Confusion plagues fusion news from the National Ignition Facility in California

At the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory (LLNL), does recent progress in fusion-energy research constitute a momentous and highly encouraging breakthrough? Is it merely one step in a many-decade process? In media reports, views on that subjective question vary. So does factual understanding.

The 192 laser beams at NIF deliver 1.7 or 1.8 megajoules (reports differ) to a capsule of deuterium–tritium fuel, ultimately—and hopefully—to achieve ignition, a self-sustaining fusion reaction that yields more energy than the lasers put in. At LLNL, the federal shutdown may have exacerbated media confusion about NIF, since reporters haven’t had access to scientists and information officers.

On 7 October, BBC science editor Paul Rincon reported online that NIF researchers had “passed a crucial milestone on the way to their ultimate goal of achieving self-sustaining nuclear fusion.” The piece was fairly widely noted. Rincon wrote that “during an experiment in late September, the amount of energy released through the fusion reaction exceeded the amount of energy being absorbed by the fuel—the first time this had been achieved at any fusion facility in the world.”

Rincon added a line that a Washington Post blogger then quoted: the achievement “has been described as the single most meaningful step for fusion in recent years, and demonstrates NIF is well on its way towards the coveted target of ignition and self-sustaining fusion.” The blog qualified that enthusiasm, however, by linking to—though not actually naming—what it called “a more measured take": the Physics Today Online (PTOL) article “Lab reports big advance in laser fusion quest.”

Though that 13 September PTOL article actually appeared before the 28 September NIF work that Rincon praised, it still has relevance. It covers a 13 August NIF experimental run that “produced as many as one quarter of the neutrons needed to trigger sustained fusion.”

The article reports the views of Ed Moses, LLNL’s principal associate director for NIF, about that 8-kilojoule yield: It “puts NIF a factor of four to five away from ignition.” Only “a factor-of-two increase in plasma energy will be needed to attain alpha heating, an intermediate milestone at which alpha particles from fusion reactions contribute twice as much energy to the plasma as the laser does.” The PTOL article adds, “One to two more kilojoules reaching the plasma from the laser should be enough to yield the 15 kJ of fusion energy and from 6 × 1015 to 8 × 1015 neutrons that will produce alpha heating, Moses says.”

Fifteen kilojoules? The more recent news engages NIF’s 28 September attainment of 14 kilojoules. “September’s yield may not be ignition,” writes Alan Boyle, NBCNews.com’s science editor, “but it represents a 75 percent improvement over the previous record output of 8,000 joules, set just a month earlier.”

When Boyle explains that the energy released by the reaction exceeded the energy absorbed by the fuel capsule, he stipulates that that’s “nowhere near” the 192 lasers’ total input of 1.8 million joules. There he touches on a crucial point of factual confusion. Some in the media fail to recognize that the ratio of energy absorbed by the capsule to input energy from the lasers is far different from the ratio of energy produced to input energy. They miss a basic point explained in the PTOL piece: “Only a few kilojoules of [the lasers’] energy actually winds up in the plasma.”

At National Journal—and leaving aside the question of energy versus power—someone should have replaced the word received with the word absorbed in this opening : “A nuclear-fusion fuel target emitted more power than it received from a massive laser array.” At Engineering.com, which claims to bring “the most influential voices in engineering to a worldwide audience of engineers,” a headline said, falsely, “Fusion reaction produces net energy.” The article reported, “Until now, break-even fusion reactions (i.e., reactions that produce as much energy as required to ignite them) have eluded scientists.” A publication called Petroleum News, citing BBC and “other news outlets,” reported , falsely, that NIF “has succeeded in generating a nuclear fusion reaction that generated more energy than was required to cause the reaction to take place.”

Fox News’s online NIF piece got the ratios wrong at first, but further along, reversed itself. The Guardian, though it didn’t confuse the two ratios, reported breathlessly in a headline that nuclear fusion had achieved a “massive energy breakthrough.” The Daily Beast confused the concepts energy and fuel, reporting that the experiment caused “more fuel to exceed the amount of fuel absorbed.” It added, “This stopped just short of ignition, where nuclear fusion generates as much fuel as the lasers supply.”

On the other hand, Boyle at NBC, the Telegraph , and Ars Technica got the ratios right. CBS News, though it showed some confusion about the phrase break-even point, reported sort of accurately—if you overlook another fuel-and-energy conflation—that the late-September experiment “succeeded in releasing more energy through a fusion reaction than it absorbed by the fuel going in.”

Though BBC’s original report also got the ratios right, it figures centrally in media criticism from Daniel Clery, a deputy news editor at Science magazine. His piece carries the headline “Fusion ‘Breakthrough’ at NIF? Uh, Not Really....” That online article’s prominently placed photo caption says, “Science reporting breakdown? Press reports of a breakthrough at the National Ignition Facility...turned out to be a bit of hype.” Citing and blaming BBC, Clery asserts that the experiment “shows important progress, but it is not the breakthrough everyone is hoping for.”

Clery reports just before his article’s close that Michael Campbell, a former director of NIF, “is concerned about overhyping each step in what is bound to be a long haul toward fusion as an energy source.” Clery’s final paragraph requires quoting:

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Steven T. Corneliussen, a media analyst for the American Institute of Physics, monitors three national newspapers, the weeklies Nature and Science, and occasionally other publications. He has published op-eds in the Washington Post and other newspapers, has written for NASA’s history program, and is a science writer at a particle-accelerator laboratory.