...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 did not have a strong understanding of which structures and systems at the plants were most vulnerable.
