Ceramic fuel development for space reactors

This paper reports that the renewed interest in manned exploration of space has rejuvenated development of advanced ceramic fuels for nuclear power and propulsion reactors. Because of their attractive thermal and neutronic properties, uranium carbides and nitrides have been developed as fuels for space propulsion and power reactors. Desirable fuel characteristics include high density, high thermal conductivity, high melting point, high temperature stability, chemical compatibility, predictable irradiation performance, and ease of fabrication. UN fuel is used in the SP-100 high-temperature, liquid-lithium-cooled, refractory metal, fast flux reactor. The SP-100 program is aimed at developing, testing, and demonstrating a 100 kWe reactor for space-based power. The main thrust of the project has been design, construction, and testing of nuclear components in the Nuclear Assembly Test (NAT) ground demonstration. The Space Exploration Initiative (SEI) has revitalized interest in the nuclear rocket technology developed during the 1960s and the potential for advancing that technology. Nuclear Thermal Propulsion (NTP) reactors offer higher specific impulse (I[sub sp]) than conventional chemical rockets because of high exhaust temperatures and low-molecular-weight hydrogen propellant.