A 3-D Quarter-Core CANDU-6 is modeled using Serpent 2 for nuclear treaty monitoring. The spatial variation of flux spectra and isotopic concentrations is analyzed to determine the potential isotopic distribution of key radionuclides from standard reactor operations relevant to non-proliferation. The initial results of the model show a 46% difference in overall flux magnitude throughout the core as well as a 2-30% difference in discrete energy flux. The coupled production rate (magnitude) and spectral differences can contribute to significant spatial variations in isotope ratios throughout the core. Initial results indicate 239 Pu/ 240 Pu ratios vary by as much as 51% across a single CANDU-6 fuel bundle at final burnup. The model is currently being used to develop an accurate representation of spent fuel to perform spatial isotopic analysis across the entire CANDU-6 core.
EPJ Web of Conferences
Burkhardt, A. W., Bevins, J. E., & Baxter, S. H. (2021). An assessment of the spatial variation of isotopic ratios in a CANDU reactor for nuclear treaty monitoring. EPJ Web of Conferences, 247, 04025. https://doi.org/10.1051/epjconf/202124704025