Radiochemical Analysis of Tritium for ITER Type B Metallic Radwastes

ITER is trying to develop destructive and non-destructive methods of tritium measurement for discarded radwaste components. The ITER Type B(medium activity with long life) metallic radwastes that need tritium measurement are mainly Divertor Cassette Body, Blanket Modules, Test Blanket Module Port Plug, Torus Cryopump, etc. It has been known that 10⁷ Bq/g of tritium is distributed within 1 mm depth from the surface of the metallic radwastes. The metallic radwastes generated from maintenance period of ITER facility will be transferred to the Hot Cell Facility (HCF) for treatment including cutting, tritium removal and pre-packaging, followed by being shipped to the disposal facility after interim storage at ITER site.

In this study, the radiochemical analysis methods of tritium measurement for ITER type B metallic radwastes were reviewed. Especially, two experimental methods, chemical acid leaching method (CALM) and heating method (HM,) were compared with each others to suggest the most suitable method for tritium measurement. The recovery yield of tritium standards for CALM and HM showed excellent results of 98 and 90 %, respectively. Since HM requires post treatment of extracted tritium species due to impurities, as shown in the analysis of sample from Nuclear Power Plant, CALM was considered more efficient method than HM for tritium analysis of Type B metallic radwastes.