Japanese nuclear reactor under-designed for earthquake?

[bananas]

Source: Nature

An earthquake off the western coast of Japan yesterday hit a nuclear plant with more than twice the jolt that the plant was expected to have to handle. The shock seems to have done little immediate damage, but has raised concerns about whether Japan's nuclear plants are designed to withstand the kind of shaking they are likely to experience.

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Based mainly on historical precedent, TEPCO designed the reactors at Kashiwazaki-Kariwa assuming that the area would have a maximum ground acceleration of 274 gal. Yesterday, the number 1 reactor at Kashiwazaki-Kariwa experienced an acceleration of 680 gal as the ground slid from east to west; the number 5 reactor accelerated at 442 gal east/west, and the number 6 reactor was hit with 488 gals up/down, as measured on site.

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Depending on the outcome of the safety report, which will need to be evaluated by the ministry, it is possible that the seven reactors will be closed down. "We just want to carry out a thorough inspection and take any necessary measures needed to operate the facilities safely," says Yoshinobu Kamijima of TEPCO's press office.

Read more: http://www.nature.com/news/2007/070716/full/070716-3.html