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oai:drum.lib.umd.edu:1903/188322017-06-13T10:34:30Zcom_1903_2263com_1903_1654com_1903_2col_1903_33173col_1903_3

Modarres, Mohammad Hudson, Daniel Wayne Digital Repository at the University of Maryland University of Maryland (College Park, Md.) Reliability Engineering 2016-09-15T05:34:31Z 2016-09-15T05:34:31Z 2016 https://doi.org/10.13016/M2ZB96 http://hdl.handle.net/1903/18832 The U.S. Nuclear Regulatory Commission implemented a safety goal policy in response to the 1979 Three Mile Island accident. This policy addresses the question “How safe is safe enough?” by specifying quantitative health objectives (QHOs) for comparison with results from nuclear power plant (NPP) probabilistic risk analyses (PRAs) to determine whether proposed regulatory actions are justified based on potential safety benefit. Lessons learned from recent operating experience—including the 2011 Fukushima accident—indicate that accidents involving multiple units at a shared site can occur with non-negligible frequency. Yet risk contributions from such scenarios are excluded by policy from safety goal evaluations—even for the nearly 60% of U.S. NPP sites that include multiple units. This research develops and applies methods for estimating risk metrics for comparison with safety goal QHOs using models from state-of-the-art consequence analyses to evaluate the effect of including multi-unit accident risk contributions in safety goal evaluations. en MULTI-UNIT ACCIDENT CONTRIBUTIONS TO U.S. NUCLEAR REGULATORY COMMISSION QUANTITATIVE HEALTH OBJECTIVES: A SAFETY GOAL POLICY ANALYSIS USING MODELS FROM STATE-OF-THE-ART REACTOR CONSEQUENCE ANALYSES Thesis Operations research Systems science Nuclear engineering multi-unit accident scenarios nuclear power plants policy analysis probabilistic risk assessment quantitative health objectives safety goals open.access