Findings and recommendations to EPA on the technical bases for YuccaMountain standards were provided in the National Research Council3 report entitled Technical Bases for Yucca Mountain Standards,4 hereafter referred to as the “TYMS report.” This report was authored by a committee of experts that was appointedby the Chairman of the National Research Council and that operatedwith oversight from the BRWM. The TYMS committee was disbanded afterits report was completed in 1995. However, the BRWM is a continuingNational Research Council committee5 and can, at its discretion and with prior approval from the NationalResearch Council’s Governing Board, prepare reports on significantand timely issues.

The Board’s objectives in preparing this self-initiated letter report are thefollowing: (1) to provide a comparison of the technical bases forYucca Mountain standards recommended by the TYMS report with thoseproposed by EPA in its draft 40 CFR Part 197 (the “proposed standards”); 6and (2) where differences are noted, to provide comments on how EPA’s draft standards could be changed to make them consistent with therecommendations in the TYMS report. This letter report describesthe major recommendations in the TYMS report that EPA followed inits proposed rule, and it also highlights several areas in whichthe recommendations were not followed.

For nine major issues, the TYMS report provided recommendations onthe technical bases for Yucca Mountain standards. A brief summaryof each of those issues, the technical bases recommended by the TYMSreport, and the standards proposed by EPA are given below. Severalof these issues are discussed in more detail later in this report.

  1. THE FORM OF THE STANDARD. Although the Energy Policy Act stipulated that EPA should developa standard that prescribes dose equivalents, the TYMS report recommendedthat EPA develop a standard that sets a limit on the risk to individuals of adverse health effects from releases from the repository.EPA did not accept the TYMS recommendation. Instead, it proposesa dose-based standard.

  2. WHO IS PROTECTED. The TYMS report recommended that EPA apply the standards to a critical group representative of those individuals in the population who, basedon cautious, but reasonable, assumptions, have the highest risk resultingfrom repository releases. EPA proposes standards based on a reasonably maximally exposed individual (RMEI). As discussed below, the proposed standards are broadly consistentwith the recommendations in the TYMS report in light of the way inwhich EPA has proposed to implement them.

  3. LEVEL OF PROTECTION. The TYMS report noted that the level of protection was a policydecision to be established through the rulemaking process. EPA hasaccepted the


    The National Research Council is the operating arm of the NationalAcademies. Its reports do not National Research Council, 1995, TechnicalBases for Yucca Mountain Standards: Washington, Academy of Engineering,or the Institute of Medicine.


    necessarily represent the views of the members of the National Academyof Sciences, the National D.C., National Academy Press. This reportcan be viewed online at the following URL: report is referenced in the text as “TYMS, p. xxx”, where xxx is the relevantpage number.


    A standing National Research Council entity on radioactive wastemanagement has been operating continuously since 1958 and is responsiblefor oversight of studies on radioactive waste management and disposal.The current BRWM membership roster is given in Attachment A.


    The Board used the TYMS report and the Federal Register notice asreference materials for this letter report. The Board did not examinethe additional documentation available from EPA.

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