In the wake of the Fukushima nuclear disaster, the Japanese government is reviewing possible active faults near or under nuclear power plants. Insufficient investigations at nuclear power plants are turning out to be common, and there is increasing skepticism regarding the validity of past safety checks, which are believed to all have been heavily influenced by the results of power firms’ investigations. Experts paid by the nuclear industry have drawn severe criticism for playing down the risk of massive quakes and tsunami before the Fukushima nuclear disaster.
NRA Chairman Shunichi Tanaka said at a press conference Wednesday the agency may reevaluate the safety of all nuclear power plants after drawing up new safety standards on quake-resistant design by next summer.
“If necessary, we’ll conduct additional inspections,” Tanaka said.
The government’s Headquarters for Earthquake Research Promotion maintains a general standard that requires checking for movements dating several hundred thousand years into the past to judge whether a fault is active.
However, the government’s guidelines for evaluating the quake resistance of nuclear power plants, compiled by the now-defunct Nuclear Safety Commission, have slightly looser standards. An active fault is defined as one with confirmed movements in the past 120,000 to 130,000 years, which is a softer requirement as it takes into account the technical problems of specifying the ages of strata.
Source: The Daily Yomiuri