously, if possible it would be better to extract all the energy locked up in natural uranium rather than just a small fraction of it.  In fact, it is possible, or very nearly so.  Breeder reactors are feasible that could burn nearly all the U238 in natural uranium as well as the U235 by converting it into Pu239.  In the process they could destroy much of the transuranic waste that is the main source of radioactive danger from spent fuel.  In as little as 500 years the residual radioactivity from running a nuclear plant for 30 years could potentially be less than that of the original naturally occurring uranium.  Unfortunately, while all this is scientifically feasible, it is not economically feasible.  It won’t happen without massive government subsidies.  Perhaps such subsidies are warranted in view of the threat of climate change and perhaps not, but, regardless, breeder reactors won’t be built without them.  Since they are really the only types of reactors it makes sense to build, we would probably be better off, at least for the time being, building no reactors at all.  That’s the “silver lining” I referred to above.  Perhaps a time will come when the world runs out of expendable sources of base load electrical power, such as oil, coal and natural gas, and no way has been found to take up the slack with renewables.  In that case, it may once again make economic sense to build breeder reactors.  Until that time, the United States would do well to build up a healthy stockpile of uranium, and put a stop to the stupid, wasteful, and counterproductive use of depleted uranium that could potentially become a source of vast amounts of energy to produce munitions and armor.

    But wait, there’s more!  What about thorium?  Thorium by itself can’t sustain a nuclear chain reaction.  It can, however, be converted into U233 by neutron absorption, and that is an ideal reactor fuel.  Among other things, it generates more neutrons per fission at lower neutron “temperatures” than either Pu239 or U235.  That means that extra neutrons are available to “breed” fuel at those lower temperatures where nuclear reactors are easier to control.  By “temperature” here, we’re referring to the average speed of the neutrons.  The slower they are, the more likely they are to be absorbed by a nucleus and cause fission reactions.  Neutrons are slowed in “moderators,” which can be any number of light types of atoms.  The most common is plain water, consisting of the elements hydrogen and oxygen.  Think of a billiard ball hitting another billiard ball head on.  It comes to a complete stop, transferring its energy to the other ball.  The same thing can happen with neutrons and the proton nucleus of hydrogen atoms, which are of approximately equal mass.  To breed plutonium effectively, reactors must be run at significantly higher neutron temperatures.

    There’s more good news about thorium.  It can be dissolved in various exotic mixtures and breed U233 in a reactor with a liquid instead of a solid core.  This would have a number of advantages.  In the first place, a “meltdown” would be impossible in a core that’s already “melted.”  If the core became too “hot” it could simply be drained into a holding pan to form a subcritical mass that would quickly cool.  It would also be possible to extract waste fission products and introduce fresh fuel, etc., into the core “on the fly.”  As a result the reactor would be able to stay in operation longer between shutdowns for maintenance and refueling.  The necessary technology has already been demonstrated at places like Oak Ridge, Tennessee and Shippingport, Pennsylvania.  Recently, a Dutch team finally began experiments with molten salt technology intended to take up where these earlier experiments left off after a hiatus of more than 40 years.

    Perhaps thorium’s biggest problem is the tendency of its proponents to over-hype its promise.  It even has a founding myth based on bogus claims that thorium technology isn’t dominant in the energy industry today because “it’s much harder to weaponize.”  For example, according to the article about the Dutch experiments linked above, entitled, ‘Safer’ thorium reactor trials could salvage nuclear power,

    But, if it’s so safe and reliable why hasn’t thorium been used all along? Because (unlike uranium) it’s much harder to weaponize. As a result, it’s historically been sidelined by nations in search of both energy and a potential source of weapons-grade plutonium.

    This yarn about a benign source of energy that might have benefited all mankind being torpedoed by evil weaponeers might sound good, but it’s complete nonsense.  Thorium itself can’t be weaponized, because it can’t sustain a nuclear chain reaction on its own.  The sole reason there’s any interest in it at all as a source of nuclear power is the possibility of transmuting it to U233.  Of course, it can’t be used to produce weapons-grade plutonium.  However, there is no better material for making nuclear bombs than U233.  As is the case with Pu239, four kilograms is sufficient to make a nuclear weapon, compared to the 25 kilograms that is a sufficient quantity of U235.  It’s main drawback as a weapons material is the fact that small amounts of U232 are produced along with it in thorium-based reactors, and U232 decays into radioactive daughters that are deadly sources of powerful gamma rays.  However, the amount of U232 produced can be reduced dramatically by cooling the neutron spectrum to a low “temperature.”  In short, thorium could definitely be used to make weapons.  The reason it isn’t the dominant technology for that purpose is the same as the reason it isn’t the dominant technology for producing electric power; it would be significantly more complex and expensive than using natural or slightly enriched uranium as a fuel.  That reason is as valid now as it was in the days of Little Boy and Fat Man.  The “dominant technology” would be the same as it is today whether nuclear weapons had ever been produced or not.

    When it comes to the technology itself, thorium proponents also tend to be coy about mentioning problems that don’t afflict other reactor types.  For example, the materials needed for practical molten salt reactors are extremely corrosive.  There has been progress towards finding a metal that can hold them, but no ideal alloy has yet been found.  This isn’t necessarily a show stopper, but it’s not an insignificant problem, either.  Such material issues have been largely solved for conventional reactors.  If, as would seem to be the case, these are no longer economically competitive with their rivals, then molten salt is pretty much out of the question, at least for the time being.  It’s important to point out that, if breeder reactors ever do become economically feasible again, it will always be necessary to insure that they are secure, and that the materials they produce can’t be diverted for making weapons.  That concern applies to both plutonium and thorium breeders.

    Meanwhile, it might behoove our political leaders to consider the question of why it was once possible to build more than 50 experimental reactors at what is now Idaho National Laboratory alone in a relatively short period of time for a small fraction of what similar reactors would cost today.  Merely negotiating the regulatory hurdles for building a power reactor based on anything as novel as the thorium fuel cycle would take the better part of a decade.  All these hurdles have been put in place in the name of “safety.”  That begs the question of how “safe” we will be if we lack reliable sources of electric energy.  There is a point beyond which excessive regulation itself becomes unsafe.

  • Of Solar Energy and Amateurish Agitprop at Fox News

    Posted on October 31st, 2015 Helian 1 comment

    Reading the “news” can be a painful experience in our time.  Most of it consists of a blend of sensationalism, human interest stories, accounts of the lives of various vapid celebrities, and attempts to inspire virtuous indignation based on a half-baked knowledge of some ideologically loaded issue or other.  One finds very little that could be accurately described as useful knowledge about things that are likely to have a major impact on our lives.  I generally find Fox News less painful to read than what is commonly described as the Mainstream Media because I happen to be emotionally conservative.  However, I must admit that Fox can occasionally be more ham-handed than the competition when it comes to dishing out propaganda.

    A story that recently turned up on the Fox website is a case in point.  It happened to be about the Ivanpah solar generating system that was recently completed in California’s Mojave Desert.  The word “solar” should enable most readers to predict the ideological slant on the story one is likely to find at Fox.  Sure enough, the title of the story is, “Taxpayer-backed solar plant actually a carbon polluter.”  In the article itself we learn that the plant,

    …is producing carbon emissions at nearly twice the amount that compels power plants and companies to participate in the state’s cap-and-trade program.

    In fact, the plant does emit CO2 because it burns natural gas to avoid damage to equipment and to serve as a baseline source of power to meet electricity needs at night or during cloudy days.  A bit further on, we learn from a “research fellow at the Heartland Institute” named H. Sterling Burnett that,

    …designers also erred in placing Ivanpah between the tallest mountains in the Mojave where there is significant cloud cover and dust which would interfere with the sunlight.

    He adds that,

    …They say it is green, but that assumes that there is a power source without any environmental impact.

    I don’t find anything as egregious as actual lies in the article.  Rather, Fox limits itself to “creative” use of the truth.  For example, it may be quite true that the plant, “…is producing carbon emissions at nearly twice the amount that compels power plants and companies to participate in the state’s cap-and-trade program,” but it’s also true that it produces far less carbon per unit of electricity delivered than a purely fossil fuel fired plant, a fact that is left unsaid in spite of its much greater relevance to the underlying issue of climate change.  A researcher at the Heartland Institute is quoted without mentioning that the institute is funded by the fossil fuel industry, and is considered a source of blatant disinformation by environmentalists.  That charge may be unfair, but one can hardly claim that it is irrelevant and should be ignored.  As for his claim that, “designers also erred in placing Ivanpah between the tallest mountains in the Mojave,” etc., I invite interested readers who may happen to visit Las Vegas to drive out and have a look at the plant.  It’s actually quite a spectacular sight.  It certainly doesn’t appear to be sitting in the shadow of towering mountains, and the cloud cover is generally minimal, as one can confirm by Googling nearby locations.  As for the dust, one surmises that it would have been worse if the plant had been built on the Los Angeles side of the mountains.  As for Burnett’s last remark, as far as I am aware not even the most wild-eyed and fanatical environmentalist has ever claimed that the description of a power source as “green” implies the assumption that it has no environmental impact at all.

    The reality is that the plant is reasonably sited given the location of the major consumers of the power it produces.  Given the current limitations in our ability to store and distribute the excess power produced by renewable energy sources like wind and solar, some form of baseline power is always necessary to insure a steady supply of electricity when the wind isn’t blowing or the sun isn’t shining.  My own choice for that purpose would be nuclear, but given the regulatory hurdles in the way, that would probably have been impractical for Ivanpah.  Natural gas produces significantly less CO2 than, for example, coal, and was probably the best choice.

    In short, the article is an example of what I have referred to above as “attempts to inspire virtuous indignation based on a half-baked knowledge of some ideologically loaded issue or other.”  If the goal at Fox had been to inform rather than propagandize, they would have provided the reader with “fair and balanced” information about the cost of electricity produced at Ivanpah compared to alternative sources, the amount actually produced in comparison with predictions, the amount of CO2 it produces per unit of electricity in comparison to coal or oil fired plants, the relative advantages of solar and nuclear in limiting greenhouse gas emissions, etc.  None of what I write here should be taken to imply a belief that solar should be preferred to any alternative.  In fact, my own choice would be to reduce the regulatory burden to rational levels and build next generation nuclear plants instead.  However, regardless of the technology involved, I would prefer to see it judged on a level playing field.

    I know, I know, the MSM is hardly innocent of slanting the news.  Indeed, its hysterical response after the announcement that Sarah Palin would be John McCain’s running mate puts anything I have ever seen at Fox News completely in the shade.  Generally, however, it tends to be at least marginally more subtle.  For example, instead of attempting to slant important news stories that don’t fit its narrative, it will often simply ignore them.  If the story is too big to ignore, it will vilify the messenger instead.  Of course, such techniques reflect a greater maturity and experience in handling agitprop than is available to the team at Fox News.  However, that doesn’t prevent them from learning by example.  Given that we will be subjected to propaganda no matter which “news” source we choose to follow, we should at least be able to demand that it not be crudely done.

    Ivanpah

  • Another Fusion White Elephant Sighted in Germany

    Posted on October 27th, 2015 Helian 2 comments

    According to an article that just appeared in Science magazine, scientists in Germany have completed building a stellarator by the name of Wendelstein 7-X (W7-X), and are seeking regulatory permission to turn the facility on in November.  If you can’t get past the Science paywall, here’s an article in the popular media with some links.  Like the much bigger ITER facility now under construction at Cadarache in France, W7-X is a magnetic fusion device.  In other words, its goal is to confine a plasma of heavy hydrogen isotopes at temperatures much hotter than the center of the sun with powerful magnetic fields in order to get them to fuse, releasing energy in the process.  There are significant differences between stellarators and the tokamak design used for ITER, but in both approaches the idea is to hold the plasma in place long enough to get significantly more fusion energy out than was necessary to confine and heat the plasma.  Both approaches are probably scientifically feasible.  Both are also white elephants, and a waste of scarce research dollars.

    The problem is that both designs have an Achilles heel.  Its name is tritium.  Tritium is a heavy isotope of hydrogen with a nucleus containing a proton and two neutrons instead of the usual lone proton.  Fusion reactions between tritium and deuterium, another heavy isotope of hydrogen with a single neutron in addition to the usual proton, begin to occur fast enough to be attractive as an energy source at plasma temperatures and densities much less than would be necessary for any alternative reaction.  The deuterium-tritium, or DT, reaction will remain the only feasible one for both stellarator and tokamak fusion reactors for the foreseeable future.  Unfortunately, tritium occurs in nature in only tiny trace amounts.

    The question is, then, where do you get the tritium fuel to keep the fusion reactions going?  Well, in addition to a helium nucleus, the DT fusion reaction produces a fast neutron.  These can react with lithium to produce tritium.  If a lithium-containing blanket could be built surrounding the reaction chamber in such a way as to avoid interfering with the magnetic fields, and yet thick enough and close enough to capture enough of the neutrons, then it should be possible to generate enough tritium to replace that burned up in the fusion process.  It sounds complicated but, again, it appears to be at least scientifically feasible.  However, it is by no means as certain that it is economically feasible.

    Consider what we’re dealing with here.  Tritium is an extremely slippery material that can pass right through walls of some types of metal.  It is also highly radioactive, with a half-life of about 12.3 years.  It will be necessary to find some way to efficiently extract it from the lithium blanket, allowing none of it to leak into the surrounding environment.  If any of it gets away, it will be easily detectable.  The neighbors are sure to complain and, probably, lawyer up.  Again, all this might be doable.  The problem is that it will never be doable at a low enough cost to make fusion reactor designs based on these approaches even remotely economically competitive with the non-fossil alternative sources of energy that will be available for, at the very least, the next several centuries.

    What’s that?  Reactor design studies by large and prestigious universities and corporations have all come to the conclusion that these magnetic fusion beasts will be able to produce electricity at least as cheaply as the competition?  I don’t think so.  I’ve participated in just such a government-funded study, conducted by a major corporation as prime contractor, with several other prominent universities and corporations participating as subcontractors.  I’m familiar with the methodology used in several others.  In general, it’s possible to make the cost electricity come out at whatever figure you choose, within reason, using the most approved methods and the most sound project management and financial software.  If the government is funding the work, it can be safely assumed that they don’t want to hear something like, “Fuggedaboudit, this thing will be way too expensive to build and run.”  That would make the office that funded the work look silly, and the fusion researchers involved in the design look like welfare queens in white coats.  The “right” cost numbers will always come out of these studies in the end.

    I submit that a better way to come up with a cost estimate is to use a little common sense.  Do you really think that a commercial power company will be able to master the intricacies of tritium production and extraction from the vicinity of a highly radioactive reaction chamber at anywhere near the cost of, say, wind and solar combined with next generation nuclear reactors for baseload power?  If you do, you’re a great deal more optimistic than me.  W7-X cost a billion euros.  ITER is slated to cost 13 billion, and will likely come in at well over that.  With research money hard to come by in Europe for much worthier projects, throwing amounts like that down a rat hole doesn’t seem like a good plan.

    All this may come as a disappointment to fusion enthusiasts.  On the other hand, you may want to consider the fact that, if fusion had been easy, we would probably have managed to blow ourselves up with pure fusion weapons by now.  Beyond that, you never know when some obscure genius might succeed in pulling a rabbit out of their hat in the form of some novel confinement scheme.  Several companies claim they have sure-fire approaches that are so good they will be able to dispense with tritium entirely in favor of more plentiful, naturally occurring isotopes.  See, for example, here, here, and here, and the summary at the Next Big Future website.  I’m not optimistic about any of them, either, but you never know.

    Stellarator

  • Fusion Power Update: Hoping for a Shortcut

    Posted on September 3rd, 2015 Helian No comments

    Think of a pile of bowling balls in a deep well.  They don’t fly out because the force of gravity holds them in.  If you roll an extra bowling ball to the edge of the well and let it drop in, energy is released when it hits the pile at the bottom.  Atomic nuclei can be compared to the well.  The neutrons and protons that make it up are the bowling balls, and the “gravity” is the far more powerful “strong force.”  Roll some of these “bowling balls” into the well and energy will be released, just as in a real well.  The process is called nuclear fusion, and it’s the source of energy that powers the sun.  We’ve been trying to produce energy by repeating the process here on earth for a good many years now, but were only “lucky” enough to succeed in the case of thermonuclear weapons.  We’ve been stymied in our efforts to harness fusion energy in less destructive forms.  The problem is the Coulomb, or electrostatic force.  It’s what causes unlike charges to attract and like charges to repel in the physics experiments you did in high school.  It’s much weaker than the strong force that holds the neutrons and protons in an atomic nucleus together, but the strong force has a very short range.  The trick is to get within that range.  All atomic nuclei contain protons, and protons are positively charged.  They repel each other, resisting our efforts to push them up to the edge of the “well,” where the strong force will finally overwhelm the Coulomb force, causing these tiny “bowling balls” to drop in.  So far, only atomic bombs have supplied enough energy to provide a “push” big enough to result in a net release of fusion energy.

    To date, we’ve tried two main approaches to supplying the “push” in a more controlled form; magnetic fusion and inertial confinement fusion, or ICF.  In both approaches the idea is to heat the nuclei to extreme temperatures, causing them to bang into each other with enough energy to overcome the Coulomb repulsion.  However, when you dump that much energy into a material, it tends to fly apart, as in a conventional explosion.  Somehow a way must be found to hold it in place long enough for significant fusion to take place.  In magnetic fusion that’s accomplished with magnetic lines of force that hold the hot nuclei within a confined space.  Some will always manage to escape, but if enough are held in place long enough, the resulting fusion reactions will release enough energy to keep the process going.  In inertial confinement fusion, as the name would imply, the magnetic fields are replaced by the material’s own inertia.  The idea is to supply so much energy in such a short period of time that significant fusion will occur before the material has time to fly apart.  That’s essentially what happens in thermonuclear weapons.  In ICF the atomic bomb that drives the reaction is replaced by powerful arrays of laser or particle beams.

    Both of these approaches are scientifically feasible.  In other words, both will almost certainly work if the magnetic fields can be made strong enough, or the laser beams powerful enough.  Unfortunately, after decades of effort, we still haven’t managed to reach those thresholds.  Our biggest ICF facility, the National Ignition Facility or NIF, has so far failed to achieve “ignition,” defined as fusion energy out equal to laser energy in, by a wide margin.  The biggest magnetic fusion facility, ITER, currently under construction in France, may reach the goal, but we’ll have to wait a long time to find out.  The last time I looked there were no plans to even fuel it with deuterium and tritium, (D and T, heavy isotopes of hydrogen with one and two neutrons in the nucleus in addition to the usual proton) until 2028!  The DT fusion reaction, shown below with some of the others, is the easiest to harness in the laboratory.  For reasons I’ve outlined elsewhere, I doubt that either the “conventional” magnetic or inertial confinement approaches will ever produce energy at a cost competitive with the alternatives.

    There are, however, other approaches out there.  Over the years, startup companies have occasionally managed to attract millions in investment capital to explore these alternatives.  Progress reports occasionally turn up on websites such as NextBigFuture.  Examples may be found here, here and here, and many others may be found by typing in the search term “fusion” at the website.  Typically, they claim they are three or four years away from building a breakeven device, or even a prototype reactor.  So far none of them have panned out, but I keep hoping that eventually one of them will pull a rabbit out of their hat and come up with a workable design.  The chances are probably slim, but at least marginally better than the odds that someone will perfect a perpetual motion machine.

    I tend to be particularly dubious when I see proposals involving fusion fuels other than the usual deuterium and tritium.  Other fusion reactions have their advantages.  For example, some produce no neutrons, which can pose a radioactive hazard, and/or use fuels other than the highly radioactive tritium, which occurs in nature only in tiny trace amounts, and must therefore be “bred” in the reactor in order to keep the process going.  Some of the most promising ones are shown along with the more “mainline” DT and DD reactions below.

    D + T → 4He (3.5 MeV) + neutron (14.1 MeV)

    D + D →  T (1.01 MeV) + proton (3.02 MeV) 50%

    D + D →  3He (0.82 MeV) + neutron (2.45 MeV) 50%

    H + 11B → 3(4He); Q = 8.68 MeV

    H + 6Li → 3He + 4He; Q = 4.023 MeV

    3He + 6Li → H + 2(4He); Q = 16.88 MeV

    3He + 6Li → D + 7Be; Q = 0.113 MeV

    The problem with the seemingly attractive alternatives to DT shown above as well as a number of others that have been proposed is that they all require significantly higher temperatures and/or confinement times for fusion “ignition” to occur.  Take a look at the graph below.

    Cross_section_1

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

    The horizontal axis is in units of the “temperature” of the fuel in thousands of electron volts, and the vertical shows the “cross-section” for any of the reactions shown in units of “barns.”  The cross-section is related to the probability that a particular reaction will occur.  It is measured in units of 10−24 cm2, or “barns,” because, at least at the atomic scale, that’s as big as the broad side of a barn.  Notice that the DT reaction is much higher at lower temperatures than all the others.  Yet we failed to achieve fusion ignition on the NIF with that reaction in spite of the fact that the facility is capable of focusing a massive 1.8 megajoules of laser energy on a fusion target in a period of a few billionths of a second!  Obviously, if we couldn’t get DT to work on the NIF, the other reactions will be difficult to harness indeed.

    In short, I tend to be dubious when I read the highly optimistic progress reports, complete with “breakthroughs,” of the latest fusion startup.  I tend to be a great deal more dubious when they announce they will dispense with DT altogether, as they are so sure of the superior qualities of their design that lithium, boron, or some other exotic fuel will work just as well.  Still, I keep my fingers crossed.

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

    Posted on August 7th, 2015 Helian No comments

    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

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

    Posted on February 22nd, 2015 Helian No comments

    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.

  • Of Smug Germans and Sinful Australians: Global Warming Update

    Posted on October 4th, 2014 Helian No comments

    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

    Posted on September 23rd, 2014 Helian No comments

    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

    Posted on March 21st, 2014 Helian 2 comments

    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