Thermionic reactors
Thermionic reactors for spacecraft auxiliary power and electric propulsion, discussing in-core conversion system and diodes
Grover, G. M.↗
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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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Survey of materials for thermionic converters
Literature survey of materials for gaseous thermionic conversion systems for use in space
Smith, A. L.↗
Post test inspection of three Brayton rotating units
Post test analysis of closed Brayton cycle space electric power conversion system for space
Dunn, J. H.↗
Design review of PCS-G condenser, P/N 268340-1, redesigned from P/N 093043
Mercury and NaK inlet and outlet port, condenser, and attachment design modifications of power conversion system for SNAP 8
Chalpin, E. S.↗
Design review of the Bare Refractory Double-Containment (BRDC) boiler number 5 for PCS, SNAP-8
Bare refractory double containment boiler for SNAP 8 power conversion system utilizing mercury, tantalum, zirconium, and type 300 stainless steel materials
Chalpin, E. S.↗
Status of advanced Rankine power conversion technology
Rankine cycle turboelectric nuclear space power conversion system with liquid K as working fluid, discussing current technology status
Gutstein, M. U.↗
Post test inspection of three Brayton rotating units
Post test inspection of Brayton Rotating Unit for closed Brayton cycle electric power conversion system for long space missions
Dunn, J. H.↗
Radioisotopes- Famine of feast - A review of availability
Radioisotopes as energy source for power conversion systems, discussing future availability of fission products and transuranium elements from commercial nuclear power reactors
Brown, P. E.↗
Heat source reentry vehicle design study
The design details are presented of a flight-type heat source reentry vehicle and heat exchanger compatible with the isotope Brayton power conversion system. The reference reentry vehicle and heat exchanger were modified, orbital and superorbital capability was assessed, and a complete set of detail design layout drawings were provided.
Ryan, R. L.↗
Experimental physics characteristics of a heavy-metal-reflected fast-spectrum critical assembly
A zero-power critical assembly was designed, constructed, and operated for the purpose of conducting a series of benchmark experiments dealing with the physics characteristics of a UN-fueled, Li-7 cooled, Mo-reflected, drum-controlled compact fast reactor for use with a space-power electric conversion system. The experimental program consisted basically of measuring the differential neutron spectra and the changes in critical mass that accompanied the stepwise addition of (Li-7)3N, Hf, Ta, and W to a basic core fueled with U metal in a pin-type Ta honeycomb structure. In addition, experimental results were obtained on power distributions, control characteristics, neutron lifetime, and reactivity worths of numerous absorber, structural, and scattering materials.
Heneveld, W. H.↗
Nuclear applications in manned space station
The zirconium hydride reactor, coupled to a thermo-electric or Brayton conversion system, and the Pu 238 isotope/Brayton system, are considered to be the viable nuclear candidates for the modular space station electrical power system. The basic integration aspects of these nuclear electrical power systems are reviewed, including unique requirements imposed by the buildup and incremental utilization considerations of the modular station. Also treated are the various programmatic aspects of nuclear power system design and selection.
Brooksbank, W. A., Jr.↗
Parallel operation of two Brayton-cycle alternators with parasitic speed controllers
The experimental paralleling characteristics of two 1200 Hz Brayton-cycle alternators are presented. Since the Brayton power conversion system uses electric speed controllers, the paralleling requirements are somewhat different from those for conventional ground-based systems. Results include the transient effects of synchronizing the two alternators with various phase-angle, voltage, and frequency differences. Based on these results, the effects of synchronizing differences can be defined, and adjustment requirements of the parasitic speed controllers during synchronizing can be established. Data indicate that parasitically loaded alternators are able to parallel over a wide range of synchronizing differences. However, equilibrium could not be reached in extreme cases where alternator load differences were great and, at the same time, the phase-angle error was large (150 deg or more).
Perz, D. A.↗
Experimental physics characteristics of a heavy-metal-reflected fast-spectrum critical assembly
A zero-power critical assembly was designed, constructed, and operated for the purpose of conducting a series of benchmark experiments dealing with the physics characteristics of a UN-fueled, Li-cooled, Mo-reflected, drum-controlled compact fast reactor for use with a space-power electric conversion system. The range of the previous experimental investigations has been expanded to include the reactivity effects of:(1) surrounding the reactor with 15.24 cm (6 in.) of polyethylene, (2) reducing the heights of a portion of the upper and lower axial reflectors by factors of 2 and 4, (3) adding 45 kg of W to the core uniformly in two steps, (4) adding 9.54 kg of Ta to the core uniformly, and (5) inserting 2.3 kg of polyethylene into the core proper and determining the effect of a Ta addition on the polyethylene worth.
Heneveld, W. H.↗
Improvements in and test results for the 2 to 15 kilowatt Brayton cycle electrical subsystem
The electrical subsystem of the 2- to 15-kW Brayton power conversion system consists of the auxiliary electrical equipment required for an integrated, self-contained system. For the last 2 years the electrical subsystem has been undergoing extensive tests. The first year of testing resulted in determining the performance characteristics of the electrical subsystem. During the second year several significant changes and improvements were investigated. An inverter designed for motor starting the alternator performed successfully. Some of the changes that have been made are a new alternator speed pickup, which is independent of the alternator output voltage; new, more efficient power supplies for the control system; and a volts-per-hertz reference for the alternator voltage regulator. Test data were taken on the temperature distribution of the electrical subsystem at startup conditions over a cold-plate temperature range of 25 to -50 C.
Vrancik, J. E.↗
Development of a Thick-film Silicon Ribbon Growth Technique for Application to Large-area Solar Cells and Arrays
A new technique is described for growth of large-area silicon ribbons. This technique is an edge-defined, film-fed growth process by which single crystals can be grown having a shape controlled by the outside dimensions of a shaping die, growth taking place from an extremely thin film of liquid fed by capillary action from a crucible below. The material from which the die is fabricated is very critical to the process. The die must be wet by the silicon, but adverse impurities must not be introduced into the silicon, and the die must not become degraded by the molten silicon. A breakthrough in die fabrication that has allowed the growth of silicon ribbons having dimensions of 1 cm by 30 cm with a thickness of 0.7 mm is described. The implications of this significant advancement with respect to development of photovoltaic solar arrays for wide-scale terrestrial solar-to-electric energy conversion systems are discussed.
Berman, P. A.↗
Experimental detailed power distribution in a fast spectrum thermionic reactor fuel element at the core/BeO reflector interface region
A zero-power critical assembly was designed, constructed, and operated for the prupose of conducting a series of benchmark experiments dealing with the physics characteristics of a UN-fueled, Li-7-cooled, Mo-reflected, drum-controlled compact fast reactor for use with a space-power conversion system. The critical assembly was modified to simulate a fast spectrum advanced thermionics reactor by: (1) using BeO as a reflector in place of some of the existing molybdenum, (2) substituting Nb-1Zr tubing for some of the existing Ta tubing, and (3) inserting four full-scale mockups of thermionic type fuel elements near the core and BeO reflector boundary. These mockups were surrounded with a buffer zone having the equivalent thermionic core composition. In addition to measuring the critical mass of this thermionic configuration, a detailed power distribution in one of the thermionic element stages in the mixed spectrum region was measured. A power peak to average ratio of two was observed for this fuel stage at the midplane of the core and adjacent to the reflector. Also, the power on the outer surface adjacent to the BeO was slightly more than a factor of two larger than the power on the inside surface of a 5.08 cm (2.0 in.) high annular fuel segment with a 2.52 cm (0.993 in. ) o.d. and a 1.86 cm (0.731 in.) i.d.
Klann, P. G.↗
Parallel operation of two Brayton-cycle alternators with parasitic speed controllers.
The experimental paralleling characteristics of two 1200-Hz Brayton-cycle alternators are presented. Since the Brayton power conversion system uses electric speed controllers, the paralleling requirements are somewhat different from those for conventional ground-based power systems. Results include the transient effects of synchronizing the two alternators with various phase-angle, voltage, and frequency differences. Based on these results, the effects of synchronizing differences can be defined, and adjustment requirements of the parasitic speed controllers during synchronizing can be established. Data indicate that parasitically loaded alternators are able to parallel over a wide range of synchronizing differences.
Perz, D. A.↗