An apparatus and method for shielding against radiation and providing thermal insulation is disclosed. The apparatus includes multiple layers including an inner layer, an outer layer, and a radiation shielding layer composed of materials such a tungsten sheet, multiple tungsten sheets, staggered rows of tungsten rods, and/or a polymer radiation shield composed of a polymer and radiation attenuating material. Insulation layers may also be incorporated into the apparatus. The method for protecting against radiation includes the steps of providing a radiation shielding apparatus and securing such apparatus to a radiation emitting structure.

An objective of the invention is to provide an austenitic stainless steel article having superior irradiation resistance and stress corrosion cracking resistance than before while maintaining mechanical properties equivalent to those of conventional ones. There is provided a dispersion strengthened austenitic stainless steel article, including: 16-26 mass % of Cr; 8-22 mass % of Ni; 0.005-0.08 mass % of C; 0.002-0.1 mass % of N; 0.02-0.4 mass % of O; at least one of 0.2-2.8 mass % of Zr, 0.4-5 mass % of Ta, and 0.2-2.6 mass % of Ti; and a balance consisting of Fe and inevitable impurities. The Zr, Ta and Ti components form inclusion particles in the stainless steel article by combining with the C, N and O components. The stainless steel article has an average grain size of 1 m or less and a maximum grain size of 5 m or less.

Disclosed is a reactor thermal management system. A molten salt reactor vessel and a second component (e.g., a drain tank) fluidly coupled with the molten salt reactor vessel are configured to receive a flow of a molten salt therewith. The reactor thermal management system includes an internal shield or vessel encompassing the molten salt reactor vessel and the second component, the internal shield or vessel defining a first thermally insulative region therein. The internal shield or vessel is configured to maintain the first thermally insulated region above a melting temperature of the molten salt during operation of the molten salt reactor vessel.

Disclosed is a reactor thermal management system. A molten salt reactor vessel and a second component (e.g., a drain tank) fluidly coupled with the molten salt reactor vessel are configured to receive a flow of a molten salt therewith. The reactor thermal management system includes an internal shield or vessel encompassing the molten salt reactor vessel and the second component, the internal shield or vessel defining a first thermally insulative region therein. The internal shield or vessel is configured to maintain the first thermally insulated region above a melting temperature of the molten salt during operation of the molten salt reactor vessel.