Japan's TEPCO restarts nuclear reactor after alarm trouble
Tokyo Electric Power Company Holdings (TEPCO) restarted the No. 6 reactor at the Kashiwazaki-Kariwa nuclear power plant in Niigata Prefecture after identifying the cause of an alarm that halted operations last month, Qazinform News Agency cites Kyodo.
The alarm was triggered on January 22 during control rod withdrawal, just hours after TEPCO had brought the unit online — its first nuclear restart since the 2011 Fukushima disaster. Investigations revealed that the inverter controlling the motor speed for the rods was not faulty, but the alarm system had been set too sensitively to detect current changes.
TEPCO adjusted the inverter’s settings, noting that other alarm systems can detect abnormalities in control rods. On Monday, the reactor reached criticality, initiating a controlled nuclear fission chain reaction.
The utility plans to begin trial power generation and transmission from Sunday, followed by further checkups. If no issues arise, the reactor is expected to enter commercial operation on March 18.
The Kashiwazaki-Kariwa plant, Japan’s largest nuclear facility, has seven reactors. The restart marks a significant step in TEPCO’s post-Fukushima nuclear operations.
Earlier Japan's TEPCO planned to restart reactor early next week after alarm trouble.