Waste Management Assessment of Candidate Materials for HiPER Reaction Chamber

One of the critical decisions in the HiPER project is to select the most appropriate material for the reaction chamber. Within this framework, we investigate the performance of different steel alloys with respect to waste management. The capabilities of commercial steels, both austenitic and ferritic/martensitic, compared to reduced-activation ferritic/martensitic steels are evaluated as for different waste management strategies (near surface burial, clearance, hands-on and remote recycling). The examined materials are: SS304, SS316, mod.9Cr-1Mo and HT9 and EUROFER. Real impurities concentrations are taken into account, and their impact is analyzed. In the study, we have assumed the most exigent HiPER 4a irradiation scenario. Commercial steels revealed to be a suitable choice for the HiPER reaction chamber, as far as their waste management options do not differ significantly from those of the reduced activation ferritic steel case. We found that for mod.9Cr-1Mo and EUROFER hands-on recycling is already possible after a cooling time shorter than 50 years and that shallow-land burial is practicable for all the steel alloys studied. The impurities present in the real heats affects the cooling time for manual recycling but not significantly. Shallow-land burial feasibility is not perturbed by the presence of impurities in the real commercial heats. Moreover, the impact of activation cross section uncertainties on the waste management assessment of the irradiated steels has been analyzed, and it is found to be of no practical significance to determine eligibility of the considered steels for the HIPER 4a reaction chamber.