Mainichi, the website of the Japanese newspaper Mainichi Shimbun, carried a piece today on the dangers to Japanese nuclear power plants from volcanic activity:
The reactivation of nuclear reactors should be deliberated only after the public has been informed of the risks volcanic explosions pose to nuclear reactors, multiple volcano experts surveyed by the Mainichi Shimbun said.
Hideyuki Ito, an associate professor at Iwate Prefectural University, said that the Sendai, Tomari, Higashidori and Genkai nuclear power plants in Kagoshima, Hokkaido, Aomori and Saga prefectures, respectively, were at “high risk” due to their location in areas that could be affected by pyroclastic flows. Akita University’s Shintaro Hayashi also said that Sendai Nuclear Power Plant carried “unacceptable risks.”
Sendai, Tomari, Higashidori and Genkai are home to a total of eleven reactors, and Tokyo Electric Power Company (TEPCO) has plans to build two new units at Higashidori.
Mainichi spelled out the dangers from volcanic activity:
Many experts believe that damage of catastrophic proportions cannot be avoided in the case of a massive volcanic eruption. With pyroclastic flows — hot gas and rocks — estimated to be at least 600 degrees Celsius bursting out of the earth at a speed of more than 100 kilometers per hour, an area of at least 100 kilometers in all four directions of a volcano would be burned down.
Even if the pyroclastic flows did not hit directly, blasts of scalding air could cause volcanic ash to fall in a wide area, cutting power lines and clogging water intakes and vents at nuclear power plants, and hindering reactor cooling. Moreover, any outside assistance would have a difficult time reaching those facilities in need.
Another expert contacted by the news organization said:
“The possibility that a caldera explosion will take place while a nuclear reactor is in operation is not zero,” said Shinshu University’s Yasuyuki Miyake. “Looking at the past four massive explosions of Mount Aso (which could possibly affect the Sendai, Genkai and Ikata nuclear power plants), it is way overdue for another explosion.”
Although the possibility of a volcanic eruption causing a major disaster at one or more nuclear power plants might seem unlikely, just think how unlikely the possibility of a 9.0 earthquake causing a nuclear disaster seemed prior to March 2011.
Here’s a link to the article: http://mainichi.jp/english/english/perspectives/news/20131223p2a00m0na010000c.html