Shielding requirements for particle bed propulsion systems
Abstract
Nuclear Thermal Propulsion systems present unique challenges in reliability and safety. Due to the radiation incident upon all components of the propulsion system, shielding must be used to keep nuclear heating in the materials within limits; in addition, electronic control systems must be protected. This report analyzes the nuclear heating due to the radiation and the shielding required to meet the established criteria while also minimizing the shield mass. Heating rates were determined in a 2000 MWt Particle Bed Reactor (PBR) system for all materials in the interstage region, between the reactor vessel and the propellant tank, with special emphasis on meeting the silicon dose criteria. Using a Lithium Hydride/Tungsten shield, the optimum shield design was found to be: 50 cm LiH/2 cm W on the axial reflector in the reactor vessel and 50 cm LiH/2 cm W in a collar extension of the inside shield outside of the pressure vessel. Within these parameters, the radiation doses in all of the components in the interstage and lower tank regions would be within acceptable limits for mission requirements.
- Publication:
-
Special Report
- Pub Date:
- June 1991
- Bibcode:
- 1991phil.rept.....G
- Keywords:
-
- Heat Shielding;
- Lithium Hydrides;
- Nuclear Heat;
- Pebble Bed Reactors;
- Radiation Shielding;
- Reactor Materials;
- Thermal Reactors;
- Tungsten Compounds;
- Electronic Equipment;
- Nuclear Propulsion;
- Nuclear Radiation;
- Pressure Vessels;
- Propellant Tanks;
- Propulsion System Configurations;
- Propulsion System Performance;
- Reflectors;
- Silicon;
- Nuclear and High-Energy Physics