Re-evaluating the current safety goals

The Safety Goals adopted by the United States Nuclear Regulatory Commission (NRC) consist of two qualitative safety goals (QSGs) backed up by two quantitative health objectives (QHOs). The QHOs establish risk limits for severe accidents in terms of their radiological consequences to affected individuals: in particular, the average individual health risks of early fatality and latent cancer fatalities from radiation exposure of members of the public living in the vicinity of a nuclear power plant. This paper is devoted to a re-examination of the coverage of the current safety goals in evaluating the total (radiological and non-radiological) risk posed by nuclear power plant operation. Specifically, we suggest the need to address societal consequences. By “societal consequences,” we mean measures of consequences that reflect the number of people affected, and not just the individual risks. Recent Level 3 Probabilistic Risk Assessments (PRAs) suggest that given a high likelihood of evacuation of the close-in population before any release occurs, the current QHOs are satisfied by large margins, and the experience of an actual severe accident at Fukushima showed that actual human health effects from released radiation were not the dominant consequences: there were no early fatalities and no measurable increases expected in cancer rates above the baseline rates in the Japanese population. Hence, regardless of accident probability, Fukushima-type accidents with evacuation would satisfy the NRC's health-related safety goals. However, there were very significant societal costs, in that large numbers of people were relocated for long periods. We argue that, in addition to the risks addressed in current safety goals, societal risk should also be considered. The paper discusses specific possibilities for a goal and an associated quantitative objective.