DEVELOPMENT OF AN OUTLINE OPERATING SYSTEM FOR THE UK MULTI-PURPOSE CANISTER SYSTEM FOR THE STORAGE, TRANSPORT AND DISPOSAL OF SPENT FUEL

The Nuclear Decommissioning Authority (NDA) has established the Radioactive Waste Management Directorate (RWMD) to manage the delivery of geological disposal for higher activity radioactive wastes as required under UK Government policy. Three illustrative concepts of geological disposal facilities (GDF), corresponding to three generic geological environments - higher strength rock, lower strength sedimentary rock and evaporite rock - have been developed to demonstrate the viability of geological disposal of intermediate level waste (ILW), high level waste (HLW) and spent fuel (SF) in the UK. For the disposal of HLW, AGR spent fuel and PWR spent fuel, a range of standardised canister designs has been developed in 2011-2012. RWMD now needs to further explore the options for the disposal of PWR spent fuel through the use of Multi-Purpose Canisters (MPC), which, in combination with a range of overpacks, would fulfil the requirements for storage at an interim storage facility, transport to, and uniquely for an MPC system, disposal at a GDF where the MPC must be capable of withstanding external loadings resulting during the post closure phase and, depending upon host geology, maintain containment for a period of 10,000 years or more. In order to design a MPC and the overpacks, the external constraints and the internal conditions need to be defined. In addition, the operation requirements and the performance requirements of each step of the operation route for the MPC also need to be defined, from which a “bounding set” of operation requirements and performance requirements can be distilled. Based on these requirements, a conceptual design of a MPC and an outline design of the overpacks can then be designed. The development programme has been organised into three stages: Stage 1: Development of an outline system within which the MPCs operate Stage 2: Development of a specification for the design of the MPC and the overpacks Stage 3: Development of a conceptual design of the MPC and an outline design of the overpacks. This paper presents the outline operating system as developed from Stage 1 of the programme.