Evaluation of Neutron Scattering and Shielding Behavior in Epoxy-hBN Composites for Nuclear Applications

This work presents a theoretical evaluation of neutron shielding performance in epoxy–hexagonal boron nitride (hBN) composites, modeled across 0 to 90 wt% hBN concentrations and densities ranging from 0.95 to 2.12 g∙cm−3. Fast neutron interaction parameters such as macroscopic removal cross section ΣR, mean free path (MFP), logarithmic energy decrement ξ, moderation power (MP), energy shared per collision Eshare, and required number of collisions ƞ were computed at 4 MeV using the code NGCal. Increasing hBN content substantially reduced fast neutron shielding efficiency: ΣR decreased from 3.67 cm−1 (0 wt% hBN) to 0.36 cm−1 (90 wt% hBN), while MFP increased from 0.23 to 1.13 cm, MP reduced from 0.58 to 0.06 cm−1, and ƞ increased from 123 to 129, underscoring hydrogen’s dominant role in elastic scattering. Thermal neutron behavior was evaluated using National Institute of Standards and Technology–based parameters at 0.025 eV. The 1/e penetration depth decreased from 163.15 cm (0 wt% hBN) to 0.03 cm (90 wt% hBN), the scattering length density changed relatively from 4.39 × 10−6 to 4.20 × 10−6 Å−2, and the thermal neutron scattering cross section increased from 0.67 to 32.14 cm−1. These computations reveal that epoxy-hBN composites offer tunable neutron shielding: Hydrogen-rich systems enhance fast neutron moderation, while boron-rich systems enable effective thermal neutron absorption, enabling advanced shielding strategies for nuclear, aerospace, and medical technologies.