Comparison of calculated and measured spent nuclear fuel decay heat with CASMO5, SNF and standard methods

Abstract

In this paper, we present a comparison between measured and calculated decay values for spent nuclear fuel assemblies from the Clab, GE-Morris EMAD facilities. Two codes are applied: CASMO5 and SNF, using different nuclear data libraries (JEF-2.2, JEFF-3.1.1, JEFF-3.2, ENDF/B-VII.1 and ENDF/B-VIII.0) and different code versions. Additionally values from four standard and guides for calculation of decay heats (ANS 2014, DIN 2014, ISO 2022 and RG-3.54 2018) were also compared with the measurements. All simulations with different codes, code versions and methods are based on the same geometry and irradiation descriptions for a single assembly, providing more convenient comparisons of results. The impact of nuclear data libraries and computational methods are shown, compared to the spread of C/E (Calculations over Experiment) values between the 256 considered measurements. Finally, a comparison of the most important nuclides contributing to the decay heat is presented between measured assemblies and more recent cases corresponding to higher burnup, initial enrichment and longer cooling times.