High-efficiency thermionic converter studies

Technical Report · Mon Nov 01 00:00:00 EST 1976

OSTI ID:7308267

Huffman, F N; Sommer, A H; Balestra, C L; Briere, D P; Oettinger, P E

The objective is to improve thermionic converter performance by means of reduced interelectrode losses, greater emitter capabilities, and lower collector work functions until the converter performance level is suitable for out-of-core space reactors and radioisotope generators. Electrode screening experiments have identified several promising collector materials. Back emission work function measurements of a ZnO collector in a thermionic diode have given values less than 1.3 eV. Diode tests were conducted over the range of temperatures of interest for space power applications. Enhanced mode converter experiments have included triodes operated in both the surface ionization and plasmatron modes. Pulsed triodes were studied as a function of pulse length, pulse potential, inert gas fill pressure, cesium pressure, spacing, emitter temperature and collector temperature. Current amplifications (i.e., mean output current/mean grid current) of several hundred were observed up to output current densities of one amp/sq cm. These data correspond to an equivalent arc drop less than 0.1 eV.

• Research Organization: Thermo Electron Corp., Waltham, MA (USA)
• DOE Contract Number: NAS3-19866
• OSTI ID: 7308267
• Report Number(s): N-77-13820; NASA-CR-135125; TE-4202-12-77
• Country of Publication: United States
• Language: English

Related Subjects

30 DIRECT ENERGY CONVERSION
THERMIONIC CONVERTERS
RESEARCH PROGRAMS
DESIGN
EFFICIENCY
PERFORMANCE
PERFORMANCE TESTING
TESTING
THERMIONIC COLLECTORS
THERMIONIC DIODES
THERMIONIC EMITTERS
WORK FUNCTIONS
ZINC OXIDES
CHALCOGENIDES
DIODE TUBES
DIRECT ENERGY CONVERTERS
ELECTRON TUBES
OXIDES
OXYGEN COMPOUNDS
THERMIONIC TUBES
ZINC COMPOUNDS
NESDPS Office of Nuclear Energy Space and Defense Power Systems
300401* - Thermionic Converters- Design & Development