Japan's nuclear industry has a poor safety record
Tokyo's main power company has restarted one of its 17 nuclear reactors which were closed down last month for safety checks.
Tokyo Electric Power Company's (Tepco) No 6 reactor at the Kashiwazaki-Kariwa nuclear power plant in Niigata prefecture will slowly raise its output over the next few days, company spokesman Hidenori Yatobo said.
Niigata Governor, Ikuo Hirayama, who was involved in the decision to restart the reactor, said "the results of the checks revealed no major problems."
Tepco was ordered to shut down its nuclear facilities for a full safety inspection after admitting last year it had covered up maintenance problems and obstructed government inspections.
Japan's nuclear industry has been hit by a series of accidents and safety scandals in recent years - including the country's worst ever nuclear accident in 1999, when two people were killed because of lax safety standards.
It is not yet known when the other 16 reactors will be restarted.
But Tepco and government officials have pushed for an early resumption, warning that at least 10 nuclear reactors are needed to meet customer demands this summer, when air conditioner use peaks in Japan's humid season.
An extended shutdown during the summer months could mean the first blackouts in two decades for the Japanese capital.
In the meantime, the capital is relying on fossil fuels to make up some of the shortfall.
The Japanese public is highly nervous about the safety of nuclear plants, especially since a radiation leak at a uranium processing facility in Tokaimura three years ago, which killed two and exposed 600 to radiation.
Afterwards it was discovered that workers at the power station had been illegally mixing uranium in buckets.