Evaluation of Induced Radioactivity Generated during LHD Deuterium Plasma Experiments

Neutrons are generated in a fusion plasma and induce various radionuclides via nuclear reaction with reactor materials. Evaluating the kinds of nuclide amount induced radioactivity is important for decommissioning planning regular maintenance. In this study, we verified long-term prediction model large helical device (LHD) by comparing during deuterium experiments LHD results calculated using high-energy particle-induced code. The metals employed activation were SUS316L, Co, Mo, Ni. During experiments, these materials placed on an 8-O port LHD, was measured weekly. To computed DCHAIN-SP, neutron energy spectrum Monte-Carlo simulation code PHITS. Although 58Co 54Mo agreed well, values 60Co 99Mo underestimated. However,low-energy components could be improved incorporating peripheral devices into model, resulting more accurate predictions.