US fusion energy dreams edge closer to reality, Congress permitting
Yields could double next year – provided the budget is passed
To say 2023 was a big year in the world of fusion research would be an understatement.
After achieving fusion ignition in late 2022, scientists at the Lawrence Livermore National Laboratory's (LLNL) National Ignition Facility (NIF) in California repeated the feat in late July, and then twice again in recent months, bringing to four the total number of times they've managed to generate more energy from a small pellet of fusion fuel than they put in.
In other words, we're finally on the path to fusion energy, sort of – replicable results and all. We're still likely a long way off from production fusion reactors, as usual: practical domestic fusion power always seems to be 10 years away.
With the US Department of Energy (DoE) recently releasing $42 million in funds for fusion energy research divided between LLNL, Colorado State University, and the University of Rochester, New York, the fusion forecast is calling for some breakthroughs.
Dr John Edwards, LLNL senior advisor and former director of the Inertial Confinement Fusion (ICF) program at Livermore, was happy to tell The Register what he sees on the horizon.
A fusion surprise, to be sure, but a welcome one
First things first, Edwards told us. He wants to make sure the world understands something about the fusion research at the NIF: It's never been about domestic fusion energy.
"These results have energized people, but all of that work and funding hasn't been for fusion energy. It's been part of the National Nuclear Security Administration's Stockpile Stewardship and Management Plan (SSMP)," Edwards explained.
The SSMP is a program to not only maintain the US's stockpile of nuclear weapons, but also to advance "the scientific, technological, and engineering skills that underpin it," the DoE stated. Part of that means understanding things like ICF, with which the DoE has tasked LLNL for years.
In other words, achieving fusion ignition for power generation purposes was never the objective of the NIF's research, but the results happen to overlap with the DoE's goals for developing a fusion energy sector in the US – which it wants to do by the 2030s, Edwards said. Thermonuclear warheads rely on fusion to achieve their yields, hence the NIF and Dept of Energy's interest in studying and developing the science involved in those weapons, and it's why we're not surprised that's spilling into possible civilian power use.
"The NIF results were phenomenal," Edwards acknowledged, but "there's a big tech gap between there and commercial fusion. [A pilot plant by the] 2030s is ambitious and there will be setbacks, but we need to be resilient because the results will be tremendous."
The fusion forecast for 2024
So what can the world expect from LLNL and other fusion research institutions in the coming year? A lot of that has to do with whether things go according to plan.
"We may run as many as 10 to 20 ignition experiments [at the NIF] in 2024," Edwards predicted, "but that all depends on funding, which is uncertain at the moment."
The US government has been wrangling to pass a budget for months, and the latest temporary funding bill only kicks the can down the road to early 2024, but doesn't cover everything. Funding for things like the LLNL and NIF are part of what's been held up, Edwards told us.
The $42 million from the DoE doesn't involve funding the NIF – that's a different pot of cash for fusion energy research, which we'll get to.
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If Congress eventually manages to fund the government, the NIF, and "everything else falls into place," Edwards predicted that the NIF will reach new fusion ignition efficiency milestones in 2024.
Anyone following the fusion news out of LLNL knows that, while the X-ray beam that hit the fusion fuel pellet – a diamond-encased, pea sized lump of deuterium and tritium – may have delivered 2.05 megajoules of energy to the pellet and produced 3.15 megajoules, it took far more energy than that to get the whole thing accomplished.
The fuel pellet sits inside a cylindrical chamber known as a hohlraum, which converts laser energy into X-rays that implode the pellet, causing the hydrogen isotopes to fuse and release energy. Those lasers output 322 megajoules of energy – all but 2.05 MJ of which is lost in the conversion to X-rays.
In essence, Edwards said, the whole system only has an efficiency of around one percent, but that could change in 2024.
To make the entire system more efficient, the NIF team is looking at several avenues. One of them involves making a larger fuel pellet relative to the size of the hohlraum, which should mean more energy makes it to the capsule. A larger capsule, in turn, means there's more fuel to burn once ignition gets going.
The quality of each capsule also has a lot to do with the efficiency of the ignition. Reaction time has to do with how long the capsule itself stays together before breaking apart, and the more flawless the longer it's likely to last. The NIF team is also working to cram more mass into each capsule, which should extend reaction time and improve efficiency as well.
If everything goes as planned, "we could see a doubling or more in fusion yields in the next year," Edwards told us.
Building a new energy industry
As for what LLNL plans to do with its share of that $42 million from the DoE, the lab will be working alongside the two universities to form an ICF energy program that will set the stage for a public energy sector – starting with making those lasers more efficient. "We'll be trying to get from 1 percent up to 10 or 15 percent efficiency," Edwards explained.
Still, "there's lots of tech advances that need to happen," Edwards admitted.
For starters, using laser fusion to generate power means shooting fuel pellets somewhere in the neighborhood of one to ten times every second – instead of once a month like the NIF.
That means mass production of targets, a method of extracting energy from said targets, and a reliable method of scaling the entire system. In other words, developing an entire framework for an integrated fusion plant – which will be a major part of LLNL's work in the coming year and beyond.
"We're looking at the emergence of a new public sector," Edwards enthused. "I'm really excited about this."
Looking ahead, the DoE wants LLNL and its partners in the public and private sectors to have a fusion pilot plant ready to fire up by the mid-2030s. Not necessarily one that'll produce a lot of energy, mind you – but a self-sustaining one.
"If we can pull this off it'd be the first time we could ever make an entire self-sustaining system," Edwards told us.
But that will require a lot of work. Self-sustaining, as far as the DoE is concerned, means producing its own deuterium and tritium and generating enough energy to keep itself running.
At the end of the day, there's a lot of collaborative feelings in the air around fusion right now. "There's quite a nice national strategy forming," Edwards noted. "If we can get everyone marching in the right direction we'll see good results."
"We're finally in a time when it makes sense to try – all the supporting technology is in place and it's reasonable to set such an ambitious goal," Edwards said of the state of fusion energy development.
So keep an eye open for more breakthroughs in 2024 – provided Congress gets its act together. ®