Cesium reservoir and interconnective components. Final test report: TFE Verification Program

Technical Report · Tue Mar 01 00:00:00 EST 1994

DOI:https://doi.org/10.2172/10155363· OSTI ID:10155363

The program objective is to demonstrate the technology readiness of a TFE (thermionic fuel element) suitable for use as the basic element in a thermionic reactor with electric power output in the 0.5 to 5.0 MW range. A thermionic converter must be supplied with cesium vapor for two reasons. Cesium atoms adsorbed on the surface of the emitter cause a reduction of the emitter work function to permit high current densities without excessive heating of the emitter. The second purpose of the cesium vapor is to provide space-charge neutralization in the emitter-collector gap so that the high current densities may flow across the gap unattenuated. The function of the cesium reservoir is to provide a source of cesium atoms, and to provide a reserve in the event that cesium is lost from the plasma by any mechanism. This can be done with a liquid cesium metal reservoir in which case it is heated to the desired temperature with auxiliary heaters. In a TFE, however, it is desirable to have the reservoir passively heated by the nuclear fuel. In this case, the reservoir must operate at a temperature intermediate between the emitter and the collector, ruling out the use of liquid reservoirs. Integral reservoirs contained within the TFE will produce cesium vapor pressures in the desired range at typical electrode temperatures. The reservoir material that appears to be the best able to meet requirements is graphite. Cesium intercalates easily into graphite, and the cesium pressure is insensitive to loading for a given intercalation stage. The goals of the cesium reservoir test program were to verify the performance of Cs-graphite reservoirs in the temperature-pressure range of interest to TFE operation, and to test the operation of these reservoirs after exposure to a fast neutron fluence corresponding to seven year mission lifetime. In addition, other materials were evaluated for possible use in the integral reservoir.

• Research Organization: General Atomics, San Diego, CA (United States)
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: AC03-86SF16298
• OSTI ID: 10155363
• Report Number(s): GA-A-21595; ON: DE94012470; BR: 400403000/400403105; TRN: 94:012055
• Resource Relation: Other Information: PBD: Mar 1994
• Country of Publication: United States
• Language: English

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30 DIRECT ENERGY CONVERSION
THERMIONIC FUEL ELEMENTS
WORKING FLUIDS
DESIGN
THERMIONIC REACTORS
PERFORMANCE TESTING
PROGRESS REPORT
TECHNOLOGY ASSESSMENT
THERMIONIC CONVERTERS
CESIUM
PERFORMANCE
FABRICATION
POST-IRRADIATION EXAMINATION
LIQUID METALS
EXPERIMENTAL DATA
NESDPS Office of Nuclear Energy Space and Defense Power Systems
210600
300403
300402
POWER REACTORS, MOBILE, PROPULSION, PACKAGE, AND TRANSPORTABLE
MATERIALS, COMPONENTS, AND AUXILIARIES
PERFORMANCE AND TESTING