Status of Siting a High Level Waste Repository in France

Abstract

Radioactive waste generated by industrial activities have been managed in France for many years, and industrial solutions have been implemented for low-level and short-lived waste. This waste is stabilized in solid matrices and sent to near-surface disposal facilities, first the Manche center and, since 1992, the Aube center. High-level long-lived radioactive waste is the subject of research to lay the groundwork for decisions on a waste management system which guarantees safety for man and his environment. These investigations have been conducted since 1991 under a law which set three research directions: separation and transmutation; reversible or irreversible disposal in a deep geological repository ; waste conditioning and long-term storage. The first alternative as well as waste conditioning are accordingly concerned with the waste of the future. Long-term storage is basically only considered for a timescale much shorter than the lifetime of the radionuclides present in the waste. Among the 3 research directions, disposal in a geological repository appears today to be the possible choice for existing waste. Barring a satisfactory alternative, it will also be the solution for the waste of the future. Research into the reversible or irreversible disposal of high-level long- lived waste in deep geological formations is carried out in France by ANDRA, with the assistance of various partners, institutes and research organizations. High-level long-lived waste from the nuclear power generation cycle in France is stabilized by reprocessing. After the uranium and plutonium present in the spent fuel are separated, the minor actinides and fission products are stabilized in a silica glass matrix. The hulls and endpieces, which were formerly immobilized in cement grout until 1995, are now compacted. Disposal studies demanda3he. development of inventory models reflecting the quantities and grades of waste which will have to be disposed of at a given date. These models can be used to design the disposal structures and to evaluate long-term safety. They are prepared on the basis of existing waste and on future production hypotheses. To offer an idea, a simple model presumes the continuation of current production, both in quantity and grade, until 2040. The typical volumes considered in this model are: about 7600 m3 of vitrified waste ; about 80,000 m3 of intermediate level waste ; about 25,000 m3 of unreprocessed spent UOX and MOX fuel. Besides this simple model, other models, assuming no reprocessing after 2010, or total reprocessing, are also being investigated. The different alternatives for repository design are considered, with proposals of modular concepts offering relative simplicity of design, as well as architectural flexibility. The studies of the relevant disposal concepts cannot be conducted in generic terms. They demand the identification of the sites for which the development of concepts can fully exploit the actual geological characteristics. Methodological studies will nonetheless serve to identify the necessary basic research guidelines, and to characterize the sites from the angle of a preliminary idea of the requirements they will have to meet. The rest of the presentation shows the lessons drawn from the first siting attempts, the research process carried into practice, its progress and first results, and the future outlook.