Generation of RBMK-1500 spent nuclear fuel one-group cross-section libraries and their evaluation against experimental data

Abstract

Depletion of RBMK-1500 spent nuclear fuel (SNF) with and without an erbium burnable absorber was modelled, and onegroup burn-up dependent cross-section libraries for Origen-ARP were created. Depletion calculations for the generation of crosssection libraries were performed using the SCALE 6.1 code package with the TRITON control module, which employs the NEWT deterministic 2D transport code with the 238-group energy library based on the ENDF-B VII library and the ORIGEN-S nuclide composition calculation code. Concentrations of the most important actinides for criticality safety were calculated using the created libraries and were compared with the available experimental data and the newest modelling results. Available experimental data of fission products (Nd and Cs isotopes) were also compared to the modelling results. Composition differences were evaluated for several fuel enrichments and water densities. The comparison shows an acceptable agreement between the values obtained using new one-group cross-section libraries and experimental data except for ²³⁸Pu and ²⁴¹Am, as well as the causes of discrepancy are discussed. It has been found that the enrichment and presence of the burnable absorber play an important role in the SNF composition. At the highest evaluated burn-up (29 GWd/tU) isotopic composition differences between 2% enrichment fuel and 2.8% burn-up for actinides important to burn-up credit (BUC) applications varied from 11 to 52%.