News & Analysis Physics World  February 2018

US must stay part of ITER, warns panel

Let’s stay together America would be isolated if it left the ITER international fusion project, experts warn. (ITER Organization / EJF Riche)

The US will be left isolated in fusion research if the country quits the ITER experiment that is currently being built in southern France. The warning comes in a report from the US National Academies of Science (NAS), which says that leaving ITER would require the US to develop a completely new approach to studying fusion. The current administration has not yet, however, shown any intention to abandon ITER.

The first of a two-phase study about US magnetic-confinement fusion research, the NAS report was commissioned by former US energy secretary Ernest Moniz and sponsored by the Department of Energy. While Moniz, who is a physicist, recommended when he was in office that the US should remain in ITER until 2018, he noted that the US should re-evaluate its membership before the 2019 financial year, which begins next October.

The report concludes that research on burning plasma is essential to develop magnetic-fusion energy and that the US has made “leading advances” in that area. It also notes that building and operating a burning plasma experiment is a “critical, but not sufficient next step” toward the realization of commercial fusion energy. “Burning plasma is an important aspect of getting to viable fusion energy; the only project that is in a position to reach a burning plasma is ITER,” says Melvyn Shochet, a particle physicist at the University of Chicago and a co-chair of the 19-member panel that wrote the report.

It also notes that, unlike its international partners, the US lacks a national plan that will lead to a fusion-energy demonstration device and that recent closures of domestic experimental facilities “threaten” the health of the field in US. As a result, the report calls for the US to maintain its membership of ITER.

“The US benefits from international co-operation to combine the scientific and engineering expertise, industrial capacity, and financial resources necessary for such as an inherently large project,” the panel asserts. “[Withdrawing] from the ITER project could isolate US fusion scientists from the international effort and would require the US to develop a new approach to studying burning plasma.”

Peter Gwynne

Boston, MA