Japan earthquake: Concerns over nuclear power stations
11 March 2011 Last updated at 20:11 GMT
There are serious concerns about Japan's nuclear power stations following the massive earthquake and tsunami that hit the country.
The government ordered thousands of residents near a nuclear power plant in Onahama city to evacuate because the plant's system was unable to cool the reactor, which was not leaking radiation.
Nuclear Physicist Walt Patterson told the BBC's Nik Gowing that even after the plant was shutdown its core would need to be cooled.