%0 Journal Article
%T An Evaluation Methodology Development and Application Process for Severe Accident Safety Issue Resolution
%A Robert P. Martin
%J Science and Technology of Nuclear Installations
%D 2012
%I Hindawi Publishing Corporation
%R 10.1155/2012/735719
%X A general evaluation methodology development and application process (EMDAP) paradigm is described for the resolution of severe accident safety issues. For the broader objective of complete and comprehensive design validation, severe accident safety issues are resolved by demonstrating comprehensive severe-accident-related engineering through applicable testing programs, process studies demonstrating certain deterministic elements, probabilistic risk assessment, and severe accident management guidelines. The basic framework described in this paper extends the top-down, bottom-up strategy described in the U.S Nuclear Regulatory Commission Regulatory Guide 1.203 to severe accident evaluations addressing U.S. NRC expectation for plant design certification applications. 1. Introduction Associated with rare, hazardous events, such as nuclear power plant (NPP) severe accidents, is a degree of uncertainty that provides a significant challenge to the evaluation and resolution of related design and analysis methods issues. For events occurring at some sufficiently observable frequency, design improvements can evolve through the understanding gained from such events and applicable test programs, leading to long-term acceptance. The broad uncertainties associated with severe accident initiators and event progression impose inherent limits on the benefits of this approach for severe accident design. As such, there is greater reliance on analysis and emphasis on the better understood severe accident phenomena. The engineering design process for an NPP¡¯s severe accident response strategy has evolved to a process that relies on the(i)establishment of safety goals,(ii)identification of processes and phenomena,(iii)iterative design processes focused on risk reduction,(iv)test programs,(v)expert elicitation on important severe accident safety issues,(vi)analysis methods development,(vii)process studies. Consistent with current US regulatory requirements and guidance, final acceptance and resolution of relevant beyond-design-basis events is demonstrated through detailed deterministic studies and probabilistic risk assessment (PRA). The unique characteristic of this process for severe accidents is the consideration of risk in the resolution of severe accident safety issues. Generation III and IV advanced reactors designs incorporate features that significantly reduced risk relative to current-generation light water reactors (LWRs). Practical consideration of this reduced risk requires that this information be incorporated into measures not only of acceptable performance,
%U http://www.hindawi.com/journals/stni/2012/735719/