Conditioning methods for beryllium waste from fusion reactors

Future fusion power plants will generate large quantities of neutron-irradiated beryllium. Although recycling is the primary waste management option for this material, considerable amounts of beryllium will require permanent geological disposal after an interim storage period of 50-100 years. For this waste, appropriate conditioning methods need to be developed. For technical beryllium grades irradiated in a fusion reactor the γ-dose rate and inhalation dose are, after a decay time of 100 years, dominated by transmutation products from impurities present in the metal. Assuming detritiation of the beryllium shortly after its service-life in the reactor, the main radionuclides contributing to γ-dose rate and inhalation dose are ⁶⁰Co and actinides. In this paper, we discuss four conditioning methods: cementation, bituminisation, vitrification and phosphatisation. When comparing the different conditioning techniques, we place the emphasis on the long-term behaviour of beryllium in the chemical environment of the immobilisation matrix. From this exercise, vitrification resulted as a viable method to immobilise the beryllium waste.