US advised to stick with troubled fusion reactor ITER.

ITER is an unprecedented collaboration between the European Union, China, India, Japan, South Korea, Russia and the United States. Its ambitious goal is to show that fusing hydrogen nuclei to make helium — the same process that heats up the Sun and powers hydrogen bombs — is a technologically feasible way to produce electricity. The experiment is under construction at a site in St-Paul-lez-Durance in southern France, but the work is more than a decade behind schedule, and its costs have spiralled far above the original budget. Davide Castelvecchi & Jeff Tollefson