Nuclear Waste: The Academy and Million-Year Estimates

P REPARING TO BUILD the world's first permanent repository for high-level nuclear waste at Yucca Mountain, Nevada, the U.S. government has spent nearly $5 billion on site studies. In its 1992 Energy Policy Act, Congress directed the Environmental Protection Agency (EPA) to develop standards for the proposed Yucca Mountain Repository. Congress also asked the U.S. National Academy of Sciences to advise the agency on the technical bases for such standards. In a report published last August, the Academy's Board on Radioactive Waste Management gave its advice to the EPA. This advice is supposed to assist the government in achieving what no one has ever accomplished: to secure nuclear waste in perpetuity, so that it presents no threat to the biosphere. The Academy report, Technical Basesfor Yucca Mountain Standards (NRC 1995), is a landmark document that significantly advances our understandings of both the science and the policy that are relevant to radioactive waste disposal. It has many positive features, notably its recommendation that compliance with the risk standard for radioactive waste be measured at the time of peak risk, whenever it occurs (NRC 1995:2, 55-56, 67); its conclusion that there is no scientific basis for limiting safety concerns to merely 10,000 years (NRC 1995: 56); and its important stance in favor of intergenerational equity. The study also does an excellentjob of emphasizing the fact that it is not possible to assess the frequency of intrusion into a permanent repository for a million years into the future (NRC 1995:2, 73). It explains that there is no system (based on active institutional controls) for postclosure oversight of the repository that is able to prevent an unreasonable risk of breaching the engineered barriers (NRC 1995:11). The document is straightforward about many important uncertainties in its recommendations about radioactive waste disposal, site modeling, and performance assessment generally (NRC 1995:19-20). It also stresses that there is no sharp dividing line between science and policy (NRC 1995:viii); that there is a limited scientific basis for choosing one waste policy option over another (NRC 1995: viii); and that the committee ought not recommend what levels of risk are acceptable because this is a policy decision (NRC 1995:20, 49). Perhaps, most importantly, the Academy report wisely recommends choosing future Yucca Mountain exposure scenarios on the basis of rulemaking with full public participation (NRC 1995:99, 127). Such conclusions are both balanced and defensible. Despite its strengths, the Academy report has at least three controversial aspects that