Cold shutdown for Takahama No.4

March 2, 2016

Halted Kansai Electric reactor in cold shutdown for probe

http://mainichi.jp/english/articles/20160302/p2g/00m/0dm/003000c

The No. 4 reactor, forefront, is seen at the Takahama Nuclear Power Plant in Takahama, Fukui Prefecture, in this picture taken from a Mainichi Shimbun helicopter on Feb. 29, 2016. (Mainichi)

FUKUI, Japan (Kyodo) -- Kansai Electric Power Co. has put a nuclear reactor at its Takahama plant in a state of cold shutdown to investigate why the automatic suspension of the unit was triggered earlier this week, the utility said Wednesday.

The No. 4 reactor at the nuclear power plant in Fukui Prefecture on the Sea of Japan shut down automatically Monday, just three days after coming back online under Japan's stricter safety regulations following the 2011 Fukushima meltdowns.

An electrical current exceeding a preset level may have been detected by a monitoring device around a transformer of the reactor, triggering a safety mechanism upon the start of power generation, the company said Tuesday.

The latest incident was the second stoppage of the reactor in 10 days, following a radioactive coolant water leak on Feb. 20 in a building attached to the same reactor.

Deeming it had taken sufficient steps to prevent a similar leak, Kansai Electric then rebooted 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 preventive steps are approved.

The nuclear regulation watchdog will examine analysis of the cause of the emergency halt and measures to prevent a similar incident that Kansai Electric will put forward in due course.

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.