Technical Evaluation of the Margins Between Established Risk Goals and Health Objectives for Nuclear Power Plants

Abstract

This work explores recent developments in severe accident analysis and risk assessment to inform and expand on these perspectives. Variations in nuclear reactor safety policy, reactor designs, extent of use of risk information in decision making, and other aspects can impact how safety policies regarding nuclear installations are developed and implemented. In particular, the relationship of nuclear policy in the United States is explored with regard to quantitative risk criteria or goals and their relationship with health objectives. In the United States and many countries around the world, health objectives are defined with regard to the potential impact to the public in terms of “early” fatalities and “latent” fatalities. This paper discusses how the link between these health objectives and quantitative risk goals have been developed and how recent information may change the perspective originally held when the policies were established (e.g., that there would be a significant margin between the risk of operating nuclear facilities and these goals). Given that these metrics play a significant role in how current risk applications are used for operating nuclear reactors, especially when results are to be compared with thresholds, it is important to recognize the evolution and current understanding of associated embedded margins. Given the additional 30 years of insights, the expansion of risk application in the commercial nuclear reactor industry, and improvements in methodologies and computing capabilities, significant additional information has been gained. These insights are discussed and presented in this paper.