Activation Analysis for LHD Experiments with Deuterium Gases

Identification of radionuclides obtained from deuterium experiments and evaluation of dose rate level were performed on the structural materials of the Large Helical Device and the Experimental Hall. Energies of neutron sources are 2.45 MeV (D-D reaction) and 14 MeV (D-T reaction). Neutron fluence was calculated using the two-dimensional transport code DOT-3.5. Generation of radionuclides was calculated using the CINAC code. Radionuclides of 93mNb, 63Ni, and 60Co for helical coils, 55Fe and 60Co for stainless steel, 55Fe, 60Co, and 93mNb for poloidal coils, and 40K and 55Fe for floor concrete were dominant after a series of experiments with deuterium gases. Evaluation of dose rate level for the structural materials and air were performed taking into account a current experimental schedule.