Materials Performance Issues in the Design of Fuel Elements for Externally Fueled Thermionic Hybrid Systems Available to Purchase

Externally fueled thermionic power systems for space applications require nuclear reactors that are capable of operating under severe conditions. Many reactor design requirements, such as high operating temperature, long lifetime and high power density, place stringent constraints on the materials of fuel element construction. Materials performance issues that impact the design of tungsten clad uranium dioxide fuel elements for these systems are discussed. These performance issues include heat transfer behavior, chemical and thermal stability, thermomechanical behavior and irradiation effects. Some potential solutions to some of the more problematical issues are given. Although some performance issues require additional development to be fully answered, this type of fuel element appears to be the optimum choice for this application.