Delays in the installation of key parts of ITER, a multibillion-euro international nuclear-fusion experiment, are forcing scientists to change ITER’s research programme to focus exclusively on the key goal of generating power by 2028. As a result, much research considered non-essential to the target, including some basic physics and studies of plasmas aimed at better understanding industrial-scale fusion, will be postponed. A 21-strong expert panel of international plasma scientists and ITER staff, convened to reassess the project’s research plan in the light of the construction delays. The plans were discussed at a meeting of ITER’s Science and Technology Advisory Committee (STAC). The meeting is the start of a year-long review by ITER to try to keep the experiment on track to generate 500 MW of power from an input of 50 MW by 2028, and so hit its target of attaining the so-called Q ≥ 10,where power output is ten times input or more.
ITER, which will be the world’s largest tokamak thermonuclear reactor (see ‘A fusion of ideas’), is being built in St-Paul-lez-Durance in southern France by the European Union, China, India, Japan, South Korea, Russia and the United States at a cost of €15 billion (US$20.3 billion). Q ≥ 10 is seen as its raison d’être, and achieving it would be likely to revitalize public and political interest in fusion. Crucial to that is getting to the point, scheduled for 2027, when the first nuclear fuel would be injected into the reactor. The fuel will be a plasma of two heavy hydrogen isotopes, deuterium and tritium (DT).
The original 2010 research plan foresaw the entire reactor being built by 2020, when ITER was also scheduled to produce its first plasma, using hydrogen as a test fuel. But cost-cutting and cash-flow problems in member states mean that while the reactor is likely to be operating by then, the delivery of some parts is being deferred until several years later. These include some diagnostics devices for analysing the physics of plasmas at the very large scales of ITER, and elements of the heating system that will eventually take the plasmas to 150,000,000 °C.