"Japanese Nuclear Plant’s Safety Analysts Brushed Off Risk of Tsunami"

"TOYKO — A Japanese government agency that spent several years evaluating the Fukushima Daiichi nuclear plant declared the facility safe after dismissing concerns from a member of its own expert panel that a tsunami could jeopardize its reactors.

Yukinobu Okamura, a prominent seismologist, warned of a debilitating tsunami in June 2009 at one of a series of meetings held by the Nuclear and Industrial Safety Agency to evaluate the readiness of Daiichi, as well as Japan’s 16 other nuclear power plants, to withstand a massive natural disaster. But in the discussion about Daiichi, Okamura was rebuffed by an executive from the Tokyo Electric Power Co., which operates the plant, because the utility and the government believed that earthquakes posed a greater threat.

That conclusion left Daiichi vulnerable to what unfolded on March 11, when a 9.0-magnitude earthquake struck off Japan’s northeast coast. Experts now say that Daiichi, as designed, withstood the quake. It was the ensuing tsunami, with waves more than 20 feet high, that knocked out the facility’s critical backup power supply and triggered a nuclear emergency, resulting in widespread releases of radiation."

David Nakamura and Chico Harlan report for the Washington Post March 23, 2011.