Experimental Study on Fusion Neutron Activation of Metal Materials in EAST

Fusion neutron activation experiments have been carried out to investigate the activation of metal materials in Experimental Advanced Superconducting Tokamak (EAST). Some cylindrical samples made of stainless steel 316L, carbon steel (A3), high purity cadmium (Cd), oxygen-free copper (Cu), and high purity aluminum (Al) were transported to Port G in the EAST hall for neutron irradiation. The characteristic gamma rays emitted by activated samples were measured with a spectrometer consisting of a digital multichannel analyzer (MCA) and a high purity germanium (HPGe) detector. Qualitative identification of the dominant radionuclides and quantitative measurement of the specific activity have been performed. The experimental results indicated that the high radioactive nuclides with short half-life were produced, such as ⁵⁶Mn in 316L and A3, ²⁸Al in Al, ⁶⁶Cu in Cu, and 111m Cd in Cd. Moreover, the long half-life radionuclides were generated in 316L, A3, Cu and Cd samples, which will become the major factors on environment and personnel. In addition, the normalized dose rate at 10 cm in the air of 316L, A3, Al, Cd, and Cu was 1.53 x 10⁻²³, 4.83 x 10⁻²⁴, 5.57 x 10⁻²³, 4.90 x 10⁻²⁴ and 1.10 x 10⁻²³ Sv/h/n, respectively. Finally, the comparison between the experimental neutron activation results and the predicted quantities calculated with FISPACT-2007 was discussed.