Workers at the Savannah River Site* in the US have started dissolving nuclear material from a Japanese research reactor, leading to its safe disposal, in what the US Department of Energy called “another critical milestone”.

The DOE Office of Environmental Management said the achievement follows years of preparation by multiple site contractors and involved replacement of an electrolytic dissolver and its support equipment to process fuel from Japan’s Fast Critical Assembly, the country’s only critical assembly for the study of the neutronic characteristics of fast reactors.

The electrolytic dissolver system was designed and built by Savannah River staff in the 1960s. Replacing it required extensive planning, testing and engineering to revitalise this one-of-a-kind capability.