NUCLEAR GENERATED PLASMAS IN NOBLE GAS THERMIONIC CONVERTERS

Journal Article · Tue Jan 01 04:00:00 EST 1963 · Advanced Energy Conversion

DOI:https://doi.org/10.1016/0365-1789(63)90106-1· OSTI ID:4687191

Jamerson, F E; Abrams, Jr, R H; Leffert, C B; Silver, R

The generation of a plasma by fission fragment ionization in noble gas thermionic converters was investigated in a series of inpile experiments at the University of Michigan reactor. The plasma generated in Ne: Ar (1000: 1) at a pressure of 20 mm Hg was investigated in a plane parallel diode with electrically heated emitter and collector of barium impregnated tungsten. The fission fragment source was uranium foil mounted on a third electrode. As calculated from diode V-- I characteristics, ion densities of order 10/sup 10/ cm/sup -3/ were generated by fission fragments in the space surrounding the converter, and ion densities of order 10/sup 11/ cm/sup -3/ were present in the interelectrode gap due to the formation of ion trapping sheaths at the electrode surfaces during normal converter operation. The effect on converter operation of cesium generated in the fission process was investigated in a tube with a diode structure and filling as above, but with a fission product source shielded from the interelectrode space. No cesium effects were observed during the 11 1/2 hr of tube operation. The ion density due to the reactor gamma flux was calculated from the V--I characteristic to be of the order 10/sup 8/ --10/sup 9/ cm/sup -3/. Fission product poisoning of the collector was observed at temperatures less than 1000 deg K; the collector could be reactivated. To investigate the plasma generated by fission fragments in Xe at a pressure of 8 mm Hg, a plane parallel diode was constructed with a nuclear heated emitter of uranium carbide--rhenium and a barium impregnated tungsten collector. The emitter operating temperature was 1950 deg K in a neutron flux of 5 x 10/sup 12/ cm/sup -2/ sec/sup -1/. Discontinuities were observed in the forward currert characteristic between 6--7 v. The effects between 6 and 7 v were attributed to the formation of xenon metastable atoms in the collector sheath that could then produce additional ionization. The discontinuity at 10 v was attributed to Xe breakdown. The ion density calculated from the V --I characteristic before the first discontinuity was of order 10/sup 9/ cm/sup -3/. (auth)

• Research Organization: General Motors Corp., Warren, Mich.
• NSA Number: NSA-17-027985
• OSTI ID: 4687191
• Journal Information: Advanced Energy Conversion, Journal Name: Advanced Energy Conversion Vol. Vol: 3
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

ARGON
BARIUM
BREAKDOWN
CESIUM
CONFIGURATION
CONVERSION
DENSITY
DIODES
ELECTRICITY
ELECTRODES
ELECTRON TUBES
ENERGY LEVELS
FISSION PRODUCTS
FOILS
GAMMA RADIATION
HEATING
IMPREGNATION
IONIZATION
IONS
LAYERS
MEASURED VALUES
METASTABLE STATES
NEON
NESDPS Office of Nuclear Energy Space and Defense Power Systems
NEUTRON FLUX
OPERATION
PHYSICS
PLASMA
POISONING
PRESSURE
RARE GASES
REACTORS
RHENIUM
SHIELDING
SURFACES
TEMPERATURE
THERMIONICS
TRAPS
TUNGSTEN
URANIUM
URANIUM CARBIDES
XENON