The operator of a nuclear power station in north-eastern Japan said Friday that the company had found water leaks at the plant after a magnitude-7.4 earthquake overnight, DPA reported.
Tohoku Electric Power Co, which runs the Onagawa Nuclear Power Plant in Miyagi prefecture, said water leaked from spent-fuel pools at two reactors and also from other parts of the plant.
Levels of radiation were unchanged outside the plant, it said.
The plant, whose operations have been suspended since a magnitude-9 March 11 earthquake, lost two of its three external power connections in Thursday night's aftershock, causing the cooling system for the spent-fuel pools to temporarily stop.
The March 11 quake crippled the cooling systems of a nuclear plant in Fukushima prefecture, causing partial meltdowns at its reactors and releases of radiation.
Thursday's quake killed three people and injured about 140. It did not cause further damage at the Fukushima plant, its operator said.