High effectiveness shielding materials and optimal shield design

In this paper a preliminary investigation of the effectiveness of new composite materials under development for shielding against neutrons and photons is reported upon. These materials are made from a proper mix of powders of tungsten, titanium or zirconium hydride and boron carbide, all bonded by hydrogenous materials such as polyethylene or silicone based materials. The investigation is carried out with the aid of the shield optimization code SWAN by considering a simplified 40-cm-thick spherical shield with Cf-252 source at its center. The shielding ability of the new, so-called polynated and siliconated, materials is found to be highly superior to that of shielding materials in common use. The flexibility in tailoring the mix of inelastic scatterers, elastic scatterers, neutron absorbers, and photon attenuators to one's shielding needs, along with the information on material effectiveness functions which can be calculated with a code such as SWAN, are expected to enable improvements in future shield designs