The NIF has been operational for over a year now, and a two year campaign is underway with the goal of achieving ignition by the end of this fiscal year.  Recently, there has been a somewhat ominous silence from the facility, manifesting itself as a lack of publications in the major journals favored by fusion scientists.  That doesn’t usually happen when there is anything interesting to report.  Finally, however, some papers have turned up in the journal Physics of Plasmas, containing reports of significant progress.

To grasp the importance of the papers, it is necessary to understand what is supposed to occur within the NIF  target chamber for fusion to occur.  Of course, just as in magnetic fusion, the goal is to bring a mixture of deuterium and tritium, two heavy isotopes of hydrogen, to the extreme conditions at which fusion takes place.  In the ICF approach, this hydrogen “fuel” is contained in a tiny, BB-sized target.  However, the lasers are not aimed directly at the fuel “capsule.”  Instead, the capsule is suspended in the middle of a tiny cylinder made of a heavy metal like gold or uranium.  The lasers are fired through holes on each end of the cylinder, striking the interior walls, where their energy is converted to x-rays.  It is these x-rays that must actually bring the target to fusion conditions.

It was recognized many years ago that one couldn’t achieve fusion ignition by simply heating up the target.  That would require a laser driver orders of magnitude bigger than the NIF.  Instead, it is first necessary to compress, or implode, the fuel material to extremely high density.  Obviously, it is harder to “squeeze” hot material than cold material to the necessary high densities, so the fuel must be kept as “cold” as possible during the implosion process.  However, cold fuel won’t ignite, begging the question of how to heat it up once the necessary high densities have been achieved.

It turns out that the answer is shocks.  When the laser generated x-rays hit the target surface, they do so with such force that it begins to implode faster than the speed of sound.  Everyone knows that when a plane breaks the sound barrier, it, too, generates a shock, which can be heard as a sonic boom.  The same thing happens in ICF fusion targets.  When such a shock converges at the center of the target, the result is a small “hot spot” in the center of the fuel.  If the temperature in the hot spot were high enough, fusion would occur.  Each fusion reaction would release a high energy helium nucleus, or alpha particle, and a neutron.  The alpha particles would be slammed to a stop in the surrounding cold fuel material, heating it, in turn, to fusion conditions.  This would result in a fusion “burn wave” that would propagate out through the rest of the fuel, completing the fusion process.

The problem is that one shock isn’t enough to create such a “hot spot.”  Four of them are required, all precisely timed by the carefully tailored NIF laser pulse to converge at the center of the target at exactly the same time.  This is where real finesse is needed in laser fusion.  The implosion must be extremely symmetric, or the shocks will not converge properly.  The timing must be exact, and the laser pulse must deliver just the right amount of energy.

One problem in the work to date has been an inability to achieve high enough implosion velocities for the above scenario to work as planned.  One of the Physics of Plasmas papers reports that, by increasing the laser energy and replacing some of the gold originally used in the wall of the cylinder, or “hohlraum,” in which the fuel capsule is mounted with depleted uranium, velocities of 99% of those required for ignition have been achieved.  In view of the recent announcement that a shot on the NIF had exceeded its design energy of 1.8 megajoules, it appears the required velocity is within reach.  Another of the Physics of Plasmas papers dealt with the degree to which implosion asymmetries were causing harmful mixing of the surrounding cold fuel material into the imploded core of the target.  It, too, provided grounds for optimism.

In the end, I suspect the success or failure of the NIF will depend on whether the complex sequence of four shocks can really be made to work as advertised.  That will depend on the accuracy of the physics algorithms in the computer codes that have been used to model the experiments.  Time and again, earlier and less sophisticated codes have been wrong because they didn’t accurately account for all the relevant physics.  There is no guarantee that critical phenomena have not been left out of the current versions as well.  We may soon find out, if the critical series of experiments planned to achieve ignition before the end of the fiscal year are carried out as planned.

One can but hope they will succeed, if only because some of our finest scientists have dedicated their careers to the quest to achieve the elusive goal of controlled fusion.  Even if they do, fusion based on the NIF approach is unlikely to become a viable source of energy, at least in the foreseeable future.  Laser fusion may prove scientifically feasible, but getting useful energy out of it will be an engineering nightmare, dangerous because of the need to rely on highly volatile and radioactive tritium, and much too expensive to compete with potential alternatives.  I know many of the faithful in the scientific community will beg to differ with me, but, trust me, laser fusion energy aint’ gonna happen.

On the other hand, if ignition is achieved, the NIF will be invaluable to the country, not as a source of energy, but for the reason it was funded in the first place – to insure that our nation has an unmatched suite of experimental facilities to study the physics of nuclear weapons in a era free of nuclear testing.  As long as we have unique access to facilities like the NIF, which can approach the extreme physical conditions within exploding nukes, we will have a significant leg up on the competition as long as the test ban remains in place.  For that, if for no other reason, we should keep our fingers crossed that the NIF team can finally clear the last technical hurdles and reach the goal they have been working towards for so long.

Fusion ignition process,courtesy of Lawrence Livermore National Laboratory

The NIF was built primarily to study various aspects of nuclear weapons science, but it is potentially also of great significance to the energy future of mankind.  Fusion is the source of the sun’s energy.  Just as energy is released when big atoms, such as uranium, are split, it is also released when the central core, or nuclei, of light atoms are “fused” together.  This “fusion” happens when the nuclei are moved close enough together for the attraction of the ”strong force,” a very powerful force but one with a range limited to the very short distances characteristic of atomic nuclei, to overwhelm the “Coulomb” repulsion, or electric force that tends to prevent two like charges, such as positively charged atomic nuclei, from approaching each other.  When that happens with deuterium, whose nucleus contains a neutron and a proton, and tritium, whose nucleus contains two neutrons and a proton, the result is a helium nucleus, containing two neutrons and two protons, and a free neutron that carries off a very large quantity of energy.

The problem is that overcoming the Coulomb force is no easy matter.  It can only be done if you pump in a lot of energy to “light” the fusion fire.  On the sun, this is accomplished by the massive force of gravity.  Here on earth the necessary energy can be supplied by a fission explosion, the source of energy that “lights” thermonuclear bombs.  Mother Nature decided, no doubt very wisely, to make it very difficult to accomplish the same thing in a controlled manner on a laboratory scale.  Otherwise we probably would have committed suicide with pure fusion weapons by now.  At the moment, two major approaches are being pursued to reach this goal.  One is inertial confinement fusion, or ICF, as used on the NIF.  In inertial confinement fusion, the necessary energy is supplied in such a short period of time by massive lasers or other “drivers” that the fuel is held in place by its own inertia long enough for significant fusion to occur.  In the other approach, magnetic fusion, the fusion fuel is confined by powerful magnetic fields as it is heated to fusion temperatures.  This is the approach being pursued with ITER, the International Thermonuclear Experimental Reactor, currently under construction in France.

Based on computer models and the results of experiments on much smaller facilities, such as NOVA at Livermore, and OMEGA at the University of Rochester, it was expected that fusion could be accomplished with the nominal 1.8 megajoules of energy available from the 192 NIF laser beams.  It was to happen like this – carefully shaped laser pulses would implode the fusion fuel to extremely high densities.  Such implosions have already been demonstrated many times in the laboratory.  The problem is that, to achieve the necessary densities, one must compress the fuel while it is in a relatively “cold” state (it is much more difficult to “squeeze” something that is “hot” in that way).  Unfortunately, fusion doesn’t happen in cold material.  Once the necessary high densities have been achieved, it is somehow necessary to heat at least a small portion of the material to the extreme temperatures necessary for fusion to occur.  If that can be done, a “burn wave” will move out from this “hot spot,” igniting the rest of the cold fuel material.   Of course, this begs the question of how one is to produce the “hot spot” to begin with.

On the NIF, the trick was to be accomplished by setting off a series of converging shocks in the fuel material during the implosion process.  Once the material had reached the necessary high density, these shocks would converge at a point in the center of the imploded target, creating a spot hot enough to set off the burn wave referred to above.  It would be a neat trick if it could be done.  Unfortunately, it was never demonstrated on a laboratory scale before the NIF was built.  Obviously, the “trick” is turning out to be harder than the scientists at Livermore expected.  There could be many reasons for this.  If the implosion isn’t almost perfectly symmetric, the hot and cold fuel materials will mix, quenching the fusion reaction.  If the timing of the shocks isn’t just right, or the velocity of the implosion is too slow, the resulting number of fusion reactions will not be enough to achieve ignition.  All kinds of complicated physical processes, such as the generation of huge magnetic and electric fields, so-called laser-plasma instabilities, and anomalies in the absorption of laser light, can happen that are extremely difficult to include in computer models.

The game isn’t up yet, though.  There are some very bright folks at Livermore, and they may yet pull a rabbit out of the hat.  Even if the current “mainline” approach using central hot spot ignition doesn’t work, it may be possible to create a hot spot on the outer surface of the imploded target using a technique known as fast ignition.  Currently, “indirect drive” is being used on the NIF.  In other words, the laser beams are shot into a cylindrical can, or “hohlraum,” where their energy is converted to x-rays.  These x-rays then “indirectly” illuminate the target.  The NIF can also accommodate a “direct drive” approach, in which the laser beams are aimed directly at the target.  Perhaps it will work better.  One hopes so.  Some of the best old knights of science have been riding towards that El Dorado for a long time.  It would be great to see them finally reach it.  Alas, to judge by the deafening silence coming out of Livermore, it seems they are still a long way off.

And what of ITER?  Let me put it this way.  Along with the International Space Station, the project is one of the two greatest scientific white elephants ever concocted by the mind of man.  The NIF is justified because it cost only a fraction of ITER, and it was never conceived as an energy project.  It was always intended as an above ground experimental facility that would enable us to maintain our nuclear arsenal in the absence of testing.  As such, it is part of an experimental capability unequalled in the rest of the world, and one which will give us a very significant advantage over any potential enemy as long the ban on testing continues.  ITER, on the other hand, can only be justified as an energy project.  The problem with that is that, while it may work scientifically, it will be an engineering nightmare.  As a result, it is virtually inconceivable that magnetic fusion reactors similar to ITER will ever produce energy economically any time in the next few hundred years.

A big part of the problem is that such reactors will require a tritium economy.  Each of them will burn on the order of 50 kilograms of tritium per year.  Tritium is highly radioactive, with a half-life of 12.3 years, is as difficult to contain as any other form of hydrogen, and does not occur naturally.  In other words, failing some outside source, each reactor will have to produce as much tritium as it consumes.  Each fusion reaction produces a single neutron, and neutrons can interact with an isotope of lithium to produce tritium.  However, some of the neutrons will inevitably be lost, so it will be necessary to multiply their number.  This trick can be accomplished with the element beryllium.  In other words, in order to build a workable reactor, it will be necessary to have a layer of some extremely durable material containing the plasma, thick enough to resist radiation embrittlement and corrosion for some reasonable period of time, followed by a layer of highly toxic beryllium thick enough to generate enough neutrons, followed by a layer of highly reactive lithium thick enough to produce enough tritium to keep the reaction going.  But wait, there’s more!  It will then be necessary to somehow quickly extract the lithium and return it to the reaction chamber without losing any of it.  Tritium?  Lithium?  Beryllium?  Forget about it!  I’m sure there are any number of reactor design studies that all “prove” that all of the above can be done economically.  I’m also sure none of them are worth the paper they are printed on.  We have other options that don’t suffer from the drawbacks of a tritium economy and are far more likely to produce the energy we need at a fraction of the cost.

Meanwhile, ITER crawls ahead, sucking enormous amounts of research money from a host of more worthy projects.  A classic welfare project for smart guys in white coats, there are no plans to even fuel it with tritium before the year 2028!  I’m sure that at this point many European scientists are asking a simple question; Can’t we please stop this thing?

Fusion is immensely promising as a potential future source of energy.  However, we should not be seduced by that promise into throwing good money after bad, funding a white elephant that has virtually no chance of ever fulfilling that promise.  I suspect that one of these days we will “finesse” Mother Nature, and devise a clever way to overcome the Coulomb barrier without gigantic superconducting magnets or massive arrays of lasers.  Scientists around the world are currently working on many novel and speculative approaches to fusion.  Few of them are likely to succeed, but it just takes one.  We would be much better off funding some of the more promising of these approaches with a fraction of the money currently being wasted on ITER, and devoting the rest to developing other technologies that have at least a fighting chance of eventually producing energy economically.

Meanwhile, I’m keeping my fingers crossed for the NIF crew at Livermore.  It ain’t over until the fat lady sings, and she’s still a long way off.

There are, in turn, two basic approaches to ICF.  In one, referred to as direct drive, the target material is directly illuminated by the laser beams.  In the other, indirect drive, the target is placed inside a small container, or “hohlraum,” with entrance holes for the laser beams.  These are aimed at the inside walls of the hohlraum, where they are absorbed, producing x-rays which then compress and ignite the target.  The NIF currently uses the latter approach.

The NIF was completed and became operational in 2009.  Since that time, the amount of news coming out of the facility about the progress of experiments has been disturbingly slight.  That is not a good thing.  If everything were working as planned, a full schedule of ignition experiments would be underway as I write this.  Instead, the facility is idle.  The results of the first experimental campaign, announced in January, sounded positive.  The NIF had operated at a large fraction of its design energy output of 1.8 Megajoules.  Surrogate targets had been successfully compressed to very high densities in symmetric implosions, as required for fusion.  However, on reading the tea leaves, things did not seem quite so rosy.  Very high levels of laser plasma interaction (LPI) had been observed.  In such complex scattering interactions, laser light can be scattered out of the hohlraum, or in other undesired directions, and hot electrons can be generated, wreaking havoc with the implosion process by preheating the target.  We were assured that ways had been found to control the excess LPI, and even turn it to advantage in controlling the symmetry of the implosion.  However, such “tuning” with LPI had not been foreseen at the time the facility was designed, and little detail was provided on how the necessary delicate, time-dependent shaping of the laser pulses would be achieved under such conditions.

After a long pause, another series of “integrated” experiments was announced in October.  Even less information was released on this occasion.  We were informed that symmetric implosions had been achieved, and that, “From both a system integration and from a physics point of view, this experiment was outstanding,”  Since then, nothing.  

It’s hard to imagine that the outlook is really as rosy as the above statement would imply.  The NIF was designed for a much higher shot rate.  If it sat idle through much of 2010, there must be a reason.  It could be that damage to the laser optics has been unexpectedly high.  This would not be surprising.  Delicate crystals are used at the end of the chain of laser optics to triple the frequency of the laser light, and, given that the output energy of the facility is more than an order of magnitude larger than that of its next largest competitor, damage may have occurred in unexpected ways, as it did on Nova, the NIF’s predecessor at Livermore.  LPI may, in fact, be more serious, more difficult to control, and more damaging than the optimistic accounts in January implied.  Unexpected physics may be occurring in the absorption of laser light at the hohlraum walls.  Whatever the problem, Livermore would be well advised to be forthcoming about it in its press releases.  After all, the NIF will achieve ignition or not, regardless of how well the PR is managed.

All this seems very discouraging for the scientists who have devoted their careers to the quest for fusion energy, not to mention the stewards of the nation’s nuclear weapons stockpile, whose needs the NIF was actually built to address.  In the end, these apparent startup problems may be overcome, and ignition achieved after all.  However, I rather doubt it, unless perhaps Livermore comes up with an alternative to its indirect drive approach.

ITER

The Baseline describes ITER all the way from the beginning of construction, through commissioning, and on to Deuterium-Tritium operation. The main milestones will be the achievement of First Plasma in November 2019 and the start of Deuterium-Tritium operation by March 2027 ultimately taking ITER to 500 MW of fusion power.

He adds that “The world is watching us closely.” If so, it appears we’re going to be watching closely for a very long time. Evidently the plasma physics guys are nursing this thing like an all day sucker. It sounds like the scheduled building time is already running neck and neck with the Great Pyramid, and will soon be giving some of the Gothic cathedrals of the Middle Ages a run for their money.

With any luck, some bright physicist(s) will finesse Mother Nature out of her fusion secrets using some known (see, for example, here and here) or yet to be discovered alternative to the “traditional” brute force magnetic and inertial confinement fusion approaches well before they ever get around to feeding tritium to this white elephant. Failing that, maybe the upcoming experiments on the National Ignition Facility (NIF) will be a lot more successful than I expect. Either way, some excuse to pull the plug on ITER is sorely needed. If nothing else, it will encourage some very bright scientists to do something useful with their talents for a change. All complex cost analyses done using the most up to date methods to the contrary, ITER will never be able to compete with the available alternative energy sources in terms of cost any time in the next few centuries.

This is an epic drama about unlimited energy, the realignment of international power in a truly new world order unlike anything envisioned before, and deadly conflict between political and military centers of power. Controlled fusion energy ignites a firestorm of competing interests from within the top levels of government to the “oil patch” to the United Nations and ultimately to the world. How is it that a visionary physicist/entrepreneur was able to achieve the technological breakthrough of the century?

The author himself adds some detail to the picture;

I wrote a novel, “On Deception Watch,” that was triggered by my visit to KMS Fusion,” a real company that in 1975 really accomplished laser fusion ignition of a deuterium/tritium target and was then harassed to death by the federal government and its assets essentially looted by the feds. My novel is about the premise of a company that does what KMS Fusion did and then what. Check out KMS Fusion, Keeve Siegel, the president of the company, and my novel. One exploration in it is about what replaces the United Nations. The story takes place about 25 years in the future.

W-e-e-e-l-l-l. It wasn’t quite like that, and I doubt the author believes it himself.  According to Xlibris, he has a Ph.D. in physics and, if so, I’m sure he doesn’t really believe KMS accomplished ignition back in 1975.  Still, the above account isn’t going to mislead anyone whose tastes don’t already run to yarns about the Da Vinci Code, the Celestine Prophecy, and the Maya calendar, because the original papers about what happened then are still available, and many of the people who did the experiments are still around.  We’ll cut Spielberg some slack and call it “poetic license,” forgivable from an author who’s just published his first novel.  Regardless, the story of KMS is certainly fascinating even without such embellishments.

In fact, there was a guy named Keeve (or “Kip” as he was better known) Siegel, his initials were KMS, and he was a brilliant entrepreneur who, back in the 60′s, became convinced that inertial confinement fusion (ICF) was within reach using the laser technology then available.  Gathering a crew of talented scientists, he founded KMS Fusion and built the “Chroma” laser in Ann Arbor, Michigan, and, without government funding, actually succeeded (in 1974, not 1975) in demonstrating fusion from a laser-driven implosion in the laboratory for the first time, beating embarrassed teams at Los Alamos and Livermore National Laboratories to the punch.  It was a remarkable achievement, but was still orders of magnitude away from “ignition,” usually defined as equivalent to “scientific breakeven,” which occurs when the energy released from fusion equals the energy carried by the laser beams driving the reaction.  Siegel, a very heavy man, died dramatically less than a year later, suffering a stroke while appealing for government funding before the Joint Congressional Committee on nuclear power.  According to the Wikipedia article about him linked above,

At this time, KMS Fusion was indisputably the most advanced laser-fusion laboratory in the world. Unfortunately, outright harassment from the AEC only increased after the announcement of these results. According to one source in the faculty of the University of Michigan, the campaign against KMS Fusion culminated with a massive incursion into the KMS Fusion facilities by federal agents, who effectively put an end to its operations by confiscating essential materials on the grounds that, inter alia, all information concerning the production of nuclear energy is classified information which belongs exclusively to the federal government.

As usual, caution is due in taking Wiki at face value, and this account is pure mythology.  The AEC was abolished in 1974, so was in no position to “harass” KMS.  If the government continued to “harass” KMS after that, it chose an odd way of doing it, because KMS actually succeeded in securing a multi-million dollar government contract to continue its research after Siegel’s death.  This was renewed several times, and KMS became a major player in the government ICF program, eventually becoming the lead laboratory for target development and production.  The company eventually ran afoul of its sponsors at the Department of Energy in the early 90′s for reasons that had nothing to do with suppressing its research results, and lost its government contract to General Atomics, which continues as the “lead lab” for inertial fusion targets to this day.  KMS continued a shadow existence for many years, but that effectively ended its role as a player in ICF.

That said, it’s quite true that there was friction between KMS and the inertial fusion guys at the national laboratories, just as there has always been friction between the national laboratories themselves.  The teams at Los Alamos, Livermore, and Sandia all coveted the research dollars that were going to KMS, whose management didn’t endear itself by a bad habit of lobbying for earmarks over and above the funding DOE wanted it to have with the aid of Michigan representatives in Congress.  The lab guys all seemed to believe that this money came out of their hide.  They argued that the Chroma laser in Ann Arbor was obsolete, and that KMS should end experiments there and concentrate on target fabrication.  Well, after KMS’ collapse, Chroma was cannibalized, the lion’s share of its optical innards going to Los Alamos.  There, after being rechristened “Trident,” this “obsolete” laser continues in operation to this day!

As for ignition, it turned out that the slogan of “online by ’79″ was a tad optimistic.  Mother Nature had other ideas.  The computer power available when KMS was founded was very limited, and the computer programs that had predicted the possibility of ignition with relatively small lasers like Chroma were limited to looking at the problem in one dimension.  It turns out that multi-dimensional effects, such as the Rayleigh-Taylor instability, make ignition much harder to achieve than the first generation of computer codes predicted.  It’s probably a good thing, too, because otherwise we may have succeeded in blowing ourselves up by now with pure fusion weapons.  In any case, we kept building bigger laser facilities, eventually culminating in the recent completion of the National Ignition Facility at Livermore, a massive, 192 beam system capable of delivering a nominal 1.8 megajoules of blue (frequency-tripled) light.  As its name implies, its goal is to achieve ignition, and the critical experiments designed to achieve that goal will take place in the next couple of years.  I am not optimistic that they will succeed, but am keeping my fingers crossed that they do.

Meanwhile, I wish Dr. Spielberg every success with his novel.  It sounds like a great yarn, and should bring a smile to the faces of ICF old timers.

If anyone around today lives to see the dawn of the era of fusion energy, it will probably be because some exceptionally clever researcher has hoodwinked Mother Nature and discovered how to finesse his way past the Coulomb barrier that usually keeps atomic nuclei too far apart to come within the range of the fusion-enabling strong force. Several promising candidates are already in the field, and one of them, Tri-Alpha Energy, has apparently managed to attract $50 million in private research funding. The company hasn’t revealed the nature of its approach, but it is apparently inspired by the work of Prof. Norman Rostoker of UC Irvine. One can get a broad hint from this paper co-authored by Rostoker and Tri-Alpha entitled, “Colliding Beam Fusion Reactors.” Rostoker is an emeritus professor who has been publishing papers since the 50′s, some co-authored with fusion superstars such as Nicholas Krall and Marshall Rosenbluth. Octogenarian physicists don’t often pull off such miracles, but you never know.

If he or someone else ever does manage to pull the fusion rabbit out of the hat, it would potentially put an end to our worries about energy for a very long time. It could also enable pure fusion weapons. Let’s keep our fingers crossed that it doesn’t.

Fusion Reaction

Lithium has become increasingly important lately as a component of small but powerful batteries. It will become a lot more important if fusion energy ever becomes a reality. I don’t expect this to happen anytime soon. Even if the remaining scientific hurdles can be overcome, the engineering difficulties of maintaining the extreme conditions necessary for fusion reliably over the long periods necessary to extract useful electric power would be daunting. Fusion power would likely be too expensive to compete with alternative energy sources under the best of circumstances. However, that’s my opinion, and a good number of very intelligent scientists disagree with me. If they’re right, and the upcoming proof of principle experiments at the National Ignition Facility prove far more successful than I expect, or some scientific breakthrough enables us to tame fusion on much smaller and less costly machines, fusion power may yet become a reality.

In that case, lithium may play a far more substantial role in energy production than it ever could as a component of batteries. It could literally become the metallic “oil” of the future. The reason for that is the fact that the easiest fusion reaction to tame is that between two heavy isotopes of hydrogen; namely, deuterium and tritium.  The “cross section” for the fusion reaction between these two isotopes, meaning the probability that it will occur under given conditions, becomes significant at substantially lower temperatures and pressures than competing candidates.  The fly in the ointment is the availability of fuel material.  Deuterium is abundant in nature.  Tritium, however, is not.  It must be produced artificially.  The raw material is lithium.

It happens that the fusion reaction between deuterium and tritium results in the production of a helium nucleus and a very energetic neutron.  This neutron can cause reactions in either of the two most common naturally occurring isotopes of lithium, Li-6 and Li-7, that produce tritium.  Thus, the fusion reactions that may one day produce energy for electric power could also be leveraged to breed tritium if the reaction were made to take place in the vicinity of lithium, either in a surrounding blanket or one of several other more fanciful proposed arrangements.   

As noted above, I don’t think that day is coming anytime soon.  If it when it does, Afghanistan may well become the Saudi Arabia of a new technological era of energy production.

In inertial confinement fusion, or ICF, the target, a thin, spherical shell containing a mixture of deuterium and tritium, two heavy isotopes of hydrogen, is first compressed and imploded to very high densities.  A series of converging shocks then create a “hot spot” in the center of the compressed material, setting off fusion reactions which release enough energy to set off a ”burn wave.”  This wave propagates out through the remaining fuel material, heating it to fusion energies as well.  The process is known as inertial confinement fusion because it takes place so fast (on the order of a nanosecond) that the material’s own inertia holds it in place long enough for the fusion reactions to occur.  There are two basic approaches; direct drive, in which the laser beams hit the fusion target directly, and indirect drive, the process that will be used in the upcoming Livermore ignition experiments, in which the beams are shot into a hollow can or “hohlraum,” producing x-rays when they hit the inner walls.  These x-rays then implode and ignite the target.  

A potential problem that must be overcome in ICF is known as laser plasma interactions (LPI).  These are parasitic interactions which can soak up laser energy and quench the fusion process.  According to the Livermore paper, special grids at the hohlraum entrance holes were used in the latest experiments, allowing the use of LPI to “tweak” the incoming beams, steering them to just the right spots.  This recent (and elegant) innovation allows the exploitation of a process that has always been considered a major headache in the past to actually improve the chances of achieving igntion.

The BBC and Spiegel both have articles about the latest experiments today, conflating the energy and military applications of the NIF as usual.  According to the Spiegel article, for example, it will be necessary for the lasers in a fusion reactor to hit the target ten times a second, whereas hours are necessary between shots at the NIF.  The reason, of course, is that the NIF was never designed as an energy project, but is being funded by the National Nuclear Security Administration (NNSA) to conduct nuclear weapons experiments.  If ignition is achieved, the prospects for fusion energy will certainly be improved, but the prospects aren’t nearly as bright as the press releases from LLNL would imply.  It will still be necessary to overcome a great number of scientific and engineering hurdles before the process can ever become useful and economical as a source of energy.

I am not optimistic about the success of the upcoming experiments.  I suspect it will be too difficult to achieve the fine beam energy balance and symmetry that will be necessary to ignite the central “hot spot.”  It will take more than one converging shock to do the job.  Several will be necessary, moving inward through the target material at just the right speed to converge at a small spot at the center.  If they really pull it off, I will be surprised, but will be more than happy to eat crow.  A lot of very talented scientists have dedicated their careers to the quest for fusion, and I’m keeping my fingers crossed for them. 

Even if these ignition experiments fail, it won’t mean the end for fusion by a long shot.  We know we can achieve the high fuel densities needed for inertial fusion, and there are other ways of creating the “hot spot” needed to achieve ignition, such as “fast ignitor.”  Other approaches to fusion keep showing up in the scientific literature, and I can’t help but think that, eventually, one of them will succeed.

Myth number one is, “We need to do everything possible to promote alternative energy.” Grunwald prefers a different emphasis: “…though the world should do everything sensible to promote alternative energy, there’s no point trying to do everything possible.” The information content of this bit of wordsmithing as it stands is epsilon (a very small number). From the left to the right of the ideological spectrum, I have never encountered anyone who proposes that we should do everything possible to promote alternative energy, including things that don’t make sense. Reading on, one notes that, in a blurb that is supposed to be about alternative energy, Grunwald studiously avoids any mention of such credible candidates as wind, solar, and geothermal. Rather, he directs his ire at alternatives that aren’t quite ready for prime time: “Hydrogen cars, cold fusion, and other speculative technologies might sound cool, but they could divert valuable resources from ideas that are already achievable and cost-effective.” This statement is logically absurd.

Consider fusion for example. The amount of resources being “diverted” worldwide to the energy applications of fusion, including both its hot and cold flavors, is utterly insignificant in comparison to the amount we spend on energy production, the total amount we spend on research, or any other number one could reasonably compare it to. I am no fusion true believer. It is a high risk technology, and one that will almost certainly not figure in the world’s energy equation before Grunwald’s target date of 2050. If, on the other hand, we can overcome the daunting technological hurdles Mother Nature has put in our path and find a way to use it, fusion has the potential to meet the world’s energy needs indefinitely while releasing no greenhouse gases and with an insignificant radiological hazard compared to nuclear and coal. There are many interesting research efforts afoot to finesse the technological problems that beset such “traditional” approaches as magnetic and inertial confinement fusion. The amount of research dollars being devoted to these efforts is miniscule. They can all be characterized as high risk, but it is hardly implausible to suggest that, eventually, one of them will succeed. If so, the payoff will be enormous. The problem of greenhouse gas emissions might be solved once and for all, without the severe environmental impact of covering massive areas with wind farms and solar collectors. In a word, if we are truly worried about global warming, it would be utterly reckless and senseless to eliminate the tiny resources we currently devote to energy applications of fusion. As we shall see, Grunwald’s reasons for rejecting such alternatives, not to mention the seeming lack of interest in such immediately available sources such as wind, solar and geothermal have more to do with psychology than logic.

Moving on to myths 2 and 3, Grunwald turns his ire on biofuels, such as ethanol derived from corn. No surprise there, as he has often hammered the “clean energy” hype emanating from that sector in the past. He notes that such “renewable fuels” have been heavily promoted by governments around the world, including ours, but points out, “…so far in the real world, the cures — mostly ethanol derived from corn in the United States or biodiesel derived from palm oil, soybeans, and rapeseed in Europe — have been significantly worse than the disease.” So far, so good. I have yet to see a convincing argument in favor of biofuels that seriously addresses such problems as the facts that their production results in a net loss in energy, horrific environmental damage, and a reduction in the world’s food supply. The problem with myths 2 and 3 is that they are strawmen. I know of no credible authority outside of industry advocates who is seriously suggesting that biofuels are a plausible solution to global warming.

Grunwald’s myth 4 is, “Nuclear power is the cure for our addiction to coal.” This seems counterintuitive, since, according to the most reliable studies, the carbon footprint of nuclear plants is a small fraction of that of its fossil fuel alternatives. Among the reasons Grunwald cites for dismissing the nuclear alternative is the fact that it will be too slow coming on line to make a dent in carbon emissions in the near term. That’s quite true, but while one may certainly point to it as an unfortunate fact of life, it is certainly no reason to abandon nuclear altogether. If global warming is really the problem Grunwald claims it is, than surely late is better than never.

Be that as it may, Grunwald cites cost as the real show stopper for nuclear power. As he puts it,

Nuke plants are supposed to be expensive to build but cheap to operate. Unfortunately, they’re turning out to be really, really expensive to build; their cost estimates have quadrupled in less than a decade. Energy guru Amory Lovins has calculated that new nukes will cost nearly three times as much as wind — and that was before their construction costs exploded for a variety of reasons, including the global credit crunch, the atrophying of the nuclear labor force, and a supplier squeeze symbolized by a Japanese company’s worldwide monopoly on steel-forging for reactors.

At this point, the familiar anti-nuclear “green” narrative emerges from the mist, and Grunwald leaves logical argument in the dust. Amory Lovins is certainly someone worth listening to. He is also one of the legacy media’s beloved “mavericks,” and hardly someone whose cost estimates represent the final word on the subject. In fact, if one looks at the credible cost estimates of nuclear versus its alternatives, not just from sources connected with the industry, but, for example, from a study done in 2003 by an interdisciplinary group of MIT professors and updated in 2009, the suggestion that nuclear is “really, really expensive” compared to the alternatives may be dismissed as bunk. Grunwald might have had some credibility if he had taken the trouble to dispute these estimates with arguments more substantial than anecdotes about Japanese steel monopolies. As it is, it is clear that his rejection of nuclear has nothing to do with its intrinsic merits or lack thereof. Rather, it simply doesn’t fit in the “conservation and efficiency” narrative he shares with Lovins. Grunwald uses myths 5 through 7 to outline the narrative.

It turns out that myth 5, “There is no silver bullet to the energy crisis,” is only a pseudo-myth. As Grunwald himself admits, “Probably not.” Be that as it may, he clearly has a silver bullet in mind; efficiency. In his words,

But some bullets are a lot better than others; we ought to give them our best shot before we commit to evidently inferior bullets. And one renewable energy resource is the cleanest, cheapest, and most abundant of them all. It doesn’t induce deforestation or require elaborate security. It doesn’t depend on the weather. And it won’t take years to build or bring to market; it’s already universally available. It is called “efficiency.”

Conservation and energy efficiency are certainly laudable goals, and ones that should be pursued aggressively. However, Grunwald’s problem is that he sees them in typical journalistic black and white. They are the one true path to salvation, as opposed to the “inferior bullets.” This setting up of artificial barriers separating the plausible alternatives to solving our energy problems into a “good” approach standing in opposition to other “bad” approaches is more a reflection of human psychology than logic. For example, the hard fact is that rejection of nuclear power has and will continue to result in the building of more fossil-fired generation capacity. That is precisely what is going on in Germany, whose “Greens” have forced the foolhardy decision to shut down nuclear plants rather than refurbish them and keep them on line, resulting in the building of new coal plants even as we speak, and in defiance of these same “Greens” warm, fuzzy rhetoric about the virtues of alternative energy. Similarly, Grunwald’s blasé attitude towards alternatives such as wind, solar, and geothermal is more likely to encourage complacency than, for example, an aggressive approach to building the power transmission infrastructure we need to accommodate these new technologies. According to Grunwald,

Al Gore has a reasonably plausible plan for zero-emissions power by 2020; he envisions an ambitious 28 percent decrease in demand through efficiency, plus some ambitious increases in supply from wind, solar, and geothermal energy. But we don’t even have to reduce our fossil fuel use to zero to reach our 2020 targets. We just have to use less.

Al Gore may be right, but he may also be wrong. Regardless, it would be foolish of us to put all of our eggs in one basket. In particular, it would be very foolish to cut off the already miniscule support we are currently giving to high risk, high payoff technologies such as fusion. It is highly unlikely that global energy demand will go down as the world’s population continues to increase, or that the citizens of emerging economic powers such as India and China will continue to be satisfied with a third world lifestyle. Ignoring technologies that could plausibly solve the problem of global warming because Grunwald thinks they are dumb would be both illogical and, potentially, suicidal. His attitude is typical of the representatives of what H. L. Mencken used to call the “uplift” on the left. Though I suspect most of them don’t realize it themselves, they are far more interested in posing as saviors of mankind than in actually saving mankind. Hence, for example, the hand waving dismissal of nuclear technology. The Grunwalds of the world will continue to dismiss it, not because it is not a plausible piece of an overall solution to the problem of global warming, but because it is unfashionable. If one would strike a truly heroic pose, one cannot afford to be unfashionable.

NIF Beam Lines

True, the NIF was built as a weapons facility, and that’s a big strike against it in the warm, fuzzy world of today. That’s not the whole story, though. The “ignition” in National Ignition Facility means inertial fusion ignition, and a great number of dedicated scientists have devoted their careers to the proposition that fusion ignition will usher in an era of clean energy with a virtually limitless fuel supply. I, personally, find that proposition dubious, at least with the hot spot ignition approach currently envisioned for the NIF. However, a lot of outstanding scientists who probably know more of the relevant physics than I are not similarly dubious, and believe the daunting technical, economic, and engineering hurdles on the path to inertial fusion energy can be overcome.

Now, 35 long, difficult years after the first confirmation of fusion neutrons produced by laser implosion, we finally have an operational facility capable, according to the theorists, of achieving significant energy gain, and we stand on the threshold of the decisive series of ignition experiments that are likely to determine whether they’re right or wrong once and for all. It seems to me that those who have dedicated their lives to a goal they believe will be of incalculable value to all mankind should now, at least, be given a fair shot at achieving that goal. The tool they need is in their hands. Given what’s at stake, not to mention the massive amounts we’ve recently been spending on far less worthy goals, does it not seem logical to give them a chance?

Perhaps Secretary Chu does not agree. It would certainly seem so. NNSA, a part of DOE, manages the NIF, and its budget has been cut to the bare bones. This budget slashing cannot help but affect the coming campaign of ignition experiments at the facility. Well, then, if Secretary Chu does not agree, perhaps it would better befit the leader that he is supposed to be to stand up and explain why, instead of playing hide and seek at dedication ceremonies. Those who have worked long and faithfully to make this project a reality deserve no less.