Development of the neutron resonance densitometry using a pulsed neutron source, 2; Design study of a D-T pulsed neutron source for nuclear material quantification in melted fuel

Takamine, Jun ; Kureta, Masatoshi   ; Harada, Hideo   ; Kitatani, Fumito  ; Koizumi, Mitsuo ; Tsuchiya, Harufumi ; Iimura, Hideki  

In the process of dismantlement and reclamation of Fukushima Daiichi Nuclear Power Plant, accounting for and control of nuclear material (NM) in the melted fuel (MF) may be demanded. In Japan Atomic Energy Agency (JAEA), The Neutron Resonance Densitometry (NRD) is proposed. In this method, continuous-energy neutrons are transmitted through NM in MF. And quantity of NM in MF is fixed using neutron resonance absorption peaks derived from measurement results. The prototype system using a compacted D-T fusion pulsed neutron source will be produced in next fiscal year. For getting enough Fixed-quantity precision using this system, it is important to decide arrangement, materials and shapes as high intensity and time resolution as we can. About several kinds of moderator system assumed to be suited for the system, Neutron spectrums and time dependent characteristics were evaluated using MCNP5. Knowledge about the configuration parameters derived from these results will be showed.