Year
2016
Abstract
JAEA is developing the techniques to analyze composition ratio of fissile nuclide (235U, 239Pu, 241Pu) and spontaneous fission nuclide (238Pu, 240Pu, 242Pu) with use of delayed gamma-ray (DG) spectroscopy (DGS). The fissile and fissionable nuclides generate fission products (FP) proportional to their unique fission yield distributions. DGS analyzes the specific delayed gamma-ray from FP decay chains by spectrum analysis. It is generally known that the energies of the emitted gamma-rays from spent fuel assembly after placing a suitable cooling period are predominantly 3MeV or less, on the other hand, DG are in a wider range of ~ 6MeV. JAEA focuses on DG of 3MeV or more and implements the preliminary research on the analysis for the composition ratio of fissile and fissionable nuclides based on the differences of DG energy spectrum. We have a plan to perform the following four stages measurement tests of DG spectrum for plutonium nitrate solution and MOX powder samples in order to confirm the applicability to the analysis for composition ratio of fissile nuclides and plutonium isotope composition which is the final goal. (1) Measurements of gamma-rays including DG originated from spontaneous fission nuclides (Passive) (2) Measurements of DG with fast neutron interrogation (Active) (3) DGSI (DGS combined with self-interrogation) measurements (Passive) (4) Measurements of DG with thermal neutron interrogation (Active) In this paper, we will present the detail of the plan of measurement tests for nuclear material samples with use of DGS.