Nuclear reactors generate high levels of radiation, including neutron radiation, which poses significant risks to human health and structural integrity. Effective neutron shielding materials are essential to ensure safety in nuclear facilities by attenuating neutron flux and reducing radiation exposure. This study presents the development and performance assessment of boron carbide (B 4 C)-enhanced concrete designed for structural integrity and neutron shielding in nuclear reactor applications. B 4 C, known for its high neutron absorption cross-section, was used as a partial fine aggregate replacement at 5%, 10%, and 15% by weight. To improve durability and mitigate potential strength reduction, 20% fly ash was used as a cement substitute. The mechanical and durability properties were evaluated through compressive strength test, water absorption, sorptivity, chloride permeability, fire resistance, and shrinkage testing. The optimized mix, which contained 15% B 4 C and 20% fly ash (CFB), had a 28-day compressive strength of 38.65 MPa, low water absorption rate of 1.58%, and significantly improved resistance to chloride ion ingress. Neutron attenuation experiments were conducted at the KAMINI research reactor, demonstrated a reduction in thermal neutron flux by over two orders of magnitude using 19 cm of B 4 C concrete, equivalent to more than 35 cm of conventional concrete. Fast neutron flux was reduced by over 35 times at an energy level of approximately 600 keV. Gamma attenuation remained comparable to standard concrete, ensuring multipurpose shielding capacity. These results demonstrate that B 4 C combined with fly ash provides a sustainable, high-performance concrete solution capable of effective neutron shielding while maintaining mechanical integrity, offering considerable advantages for radiation-prone infrastructure.
Gokul et al. (2026) studied this question.