Nuclear fusion's future, according to the woman leading the charge

Inside the gigantic Lawrence Livermore National Laboratory, where in December, a breakthrough in nuclear fusion was made, the man who first predicted it still works – 60 years later.

John Nuckolls, now in his 90s, was one of the pioneers of inertial confinement fusion.

"He's a great physicist and tremendously passionate about this work," Kim Budil, the Director of the Lawrence Livermore National Laboratory (LLNL) told the World Economic Forum during the Annual Meeting 2023 in Davos, Switzerland. "He's worked now with many generations of researchers to advance the cause ... Although when we told him what happened, his first comment was, 'What's the next thing that you're going to do?'"

Budil and her team of 8,000 engineers, physicists, chemists and materials scientists at the LLNL facility in the US state of California successfully used lasers to create the star-like conditions of fusion ignition in a lab. The ignition resulted in a net energy gain for the first time, meaning the fusion reaction produced more energy than it consumed - a net gain of 1.5 megajoules.

In a statement, the US Department of Energy hailed the breakthrough as a "historic, first-of-its kind achievement" that will provide "invaluable insights into the prospects of clean fusion energy."

Budil spoke to the World Economic Forum about how fusion can provide a "clean, abundant source of energy for the planet" and detailed what needs to happen to scale the technology to create fusion power.

Below is an edited transcript of Budil's remarks.

"It is the world's most energetic laser. The footprint of the laser facility itself is about the size of three American football fields. And about 10 stories tall. That laser produces about two megajoules of laser energy that goes to the target. What we do with that energy is concentrate it down to a small volume to get to extremely high temperatures and densities.

"We get a small gold can, focus 192 laser beams into that can to generate an x-ray bath. They bathe a tiny capsule in the centre which is filled with hydrogen fuel. As the outer surface of the capsule, made out of diamond, blows off, the inner surface moves in, that compresses the hydrogen fuel. If you compress it fast enough and hold it together long enough, the fusion reaction becomes self-sustaining.

"What we saw from that experiment on 5 December is we produced three megajoules of fusion energy for two megajoules of laser energy in, for a gain of about 1.5. That is the first time in a laboratory that anyone has produced more fusion gain out than the energy put into the capsule. It takes about 300-ish megajoules off the grid to run the laser, this facility was not built to be a power plant, it was built to be a scientific facility but the demonstration of the self-sustaining fusion reaction is a really big deal and demonstrates for the first time the fundamental building block of what a fusion energy system could look like."

"Definitely not next week! It's probably two or three decades. Scaling from where we are today to what you would require for a power-generating plant is a pretty significant challenge. All of that is plausible, we have strategies and approaches that we think would work for making a more efficient driver, for making targets that are simpler at the scale and cost you would need to be economically viable. So, you need to be able to do this not once a week, but 10 times a second. That is a pretty big scale up. And you need the balance of plant. You need the reactor vessel, as it were, that will capture the neutrons produced, turn those into heat that you can use to drive your power generating system."

"What we need now is a scientific and investment strategy that allows us to make progress on all of these fronts simultaneously. We will continue working on the targets and the fusion source, as it were, working to make the gains higher. We need gain of a few hundred to make an energy system. That is plausible, we have pathways to work towards that but it will require research. To make lasers that are much more efficient, that we actually know how to do, our laser was built on 1980s laser technology. Lasers are much more efficient now and we have much better strategies but we need to demonstrate those and build prototype lines and work on all the systems that will go into a power plant. The timescale is almost a direct function of resource investment."

"It cost about $3.5 billion to build the facility and we spend about $350 million a year running it. It was a leading edge, high-risk project when we began to build the laser. Seven of the 10 critical technologies did not exist, they had to be created along the way. This is what public-sector investment is good at, large-scale, able to manage risk over time and bring resources to bear at the laboratory from a wide range of disciplines.

"Our laser was not built for energy generation, it was built as a backbone of a national security programme. If we want to take this forward, public-private partnerships are going to be essential. If I look at the private-sector fusion companies that have already been spun out, they have needs for expertise and certain specific skills that it would be cost prohibitive to develop within a start-up framework. So they can partner with the laboratories to get access to that capability and expertise. In the inertial confinement fusion space, it's essential.

"We have worked hard and diligently over 60 years. [Back then] lasers had just been invented, it was not a well-known technology like it is today. The public-sector money for inertial fusion energy is small and the Department of Energy's building that programme and our hope is that with the great announcement, this important building block will be able to increase support for that element of the programme and bring many more players to bear. This is a very challenging technology path. It is plausible but we need the best people working on this and lots of ideas going forward."

"To advance the cause of fusion, we have to create an ecosystem where any private sector players in this area who want to commercialize the technology can work with us to help advance the target designs, think about laser architectures or other driver architectures, to benefit from our expertise and what will be required to operate a facility at this scale. I'm hopeful we will start seeing significant public sector investments in the energy application of this technology. We already have several companies formed around inertial confinement fusion that are starting to explore partnerships with us on how to take the technology forward.

"For the next few years, it's essential to work together. The challenge in increasing the gain for the targets, making them more efficient and simpler, which will make it more cost- effective for an energy application, that work is the same, whether astrophysics, or energy applications. At some point the paths diverged, I need to work with all of them in concert with each other now, and then I need to know there is an off-ramp for the energy application for it to be supported independently."

Watch the full session with Budil here.