Kansai Electric Power Co. has placed a nuclear reactor at its Takahama plant in a state of cold shutdown to investigate why the automatic safety shutoff was triggered earlier this week, the utility said Wednesday.
The No. 4 reactor at the nuclear power plant in Fukui Prefecture shut down automatically Monday, just three days after going back online under the stricter safety regulations implemented following the 2011 Fukushima meltdowns.
A monitoring device around a transformer of the reactor may have detected an electrical current that exceeded a preset level, triggering a safety mechanism, the company said Tuesday.
The latest incident was the second stoppage of the reactor in 10 days following a radioactive coolant leak on Feb. 20 in a building attached to the same reactor.
Deeming it had taken sufficient steps to prevent a similar water leak, Kansai Electric restarted the reactor on Feb. 26.
Commercial operation of the reactor will likely be pushed back to April from the initial plan to start it in late March, as the Nuclear Regulation Authority said Tuesday it will be difficult to restart the facility until further safety measures are approved.
The nuclear regulation watchdog will examine analysis of the cause of the emergency stoppage and measures to prevent a similar incident by Kansai Electric.
Even if it gets the go-ahead for another restart, the No. 4 reactor will need to go through a final inspection by the regulator again before reactivation and subsequent commercial operation.
