Space-time-energy distribution of neutron in a delayed ray measurement system with a 14-MeV D-T neutron source
Takamine, Jun ; Rossi, F. ; Rodriguez, D. ; Koizumi, Mitsuo ; Seya, Michio
Among the nuclear materials, spent fuels and new fuels containing transuranic elements have a high neutron and ray background, so no certification measurement technique by nondestructive measurement has been established. In order to measure the composition ratio of fissile nuclides contained in nuclear material nondestructively, we are developing a delayed ray analysis method using a small pulsed D - T neutron generator. In the delayed ray analysis technique, it is important to decelerate the 14 MeV neutrons generated from the DT neutron source and generate a neutron field suitable for measurement. Therefore, a conceptual design of a device combining a neutron moderator with the Monte Carlo code MCNP 6 was performed. In order to confirm the effectiveness of the present moderator, neutron flux space inside the decelerator, energy distribution, and neutron flux time distribution were analyzed. From these results, it was found that the present moderator is optimal for delayed ray analysis technique, which can be confirmed experimentally.