Jan. 22 (UPI) -- Japan's Tokyo Electric Power Co. shut down a nuclear reactor Thursday morning at the Kashiwazaki-Kariwa nuclear power plant because of an alarm issue just hours after it went live.

The company restarted operations on Wednesday at the world's largest nuclear power plant by output after it had been down for about 14 years. It had planned to restart Tuesday, but a test revealed a faulty alarm during the removal of a control rod in the No. 6 reactor. After it was fixed, the Japanese Nuclear Regulatory Authority gave its approval for the restart.

TEPCO said Thursday that it would shut down a reactor because an alarm was triggered during control rod withdrawal operations. It had suspended control rod withdrawal at the No. 6 unit earlier in the day. Control rods are used to adjust the nuclear fission of a reactor, and no abnormal levels of radioactivity were detected, Kyodo News reported.

The No. 6 unit was restarted at 7:02 p.m. JST Wednesday, and the alarm was triggered at 12:28 a.m. Thursday.

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