24 Avril 2012
4 nuclear plants asked to review quake safety
Japan's nuclear safety agency is set to ask the operators of 4 nuclear power plants to re-examine the effects of seismic activities that it says became more active after the March 2011 earthquake in northern Japan.
The Nuclear and Industrial Safety Agency will request the reassessment of quake resistance for the Tomari plant in Hokkaido, Tsuruga and Monju plants in Fukui Prefecture and the Shimane plant in Shimane.
It says the risk has increased of active faults more than 5 kilometers away from each other shifting simultaneously and causing a greater earthquake than predicted.
Hokkaido Electric Power Company says even if the 2 active faults on the sea and the land move at the same time, the assumed temblor in part of the Tomari facility will be a little larger than that previously calculated. It says quake resistance can be secured as important buildings are little affected by the quake.
But experts at the agency pointed out at a meeting that the tremor will be further intensified if the 2 active faults shift simultaneously.
They asked the company to reassess quake resistance based on the new assumption.
The company says it will respond appropriately in line with the experts' views, but it insisted that there will be no problem with the ability of key equipment to safeguard the nuclear plant.
Results of the reassessment could force a revision of quake resistance standards at the plants.
They could also affect the outcome of the stress tests required for restarting the idled plants.
The power companies say they will submit reports on their reassessments.