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  • Another Fusion Tease?

    Posted on October 10th, 2013 Helian No comments

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

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

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

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

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

  • Of Cold Fusion and the Timidity of ARPA-E

    Posted on October 23rd, 2012 Helian No comments

    ARPA-E, or the Advanced Research Projects Agency – Energy, is supposed to be DOE’s version of DARPA.  According to its website, its mission,

    …is to fund projects that will develop transformational technologies that reduce America’s dependence on foreign energy imports; reduce U.S. energy related emissions (including greenhouse gasses); improve energy efficiency across all sectors of the U.S. economy and ensure that the U.S. maintains its leadership in developing and deploying advanced energy technologies.

    So far, it has not come up with anything quite as “transformational” as the Internet or stealth technology.  There is good reason for this.  Its source selection people are decidedly weak in the knees.  Consider the sort of stuff it’s funded in the latest round of contract awards.  The people at DARPA would probably call it “workman like.”  H. L. Mencken, the great Sage of Baltimore, would more likely have called it “pure fla fla.”  For example, there are “transformational” systems to twiddle with natural gas storage that the industry, not exactly short of cash at the moment, would have been better left to develop on its own, such as,

    Liquid-Piston Isothermal Home Natural Gas Compressor

    Chilled Natural Gas At-Home Refueling

    and,

    Superplastic-Formed Gas Storage Tanks

    There is the “transformational” university research that is eye-glazingly mundane, and best reserved as filler for the pages of obscure academic journals, such as,

    Cell-level Power Management of Large Battery Packs

    Health Management System for Reconfigurable Battery Packs

    and,

    Optimal Operation and Management of Batteries Based on  Real Time Predictive Modeling and Adaptive Battery  Management Techniques.

    There is some “groundbreaking” stuff under the rubric of “build a better magnet, and the world will beat a pathway to your door.”

    Manganese-Based Permanent Magnet with 40 MGOe at 200°C

    Rare‐Earth‐Free Permanent Magnets for Electrical Vehicle Motors and Wind Turbine Generators: Hexagonal Symmetry Based Materials Systems Mn‐Bi and M‐type Hexaferrite

    and,

    Discovery and Design of Novel Permanent Magnets using Non-strategic Elements having Secure Supply Chains

    …and so on. Far be it for me to claim that any of this research is useless.  It is, however, also what the people at DARPA would call “incremental,” rather than transformational.  Of course, truly transformational ideas don’t grow on trees, and DARPA also funds its share of “workmanlike” projects, but at least the source selection people there occasionally go out on a limb. In the work funded by ARPA-E, on the other hand, I can find nothing that might induce the bureaucrats on Secretary Chu’s staff to swallow their gum.

    If the agency is really serious about fulfilling its mission, it might consider some of the innovative ideas out there for harnessing fusion energy.  All of them can be described as “high risk, high payoff,” but isn’t that the kind of work ARPA-E is supposed to be funding?  According to a recent article on the Science Magazine website, the White House has proposed cutting domestic fusion research by 16%to help pay for the U.S. contribution to the international fusion experiment, ITER, under construction in Cadarache, France.  As I’ve pointed out elsewhere, ITER is second only to the International Space Station as the greatest white elephant of all time, and is similarly vacuuming up funds that might otherwise have supported worthwhile research in several other countries.  All the more reason to give a leg up to fusion, a technology that has bedeviled scientists for decades, but that could potentially supply mankind’s energy needs for millennia to come.  Ideas being floated at the moment include advanced fusor concepts such as the Bussard polywell, magneto-inertial fusion, focus fusion, etc.  None of them look particularly promising to me, but if any of them pan out, the potential payoff is huge.  I’ve always been of the opinion that, if we ever do harness fusion energy, it will be by way of some such clever idea rather than by building anything like the current “conventional” inertial or magnetic fusion reactor designs.

    When it comes to conventional nuclear energy, we are currently in the process of being left in the dust by countries like India and China.  Don’t expect any help from industry here.  They are in the business to make a profit.  There’s certainly nothing intrinsically wrong with that, but at the moment, profits are best maximized by building light water reactors that consume the world’s limited supply of fissile uranium 235 without breeding more fuel to replace it, and spawn long-lived and highly radioactive transuranic actinides in the process that it will be necessary to find a way to safely store for thousands of years into the future.  This may be good for profits, but it’s definitely bad for future generations.  Alternative designs exist that would breed as much new fuel as they consume, be intrinsically safe against meltdown, would destroy the actinides along with some of the worst radioactive fission products, and would leave waste that could be potentially less radioactive than the original ore in a matter of a few hundred years.  DOE’s Office of Nuclear Energy already funds some research in these areas.  Unfortunately, in keeping with the time-honored traditions of government research funding, they like to play it safe, funneling awards to “noted experts” who tend to keep plodding down well-established paths even when they are clearly leading to dead ends.  ITER and the International Space Station are costly examples of where that kind of thinking leads.  If it were really doing its job, an agency like ARPA-E might really help to shake things up a little.

    Finally, we come to that scariest of boogeymen of “noted experts” the world over; cold fusion, or, as some of its advocates more reticently call it, Low Energy Nuclear Reactions (LENR).  Following the initial spate of excitement on the heels of the announcement by Pons and Fleischmann of excess heat in their experiments with palladium cells, the scientific establishment agreed that such ideas were to be denounced as heretical.  Anathemas and interdicts rained down on their remaining proponents.  Now, I must admit that I don’t have much faith in LENR myself.  I happened to attend the Cold Fusion Workshop in Sante Fe, NM which was held in 1989, not long after the Pons/Fleischmann bombshell, and saw and heard some memorably whacky posters and talks.  I’ve talked to several cold fusion advocates since then, and some appeared perfectly sober, but an unsettlingly large proportion of others seemed to be treading close to the lunatic fringe.  Just as fusion energy is always “30 years in the future,” cold fusion proponents have been claiming that their opponents will be “eating crow in six months” ever since 1989.  Some very interesting results have been reported.  Unfortunately, they haven’t been reproducible.

    For all that, LENR keeps hanging around.  It continues to find advocates among those who, for one reason or another, aren’t worried about their careers, or lack respect for authority, or are just downright contrarians.  The Science of Low Energy Nuclear Reactions by Edmund Storms is a useful source for the history of and evidence for LENR.  Websites run by the cold fusion faithful may be found here and here.  Recently, stories have begun cropping up again in “respectable” mags, such as Forbes and Wired.  Limited government funding has been forthcoming from NASA Langley and, at least until recently, from the Navy at its Space and Naval Warfare Systems Command (SPAWAR).  Predictably, such funding is routinely attacked as support for scientific quackery.  The proper response to that from the source selection folks at ARPA-E should be, “So what?”  After all,

    ARPA-E was created to be a catalyst for innovation. ARPA-E’s objective is to tap into the risk-taking American ethos and to identify and support the pioneers of the future. With the best research and development infrastructure in the world, a thriving innovation ecosystem in business and entrepreneurship, and a generation of youth that is willing to engage with fearless intensity, the U.S. has all the ingredients necessary for future success. The goal of ARPA-E is to harness these ingredients and make a full-court press to address the U.S.’s technological gaps and leapfrog over current energy approaches.

    The best way to “harness these ingredients and make a full-court press” is not by funding of the next round of incremental improvements in rare earth magnets.  Throwing a few dollars to the LENR people, on the other hand, will certainly be “high risk,” but it just might pan out.  I hope the people at ARPA-E can work up the minimal level of courage it takes to do so.  If the Paris fashions can face down ridicule, so can they.  If they lack the nerve, then DOE would probably do better to terminate its bad imitation of DARPA and feed the money back to its existing offices.  They can continue funding mediocrity just as well as ARPA-E.

    Pons & Fleischmann

  • The NIF Misses its Ignition Milestone

    Posted on October 22nd, 2012 Helian 2 comments

    We have passed the end of the fiscal year, and the National Ignition Facility, or NIF, at Lawrence Livermore National Laboratory (LLNL) failed to achieve its goal of ignition (more fusion energy out than laser energy in). As I noted in earlier post about the NIF more than three years ago, this doesn’t surprise me. Ignition using the current indirect drive approach (most of the jargon and buzzwords are explained in the Wiki article on the NIF) requires conversion of the laser energy into an almost perfectly symmetric bath of x-rays. These must implode the target, preserving its spherical shape in the process in spite of a very high convergence ratio (initial radius divided by final radius), and launching a train of four shocks in the process, which must all converge in a tiny volume at the center of the target, heating it to fusion conditions. That will release energetic alpha particles (helium nuclei) which must then dump their energy in the surrounding, cold fuel material, causing a “burn wave” to propagate out from the center, consuming the remaining fuel. It would have been a spectacular achievement if LLNL had pulled it off. Unfortunately, they didn’t, for reasons that are explained in an excellent article that recently appeared in the journal Science. (Unfortunately, it’s behind a subscriber wall, and I haven’t found anything as good on the web at the moment. You can get the gist from this article at Huffpo.)  The potential political implications of the failure were addressed in a recent article in the New York Times.

    All of which begs the question, “What now?” My opinion, in short, is that the facility should remain operational, at full capacity (not on half shifts, which, for various reasons, would reduce the experimental value of the facility by significantly more than half).

    I certainly don’t base that opinion on the potential of inertial confinement fusion (ICF), the technology implemented on the NIF, for supplying our future energy needs.  While many scientists would disagree with me, I feel it has virtually none.  Although they may well be scientifically feasible, ICF reactors would be engineering nightmares, and far too expensive to compete with alternative energy sources.  It would be necessary to fabricate many thousands of delicate, precisely built targets every day and fill them with highly radioactive tritium.  Tritium is not a naturally occurring isotope of hydrogen, and its half-life (the time it takes for half of a given quantity to undergo radioactive decay) is just over 12 years, so it can’t be stored indefinitely.  It would be necessary to breed and extract the stuff from the reactor on the fly without releasing any into the environment (hydrogen is notoriously slippery stuff, that can easily leak right through several types of metal barriers), load it into the targets, and then cool them to cryogenic temperatures.  There is not a reactor design study out there that doesn’t claim that this can be done cheaply enough to make ICF fusion energy cost-competitive.  They are all poppycock.  The usual procedure in such studies is to pick the cost number you need, and then apply “science” to make it seem plausible.

    However, despite all the LLNL hype, the NIF was never funded as an energy project, but as an experimental tool to help maintain the safety and reliability of our nuclear stockpile in the absence of nuclear testing.  The idea that it will be useless for that purpose, whether it achieves ignition or not, is nonsense.  The facility has met and in some cases exceeded its design goals in terms of energy and precision.  Few if any other facilities in the world, whether existing or planned, will be able to rival its ability to explore equations of state, opacities, and other weapons-relevant physics information about materials at conditions approaching those that exist in nuclear detonations.  As long as the ban on nuclear testing remains in effect, the NIF will give us a significant advantage over other nuclear states.  It seems to me that maintaining the ban is a good thing.

    It also seems to me that it would behoove us to maintain a robust nuclear stockpile.  Nuclear disarmament sounds nice on paper.  In reality it would invite nuclear attack.  The fact that nuclear weapons have not been used since 1945 is a tremendous stroke of luck.  However, it has also seduced us into assuming they will never be used again.  They will.  The question is not if, but when.  We could continue to be very lucky.  We could also suffer a nuclear attack tomorrow, whether by miscalculation, or the actions of terrorists or rogue states.  If we continue to have a stockpile, it must be maintained.  Highly trained scientists must be available to maintain it.  Unfortunately, babysitting a pile of nuclear bombs while they gather dust is not an attractive career path.  Access to facilities like the NIF is a powerful incentive to those who would not otherwise consider such a career.

    One of the reasons this is true is the “dual use” capability of the NIF.  It can be used to study many aspects of high energy density physics that may not be relevant to nuclear weapons, but are of great interest to scientists in academia and elsewhere who are interested in fusion energy, the basic science of matter at extreme conditions, astrophysics, etc.  Some of the available time on the facility will be reserved for these outside users.

    As for the elusive goal of ignition itself, we know that it is scientifically feasible, just as we know that its magnetic fusion equivalent is scientifically feasible.  The only question remaining is how big the lasers have to be to reach it.  It may eventually turn out that the ones available on the NIF are not big enough.  However, the idea that because we didn’t get ignition in the first attempts somehow proves that ignition is impossible and out of the question is ridiculous.  It has not even been “proven” that the current indirect drive approach won’t work.  If it doesn’t, there are several alternatives.  The NIF is capable of being reconfigured for direct drive, in which the lasers are aimed directly at the fusion target.  For various reasons, the beams are currently being frequency-tripled from the original “red” light of the glass lasers to “blue.”  Much more energy, up to around four megajoules instead of the current 1.8, would be available if the beams were only frequency-doubled to “green”.  It may be that the advantage of the extra energy will outweigh the physics-related disadvantages of green light.  An interesting dark horse candidate is the “fast ignitor” scenario, in which the target would be imploded as before, but a separate beam or beams would then be used to heat a small spot on the outer surface to ignition conditions.  An alpha particle “burn wave” would then propagate out, igniting the rest of the fuel, just as originally envisioned for the central hot spot approach.

    Some of the comments following the Internet posts about NIF’s failure to reach ignition are amusing.  For example, following an article on the Physics Today website we learn to our dismay:

    With all due respect to the NIF and its team of well-meaning and enthusiastic researchers here, I am sorry to state hereby that sustainable nuclear fusion is predestined to fail, whether it be in the NIC, the Tokamak or anywhere else in solar space, for fundamentally two simple reasons paramount for fusion: ((1) vibrational synchronism (high-amplitude resonance) of reacting particles; and (2) the overall isotropy of their ambient field.

    Obviously the commenter hadn’t heard that the scientific feasibility of both inertial and magnetic fusion has already been established.  He reminds me of a learned doctor who predicted that Zadig, the hero of Voltaire’s novel of that name, must inevitably die of an injury.  When Zadig promptly recovered, he wrote a thick tome insisting that Zadig must inevitably have died.  Voltaire informs us that Zadig did not read the book.  In an article on the IEEE Spectrum website, suggestively entitled National Ignition Facility:  Mother of All Boondoggles?, another commenter chimes in:

    How about we spend the billions on real research that actually has a chance of producing something useful? There are a gazillion ideas out there for research that has a much higher probability of producing useful results. Must be nice to work for LLNL where your ideas don’t need vetting.

    In fact, the NIF was “vetted” by a full scale Federal Advisory Committee.  Known as the Inertial Confinement Fusion Advisory Committee, or ICFAC, its members included Conrad Longmire, Marshall Rosenbluth, and several other experts in plasma physics and technology of world renown who had nothing whatsoever to gain by serving as shills for LLNL.  It heard extensive testimony on plans to build the NIF, both pro and con, in the mid-90’s.  Prominent among those who opposed the project was Steve Bodner, head of the ICF Program at the Naval Research Laboratory (NRL) at the time.  Steve cited a number of excellent reasons for delaying major new starts like the NIF until some of the outstanding physics issues could be better understood.  The Committee certainly didn’t ignore what he and other critics had to say.  However, only one of the 15 or so members dissented from the final decision to recommend proceeding with the NIF.  I suspect that LLNL’s possession of the biggest, baddest ICF computer code at the time had something to do with it.  No one is better at bamboozling himself and others than a computational physicist with a big code.  The one dissenter, BTW, was Tim Coffey, Director of NRL at the time, who was convinced that Bodner was right.

    There are, of course, the predictable comments by those in the habit of imagining themselves geniuses after the fact, such as,

    I am convinced. Garbage research.

    and,

    Don’t these people feel ashamed telling so many lies?

    after the IEEE Spectrum article, and,

    It’s amazing to think that you can spout lies to the government to receive $6 billion for a machine that doesn’t come close to performing to spec and there are no consequences for your actions.

    Following a post on the NIF at the LLNL – The True Story blog.  Fortunately, most of the comments I’ve seen recently have been at a rather more thoughtful level.  In any event, I hope Congress doesn’t decide to cut and run on the NIF.  Pulling the plug at this point would be penny-wise and pound-foolish.

    One of the two NIF laser bays

  • More Silly Thorium Tricks

    Posted on September 13th, 2012 Helian No comments

    You might get the idea from reading my blog that I have something against thorium.  It ain’t so!  I consider thorium a very promising candidate for supplying our future energy needs.  It’s just that there’s something about the stuff that seems to drive people off the deep end.  I actually missed the really bad thorium idea that’s the subject of this post when it turned up on the Internet about a year ago.  However, the articles are still out there, and are interesting examples of how really bad science can be promoted as perfectly plausible by people who have impressive credentials, but actually don’t know what they’re talking about.

    The idea in question was the use of thorium fueled mini-subcritical reactors to generate power for a new generation of electric cars.  It was proposed by an outfit called Laser Power Systems (LPS).  Science may not be their strong suit, but their PR people must be top drawer.  They actually convinced the people at Cadillac to embarrass themselves by designing a “concept car” around the idea.

    Steven Ashley penned an article for GE’s Txchnologist website about the idea entitled, “Thorium lasers:  the perfectly plausible idea for nuclear cars.”  Ashley, who is described as a contributing editor for Scientific American and whose work has appeared in such venues as Popular Mechanics, MIT’s Technology Review, and Physics Today, does not explain on what credentials or academic background he bases his conclusion that the idea is “perfectly plausible.”  Presumably, none, because it isn’t.  He tells us, quoting an LPS official, that they are “working on a turbine/electric generator system that is powered by ‘an accelerator-driven thorium-based laser.'”  The same individual further assured him that the new technology “would be totally emissions-free, with no need for recharging.”  Ashley adds that,

    …because a gram of thorium has the equivalent potential energy content of 7,500 gallons of gasoline, LPS calculates that using just 8 grams of thorium in the unit could power an average car for 5,000 hours, or about 300,000 miles of normal driving.

    Where, the interested reader might ask, is all this energy to come from?  Lasers, after all, are not a source of energy.  In general, they are rather inefficient energy sinks.  I found several similar articles, and none of them ever gets around to explaining this intriguing mystery.  Well, the only possible way that such a small amount of thorium could come close to producing that much energy is via fission, and even if every bit of it underwent fission, it would still produce about an order of magnitude less energy than 7,500 gallons of gasoline.  We are assured that, “only a thin layer of aluminum foil is needed to shield people from the weakly emitting metal.”  True, but the same doesn’t apply to thorium’s fission products.  They would eventually accumulate to become a potentially deadly source of radiation unless heavily shielded.  None of the articles ever gets around to explaining where, exactly, the “thorium laser” comes in, what specific atomic transitions it would rely on, how, exactly, it would be pumped, and similar seemingly obvious questions.

    What can one do but shake one’s head and congratulate the LPS people on their brilliant success in bamboozling Cadillac and a whole host of ostensibly perfectly respectable science writers into taking seriously an idea that is completely wacky on the face of it?  I’m certainly glad that I don’t fall for such pseudo-scientific nonsense.  Oh, by the way, would anyone out there like to purchase a slightly used supply of fish oil pills?