Reflector and Control Drum Design for a Nuclear Thermal Rocket

摘要

Solid-core nuclear thermal rocket engines will play a vital role in near-term manned deep space missions. Supporting the Space-Capable Cryogenic Thermal Engine (SCCTE) project, different ideas for the radial neutron reflector and control drums are explored. The design under consideration is a radial reflector made of beryllium with dispersed cooling channels for flowing cryogenic hydrogen. Embedded in the reflector, sixteen control drums made from beryllium with boron carbide poison elements control reactivity. The control drums have dispersed cooling channels for cryogenic hydrogen flow. Autodesk Simulation is used to study thermal and flow behavior of the components, and Monte Carlo N-Particle Transport code (MCNP) is used to investigate nuclear aspects. An iterative design approach using Autodesk Simulation and MCNP was undertaken to optimize the integral and differential reactivity worth of the control drums to ensure smooth power transitions during rotation and an adequate Shutdown Margin (SDM) of the reactor, while considering mechanical and thermal aspects of the materials. This was done by varying the size, number, and positioning of cooling channels within the reflector and control drum regions, as well as the geometry of the of the poison elements within the control drums. One potential design for the radial neutron reflector that meets the criteria of the SCCTE project is presented.