nuclear-news

Japan’s political gamble; they cannot be sure that nuclear restart will be safe

Japan’s nuclear dilemma 03 December 2014 by Robert J. Geller Some Japanese nuclear reactors, mothballed since the 2011 Tohoku quake, may soon restart. But nature can outpace new safety precautions, warns a geophysicist “………The Sendai plant faces some specific risks. The site is about 50 kilometres from a large active volcano, Sakurajima, and there are several other active volcanoes on Kyushu. A large eruption would pose obvious safety issues for the plant, but its operator has said that advance warnings of an impending eruption would allow them to take appropriate measures. Doubts about this sanguine view were reinforced by the eruption of Mount Ontake on Honshu, without warning, in September. It killed more than 50 climbers out for a weekend stroll.

A variety of natural hazards, including earthquakes and subsequent tsunamis, pose risks to reactors throughout Japan. I have written extensively about the lack of success of both short and long-term earthquake prediction (Nature, vol 472, p 407). It is well known that accurate predictions of fracture and failure phenomena such as earthquakes are, in general, impossible. Intellectually honest discussions of nuclear safety with regard to earthquakes must start by acknowledging this.

Before Tohoku, the Japanese government’s seismic hazard map assumed that earthquakes off that coast would not exceed magnitude 7.5 to 8.0. The most authoritative estimate for the size of the Tohoku quake is magnitude 9.1. Given that the energy released by an earthquake increases 30-fold for every 1.0 increase in magnitude, this is a huge discrepancy………

• And although advice from specialists is necessary, it is Japan’s political leaders, as well as the voters who elect them, who must take ultimate responsibility for the decision to restart its nuclear plants.Robert J. Geller is professor of geophysics at the University of Tokyo http://www.newscientist.com/article/mg22429972.800-total-safety-an-illusion-for-japans-nuclear-restart.html#.VIJRwNLF8nn

December 5, 2014 - Posted by Christina Macpherson | Japan, safety