Radioactivity released by the Fukushima accident posed a low risk to Japan's population, said the World Health Organisation. It expects no observable health effect in the wider population, but raised estimations of cancer risk for two towns.
Japan's new nuclear regulations could demand that operators are prepared to avoid an accident even in the case of war or deliberate aircraft impact. Draft rules are at the first public comment stage.
A large twisted steel truss has been removed from the fuel pool of Fukushima Daiichi 3 as part of efforts to clear debris from the pond and service floor area.
Japanese spending on imported fossil fuels soared in the latter part of last year, helping push the country to a trade deficit for the second year in a row. Emissions targets are under revision as most nuclear power plants remain closed.