The magnitude 8.9 quake hit at 2.46pm, centred offshore of the Sendai region, which contains the capital Tokyo. Serious secondary effects followed including a significant tsunami and a major fire at a fossil fuel installation. The quake comes just two days after one of magnitude 7.3 also offshore in the same general region.
The Japan Atomic Industry Forum (JAIF) issued a notice saying all reactors in the north-eastern part of Japan had shut down automatically. It noted that the Nuclear and Industrial Safety Agency (Nisa) had said no damage to nuclear power plants had been reported as of 3.16pm. Japanese prime minister Naoto Kan made a statement on television in which he noted that there was no indication of any radioactive release.
Tokyo Electric Power Company (Tepco) has reported that emergency diesel generators started as expected at the Fukushima Daiichi nuclear power plant, but then stopped after one hour, leaving units 1, 2 and 3 with no power for important cooling functions. This led the company to notify the government of an ’emergency’ situation, which allows local authorities to take additional precautionary measures. An evacuation has been ordered of people living within three kilometres, while engineers work to restore power.
At neighbouring Fukushima Daini, sufficient cooling water is being maintained by injection using the reactor core isolation cooling systems of units 1 to 4. At unit 1 an increase in reactor containment pressure has been noted, and “assumed to be caused by leakage of reactor coolant in the reactor containment” this led Tepco to notify government of another emergency status.
Nisa has noted that emissions from the exhaust stack of the these power plants show no increase in radioactivity.
Tohoku Electric Power Company has reported a fire in the non-nuclear turbine building of Onagawa 1. A minor fire burned in a non-nuclear service building of Tepco’s Fukushima Daini 1 but this was extinguished within two hours.
A tsunami warning was issued for most of the Pacific Ocean, including Taiwan, but reactors there operated normally throughout. There was no tsunami concern for nuclear power plants in South Korea or China.