The U.S. Department of Energy (DOE) is considering the possible recommendation of a site at Yucca Mountain, Nevada, for development as a geologic repository for the disposal of high-level radioactive waste and spent nuclear fuel. To facilitate public review and comment, in May 2001 the DOE released the Yucca Mountain Science and Engineering Report (S&ER) (DOE 2001 [DIRS 153849]), which presents technical information supporting the consideration of the possible site recommendation. The report summarizes the results of more than 20 years of scientific and engineering studies. A decision to recommend the site has not been made: the DOE has provided the S&ER and its supporting documents as an aid to the public in formulating comments on the possible recommendation. When the S&ER (DOE 2001 [DIRS 153849]) was released, the DOE acknowledged that technical and scientific analyses of the site were ongoing. Therefore, the DOE noted in the Federal Register Notice accompanying the report (66 FR 23013 [DIRS 155009], p. 2) that additional technical information would be released before the dates, locations, and times for public hearings on the possible recommendation were announced. This information includes: (1) the results of additional technical studies of a potential repository at Yucca Mountain, contained …