Volume reduction of large components - minimising waste volumes by maximizing recycling

One of many decommissioning challenges is the treatment and disposal of retired large components. Due to their size it is not always feasible to dispose of the components in a repository as they occupy large amounts of space. Further more, the nuclide inventory does not always allow for storage in a repository, while chemical decontamination creates a liquid secondary waste that has to be managed and disposed of. Studsvik, Sweden, has been recycling contaminated metals from the international nuclear industry since 1987. Accepted metals are stainless steel, carbon steel, aluminium, copper, brass and lead. The recycling concept comprises segmentation, decontamination, melting and clearance for recycling. Both metal scrap and large components are treated. The objective is to reduce the volume and weight of the waste and to recycle as much material as possible in order to reduce costs for storage in repository. Clearance of metals is applied in accordance with the European Commission Recommendations for nuclear specific clearance, RP-89, Table 3. During the years, the demands for reduction of waste volumes have lead to improved techniques for pre-treatment of large components prior to melting as well as minimization of the waste volumes generated from the processes. In addition, the environmental aspect of a process that allows for recycling of valuable metals has become increasingly important. The most recent achievement is treatment and volume reduction of a full size 310 MT PWR steam generator. It began as a R and D project in co-operation with the Swedish nuclear power plant Ringhals and resulted in a unique concept for volume reduction and recycling of metal from steam generators. (authors)