Japan Test Reactor Was Shaken Beyond Design Limit in March Quake

A research reactor operated by the Japan Atomic Energy Agency was shaken beyond its design limits during the earthquake that struck in March and another of the agency’s nuclear facilities was likely damaged in the disaster.

The Japan Research Reactor No. 3 in Tokai village, 115 kilometers (71 miles) northeast of Tokyo, was shaken as much as 5.7 times more than its design allowed, the Ministry of Education, Culture, Sports, Science and Technology said in a statement.

Parts of the roof of the experimental Japan Materials Testing Reactor building in the agency’s research center in Oarari, 60 kilometers from Tokyo, was damaged, possibly by the quake, the ministry said. No radiation leaks were found at either site, according to the ministry.

The magnitude-9 quake and subsequent tsunami on March 11 knocked out power and cooling at Tokyo Electric Power Co.’s Fukushima Dai-Ichi plant, causing the worst nuclear accident since Chernobyl 25 years ago.

Neither of the Japan Atomic reactors were running when the quake hit, said Kunimi Yoshida, an official involved in nuclear power regulation at the science ministry.

Tokai village was the site of an accident in 1999 at a nuclear plant operated by Sumitomo Metal Mining Co.’s unit JCO Co. Two workers were killed by radiation after pouring uranium from a bucket into a processing tank, leading to a chain reaction.

To contact the reporters on this story: Tsuyoshi Inajima in Tokyo at tinajima@bloomberg.net

To contact the editor responsible for this story: Amit Prakash in Singapore at aprakash1@bloomberg.net