Breakeven breakthrough at the National Ignition Facility

December 13, 2022, 3:02PMNuclear News
The target chamber of LLNL’s NIF, where 192 laser beams delivered more than 2 million joules of ultraviolet energy to a tiny fuel pellet to create fusion ignition on December 5, 2022.

It’s official: Early in the morning on December 5 at Lawrence Livermore National Laboratory’s National Ignition Facility (NIF), the laser-triggered implosion of a meticulously engineered capsule of deuterium and tritium about the size of a peppercorn yielded, for the first time on Earth, more energy from a fusion reaction than was delivered to the capsule. The input of 2.05 megajoules (MJ) to the target heated the diamond-shelled, spherical capsule to over 3 million degrees Celsius and yielded 3.15 MJ of fusion energy output. The achievement was announced earlier today by officials and scientists representing the Department of Energy and its National Nuclear Security Administration, the White House, and LLNL during a livestreamed event.

News headlines that preceded the announcement fused awe and skepticism about the timeline for fusion power deployment. To the public looking for an immediate clean energy breakthrough, today’s announcement of scientific breakeven—and the acknowledgment that decades of work are ahead before laser-driven inertial confinement fusion could yield grid-ready energy—may not match the media hype. But for the generations of researchers who contributed to the achievement, it is an inspiring affirmation that incremental advances in science and engineering do yield breakthroughs. The announcement of a landmark achievement in inertial confinement fusion drops at a time when private-sector fusion energy developers—most but not all using magnetic confinement concepts—are already generating buzz and funding, and the U.S. (once again) has a target date to generate power from a pilot-scale fusion plant in the late 2030s.

We have a plan: This is where the nation’s “bold decadal plan” to accelerate fusion research, development, and demonstration, announced during a March 2022 White House Fusion Summit, comes in. That mission to accelerate the viability of commercial fusion energy in partnership with the private sector is based in part on the National Academies of Sciences, Engineering, and Medicine report Bringing Fusion to the U.S. Grid. That report, published in February 2021, targets the 2035–2040 time frame for an operational 50-MWe fusion pilot plant. A viable design for the plant would be needed by 2028, the report says.

In September 2022, the DOE announced up to $50 million for a new milestone-based fusion energy development program open to for-profit companies—possibly teamed with national laboratories, universities, and others—that are prepared to meet major technical and commercialization milestones leading to a pilot fusion power plant design.

During the December 13 livestream event, energy secretary Jennifer Granholm confirmed that the funding opportunity announcement is open to both magnetic and inertial confinement fusion power plant designs. “We are just looking at the best proposals that come in, and hopefully we'll have a decision on that first $50 million early in the new year,” she said.

Fusion energy requires a machine that can generate a triple product (an industry measure of plasma density, temperature, and confinement) high enough to produce net gain, and inertial and magnetic confinement concepts take different approaches to push that triple product higher. As LLNL director Kim Budil explained, “Essentially magnetic fusion works at low pressures and densities and for long times, whereas inertial confinement fusion works at high pressures and densities for very short times. So there are some similarities in the underlying physics, but the fundamental concepts are quite different.”

A date to remember: According to a press release issued today by LLNL, “On December 5, a team at LLNL’s National Ignition Facility (NIF) conducted the first controlled fusion experiment in history to reach this milestone, also known as scientific energy breakeven, meaning it produced more energy from fusion than the laser energy used to drive it. This first-of-its-kind feat will provide unprecedented capability to support NNSA’s Stockpile Stewardship Program and will provide invaluable insights into the prospects of clean fusion energy, which would be a game-changer for efforts to achieve President Biden’s goal of a net-zero carbon economy.”

Whether or not December 5, 2022, will be seen years from now as a fusion parallel to December 2, 1942, the date of the first controlled nuclear fission chain reaction, both breakthroughs emerged from publicly funded U.S. research with direct links to national security.

According to NNSA administrator Jill Hruby, “Monday, December 5, 2022, was an important day in science. Reaching ignition in a controlled fusion experiment is an achievement that has come after more than 60 years of global research, development, engineering, and experimentation. The people at Lawrence Livermore National Laboratory’s National Ignition Facility reached this ignition milestone because of the work others did before them, their analysis of data and models, their continued pursuit to have the best possible facility, and their sheer excellence and grit.”

NNSA deputy administrator for defense programs Marvin “Marv” Adams described the experiment this way: “192 laser beams entered from the two ends of the cylinder and struck the inner wall. They didn't strike the capsule, they struck the inner wall of this cylinder. . . . X-rays from the wall impinged on the spherical capsule; fusion fuel in the capsule got squeezed; fusion reaction started. This had all happened before, 100 times before. But last week, for the first time, they designed this experiment so that the fusion fuel stayed hot enough, dense enough, and round enough for long enough that it ignited and it produced more energies than the lasers had deposited. About 2 megajoules in, about 3 megajoules out, a gain of 1.5.”

Perseverance pays off: Budil paid tribute to the researchers, past and present, who can take credit for the achievement while joking that “people often say that LLNL stands for lasers, lasers, nothing but lasers.”

“Our pursuit of fusion ignition over the past decade at NIF was an incredibly ambitious technical goal,” Budil said. “Many said it was not possible. The laser wasn't energetic enough. The targets would never be precise enough. Our modeling and simulation tools were just not up to the task of this complex physics. Progress has taken time, but last August when we achieved a then-record yield of 1.35 megajoules putting us at the threshold of ignition, many took notice. And last week our pre-shot predictions improved by machine learning and the wealth of data we've collected indicated that we had a better than 50 percent chance of exceeding target gain of one. Sixty years ago, when John Nuckolls and his team proposed that lasers could be used to produce fusion ignition in the laboratory, it was beyond audacious. The laser had just been invented and was far from the mature tool we know today. But this is really what national labs are for—tackling the most difficult scientific challenges head on, learning from the inevitable setbacks, and building toward the next idea.”

Asked by a journalist why the news of the December 5 NIF shot was not officially announced until December 13 (the Financial Times on December 11 first broke the news that an announcement was coming), Budil said, “On the question of what we've been doing for the last week, the team has been hard at work analyzing data. It turns out that when you ignite one of these capsules, it's unambiguous that something big happened. You make a lot of neutrons, but the data are not trivial to analyze.”

What’s next: Adams, as a representative of the NNSA, which provides the bulk of LLNL’s funding, underscored the implications of the achievement for national defense. “As you have heard and will hear more, the breakthrough at NIF does have ramifications for clean energy,” he said. “More immediately, this achievement will advance our national security in at least three ways. First, it will lead to laboratory experiments that help NNSA defense programs continue to maintain confidence in our deterrent without nuclear explosive testing. Second, it underpins the credibility of our deterrent by demonstrating world-leading expertise in weapons-relevant technologies. That is, we know what we're doing. Third, continuing to assure our allies that we know what we're doing and continuing to avoid testing will advance our nonproliferation goals, also increasing our national security.”

Budil hinted at the next engineering challenges for the NIF team. “Now that we have a capsule that ignites, we need to figure out: Can we make it simpler? Can we begin to make this process easier and more repeatable? Can we begin to do it more than one time a day? Can we start working toward rep rate? And each of these is an incredible scientific and engineering challenge for us.”

Fusion headlines from 2022: Clearly, fusion is heating up. Explore what you might have missed with this selection of some of the top fusion news articles published in the past year on Nuclear Newswire.

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