Thermal analysis for optimisation ways of the repository concept for High Level long lived waste glass packages

Abstract

Paper presented at the 6th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, South Africa, 30 June - 2 July, 2008.This paper is devoted to the thermal and economic aspects involved in the design and conception of a repository for High Level long-lived (HLLL) radioactive waste. The design under consideration is a deep geological disposal in argillite. The French National Radioactive Waste Management Agency (ANDRA) is in charge of the design and building of the repository. The dimensioning repository design has to meet a thermal criterion to prevent any damage on the argillite and account for the compactness of the disposal underground installation to limit the cost. In the first stage, a description of the ANDRA design, followed by the development of its 3D modelling are presented. Then, a methodology to optimise the repository design is carried out in order to determine the best concept dimensioning. Afterwards, an additional investigation of a further optimisation focuses on the reduction of the container steel thickness, the associated analyses show that two antagonist effects (geometrical and thermal effects) compete with respect to the economical optimisation of the concept.