Evaluation of Key Elements in the U.S. Department of Energy's Proposed System for Isolating and Containing Radioactive Waste

摘要

At meetings of the U. S. Nuclear Waste Technical Review Board (Board) held in May and September 2003, the U. S. Department of Energy (DOE) made five presentations about how its high-temperature repository design proposed for Yucca Mountain in Nevada might behave. The presentations included an extended discussion of how the natural system and the waste packages might function over many thousands of years. This paper presents the Boards views on the validity of the DOEs technical arguments, made at those meetings, about repository behavior. The paper concentrates on the first 1,000 years after the repository is closed. During that time, commonly referred to as the thermal pulse, temperatures within the repositorys drifts would be above the boiling point of water, reaching a high of 160DGC to 180DGC. In the following evaluation, the Board also considers other related issues and relies on technical analyses carried out by the DOE but not presented at the May or September meetings. This paper is not designed to present an exhaustive analysis of the entire repository system as proposed by the DOE. Some elements of that system are not addressed at all, such as the role the interior waste package and the design of the waste form might play in inhibiting the mobilization of radionuclides and how the unsaturated zone below the repository horizon and the saturated zone might delay transport of radionuclides.