The national and Fukui prefectural governments held a disaster-prevention drill Thursday in the town of Oi dealing with radioactive material leaking from a nuclear reactor.
Local residents, including people living at a facility for the disabled, took part in the drill.
It was the third such drill held under a disaster law involving reactors that was enacted in December 1999 following a deadly nuclear accident that year in Tokai, Ibaraki Prefecture.
The drill covered a scenario in which the No. 3 reactor at the Oi nuclear power station of Kansai Electric Power Co. had automatically shut down because its core was damaged and radioactive material was leaking from the reactor container.
Prime Minister Junichiro Koizumi monitored the drill through a teleconferencing system at his office in Tokyo.
He declared a state of nuclear emergency shortly after 8 a.m. and instructed Fukui Gov. Yukio Kurita, as head of the local emergency task force, to put priority on ensuring public safety, government officials said.
Officials from the Fukui prefectural and Oi municipal governments gathered and established the task force to deal with a possible disaster.
At Oshima Fukushi Gakuen, a facility for the disabled located about 1 km from the reactor, some 50 residents wearing emergency packs headed for an evacuation center at around 10:30 a.m.
Officials were also sent from neighboring Kyoto Prefecture under an agreement for mutual assistance in an emergency.
Yosaku Fuji, president of Kansai Electric Power, monitored the situation at the utility's head office in Osaka, company officials said.