Second Unit Restarts At Japan’s Kashiwazaki-Kariwa Nuclear Plant
Written by NucNet
Wednesday, 26 August 2009
Unit 6 of Japan’s Kashiwazaki-Kariwa nuclear power plant in Niigata prefecture was restarted today, just over two years after a major earthquake hit the area.
Kashiwazaki-Kariwa-6, along with units 1 and 5 at the seven-unit plant in Niigata prefecture, was undergoing a periodic inspection when the earthquake struck on 16 July 2007. Units 3, 4 and 7 automatically shut down safely. Unit 2, which was technically undergoing a periodic inspection and where start-up operations had just begun, was also shut down safely.
However, all units have remained shut down since the earthquake while inspection, repairs, and tests were carried out, including back-checks using revised national seismic safety standards.
Plant operator and owner Tokyo Electric Power Company (Tepco) confirmed today that a series of functional tests for unit 6 were successfully completed yesterday and that the reactor was restarted earlier this afternoon local time, to be followed by further pre-planned tests.
In May 2009, Kashiwakaki Kariwa-7 was temporarily connected to the grid for the first time since the earthquake. Last month, procedures began for unit 7 to return to commercial operation following the approval of Japan’s government, the country’s Nuclear and Industrial Safety Agency and the heads of local government in three neighbouring areas.
In January 2009, a report by the International Atomic Energy Agency (IAEA) said the consequences of the earthquake on the plant were “unique in the sense that the levels of seismic ground motion estimated in the design process were very significantly exceeded by the event.”
However, the IAEA said the newly-calculated seismic hazard at the site is much higher than both the July 2007 event and the original design earthquake level.
