Analysis of the Antineutrino Signature of LEU/MOX Fueled LWRs

Antineutrinos are produced in nuclear reactors by the beta decay of fission products. Because of their low interaction probability, most of the antineutrinos produced in a reactor will escape. They can then be detected through another low-probability event, inverse beta decay, in detectors located outside of the reactor. Differences in antineutrino production from a nuclear reactor can be used to determine whether the reactor is loaded with low-enriched uranium (LEU) or mixed-oxide (MOX) fuel and to discriminate between weapons-grade and reactor-grade MOX fuel. The differences between fuel types occur because fission product yields, and therefore antineutrino production rates, are isotope dependent. An analysis of the time-dependent antineutrino production rates for MOX and mixed LEU/MOX cores is done with the HELIOS/PARCS code package. The results of parametric studies performed on these cores are presented and situations in which the diversion of weapons-grade MOX is detectable are identified. Parametric studies include the replacement of one or more weapons-grade MOX assemblies from the core and atypical fuel shuffling.