Calculation of Isotope-Specific Fission Rates for Neutrino Source Calculation in PWR Fuel Diversion Safeguarding

The emission of antineutrinos from nuclear reactors offers a potential avenue for the international enforcement of reactor safeguards. A variety of frameworks have been proposed for detecting these particles, with the objective of verifying an agreed-upon composition of fuel in the operating reactor. More specifically, these frameworks should identify the diversion of a “significant quantity” of fissile material from an agreed upon core loading. For any quantitative analysis of these frameworks, isotope-specific fission rates of a nuclear reactor are required to calculate the reactor neutrino source. Unfortunately, the calculation of isotope-specific fission rates for a realistic core is nontrivial and can require significant simulation efforts.

Therefore, this work uses industry-standard simulation tools (CASMO-4/SIMULATE-3) to provide isotope-specific fission rates for a set of 15 plutonium diversion scenarios for a mixed-oxide-loaded pressure water reactor. These diversion scenarios span a wide range of diverted fuel amounts, from 2.17 to 655.19 kg of fissile plutonium. The isotope-specific fission rates reported in this paper can be combined with a neutrino emission model for the direct calculation of the reactor neutrino source. This work can be considered a dedicated effort toward the calculation of realistic isotope-specific reaction rates for use in the development and analysis of safeguarding frameworks. As such, these isotope-specific fission rates are provided over three cycles with realistic fuel loading and shuffling patterns. In this way, this work can act as a standard neutrino source reference for the development and comparison of safeguarding frameworks.