Radiation characteristics of megawatt space nuclear reactors

Abstract

In this study, a nuclear-powered spacecraft is taken as the object, the radiation characteristics of shielding materials and structural materials in view of the material selection of a shadow shield and layout of an instrument warehouse are examined, and the radiation field distribution in the shadow area of the shield is calculated and obtained. The Monte Carlo method is used to calculate the transport of neutrons and photons in the shielded shadow area, and the distribution of neutrons and photons in space is obtained. The shielding effects of different shielding materials and structural materials on neutrons and photons with specific energy spectra are obtained, and materials suitable for the design of space reactor shields are selected. Then, a combination of shielding materials that meets the requirements of radiation protection restrictions is determined. Research shows that lead, zirconium hydride and polyethylene used in the radiation shielding of the space reactor can make the shielding lighter. The shielding effect of the polyethylene composite material doped with zirconium hydride powder is better than that of a single material. And that the distribution of neutrons and photons also can provides a reference for the layout design of instrument cabins.