The United States approach to nuclear energy is interesting, to say the least. Of all the countries harnessing the power of the atom, the United States is perhaps the most privatized nuclear energy system in the world. Most countries treat nuclear fission as a government affair — China runs its reactors through state-owned enterprises, and France went so far as to fully renationalize its main nuclear company in 2023. The States, meanwhile, leave their reactors almost entirely in the hands of the private sector.

Disciples of the free market will tell you this is exactly how things should be. If you don’t have a financial stake in the nuclear race, however, you might notice this arrangement comes with side effects like chronic understaffing and public subsidies of private profit. It also raises serious safety questions as a rising number of nuclear startups jostle for a piece of the atomic pie.

https://www.bloomberg.com/news/articles/2025-08-28/nvidia-joins-google-to-fund-commonwealth-s-fusion-power-plant

In nuclear fusion, the triple product – also known as the Lawson criterion – defines the point at which a nuclear fusion reaction produces more power than is needed to sustain the fusion reaction. Recently the German Wendelstein 7-X stellarator managed to hit new records here during its most recent OP 2.3 experimental campaign, courtesy of a frozen hydrogen pellet injector developed by the US Department of Energy’s Oak Ridge National Laboratory. With this injector the stellarator was able to sustain plasma for over 43 seconds as microwaves heated the freshly injected pellets.

https://www.ipp.mpg.de/5532945/w7x?c=5481737
Wendelstein 7-X sets new performance records in fusion research [UPDATE]

On May 22, the latest experimental campaign concluded at the world’s most powerful nuclear fusion device of the stellarator type. Through collaboration between researchers from Europe and the USA, Wendelstein 7-X achieved, among other milestones, a world record in a key parameter of fusion physics: the triple product. This value now exceeds previous tokamak records for long plasma durations (see UPDATE at the end of the article).

UPDATE from 30 June 2025
The updated graphic now also shows JET’s unpublished record values in green.

The updated graphic now also shows JET’s unpublished record values in green.

MPI for Plasma Physics, Dinklage et al. (to be published) / X. Litaudon et al. 2024 Nucl. Fusion 64 015001 / E. Lerche… [more]

After publishing this news item, members of the JET community informed us about previously unpublished results from the now decommissioned tokamak in the United Kingdom. At the end of JET’s operating life, experiments were carried out there to maximise pulse lengths and energy conversion. In terms of the duration of the high-performance phase, JET also achieved a new world records for triple products. These are comparable to the best values achieved by Wendelstein 7-X. The record pulses were even sustained for up to 60 seconds. The corresponding technical article is currently being reviewed and will soon be published in a scientific journal.

What does this mean for the statements about Wendelstein 7-X? If the as yet unpublished JET data are included, the Wendelstein 7-X stellarator and the JET tokamak are now joint leaders in sustaining the triple product level for longer times. The fact that W7-X results are on a par with JET is remarkable because JET had three times the plasma volume of Wendelstein 7-X.