155/157Gd areal density: A model for design and fabrication of Gd2O3/316L novel neutron shielding composites

The Monte Carlo N-Particle Code were used to design a novel Gd2O3/316L stainless steel neutron shielding composites (Gd2O3/316L NSCs). And the constitutive equation between the Gd-155/157 areal density and the neutron shielding rate was established by MCNP. When the areal density of Gd-155/157 is larger than 0.01 g/cm(2), the thermal neutron shielding rate of the composites reaches 99%. The NSCs with three weight fractions (1.5 wt %, 2.5 wt%, and 4.5 wt% Gd2O3) were successfully fabricated by spark plasma sintering. And Gd2O3 particles evenly distributed in 316L matrix. The main phases of the composite are austenite (gamma-Fe) and Gd2O3, and in addition Fe2Gd and Gd2Ni17 are present at the interface of Gd2O3 and 316L matrix particles. The debonding of the Gd2O3 particles is the main cause of material fracture.