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Title: Thermionic Reactor Design Studies

Abstract

Paper presented at the 29th IECEC in Monterey, CA in August 1994. The present paper describes some of the author's conceptual designs and their rationale, and the special analytical techniques developed to analyze their (thermionic reactor) performance. The basic designs, first published in 1963, are based on single-cell converters, either double-ended diodes extending over the full height of the reactor core or single-ended diodes extending over half the core height. In that respect they are similar to the thermionic fuel elements employed in the Topaz-2 reactor subsequently developed in the Soviet Union, copies of which were recently imported by the U.S. As in the Topaz-2 case, electrically heated steady-state performance tests of the converters are possible before fueling.

Authors:
Publication Date:
Research Org.:
Fairchild Space and Defense Corporation
Sponsoring Org.:
NE Office of Space and Defense Power Systems
OSTI Identifier:
1033362
Report Number(s):
AIAA-94-3885-CP; FSC-ESD-217-94-528
Orbital ID: 8573; Call Number: ESD files
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
NESDPS Office of Nuclear Energy Space and Defense Power Systems; Thermionic Reactors; Design; Review

Citation Formats

Schock, Alfred. Thermionic Reactor Design Studies. United States: N. p., 1994. Web. doi:10.2172/1033362.
Schock, Alfred. Thermionic Reactor Design Studies. United States. doi:10.2172/1033362.
Schock, Alfred. 1994. "Thermionic Reactor Design Studies". United States. doi:10.2172/1033362. https://www.osti.gov/servlets/purl/1033362.
@article{osti_1033362,
title = {Thermionic Reactor Design Studies},
author = {Schock, Alfred},
abstractNote = {Paper presented at the 29th IECEC in Monterey, CA in August 1994. The present paper describes some of the author's conceptual designs and their rationale, and the special analytical techniques developed to analyze their (thermionic reactor) performance. The basic designs, first published in 1963, are based on single-cell converters, either double-ended diodes extending over the full height of the reactor core or single-ended diodes extending over half the core height. In that respect they are similar to the thermionic fuel elements employed in the Topaz-2 reactor subsequently developed in the Soviet Union, copies of which were recently imported by the U.S. As in the Topaz-2 case, electrically heated steady-state performance tests of the converters are possible before fueling.},
doi = {10.2172/1033362},
journal = {},
number = ,
volume = ,
place = {United States},
year = 1994,
month = 8
}

Technical Report:

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  • During the 1960's and early 70's the author performed extensive design studies, analyses, and tests aimed at thermionic reactor concepts that differed significantly from those pursued by other investigators. Those studies, like most others under Atomic Energy Commission (AEC and DOE) and the National Aeronautics and Space Administration (NASA) sponsorship, were terminated in the early 1970's. Some of this work was previously published, but much of it was never made available in the open literature. U.S. interest in thermionic reactors resumed in the early 80's, and was greatly intensified by reports about Soviet ground and flight tests in the latemore » 80's. This recent interest resulted in renewed U.S. thermionic reactor development programs, primarily under Department of Defense (DOD) and Department of Energy (DOE) sponsorship. Since most current investigators have not had an opportunity to study all of the author's previous work, a review of the highlights of that work may be of value to them. The present paper describes some of the author's conceptual designs and their rationale, and the special analytical techniques developed to analyze their performance. The basic designs, first published in 1963, are based on single-cell converters, either double-ended diodes extending over the full height of the reactor core or single-ended diodes extending over half the core height. In that respect they are similar to the thermionic fuel elements employed in the Topaz-2 reactor subsequently developed in the Soviet Union, copies of which were recently imported by the U.S. As in the Topaz-2 case, electrically heated steady-state performance tests of the converters are possible before fueling. Where the author's concepts differed from the later Topaz-2 design was in the relative location of the emitter and the collector. Placing the fueled emitter on the outside of the cylindrical diodes permits much higher axial conductances to reduce ohmic losses in the electrodes of full-core-height diodes. Moreover, placing the fuel on the outside of the diode makes possible reactors with much higher fuel volume fractions, which enable power-flattened fast reactors scalable to very low power levels without the need for life-limiting hydride moderators or the use of efficiency-limiting driver fuel. In addition, with the fuel on the outside its swelling does not increase the emitter diameter or reduce the interelectrode gap. This should permit long lifetimes even with closer spacings, which can significantly improve the system efficiences. This was confirmed by coupled neutronic, thermal, thermionic, and electrical system analyses - some of which are presented in this paper - and by subsequent experiments. A companion paper presented next describes the fabrication and testing of full-scale converter elements, both fueled and unfueled, and summarizes the test results obtained. There is a duplicate copy in the file.« less
  • A parametric study of a heat recovery train for thermionic-topped combined cycle utility plants is performed for three discrete thermal inputs of 900, 1800 and 2700 MW/sub t/. Secondary air temperatures of 1089K (1500/sup 0/F), 1367K (2000/sup 0/F), and 1589K (2500/sup 0/F) are evaluated for each thermal input, roughly reflecting various stages of development of a high-temperature air heater. The effects of the parametric variables on the size, arrangement, and cost of the heat recovery train components are evaluated. Efforts are made in all cases to utilize commercial fabrication techniques and materials of construction, so as to minimize uncertainties inmore » the cost estimates. The results of this study were supplied to Rasor Associates, Inc. and Bechtel National, Inc., who in turn used this component data to determine the optimum size and arrangement of a thermionic-topped combined cycle power plant.« less