ABSTRACT

The 96 nuclear reactors in the central and eastern United States face previously unrecognized threats from big earthquakes, according to a report of the U.S. Nuclear Regulatory Commission (NRC) in late January 2012 (Smith 2012). The NRC plans to give operators of nuclear plants a period of four years to reevaluate seismic risks for all structures, systems and components according to a complex model jointly developed by the

NRC, the U.S. Department of Energy and the industry-funded Electric Power Research Institute. The model incorporates data from about 1,000 earthquakes that were previously not cataloged, bringing the total for the region to nearly 3,300 earthquakes since 1568. Retrofi tting old nuclear plants to conform to the model and to withstand the single worst earthquake most likely to occur in 10,000 years, however, may be so costly that the reactors might be closed altogether (Smith 2012).