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Title: Sodium Heat Engine Development Program. Phase 1, Final report

The Sodium Heat Engine (SHE) is an efficient thermoelectric conversion device which directly generates electricity from a thermally regenerative electrochemical cell that relies on the unique conduction properties of {beta}{double_prime}-alumina solid electrolyte (BASE). Laboratory models of a variety of SHE devices have demonstrated the feasibility and efficiency of the system, engineering development of large prototype devices has been slowed by a series of materials and fabrication problems. Failure of the electrolyte tubes has been a recurring problem and a number of possible causes have been postulated. To address these issues, a two-phase engineering development program was undertaken. This report summarizes the final results of the first phase of the program, which included extensive materials characterization activities, a study of applicable nondestructive evaluation methods, an investigation of possible stress states that would contribute to fracture, and certain operational issues associated with the electromagnetic pumps used in the SHE prototype. Mechanical and microstructural evaluation of commercially obtained BASE tubes revealed that they should be adequate for SHE applications and that sodium exposure produced no appreciable deleterious strength effects. Processing activities to produce a more uniform and smaller grain size for the BASE tubes were completed using isostatic pressing, extrusion, and slip casting.more » Green tubes were sintered by conventional and microwave plasma methods. Of particular interest is the residual stress state in the BASE tubes, and both analysis and nondestructive evaluation methods were employed to evaluate these stresses. X-ray and neutron diffraction experiments were performed to determine the bulk residual stresses in commercially fabricated BASE tubes; however, tube-to-tube variations and variations among the various methods employed did not allow formulation of a definitive definition of the as-fabricated stress state.« less
Authors:
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Publication Date:
OSTI Identifier:
10139496
Report Number(s):
ANL--91/45
ON: DE92012398
DOE Contract Number:
W-31109-ENG-38
Resource Type:
Technical Report
Resource Relation:
Other Information: PBD: Jan 1992
Research Org:
Argonne National Lab., IL (United States)
Sponsoring Org:
USDOE, Washington, DC (United States)
Country of Publication:
United States
Language:
English
Subject:
30 DIRECT ENERGY CONVERSION; 36 MATERIALS SCIENCE; THERMOELECTRIC GENERATORS; FABRICATION; ALUMINIUM OXIDES; MECHANICAL PROPERTIES; TUBES; PROGRESS REPORT; MATERIALS; HEAT ENGINES; SODIUM; SOLID ELECTROLYTES; STRESS ANALYSIS; STRESSES; EXTRUSION; PRESSING; GRAIN SIZE; SINTERING; DIRECT ENERGY CONVERSION; CERAMICS; X-RAY DIFFRACTION; NEUTRON DIFFRACTION NESDPS Office of Nuclear Energy Space and Defense Power Systems 300303; 360203; 360201; MATERIALS, COMPONENTS, AND AUXILIARIES; MECHANICAL PROPERTIES; PREPARATION AND FABRICATION