Abstract

The safety goals adopted by the U.S. Nuclear Regulatory Commission (NRC) consist of two qualitative safety goals 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 cancers from radiation exposure of members of the public living in the vicinity of a nuclear power plant. This paper is devoted to a reexamination of the coverage of the current safety goals as they constrain (or fail to constrain) the total (radiological and nonradiological) 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 the offsite effects both radiological and nonradiological, not just the individual risks. Recent Level 3 probabilistic risk assessments 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, as 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 and there was substantial property damage and community disruption along with the costs of recovery and decontamination. We argue that, in addition to the risks addressed in the current safety goals, societal risk should also be considered. This paper discusses specific possibilities for a goal and an associated quantitative objective.

摘要

美国核监管委员会（NRC）通过的安全目标包括两个定性安全目标，以及两个定量健康目标（QHO）。QHO根据对受影响个体的放射学后果，特别是居住在核电厂附近的公众成员的辐射暴露，对个人造成的早期死亡和潜在癌症的平均健康风险，确定了严重事故的风险极限。本文致力于重新检查当前安全目标的覆盖范围，因为它们会限制（或无法限制）核电站运行带来的总（放射和非放射）风险。具体而言，我们建议需要解决社会后果。由于社会后果，我们指的是衡量后果的指标，这些指标反映的是受影响的人数以及放射和非放射方面的异地影响，而不仅仅是个人风险。最近的3级概率风险评估表明，鉴于在释放前有大量疏散近亲人群的可能性，目前的QHO可以满足很大的要求，而福岛发生的一次严重事故则表明，实际的人类健康影响来自释放的放射线不是主要的后果，因为没有早期的死亡，而且在日本人群中，癌症发生率没有超过基线发生率的预期可测量的增加。因此，无论发生事故的可能性如何，带疏散的福岛型事故都可以满足NRC与健康相关的安全目标。然而，社会成本非常高昂，因为大量人员需要长期搬迁，财产损失和社区破坏严重，还有恢复和净化费用。我们认为，除了当前安全目标中解决的风险外，还应考虑社会风险。本文讨论了目标和相关定量目标的特定可能性。