An advanced Japanese thermal reactor was closed down this morning when a small leakage of steam containing radiation was detected.
The incident at the Fugen reactor, which officials at the state-run Japan Nuclear Cycle Development Institute (JNC) said posed no health risks, came on the same day the government reported that its nuclear safety record had improved.
A spokesman for JNC, the company which operates the reactor said the steam did not leak outside the facility and that the amount of radiation involved was so small there was no health danger.
He said the cause of the leak was being investigated and it was too early to say when the reactor might be restarted.
The 165,000-kilowatt Fugen, located in western Japan, was only restarted yesterday after being shut down last May when a tritium leak was detected between the outside of the reactor container and the concrete wall surrounding the facility.