Assessment of the proposed rule (10CFR60) for disposal of high-level radioactive wastes in geologic repositories. Volume I

This report summarizes the work performed for the Nuclear Regulatory Commission (NRC) to assess its proposed Rule (10CFR60) for disposal of high-level radioactive wastes in geologic repositories. The objectives of this project were to provide information that NRC could use to evaluate the rationale for the technical requirements in the Rule, to respond to public comments on the proposed Rule, and to analyze the benefits of alternative criteria for the final rule. Three of the numerical criteria of the Performance Objectives of the Rule were analyzed in detail in this study. The three criteria pertain to: a containment period, a controlled release rate, and a pre-waste emplacement ground-water travel time. The Rule requires geologic repositories to comply with the draft EPA Standard (40CFR191); accordingly, this study assesses the relevance of the three numerical criteria to the draft EPA Standard. A series of parametric analyses were performed on the potential releases of radionuclides to the accessible environment in order to determine the impact of the three criteria on compliance with the draft EPA Standard. The analyses were performed for three geologic media: basalt, bedded salt, and tuff. The study also examined the achievability of the three numerical criteria based on an assessment of the existing technology. Parameters and techniques that could be used to assess compliance were identified. In addition to the three numerical criteria, certain other requirements were also addressed in varying degrees of detail. The structure and content of the Rule were analyzed for completeness, consistency, and redundancy. As part of this study, a panel of experts was formed to address and debate the issues relating to the requirements contained in the proposed Rule. A number of recommendations have been made in the report based on the analyses performed and the outcome of the panel discussions