2011 Fukushima disaster forced the country to shut all of its reactors. The decision to restart reactor number 6 at Kashiwazaki-Kariwa north-west of Tokyo was taken despite local residents' safety concerns.  It was delayed by a day because of an alarm malfunction and is due to begin operating commercially next month. Japan, which had always heavily relied on energy imports, was an early adopter of nuclear power. But in 2011 all 54 of its reactors had to be shut after a massive earthquake and tsunami triggered a meltdown at Fukushima, causing one of the worst nuclear disasters in history.

This is the latest installment in Japan's nuclear power reboot, which still has a long way to go. The seventh reactor at Kashiwazaki-Kariwa is not expected to be brought back on until 2030, and the other five could be decommissioned. That leaves the plant with far less capacity than it once had when all seven reactors were operational: 8.2 gigawatts.

Triggered by the most powerful earthquake ever recorded in Japan, the meltdown in the reactors at Fukushima Daiichi, 220km (135 miles) north-east of Tokyo on the coast, led to radioactive leakage. Local communities were evacuated, and many have not returned despite official assurances that it was safe to do so. Critics say the plant's owner Tokyo Electric Power Company, or Tepco, was not prepared, and the response from them and government was not well co-ordinated. An independent government report called it a "man-made disaster" and blamed Tepco, although a court later cleared three of their executives of negligence. Still the fear and lack of trust fuelled public opposition to nuclear power and Japan suspended all of its 54 reactors shortly after the Fukushima disaster.

It has now spent the past decade trying to wake up those power plants, as it seeks to reach net zero emissions by 2050. Since 2015, Japan has restarted 15 out of its 33 operable reactors. The Kashiwazaki-Kariwa plant is the first of those owned by Tepco to be turned back on. (BBC)