TOKYO – A reactor at the Kashiwazaki-Kariwa nuclear power plant began power generation and transmission on a trial basis Monday, as Tokyo Electric Power Company Holdings Inc. geared up to resume nuclear power supply for the first time in 14 years.

TEPCO, still grappling with the aftermath of the 2011 Fukushima nuclear accident, plans to start full-fledged electricity transmission from the No. 6 unit at the seven-reactor plant in Niigata Prefecture on March 18. The complex is located 220 kilometers northwest of Tokyo.

The No. 6 reactor in late January became TEPCO’s first reactor to be brought back online since the meltdowns at its Fukushima Daiichi nuclear complex in the wake of the massive earthquake and tsunami on March 11, 2011. The unit will supply electricity to Tokyo and its nearby areas.

TEPCO started running a turbine powered by steam generated by heat from the reactor at 7:10 p.m. on Sunday and confirmed there were no abnormalities. It then began transmitting electricity at 2:55 a.m. on Monday.

The operator plans to disconnect the power generator from the grid and then reconnect it multiple times before the trial ends, boosting its output gradually to 50 percent from 20 percent and then to its maximum level.

The last time electricity was transmitted from the No. 6 unit was in late March 2012 before it was shut down for a regular checkup.

Another reactor at the nuclear power plant is also expected to be restarted, with approval already secured from Japan’s nuclear watchdog.

Most of the country’s nuclear reactors remain offline, with safety concerns among residents near plants persisting after the Fukushima Daiichi nuclear accident.

With its push for decarbonization, the government is now seeking to make maximum use of nuclear power by restarting reactors that meet stringent safety standards.

The No. 6 unit was rebooted Jan. 21 but was shut down after an alarm went off during work to withdraw control rods from the reactor. It went back online on Feb. 9.

Monday’s electricity transmission was also delayed from its initial schedule as a device to measure neurons inside the reactor did not function properly.