DISPOSAL OF SPENT FUEL IN SALT USING BOREHOLE TECHNOLOGY: BSK 3 CONCEPT

The “direct disposal of spent fuel” as a part of the current German reference concept was developed as an alternative to spent fuel reprocessing and vitrified HLW disposal. The technical facilities necessary for the implementation of this part of the reference concept, the so called POLLUX® concept, i.e. interim storage buildings for casks containing spent fuel, a pilot conditioning facility, and a special cask “POLLUX” for final disposal have been built. With view to a geological salt formation all handling procedures for the direct disposal of spent fuel were tested aboveground in full-scale test facilities. To optimise the reference concept, all operational steps have been reviewed for possible improvements. As additional concept for the direct disposal of SF, the BSK 3 concept has undergone full scale inactive handling tests and all components necessary for handling the waste package itself have been designed for a preliminary set of requirements. Supported by the EU and the German Federal Ministry of Economics and Technology (BMWi), DBE TECHNOLOGY built an aboveground full-scale test facility to simulate all relevant handling procedures for the BSK 3 disposal concept. GNS (Company for Nuclear Service), representing the German utilities, provided the main components and its know-how concerning cask design and manufacturing. The test program was concluded in 2009 after more than 1,000 emplacement operations had been performed successfully. The BSK 3 emplacement system in total comprises an emplacement device, a borehole lock, a transport cart, a transfer cask which will shuttle between the aboveground conditioning facility and the underground repository, and the BSK 3 canister itself, designed to contain the fuel rods of three PWR-fuel assemblies with a total of about 1.6 tHM. The BSK 3 concept simplifies the operation of the repository because the handling procedures and techniques can also be applied for the disposal of reprocessing residues and reduces operational risk without any compromise in long-term radiological safety aspects.