A group of residents of Tsuruga, Fukui Prefecture, on Friday appealed to the Nagoya High Court a lower court ruling that rejected their suit calling for the permanent closure of Japan's only prototype fast-breeder nuclear reactor.
The suit seeking to close the Monju reactor, filed in September 1985, will now shift to the Kanazawa branch of the Nagoya High Court.
The Fukui District Court on Wednesday rejected the suit, with Judge Yoshihiko Iwata saying the reactor does not pose "any visible danger to infringe upon the lives or health of the plaintiffs," despite a massive sodium leak in 1995.
The Monju reactor is considered the linchpin of efforts by the government and nuclear power industry to establish a nuclear fuel-cycle program.
Operations have been suspended since December 1995 when a coolant leak and fire broke out at the in the reactor's housing.
The plaintiffs demanded the retraction of government permission for the plant in the suit. They also sued the plant's operator, demanding a permanent halt to the reactor's operations.
Critics said the district court ruling goes against current trends, citing stronger-than-ever antinuclear sentiment following the Tokai nuclear accident in September.
In that incident three plant workers were exposed to massive doses of radiation, one of whom died in December, becoming the first nuclear fatality in Japan not related to nuclear weapons.
Unlike light-water reactors fueled by uranium, fast-breeder reactors use plutonium-uranium mixed oxide (MOX) fuel and produce more plutonium than they consume. Plutonium is an extremely toxic substance that can be used to make nuclear weapons.