Opinion ID: 407564
Heading Depth: 3
Heading Rank: 2

Heading: The Commission's Methodology

Text: 342 To derive a conservative table of useable estimates amidst uncertainty about future technology, the NRC staff had to select some methodology. The staff chose to analyze intensively the most credible long-term waste disposal method then known-burial of the wastes in a bedded-salt geologic repository several hundred meters below ground-then estimate(d) its impact conservatively, based on the best available information and analysis. 71 Because such a repository had not yet been built, the staff had to make a number of preliminary assumptions even to begin analysis. At the outset, it assumed that an appropriate salt deposit site would be found 72 that the particular salt formation chosen would likely remain essentially undisturbed for millions of years, 73 and that whatever repository built would be designed, operated, and regulated in such a way as to minimize the possibility of long-term failure. 74 343 The staff then analyzed the possibility of a repository failure resulting from two types of events: (1) commonplace occurrences, such as long-term corrosion of waste cannisters and subsequent leakage into the groundwater; 75 and (2) unusual occurrences, such as violent disruption of the repository by sabotage or natural catastrophe. 76 Having thereby established a range of probabilities for potential waste release based on a variety of repository failure scenarios, the staff then used two approaches to assess the consequences to human life of a waste release: a hazard index 77 and a modeling of waste transport to the human environment. 78 Throughout the staff's analysis, working assumptions were expressly spelled out and uncertainties inherent in the models employed were candidly acknowledged. 79