Space fission reactor structural materials: Choices past, present, and future

Nuclear powered spacecraft will enable missions well beyond the capabilities of current chemical, radioisotope thermoelectric generator and solar technologies. The use of fission reactors for space applications has been studied for over 50 years. Structural material performance has often limited the potential performance of space reactors. Space fission reactors are an extremely harsh environment for structural materials with high temperatures, high neutron fields, potential contact with liquid metals, and the need for up to 15–20 year reliability with no inspection or preventative maintenance. Many different structural materials have been proposed. While all of those proposed meet many of the requirements for space reactor service, none satisfy all of them. However, continued development and testing may resolve these issues and provide qualified materials for fission reactors for space power.