Part 4 of 6 Parts

Power plants generally produce around five hundred megawatts of power, give or take a factor of two. To achieve that figure, a power plant based on NIF would have to reliably implode a fuel target about once a second, every second, for days, months, and years on end. In the three years since NIF first achieved ignition, it has repeated that feat exactly five more times. Tammy Mac is one of the lead NIF scientists. She said, “Sometimes you’ll hear folks say that the science behind fusion is solved, it’s all just an engineering problem. I disagree with that statement. “The science of fusion is not solved….NIF is the most successful fusion experiment to date, but we don’t get ignition every time.”.

Pacific Fusion faces challenges similar to NIF. Their technology hasn’t yet proven it can achieve net energy, though simulations suggest it will. Even if their machine does produce net energy, it could easily take longer to reach that point than their current estimate, which places that milestone in the early 2030s.

Alberto Loarte is head of the Science Division at ITER. He said, “We know from fusion experiments that since you start, until you get something [close to peak performance], it takes you ten to fifteen years. Fusion has worked in a given way since 1960 until 2020 and it’s very unlikely that tomorrow will be different.”. This ten-year shakedown period isn’t included in any of the published corporate timelines from Pacific, Commonwealth, or the rest of the current group of fusion startups.

Commonwealth has its own serious problems too. Its systems are modeled after ITER, but ITER is so big for a reason. The superconducting magnets used for Commonwealth’s SPARC as well as for ITER must be kept very cold, not far above absolute zero. However, inside the tokamak, on the other side of the wall from the cold magnets, there’s a one hundred-million-degree plasma. Inside SPARC there’s less room to work with. The temperature of the inner wall of the tokamak is expected to be five to six times greater than in ITER. SPARC won’t be able to run longer than about thirty seconds at a time. Any longer than that, heat would overwhelm its magnets. Loarte said, “If they get fusion power production under this condition, then the issue is how you get this to longer steps. So you may get a plasma that gets to produce fusion and does not then extrapolate to a reactor.”.

Pacific, Commonwealth, and nearly all other fusion companies also face another serious problem. The isotopic mixture of hydrogen they’re using as fuel is the same type that NIF uses in its successful fusion shots. It is a deuterium-tritium, or “DT” mix. (Deuterium is abundant in all water on Earth, but a fusion power plant would ultimately have to create its own tritium which is another difficulty.) About seventy-five percent of the energy released by DT fusion is in the form of neutrons which are electrically neutral subatomic particles. It’s difficult to capture the energy of neutrons in a useful way. Daniel Jassby is a plasma physicist. He said, “In seventy-five years of fusion R&D, nobody has produced a tiny amount of electric power. I’m not talking about net electric power, I’m just talking about any electric power,” says the plasma physicist. “Nobody has ever been able to convert neutron barrages into electricity.”

Pacific Fusion

Please read Part 5 next