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Title: Output power characteristics and performance of TOPAZ II Thermionic Fuel Element No. 24

Abstract

A final report on the output power characteristics and capabilities of single cell TOPAZ II Thermionic Fuel Element (TFE) No. 24 is presented. Thermal power tests were conducted for over 3000 hours to investigate converter performance under normal and adverse operating conditions. Experiments conducted include low power testing, high power testing, air introduction to the interelectrode gap, collector temperature optimization, thermal modeling, and output power characteristic measurements. During testing, no unexpected degradation in converter performance was observed. The TFE has been removed from the test stand and returned to Scientific Industrial Association {open_quote}{open_quote}LUCH{close_quote}{close_quote} for materials analysis and report. This research was conducted at the Thermionic System Evaluation Test (TSET) Facility at the New Mexico Engineering Research Institute (NMERI) as a part of the Topaz International Program (TIP) by the Air Force Phillips Laboratory (PL). {copyright} {ital 1996 American Institute of Physics.}

Authors:
;  [1]; ;  [2]
  1. Team Specialty Services, Inc., TOPAZ International Program, 901 University Blvd., SE, Albuquerque, New Mexico 87106 (United States)
  2. JV INERTEK, Scientific Industrial Association ``Luch``, 24 Zheleznodorozhnaya, Podolsk, (Russia) 142100
Publication Date:
OSTI Identifier:
385472
Report Number(s):
CONF-960109-
Journal ID: APCPCS; ISSN 0094-243X; TRN: 9618M0077
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 361; Journal Issue: 1; Conference: STAIF 96: space technology and applications international forum, Albuquerque, NM (United States), 7-11 Jan 1996; Other Information: PBD: Mar 1996
Country of Publication:
United States
Language:
English
Subject:
30 DIRECT ENERGY CONVERSION; THERMIONIC FUEL ELEMENTS; PERFORMANCE; ENERGY CONVERSION; TESTING; ELECTRICAL INSULATION; SPACE VEHICLE COMPONENTS

Citation Formats

Luchau, D.W., Bruns, D.R., Izhvanov, O., and Androsov, V. Output power characteristics and performance of TOPAZ II Thermionic Fuel Element No. 24. United States: N. p., 1996. Web. doi:10.1063/1.50056.
Luchau, D.W., Bruns, D.R., Izhvanov, O., & Androsov, V. Output power characteristics and performance of TOPAZ II Thermionic Fuel Element No. 24. United States. doi:10.1063/1.50056.
Luchau, D.W., Bruns, D.R., Izhvanov, O., and Androsov, V. 1996. "Output power characteristics and performance of TOPAZ II Thermionic Fuel Element No. 24". United States. doi:10.1063/1.50056.
@article{osti_385472,
title = {Output power characteristics and performance of TOPAZ II Thermionic Fuel Element No. 24},
author = {Luchau, D.W. and Bruns, D.R. and Izhvanov, O. and Androsov, V.},
abstractNote = {A final report on the output power characteristics and capabilities of single cell TOPAZ II Thermionic Fuel Element (TFE) No. 24 is presented. Thermal power tests were conducted for over 3000 hours to investigate converter performance under normal and adverse operating conditions. Experiments conducted include low power testing, high power testing, air introduction to the interelectrode gap, collector temperature optimization, thermal modeling, and output power characteristic measurements. During testing, no unexpected degradation in converter performance was observed. The TFE has been removed from the test stand and returned to Scientific Industrial Association {open_quote}{open_quote}LUCH{close_quote}{close_quote} for materials analysis and report. This research was conducted at the Thermionic System Evaluation Test (TSET) Facility at the New Mexico Engineering Research Institute (NMERI) as a part of the Topaz International Program (TIP) by the Air Force Phillips Laboratory (PL). {copyright} {ital 1996 American Institute of Physics.}},
doi = {10.1063/1.50056},
journal = {AIP Conference Proceedings},
number = 1,
volume = 361,
place = {United States},
year = 1996,
month = 3
}
  • A final report on the output power characteristics and capabilities of the TOPAZ II Space Nuclear Power Unit Ya-21u is presented. Results showed that after a total of almost 8,000 hours of system testing in the U.S. and Russia, several emergency cooldowns, and three inadvertent air introductions to the interelectrode gap (IEG) that the TOPAZ II demonstrates the potential for providing reliable power in a space environment. Output power optimizations and system characteristics following a shock and vibration test are shown. These tests were performed using electrical heaters that simulate nuclear fuel heating. This paper will focus primarily on themore » changes in output power characteristics over the lifetime of Ya-21u. All U.S. testing was conducted at the Thermionic System Evaluation Test (TSET) Facility of the New Mexico Engineering Research Institute (NMERI) as a part of the TOPAZ International Program (TIP). TIP is managed by the Air Force Phillips Laboratory (PL) for the Ballistic Missile Defense Organization (BMDO). {copyright} {ital 1996 American Institute of Physics.}« less
  • Data reported by Russian Scientists and engineers for the TOPAZ-II single cell thermionic fuel elments (TFE) is compared with analytical results calculated using the TFEHX computer program in order to benchmark the code. The results of this comparison show good agreement with the TOPAZ-II results over a wide range of power inputs, cesium vapor pressures, and other design variables. Future refinements of the TFEHX methodology should enhance the performance of the code to better predict single cell TFE behavior.
  • A thermionic transient analyses model is developed to simulate transient and steady-state operations of a fully integrated, single-cell thermionic fuel element (TFE). The response of the TFE to a step input in reactivity and changes in the cesium pressure or in the size of the interelectrode gap, the coolant temperature, and the load demand are investigated. Also, the effects of these parameters on the load electric power, emitter temperature, overall conversion efficiency, and load following characteristics of the TFE are determined. Results show that although nuclear reactors having negative temperature reactivity coefficients are always load following, TFEs are only partiallymore » load following. For TFEs having a large interelectrode gap, it is desirable to conserve cesium by lowering its vapor pressure at the beginning of life since increasing the cesium pressure insignificantly affects the load electric power. However, should fuel swelling reduce the width of the interelectrode gap (after operating the reactor for an extended period of time), both the conversion efficiency and the load electric power will decrease. In this case, the load electric power could be restored by increasing the fission power and only partially by increasing the cesium vapor pressure.« less
  • The use of electric heaters in the single-cell thermionic fuel elements(TFE) of the Topaz-II power systems provides the ability to gain actual operating parameters of the power source prior to loading nuclear fuel. This feature can provide satellite payload designers with the output parameters of the power source that would be used for space operations. This design also allows personnel to work on the system after operation without the concerns associated with radioactive material produced from nuclear tests. The results of electrically testing a complete system provide a high level of confidence that the device will perform as expected inmore » orbit.« less