Recommended OSC design and analysis of AMTEC power system for outer-planet missions
- Orbital Sciences Corporation (OSC), 20301 Century Boulevard, Germantown, Maryland 20874 (United States)
The paper describes OSC designs and analyses of AMTEC cells and radioisotope power systems for possible application to NASA{close_quote}s Europa Orbiter and Pluto Kuiper Express missions, and compares their predicted performance with JPL{close_quote}s preliminary mission goals. The latest cell and generator designs presented here were the culmination of studies covering a wide variety of generator configurations and operating parameters. The many steps and rationale leading to OSC{close_quote}s design evolution and materials selection were discussed in earlier publications and will not be repeated here except for a description of OSC{close_quote}s latest design, including a recent heat source support scheme and cell configuration that have not been described in previous publications. As shown, that heat source support scheme eliminates all contact between the heat source and the AMTEC (Alkali Metal Thermal-to-Electrical Conversion) cells, which simplifies the generator{close_quote}s structural design as well as its fabrication and assembly procedure. An additional purpose of the paper is to describe a revised cell design and fabrication procedure which represent a major departure from previous OSC designs. Previous cells had a uniform diameter, but in the revised design the cell wall beyond the BASE tubes has a greatly reduced diameter. The paper presents analytical performance predictions which show that the revised ({open_quotes}chimney{close_quotes}) cell design yields substantially higher efficiencies than the previous (cylindrical) design. This makes it possible to meet and substantially exceed the JPL-stipulated EOM power goal with four instead of six General Purpose Heat Source (GPHS) modules, resulting in a one-third reduction in the heat source mass, cost, and fuel requirements. OSC{close_quote}s performance predictions were based on its techniques for the coupled thermal, electrical, and fluid flow analyses of AMTEC generators. Those analytical techniques have been partially validated by tests of prototypic test assemblies designed by OSC, built by AMPS, and tested by AFRL. The analytical results indicate that the OSC power system design, operating within the stipulated evaporator and clad temperature limits and well within its mass goals, can yield EOM power outputs and system efficiencies that substantially exceed the JPL-specified goals for the Europa and Pluto missions. However, those results only account for radioisotope decay. Other degradation mechanisms are still under study, and their short-and long-term effects must be quantified and understood before final conclusions about the adequacy and competitiveness of the AMTEC system can be drawn. {copyright} {ital 1999 American Institute of Physics.}
- OSTI ID:
- 341324
- Report Number(s):
- CONF-990103-; ISSN 0094-243X; TRN: 99:005853
- Journal Information:
- AIP Conference Proceedings, Vol. 458, Issue 1; Conference: 1999 space technology and applications international forum, Albuquerque, NM (United States), 31 Jan - 4 Feb 1999; Other Information: PBD: Jan 1999
- Country of Publication:
- United States
- Language:
- English
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Coupled thermal, electrical, and fluid flow analyses of AMTEC converters, with illustrative application to OSC`s cell design
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Related Subjects
07 ISOTOPE AND RADIATION SOURCE TECHNOLOGY
SPACE FLIGHT
THERMOELECTRIC CONVERSION
RADIOISOTOPE GENERATORS
RADIOISOTOPE HEAT SOURCES
PERFORMANCE TESTING
MATERIALS
THERMAL INSULATION
EMISSIVITY
TEMPERATURE DISTRIBUTION
NESDPS Office of Nuclear Energy Space and Defense Power Systems