OSAKA -- Plutonium-uranium mixed oxide (MOX) fuel being stored at a nuclear plant in Takahama, Fukui Prefecture, will probably be shipped back to Britain in June, the environmental watchdog group Greenpeace said Thursday.

The fuel, purchased by Kansai Electric Power Co., consists of nearly 255 kg of plutonium. It has been sitting in Takahama since fall 1999, after if was revealed that data related to the fuel's quality control procedures were faked by the manufacturer, British Nuclear Fuels PLC.

For the past 2 1/2 years, the Japanese and British governments have been negotiating when the fuel would be shipped back to Britain; June has been mentioned as a possible date.