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U.S. Department of Energy
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QUARTERLY STATUS REPORT OF THE LASL PLASMA THERMOCOUPLE DEVELOPMENT PROGRAM FOR PERIOD ENDING SEPTEMBER 20, 1959

Technical Report ·
OSTI ID:4228498

A "standardized" basic design of a plasma thermocouple for in-pile testing was selected. This utilizes a ZrC-UC fuel pin, 1/4 in. in diameter by 1 in. long, centered within a zirconium collector, leaving a 1-mm annular gap. With a pin of ZrC-30 mole % UC solid solution, in-pile testing was carried out at various reactor power levels. A pyrometer, thermal conductivity, and life tests were accomplished. Using the plasma cell described in the preceding report, considerable information concerning its operation was obtained by means of a Langmuir-type probe. Such a probe can reasonably be expected to yield information about electron energies, electron densities, and potentials in the cesium plasma for cesium vapor pressures up to about 0.5 mm Hg. Preparation of a cathode for higher efficiency is described. The most serious obstacle to designing and constructing cells with desirable and predictable temperature distributions in the collector and insulation is the inability to maintainn good thermal contact between the varions radial cell walls. Experiments were carried out with spraying insulating and cladding materials on collectors. This method of fabrication offers considerable promise of eliminating difficulties with radial gaps. Anomalous thermionic emission was studied. Thermionic electron emission characteristics of NbC/sub 0.94/, NbCO/sub 0.47/, and Nb metal were measured over the temperature range between 1725 and 2200 deg K. Weight loss data were obtained on a fuel pin (70-30 mole% ZrC -UC) heated in vacuum at about 2200 deg C for 212 hr. Measurements of fussion cadmium ratios for ZrC-30 mole% UC were made in the Omega West Reactor. (For preceding period see LAMS-2333). (W.D.M.)

Research Organization:
Los Alamos Scientific Lab., N. Mex.
NSA Number:
NSA-14-001636
OSTI ID:
4228498
Report Number(s):
LAMS-2364
Country of Publication:
Country unknown/Code not available
Language:
English