Architecture and management of a geological repository - Andra

4 – Waste disposal PackagesFigure 4.3.2Small diameter disposal package, 1 assembly (UOX or MOX)4.3.2.3 Comparison with solutions developed abroadIn the reference concept of Nagra (Switzerland) [44], spent fuel assemblies are placed in a containerby 4 or 9 (depending on whether they have been unloaded from pressurised water reactors (PWR) orboiling water reactor (BWR)). This container is made of steel with a diameter of 1,050 mm andthickness of 150 mm and is designed to last for 1,000 to 10,000 years. One variant considers acontainer made of copper with insert in steel, or possibly in ceramic. This variant increases durabilityby an order of magnitude.In Sweden, the KBS-3 project [49] located in a granitic environment, envisages a copper container 50mm thick with a cast iron insert which can take 4 PWR assemblies or 12 BWR assemblies. Targetwatertightness duration for this container is more than 100,000 years.In Finland, the project is similar to the Swedish KBS-3 project. Canada and Spain also envisagedesigning a copper container.In the United States [52], the container envisaged for spent fuel for the « Yucca Mountain » project issimilar in principle to that of HLW (an internal envelope in stainless steel about 50 mm thick toprovide mechanical resistance and an outer envelope in nickel alloy about 20 mm thick to providecorrosion resistance). This container with larger dimensions (diameter of about 2,100 mm) andsignificantly heavier (up to 75 metric tons depending on the models) than those studied by Andra cantake a high number of fuel assemblies (about twenty).4.3.3 Description and performanceThis section provides further details on design parameters of the adopted solution for CU1 and CU2type fuel. It justifies the design basis, as pertains to expected durability and demonstrates thecompatibility of the object with handling procedures.Regarding waste packages for C0.3 type spent duel, see section 4.2.3 and more specifically thoseaspects potaining to C0.3 type waste packages. Repository containers are indeed in external diameterand steel thickness, with length adapted to that of the various assembly claddings.DOSSIER 2005 ARGILE -ARCHITECTURE AND MANAGEMENT OF A GEOLOGICAL DISPOSAL SYSTEM147/495