The role of reliability and risk assessment in LMFBR design: Implementation of reliability in LMFBR design

This paper concerns future developments in LMFBR licensing technology.Federal Regulations (10 CFR 50.34) require that the preliminary safety analysis provide analysis and evaluation “with the objective of assessing the risk to public health and safety” to determine margins of safety and the adequacy of the plant. Hitherto the assessment of risk has been qualitative but it has become increasingly apparent that quantitative assessments would provide a better basis for judgement. Potential future roles of reliability and risk assessment are discussed in the context of providing additional confirmation of the safety of LMFBR designs. Potential acceptability criteria for risk evaluations are outlined.The reliability implications of designing components to the ASME Code Section III requirements are discussed. General judgements are provided as well as the preliminary results of probabilistic studies of selected specific limits. There is a different reliability significance for the mandatory rules for normal, upset, and emergency conditions versus the non-mandatory rules for normal, upset, and emergency conditions versus the non-mandatory guidance for faulted conditions.