Fabrication and development of neutron shielding materials based on natural rubber and boron carbide

Neutron shielding materials were fabricated based on natural rubber (NR) and boron carbide (B₄C) as their main components. Natural rubber, which is abundant in hydrogen, can lower the energy of a neutron. Boron carbide could be utilized as a neutron shielding material due to its high boron content. The shielding materials were fabricated with boron carbide concentrations of 0, 20, 40, 60 parts per hundred rubber (phr), and 50 wt%. Each sample has been fabricated with thicknesses of 5, 10, 15, 20, and 24 mm. The fabricated materials were examined for mechanical and neutron attenuation tests. The Am/Be at the Radiation Measurement Laboratory at the Nuclear Engineering Department, Faculty of Engineering, Chulalongkorn University, was used as a neutron source. The results show that boron carbide has the effect of reducing the toughness while increasing the hardness of NR composites. The NR sample of 50 wt% in boron carbide allows only 14.1% of neutron transmission according to fast neutron attenuation tests, which is similar to that of a sample of the commercial product obtained from a Japanese company. Our findings will later be compared to those of a Monte Carlo N-Particle (MCNP) transport code.