Concepedia

Abstract

The spent fuels from the JPDR-I reactor were measured by means of a γ-scanning facility installed in the fuel storage pool. The spatial distributions of the fission products (134Cs and 137Cs) were measured and analyzed in reference to the effects of control rod pattern. The ratios holding between the products of neutron capture and of direct fission (134Cs/137Cs and 154Eu/137Cs) were also examined for its relevance to non-destructive burnup determination. The activity ratios of the fission products can be expressed by a linear function of burnup, provided that corrections are made to account for differences in irradiation history and for spatial variations in the neutron spectrum.