FP concentrations evaluation with FPY data considering fission rate spectrum

It is known that the Fission Product Yield (FPY) depends on the incident neutron energy. The FPY data in Japan gives FPYs at incident energies of 0.0253 eV, 500 keV, and 14 MeV. Among three incident energies, one incident energy is used as the representative energy of FPY of the target core in the conventional burn-up calculation. FPYs of 500 keV used as a representative in fast reactor calculations are measured mainly in fast reactor. If the neutron spectrum of that reactor differs from that of the reactor targeted in the calculation, there would be a difference in Fission Product (FP) concentrations. In the present study, FPYs considering the energy spectrum of the incident neutron are obtained by interpolation of the existing FPY data, then the validity of the interpolated FPYs is discussed. Also, the results of the burn-up calculation in ORIGEN using the FPYs obtained by interpolation were compared with the results of conventional calculation in terms of criticality. As a result, the relative differences are within 5 % for nuclides with mass numbers around 90 and around 140 for U235 and Pu239. Also, focusing on concentrations of nuclides that are related to the criticality, the relative differences is very small for U235, but that of Sm152, Eu153 and Gd155 decrease by about 3-7 % for Pu239. We found that there are nuclides for which interpolation of FPYs is valid and others for which it is not, depending on the mass number. (author)