Analytical study on uranium measurement in uranium waste drums by the fast neutron direct interrogation method

The Fast Neutron Direct Interrogation (FNDI) method is one of the NDA methods which measures fission neutrons induced by injecting pulsed neutrons with 14 MeV into uranium or plutonium bearing waste drums. The features with quick determination mass of fissile materials will be expected to apply to practical use in the safeguards field.Compared to the past passive method whose methodology is applied to detect neutrons generated from U-234 (a,n) reaction or U-238 spontaneous fission neutrons in waste drums, the FNDI method verified several advantages in the point of quick measuring time, less source position dependency, no source chemical form dependency. We have researched and developed the FNDI method for a long time through experiments in the NUCEF (Nuclear fuel Cycle safety Engineering research Facility) in JAEA TOKAI. Referred from the pilot machine, we designed a demonstrator, called as JAWAS-N, for applying to non-destructive assay tools for uranium bearing waste drums in JAEA NINGYO. We carried out analytical study on simulations of neutron detection response used MCNP5 code as Monte Carlo transport calculation in order to design the demonstrator JAWAS-N, in parallel configurated the whole equipment. Following above the basic characteristic tests had been tried to validate our predictions. In this paper, we present the modeling and the simulations concerning JAWAS-N’s characteristics, and discuss for practical use compared analytical results with obtained some experimental data.