Application of the Partitioned Multiobjective Risk Method to Analysis of Nuclear Facility Safety Features. Stanley D. Calvert, U.S. Department of Energy, Washington, DC; and Yacov Y Haimes, Center for Risk Management of Engineering Systems, University of Virginia, Charlottesville, VA 22903
A methodology is presented that implements the Partitioned Multiobjective Risk Method (PMRM) to enable objective evaluation of trade-offs in the selection of safety features for nuclear facilities. The PMRM is an analytical method for making risk-related policy decisions, with previous applications including dam safety, groundwater contamination, and aerospace technologies. The PMRM offers expanded treatment of risk information through partitioning and conditional expectation, and provides a framework for comprehensive evaluation of available information without the need for subjective expression of decision-maker utility functions. Elements required for application of the PMRM are defined for the nuclear facility context. The development of distributions to characterize health, investment and off-site damage risk is emphasized. A structure is described for organizing and presenting input information and analysis results. Decision-making results are demonstrated through a case study of a prospective nuclear reactor project. In particular, the case study demonstrates that the conditional evaluation of partitioned risk regimes enables insights beyond what traditional, unconditional expected value treatment of risk information can provide. Such inferences are critical to ensure that representations of high probability/low consequence events do not override those of low probability/high consequence events---a driving concern for nuclear safety. Sensitivity studies are performed to assess how these inferences are affected by variation of key model parameters.