via Science20.com / September 28, 2015 / The worst nuclear disaster since the 1986 Chernobyl meltdown never should have happened, according to a new study.
In Philosophical Transactions A of the Royal Society, researchers Costas Synolakis of the USC Viterbi School of Engineering and Utku Kâno’lu of the Middle East Technical University in Turkey distilled thousands of pages of government and industry reports and hundreds of news stories, focusing on the run-up to the disaster. They found that “arrogance and ignorance,” design flaws, regulatory failures and improper hazard analyses doomed the costal nuclear power plant even before the tsunami hit.
“While most studies have focused on the response to the accident, we’ve found that there were design problems that led to the disaster that should have been dealt with long before the earthquake hit,” said Synolakis, professor of civil and environmental engineering at USC Viterbi. “Earlier government and industry studies focused on the mechanical failures and ‘buried the lead.’ The pre-event tsunami hazards study if done properly, would have identified the diesel generators as the lynch pin of a future disaster. Fukushima Dai-ichi was a siting duck waiting to be flooded.”
The authors describe the disaster as a “cascade of industrial, regulatory and engineering failures,” leading to a situation where critical infrastructure – in this case, backup generators to keep the cooling the plant in the event of main power loss – was built in harm’s way.
At the four damaged nuclear power plants (Onagawa, Fukushima Dai-ichi, Fukushimi Dai-ni, and Toka Dai-ni) 22 of the 33 total backup diesel generators were washed away, including 12 of 13 at Fukushima Dai-ichi. Of the 33 total backup power lines to off-site generators, all but two were obliterated by the tsunami.
Unable to cool itself, Fukushima Dai-ichi’s reactors melted down one by one.
“What doomed Fukushima Dai-ichi was the elevation of the EDGs (emergency diesel generators),” the authors wrote. One set was located in a basement, and the others at 10 and 13 meters above sea level; inexplicably and fatally low, Synolakis said.
Synolakis and Kâno’lu report that the Tokyo Electric Power Company (TEPCO), which ran the plant, first reduced the height of the coastal cliffs where the plant was built, underestimated potential tsunami heights, relied on its own internal faulty data and incomplete modeling – and ignored warnings from Japanese scientists that larger tsunamis were possible.