Abstract
This study presents the analysis of the influence of the protective capsule material on the neutron-physical characteristics of fuel element irradiation during experiments conducted at the IGR research reactor. The calculations were performed using the MCNP6 code and the ENDF/B-VII nuclear data libraries. Different structural materials of protective capsules used in the testing of experimental fuel assemblies were considered. The dependences of energy deposition, spectral characteristics of the neutron field, and spatial distribution of neutron flux on the composition and wall thickness of the protective capsule were determined. It was found that the choice of capsule material has a quantitatively measurable effect on the irradiation conditions of the fuel elements, which must be taken into account when interpreting the results of reactor experiments. The obtained results provide a basis for substantiating design solutions and optimizing the irradiation conditions of fuel elements.