Episode 158 | Fusion First | Lawrence Livermore Nat’l Lab
It’s the story that folks are calling one of the greatest scientific feats of the 21st century. On December 5 at 1am, scientists at the National Ignition Facility (NIF) at California’s Lawrence Livermore National Laboratory achieved “ignition” in nuclear fusion—more energy out than energy in.
The test was one of many performed by the lab to get to this point. In fact, my guest, team lead Tammy Ma, was at an airport across the country. She got the news from her boss, “whispering the news” because the data had not yet been verified. That didn’t stop early reports from breaking the news. The official press announcement came on December 14.
“This is the holy grail of fusion research,” says Tammy. There are many kinds of fusion technologies. The most prominent one uses magnets to confine the reaction. The NIF uses lasers to fuse a frozen mixture of deuterium and tritium into helium and neutrons—one hundred and ninety-two lasers to be exact.
NIF scientists knew they were close in August ’21 when they achieved 70% ignition. “The big improvement was that we were able to up the laser energy by 7% over previous experiments,” she says, “and that seemed to give us just that extra push that we needed.”
Reports show the “shot” produced 3.15 megajoules (MJ) from 2.05 MJ. In an actual fusion power plant, Tammy says the following would be needed:
- Reaction would have to occur approx. 10 times/second
- Gain would have to be 10 or 100 (NIF ignition was 1.5)
- Facility would be about the same as the NIF
- Lasers would track targets and “shoot”
- Target would be a few millimeters (NIF target was 2 mm)
- Laser intensity would be 1 MJ and up (the higher the intensity makes system more robust)
- Tritium recycling system (only 30% is burned in a shot)
- Heat Extraction System, or “wall,” to collect neutron energy
- Heat would then be run through conventional power plant
After the initial announcement, some articles pointed out the energy needed to prime the lasers was not part of the energy reaction. Tammy says the goal of their team has always been the energy equation at the target.
“The rest of it becomes, you could say, engineering. Stuff that we have really have not been focused on.”
Moving forward, Tammy says the effort should be focused on raising the ignition ratio, as well as developing the supporting technologies for a physical plant. It should be noted that the NIF’s primary purpose is to simulate the nation’s nuclear weapons efficacy without the mess of live testing. Construction began on the facility shortly after the passage of the Comprehensive Nuclear-Test-Ban Treaty in 1996.
“We’re still getting paid!” laughs Tammy, “We’re still working.”
Useful Links: