Japan's nuclear power plants are desperately trying to find somewhere to send spent nuclear fuel after their last contract with a European enterprise expired last week. Japan's power companies, which produce 900 tons of spent nuclear fuel a year, had been transporting used fuel to reprocessing plants in England and France since 1982. The final contract with a European facility expired last week when Hokuriku Electric Power Co.'s Shika power plant sent its last shipment, 84 fuel assemblies, or 15 tons of used nuclear fuel, to a reprocessing plant in Sheffield, northwestern England.