Groups opposed to the nuclear-fuel reprocessing plant in Aomori Prefecture handed an 850,000-signature petition to the government Monday, demanding it rethink atomic power strategy.

The reprocessing facility in Rokkasho, set to begin operations next month, will gather spent nuclear fuel from power plants nationwide and extract uranium and plutonium for reuse. It has been on its final test run since March 2006.

Studies show the plant, after it goes into full operation, may release in a single day a year's worth of a regular nuclear plant's radioactivity. A portion of this will be drained into the sea, which the government claims will be absorbed safely in the environment.

Representatives of the protesters, which include fishery associations, consumer cooperatives and surfer groups, handed the petition to the Cabinet Office and the Ministry of Economy, Trade and Industry.

"The new facility in Rokkasho will endanger the ocean. It is a threat to all living things," said Michiyaki Moriya, representative of Surfrider Foundation Japan.

"The radioactivity may accumulate over years but not be visible to our eyes. We will not be able to provide safe marine products to consumers," said Shuichi Ito, a representative of the Omoe Fishery Association in Iwate Prefecture.

Construction of Rokkasho's nuclear-fuel reprocessing plant began in 1993 on a budget of ¥2.1 trillion. Although both the Cabinet Office and METI have given safety assurances for the facility, some suggest their safety tests are based on partial studies.

"There is a lot of research that has proved government test results to be wrong. It is unacceptable to ignore" such figures, Atsuko Shimoda, an Upper House member of the Democratic Party of Japan from Aomori, said at the gathering.

Japan Nuclear Fuel Ltd. and the Japan Atomic Energy Agency operate a range of nuclear facilities at Rokkasho, including a uranium-enrichment plant.