27 Avril 2012
April 27, 2012
Tokyo Electric Power Co. (TEPCO) announced April 26 that it will recalculate the height of a potential tsunami that may strike its Kashiwazaki-Kariwa Nuclear Power Plant in Niigata Prefecture.
The move was pushed forward after four prefectures located along the Sea of Japan released their own estimates, which state that the scale of a potential earthquake in the area where the nuclear plant is located is in fact up to around 2.8 times stronger than what TEPCO has estimated.
Based on current TEPCO estimations, a magnitude 7.85 quake may occur at a fault extending some 131 kilometers near Niigata Prefecture's Sado Island, which could trigger a 3.3-meter-high tsunami. Based on these estimations, the company is currently proceeding with the construction of an embankment that would resist waves of up to some 15 meters in height.
However, based on a report issued by the Tottori Prefectural Government, there is a risk that a fault running for 220 kilometers located within the same area may trigger an 8.15 magnitude earthquake. Separate reports released by the Shimane and Ishikawa prefectural governments point to a risk of magnitude 8.01 and magnitude 7.99 earthquakes in the area, respectively.
Judging the reports to be of "valuable information that must be reflected in safety assessments," TEPCO submitted a report on those estimates to the Ministry of Economy, Trade and Industry's Nuclear and Industrial Safety Agency.
Results of the recalculation may affect future safety assessments, including stress tests, at the plant.