10 Aug (NucNet): An initial report about the effects of the Great East Japan Earthquake on the Onagawa nuclear power station says the plant was “remarkably undamaged” despite “very high levels of ground shaking”.
The report, compiled by a team of International Atomic Energy Agency (IAEA) experts, says the structural elements of the three-unit station were “remarkably undamaged” given the magnitude of ground motion experienced and the duration and size of this great earthquake.
Onagawa, facing the Pacific Ocean on Japan’s northeast coast, was the nuclear power station closest to the epicentre of the 11 March 2011 magnitude 9.0 earthquake that struck Japan and resulted in a devastating tsunami.
Findings from the IAEA’s investigation will be added to a database being compiled by its International Seismic Safety Centre (ISSC) to provide knowledge about the impact of external hazards on nuclear power stations.
The IAEA said the ISSC database makes an important contribution to the IAEA's Action Plan on Nuclear Safety, which was unanimously endorsed by the agency's member states following last year's nuclear accident at the Fukushima-Daiichi nuclear station.
The aim of the IAEA’s mission to Onagawa was to see how structures, systems and components with significance to the safety of the plant responded to the earthquake and heavy shaking.
At Fukushima-Daiichi, nearly 120 km south of Onagawa, the effects of the earthquake, tsunami and hydrogen explosions make it impossible to single out the impact of external hazards on safety-related parts of the power station, the IAEA said.
