Japan Finishes World's Largest Fusion Reactor

Six stories high. 360 million degrees Fahrenheit.

Blowing Fusion

Japan has officially inaugurated the world's biggest experimental nuclear fusion reactor.

The reactor, dubbed JT-60SA, represents the latest testbed for a potentially transformative source of renewable energy harvested from atoms fusing together under immense pressure and incredibly high temperatures — without risking a nuclear meltdown.

But despite almost a century of fusion research, we've only been able to make small, incremental steps towards achieving the "holy grail" of producing a meaningful amount of net positive energy. Whether this grand new facility will make any strides toward a practical solution is anyone's guess.

Smash of Clans

Japan's latest reactor is six stories high and can heat plasma to a blistering 360 million degrees Fahrenheit inside its donut-shaped "tokamak" chamber. It's meant to lay the groundwork for the even larger International Thermonuclear Experimental Reactor (ITER), which is currently being constructed in France.

As Agence France-Presse reports, ITER is already well over budget and technical problems are delaying its development significantly.

Despite these setbacks, scientists are eager to give the JT-60SA reactor, a Japan-European Union collaboration, a whirl.

"It's the result of a collaboration between more than 500 scientists and engineers and more than 70 companies throughout Europe and Japan," said Sam Davis, deputy project leader for the JT-60SA, during the inauguration last week.

Despite plenty of disappointing results and setbacks over the years, it's an exciting time for fusion energy. The inauguration comes after researchers at the Lawrence Livermore National Laboratory claimed to have produced a net energy gain using the "world's largest and highest energy laser system," a fusion reactor that works very differently from both ITER and JT-60SA.

In August, the team claimed it had achieved the feat for a second time. However, the jury is still out on whether these experiments actually represent a major breakthrough, as the results have yet to be thoroughly vetted by outside experts.

Whether JT-60SA, or its much larger sibling, will finally be able to demonstrate that fusing atoms can represent a sea change in our efforts to power the world with renewable energy remains to be seen as well.

More on fusion: Microsoft Signs Deal to Get Fusion Power by 2028