TOKYO (AP) -- Japan feared aftershocks could further damage one of the tsunami-hit Fukushima nuclear plant's fuel pools and cause spent fuel rods to melt and spew radiation within hours.
The Japan Nuclear Energy Safety Organization says its simulation showed some 1,500 mostly used fuel rods at the plant's No. 4 reactor building could start breaking in two hours if aftershocks further damaged the pool and caused cooling water to escape. The fuel rods could start melting within eight hours, the organization said in a paper dated June and released late Friday.
The March quake and tsunami triggered meltdowns at the plant's reactors. Explosions also damaged buildings, including Unit 4. Its operator has since reinforced Unit 4's spent fuel pool to increase quake resistance.