Seismic Study to Aid Some Nuclear Plants' Hazard Reviews
It was released Jan. 31 by the Electric Power Research Institute, the U.S. Department of Energy, and the U.S. Nuclear Regulatory Commission and replaces source models used since the 1980s.
"The Central and Eastern United States Seismic Source Characterization for Nuclear Facilities" model and report were issued Jan. 31 by the Electric Power Research Institute, the U.S. Department of Energy, and the U.S. Nuclear Regulatory Commission to help U.S. nuclear facilities in the central and eastern United States reassess their seismic hazards. It caps a four-year effort among those organizations and replaces seismic source models used by industry and government since the late 1980s, according to NRC, which has asked U.S. nuclear power plants to re-evaluate seismic hazards.
The new documents are part of NRC's implementation of lessons learned from the Fukushima Daiichi nuclear power plant crisis in March 2011 after the earthquake and tsunami in northeastern Japan. The commission also will use the model for licensing of new nuclear facilities.
The project analyzed an expanded data set, including historical earthquake and geological data for the entire study region from 1568 through 2008, "using a rigorous, peer-reviewed assessment process," according to the NRC's news release, which says national and international experts from industry, government, academia, and various research organizations were engaged to develop the model.
"The model can be used to calculate the likelihood of various levels of earthquake-caused ground motions. Calculations with the new model are expected to result in a higher likelihood of a given ground motion compared to calculations done using previous models. These calculations, however, are not equivalent to a nuclear power plant's overall risk. Plant operators must combine the information from the new model with a plant's design and safety features to determine site-specific risks," it says.
When the new model was compared to previous models by calculating seismic hazards at seven test sites, those calculations showed the largest predicted ground motions could occur near repeated large-magnitude earthquake sources, such as New Madrid, Mo., and Charleston, S.C. The report and model are available at http://www.ceus-ssc.com.
The development project behind them was conducted from April 2008 to December 2011.