Some radioactive water splashed out of the pool it was in at a nuclear power plant in north-eastern Japan when a magnitude-7 earthquake hit Saturday morning, dpa reported.
In total 19 litres of waste water and radioactive water splashed out at Tokyo Electric's No 2 Power Plant in Fukushima province, according to the Nuclear and Industrial Safety Agency.
However, there was no leakage reported outside the facility and the level of radioactivity was not harmful to the environment, the agency said.
No other leakage or damage was reported at four nuclear power plants in the region hit by the earthquake which killed at least three and injured more than 100.