More than 6,000 workers cycle through the world's biggest nuclear plant every day to operate and maintain a facility that hasn't sold a kilowatt of electricity in more than four years.

The buzz at Tokyo Electric Power Co. Holdings Inc.'s Kashiwazaki-Kariwa plant plays out daily across Japan, where utilities employ thousands of workers and spend billions of dollars awaiting the green light to restart commercial operations. With only three of the country's 42 operable reactors running, they're betting a central government committed to nuclear power will win over local officials and a wary public who don't believe enough has been done to guarantee safety since the worst meltdown disaster since Chernobyl.

"Even though operating expenses of nongenerating reactors remain high, utilities would prefer to keep them open while there is any chance they can restart," said James Taverner, a Tokyo-based analyst at IHS Markit Ltd. "Utilities have already committed significant expenditure for plants to meet new safety standards, and decommissioning costs are considerable."