The Associated Press has obtained the tsunami preparation document for the Fukushima Daiichi nuclear power facility under Japan’s open records act. As the AP reported earlier today:
Japanese nuclear regulators trusted that the reactors at Fukushima Dai-ichi were safe from the worst waves an earthquake could muster based on a single-page memo from the plant operator nearly a decade ago.
In the Dec. 19, 2001 document — one double-sized page obtained by The Associated Press under Japan’s public records law — Tokyo Electric Power Co. rules out the possibility of a tsunami large enough to knock the plant offline and gives scant details to justify this conclusion, which proved to be wildly optimistic.
Regulators at the Nuclear and Industrial Safety Agency, or NISA, had asked plant operators for assessments of their earthquake and tsunami preparedness. They didn’t mind the brevity of TEPCO’s response, and apparently made no moves to verify its calculations or ask for supporting documents.
TEPCO re-examined emergency plans last year:
When TEPCO finally did revisit tsunami preparedness last year, it was the most cursory of checks. And the conclusion was the same: The facility would remain dry under every scenario the utility envisioned.
“There was an attitude of disrespecting nature,” said Kobe University professor emeritus Katsuhiko Ishibashi, who has sat on government nuclear safety advisory panels.
TEPCO can’t blame the poor planning on the state of tsunami knowledge at the time the plan was prepared:
Ishibashi said the problem with the plant’s tsunami preparedness didn’t lie with the limitations of science back in 2001. The problem was that TEPCO and regulators didn’t look at risk factors more carefully.
“It is critical to be prepared for what might happen even if the possibilities are small,” he said.
The assessment vastly understated the worst-case scenario:
The company said it used measures for expected earthquakes and other “parameters” to calculate that water would not surpass 5.7 meters (18.7 feet) at Fukushima Dai-ichi.
The waters set off by the March tsunami reached 14 meters (46 feet) above sea level, according to TEPCO.
One big reason for the underestimate: TEPCO’s experts asserted that the biggest earthquake that the nearest fault could produce was 8.6 magnitude. At a 9.0 magnitude, the quake that struck was four times more powerful than that.