Testability of the S-prime thermionic power system

The Thermionic Space Nuclear System Design and Technology Demonstration (TI-SNPS) program requires a low-risk, compact space nuclear power with a 5- to 40-kWe scalability, high conversion efficiency and the potential for long life. The 40-kWe S-PRIME system uses conventional materials in a known operating environment and the multicell thermionic fuel element (TFE) technology database to produce a low-risk approach to meeting the TI-SNPS flight system requirements. This design approach limits the risks to four key areas: TFE performance and lifetime, TFE testability demonstration, hydrogen control, and radiator heat pipe performance. These areas require critical component testing reduce risks within the development program (Mills et al. 1993). A TFE testability critical component demonstration was one of the six demonstrations scheduled in the S-PRIME Phase I Program. Multicell TFE testing techniques were pioneered in the countries of the former Soviet Union. The Institute of Physics and Power Engineering (IPPE) in Obninsk, Russia, a key S-PRIME subcontractor, was tasked with reviewing this database and recommending the best technical approach for acceptance testing individual S-PRIME TFEs and a network of TFEs in a reactor core assembly. IPPE developed (PPTE). Using the PPTF as a starting point, a 10-step process is defined for acceptance testing the overall S-PRIME power system, starting from the manufacturing process line for the individual TFEs to a final assembly and shipment of the power system to the launch site and its integration/checkout with the payload. copyright 1995 American Institute of Physics