TOKYO, April 17 (Xinhua) -- Tokyo Electric Power Company (TEPCO) has begun commercial operation of a reactor at the recently restarted Kashiwazaki-Kariwa nuclear power plant, 14 years after it was taken offline, local media reported.

File photo: Xinhua

Japan's Nuclear Regulation Authority on Thursday conducted a final check of the No. 6 reactor at the Kashiwazaki-Kariwa plant in Niigata Prefecture before giving the utility approval to restart commercial operation in the afternoon, public broadcaster NHK reported.

Despite being nearly two months later than initially scheduled, it marks the first time in 14 years that a TEPCO-operated nuclear reactor has sent electricity on a commercial basis to its grid system covering the Greater Tokyo Area and the eastern part of Shizuoka Prefecture.

The reactor was initially scheduled to resume commercial operation in late February after being reactivated in January. However, a malfunctioning alarm system and other issues forced TEPCO to postpone the restart date twice.

The Kashiwazaki-Kariwa plant, about 220 km northwest of Tokyo, is the world's biggest nuclear power plant by potential capacity. The facility had been offline since Japan pulled the plug on nuclear power following the March 2011 core meltdowns at TEPCO's tsunami-stricken Fukushima Daiichi plant.

The company restarted the No. 6 reactor at the seven-unit complex on Jan. 21 for the first time in about 14 years, marking the first TEPCO-run unit to go back online since the Fukushima nuclear disaster, which has met local opposition amid criticism that the plant sits on an active seismic fault zone.