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New study on earthquake risks near USA nuclear plants

Quakes and U.S. Reactors: An Analytic Tool, NYT. By MATTHEW L. WALD  With the release of a computer model of all known geologic faults east of Denver, nearly all of the nuclear power plants in the United States are about to embark on a broad re-evaluation of their vulnerability to earthquakes. The new mapping is the first major update of the fault situation for plants since 1989.

The map has been in preparation since 2008, well before the earthquake and tsunami that caused three meltdowns at Fukushima Daiichi in Japan last March or the quake near Mineral, Va., last summer that shook a twin-reactor plant beyond the degree expected. Still, those events have lent urgency to the effort to assess the American plants’ ability to withstand quakes.

The new study does not calculate the risk of damage from an earthquake or even specify how much ground motion is likely at the reactor sites. That work is left to the plants’ owners, supervised by the Nuclear Regulatory Commission.

The industry began to realize after the Fukushima disaster that engineers do not have a strong understanding of which structures and systems at the plants are most vulnerable…..

Not everyone is pleased with the route that the commission is taking when it comes to future construction. David Lochbaum, a reactor expert with the Union of Concerned Scientists, said that the agency had already approved sites for new reactors and designs for new reactors based on computer analyses of earthquake hazards.

If considerable study is needed on the quake vulnerability of existing reactors, he argues, the uncertainty surrounding the soundness of future plants must be even greater. “How can we know more about the reactors that haven’t been built than the ones that have been built?’’ he said.     http://green.blogs.nytimes.com/2012/01/31/quakes-and-u-s-reactors-an-analytic-tool/

February 1, 2012 - Posted by Christina Macpherson | safety, USA