Physical analysis of spent nuclear fuel decay heatLetnar, Gašper (Avtor) Snoj, Luka (Mentor) Schillebeeckx, Peter (Komentor) Neutron transportSNFReactorDecay heatNuclear physicsMonte CarloFor the safe and reliable design of long-term spent fuel storage solutions, an accurate characterization of spent nuclear fuel is of paramount importance. Among the key parameters in this context is decay heat, the calculation of which requires coupled neutron transport and depletion simulations. In this work, an industry-standard two-dimensional modeling approach utilizing the Serpent Monte Carlo code is validated against 173 spent fuel decay heat measurements performed at the Central Interim Storage Facility for Spent Nuclear Fuel (CLAB). A comparison between the calculated and measured values yields a mean Calculation to-Experiment (C/E) ratio of 0.994(26) when utilizing the ENDF/B-VIII.1 nuclear data library, and 0.999(27) for the older ENDF/B-VII.1 library, demonstrating excellent global agreement between the modeling methodology and experimental benchmarks. In addition to evaluating the total decay heat, this work also compares the correction, required due to the escape of high-energy photons from the calorimeter, with the values reported in the literature. This is achieved through an independent, decoupled computational scheme combining neutron and photon transport simulations in Serpent with localized electron transport simulations in MCNP. Comparison of escaped power yields a global 11 % to 14 % underprediction, likely due to modeling limitations. Application of photon escape correction to the total decay heat power yields a marginal improvement in the net decay heat comparison, resulting in an updated mean C/E value of 0.996(26) for the calculations using the ENDF/B-VIII.1 library.20262026-09-06 08:15:07Magistrsko delo/naloga186875sl