LSDS System Development for Isotopic Fissile Assay

LSDS is under development in KAERI to assay isotopic fissile content in recycled nuclear material and spent fuel. Pyro process produces source material to fabricate SFR fuel using PWR spent fuel. The source material involves uranium-TRU (mainly plutonium) mixture with some fission products. The fissile content analysis is very important in quality assurance of the fabricated fuel and safety of the reactor operation. Several sensitivity calculations were performed in the designed geometry. Detection sensitivity was done and neutron spectrum influence by surrounding detector was investigated. Neutron gain and spectrum broadening must be considered. Based on the designed target, neutron production rate was calculated, 1E-2 n’s/sec-e. For high neutron yield, 40MeV electron energy was decided with 500mA current. Additionally, LSDS will contribute to spent fuel management, optimum storage design and maximum burnup credit. An accurate fissile material content will increase international transparence and credibility for the reuse of PWR spent fuel as well.