Sun in a Bottle (30 page)

It was as if everything that could possibly go wrong with NIF was, in fact, going wrong. Some of the issues were minor annoyances: a brief delay in construction followed when workers found mammoth bones on the NIF site. Some were major: the glass supplier was having difficulty producing glass pure enough to use in the laser, forcing a revamp of the entire manufacturing process. Some were just bizarre. The head of NIF, Michael Campbell, was forced to resign in 1997 when officials discovered he had lied about earning a PhD from Princeton University.

Some problems were unexpected but easy to deal with, such as an issue with the capacitors, the devices that store the energy used to pump the laser glass. These devices were packed so full of energy that occasionally one would spontaneously vaporize. It would explode, spraying shrapnel around the room. Engineers solved the problem by putting a steel shield around the capacitors; when one exploded, flapper doors would open and the debris would spray toward the floor.

Some problems were more complex. For example, scientists had long since gone from infrared to green to ultraviolet light to reduce the disproportional heating of electrons compared with nuclei, but ultraviolet light at such high intensities was extremely nasty to optics. It would pit anything it came into contact with. The laser would damage itself every time it would fire. The solution was less than perfect: at NIF’s full power, the optics will have to be replaced every fifty to one hundred shots or so, an extremely expensive prospect.

Furthermore, scientists were still struggling to deal with the Rayleigh-Taylor instability—the one that turns small imperfections on the surface of the fuel pellet into large mountains and deep valleys, destroying any hope of compressing the fuel to the point of ignition. Not only did scientists have to zap the target very carefully—so that the energy shining on the target was the same intensity on every part of the pellet—they also had to ensure that the pellet was extremely smooth. Even tiny imperfections on its surface would quickly grow and disrupt the collapsing plasma. To have any hope of achieving ignition, NIF’s target pellets—about a millimeter in size—cannot have bumps bigger than fifty nanometers high. It’s a tough task to manufacture such an object and fill it with fuel. Plastics, such as polystyrene, are relatively easy to produce with the required smoothness, but they don’t implode very well when struck with light. Beryllium metal implodes nicely, but it’s hard to make a metal sphere with the required smoothness. It was a really difficult problem that wasn’t getting any easier as NIF scientists worked on it.

The cost of the star-crossed project ballooned from about $1 billion to more than $4 billion; the completion date slipped from 2003 to 2008. Worst of all, even if everything worked perfectly, even if NIF’s lasers delivered the right power on target, nobody knew whether the pellet would ignite and burn. As early as the mid-1990s, outside reviewers, such as the JASON panel of scientists, warned that it was quite unlikely that NIF would achieve breakeven as easily as advertised. The prospects for breakeven grew worse as time passed. By 2000, NIF officials, if pressed, might say that the laser had a fifty-fifty shot of achieving ignition. NIF critics, on the other hand, were much less kind. “From my point of view, the chance that [NIF] reaches ignition is zero,” said Leo Mascheroni, one of NIF’s main detractors. “Not 1%. Those who say 5% are just being generous to be polite.” The truth is probably somewhere in between, but nobody will know for sure until NIF starts doing full-scale experiments with all 192 beams.

If NIF fails to ignite its pellets, and if it fails to reach breakeven, laser fusion experiments will still be absorbing energy rather than producing it; the dream of fusion energy will be just as far away as before.
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Furthermore, analysts argued, NIF wouldn’t be terribly useful for stockpile stewardship without achieving breakeven. And NIF’s contribution to stockpile stewardship is crucial for... what, exactly? It’s hard to say for sure. Assume that NIF achieves ignition. For a brief moment, it compresses,confines, and heats a plasma so that it fuses, the fusion reaction spreads, and it produces more energy than it consumes. How does that translate into assuring the integrity of America’s nuclear stockpile?

At first glance, it is not obvious how it would contribute at all. Most of the problems with aging weapons involve the decay of the plutonium “pits” that start the reaction going. Will the pits work? Are they safe? Can you remanufacture old pits or must you rebuild them from scratch? These issues are relevant only to a bomb’s primary stage, the stage powered by fission, not fusion (except for the slight boost given by the injection of a little fusion fuel at the center of the bomb). The fusion happens in the bomb’s secondary stage, and there doesn’t seem to be nearly as much concern about aging problems with a bomb’s secondary. If the primary is where most of the problems are, what good does it do to study fusion reactions at NIF? NIF’s results would seem to apply mostly to the secondary, not the primary.

Since so much about weapons work is classified, it is hard to see precisely what problems NIF is intended to solve. But some of the people in the know say that NIF has a point. The “JASONs,” for example, argue that NIF does help maintain the stockpile—but not right away. NIF will contribute to science-based stockpile stewardship, the panel wrote in 1996, “but its contribution is almost exclusively to the long-term tasks, not to immediate needs associated with short-term tasks.” That is, NIF will help eventually, but it is not terribly useful in the short term.

What are those long-term tasks? Two years earlier, the JASON panel was a little more explicit. NIF would help a bit with understanding what happens when tritium in a primary’s booster decays. (However, since tritium has a half-life of only twelve years, it stands to reason that weapons designers periodically must replace old tritium in weapons with fresh tritium. This is probably routine by now.) NIF will also help scientists understand the underlying physics and “benchmark” the computer codes—like LASNEX—that simulate imploding and fusing plasma. (But why is this important if you are not designing new weapons? The ones in the stockpile already presumably work just fine, so you presumably don’t need a finer understanding of plasma physics to maintain them.) The JASON members have access to classified information, but even so, their justifications for NIF seem a little thin—at first. And then JASON lists one more contribution that NIF makes to stockpile stewardship: “NIF will contribute to training and retaining expertise in weapons science and engineering, thereby permitting responsible stewardship without further underground tests.” That’s the main reason for NIF.

With the moratorium in place, nuclear tests are at an end. New scientists entering the program will never have a chance to design a bomb and test it. They will never have a chance to study a live nuclear explosion. All they have left are computer simulations and experiments that mimic one part of a nuclear explosion. NIF would be the only facility that mimics the explosion of a secondary; it would give young scientists a chance to study secondary physics without ever seeing a nuclear test. And that’s the point of NIF. NIF is essentially a training ground for weapons scientists. As old ones retire and new ones grow up without ever having seen a nuclear test, NIF is a way to give them some level of experience so that America doesn’t lose its nuclear expertise.

NIF isn’t truly about energy. It is not about keeping our stockpile safe, at least not directly. It is about keeping the United States’ weapons community going in the absence of nuclear tests. However, it is contributing next to nothing to the stockpile stewardship program at the moment, and the program is heading toward a crisis. Weaponeers are complaining that the United States is increasingly unable to vouch for its nuclear arsenal, and the government seems to be slowly slouching toward a resumption of nuclear detonations.

A number of ominous signs suggest that nuclear testing might begin again before too long. The debate in the early 2000s about the new Robust Nuclear Earth Penetrator warhead was an indication that the government was thinking beyond the test ban; before deploying the weapon, it almost certainly would need a test. Even though Congress strangled that program, it has blessed the Department of Energy’s campaign to design yet another warhead. The Reliable Replacement Warhead (RRW), as it is called, is supposed to obviate the need for nuclear testing because it would be a hardier device less susceptible to aging. It would be able to assure the reliability of the nation’s nuclear arsenal for decades without nuclear tests. The only problem is that the RRW would probably require a few nuclear tests before anyone was convinced of its reliability in the first place. It’s a paradox: to maintain the nuclear test ban, the United States might have to resume testing.

A debate is also ongoing about shortening the time it will take to prepare the Nevada nuclear test site for a resumption of underground tests. President George W. Bush tried to make the site ready to resume testing within eighteen months, rather than maintain the previous twenty-four-month lead time. But going to a higher level of readiness announced to the world that the nation was moving toward ending the moratorium, and this could hamstring American attempts to stem the proliferation of nuclear weapons around the world. Year after year, the president put money for eighteen-month readiness in the budget; year after year, Congress took it out. Even without the cash, though, the National Nuclear Security Administration, the organization inside the Department of Energy responsible for nuclear weapons, lists eighteen-month test-site readiness as an integral part of the stockpile stewardship program.

The stockpile stewardship program will soon reach a crisis point. Will the federal government be able to assure the reliability of the stockpile without testing nuclear weapons as the program originally promised? Or will it fail, forcing a resumption of testing, breaching the moratorium in place for over a decade? The move toward renewed nuclear testing is happening now, and NIF, if it helps with stockpile stewardship at all, will do so indirectly and in the distant future. The nontesting regime might well be in tatters by the time scientists get any benefit from the multibillion-dollar machine supposedly designed to uphold it.

NIF is the state of the art in laser fusion, yet it is a deeply troubled project. It is vastly more expensive than originally projected. Even if it works perfectly, it won’t keep the country’s nuclear arsenal working or the nontesting policy alive. For a decade, experts have questioned whether it would be sufficiently powerful to achieve ignition and breakeven—and if the history of laser fusion is any guide, NIF, like Nova, will fail to reach its goal. Yet NIF marches on. Laser fusion scientists won’t give up their decades-old dream to put a star in a bottle. And if they fail, as it appears they will, after spending more than $4 billion, there is little hope that they can sucker the government into building yet another bigger and better laser machine.

 

 

In 2002, five years after the United States abruptly left the ITER project, fusion scientists were about to get a serious case of déjà vu.

The American departure shook the ITER collaboration—and branded the United States as an unreliable partner when it came to international science—but the project limped along. Russia, Europe, and Japan continued designing an international fusion reactor. The plans they came up with were much less ambitious than the original ITER. The plasma in the reactor would span twelve meters rather than sixteen meters. It would not achieve ignition and sustained burn—the plasma would never be fusing enough to keep itself warm—but if all went well, the reactor would be able to keep a plasma confined for up to an hour and produce ten times as much power as it consumed. (It would finally achieve breakeven—for real, this time.) It would cost half as much as the original ITER: $5 billion, rather than $10 billion.
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The American magnetic fusion program, in the meantime, was in ruins. There was no big domestic tokamak, just a few lesser ones in Boston and in San Diego. The big domestic tokamak, TFTR, had been shut down in 1997 to make room for ITER. Princeton, once home of the $100 million giants, was reduced to working on a tiny, $25 million spherical torus. Plans existed for larger machines, such as billion-dollar tokamaks, but they were just dreams; there was no chance they would be built. The United States was rapidly retreating from the cutting edge of magnetic fusion. Instead of getting a robust domestic program along with an enormous international reactor, American fusion scientists had neither. By 2002, with slim pickings at home, those scientists began to eye the slimmed-down ITER project, argued that many of the design flaws of the original machine had been fixed, and asked to rejoin the collaboration. At a cost of only about $1 billion, they argued, the United States could become an ITER partner again. The request worked its way up the food chain—from the scientists to a fusion advisory panel, to the head of the Department of Energy’s Office of Science, to the secretary of energy, to the president. The answer was yes.

In early 2003, President Bush announced that the United States was back in the collaboration. The Americans would rejoin ITER.
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Even though the machine’s design had been revamped and the collaboration had expanded—China, South Korea, and Canada had joined in—the same problems that haunted the first incarnation of ITER remained. For one thing the partners were still fighting over where the machine would be built.

Japan and Europe were the main contenders. Each attacked the other’s proposal. Japan complained that the proposed European site in the south of France was too far from a port. The French argued that the Japanese site was prone to earthquakes. Most scientists in the United States understandably seemed to prefer a laboratory a short drive from the French Riviera to one near a dismal brackish lake in the north of Japan, but the United States officially backed the Japanese site. Some Europeans hinted, darkly, that American support of Japan over France was political payback for France’s criticism of the Iraq war. The Japanese accused the Europeans of circulating a nasty anonymous memo to the ITER parties that faulted the Japanese choice of site. China and Russia backed France. Canada pulled out of the collaboration entirely. Europe threatened to do so as well. In early 2005, more than three years after the United States had reentered the collaboration, ITER was deadlocked and on the brink of unraveling once again.