摘要:

The Thermionic Space Nuclear System Design and Technology Demonstration (TI‐SNPS) program requires a low‐risk, compact space nuclear power with a 5‐ to 40‐kWe scalability, high conversion efficiency and the potential for long life. The 40‐kWe S‐PRIME system uses conventional materials in a known operating environment and the multicell thermionic fuel element (TFE) technology database to produce a low‐risk approach to meeting the TI‐SNPS flight system requirements. This design approach limits the risks to four key areas: TFE performance and lifetime, TFE testability demonstration, hydrogen control, and radiator heat pipe performance. These areas require critical component testing reduce risks within the development program (Millset al.1993). A TFE testability critical component demonstration was one of the six demonstrations scheduled in the S‐PRIME Phase I Program. Multicell TFE testing techniques were pioneered in the countries of the former Soviet Union. The Institute of Physics and Power Engineering (IPPE) in Obninsk, Russia, a key S‐PRIME subcontractor, was tasked with reviewing this database and recommending the best technical approach for acceptance testing individual S‐PRIME TFEs and a network of TFEs in a reactor core assembly. IPPE developed (PPTE). Using the PPTF as a starting point, a 10‐step process is defined for acceptance testing the overall S‐PRIME power system, starting from the manufacturing process line for the individual TFEs to a final assembly and shipment of the power system to the launch site and its integration/checkout with the payload. © 1995American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.47168

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

The Thermionic System Evaluation Test (TSET) facility, part of the TOPAZ International Program, in Albuquerque is currently testing Russian TOPAZ II space power systems (Wold 1993). The TOPAZ International Program has received six TOPAZ II Space Nuclear Power Reactors. Two of these reactors (Eh‐43 and Eh‐44) are considered ‘‘flight quality.’’ A considerable transfer of technology has occurred during the preparations for acceptance testing of the Eh‐43 and Eh‐44 TOPAZ II reactors. Eh‐43 and Eh‐44 are new systems that require the coolant loop and gas cavities to be filled and have not undergone any testing. In comparison to the tests performed on the V‐71 and Ya‐21u systems, the future operations with the flight units Eh‐43 and Eh‐44 will require expansion of the Baikal Test Stand’s capabilities. © 1995American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.47169

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

To satisfy the safety requirements of a terrestrial 60‐Watt Radioisotope Heat Source, it was necessary to determine whether the internal pressure buildup from the helium generated from Pu‐238 decay would pose problems in a fire environment (time/temperature/internal pressure). Nine T‐111 strength members were pressure burst tested; three were of the flat end cap weld design and six of the girth weld design. The flat end cap weld design was not successful, with failure times of less than 180 seconds. The girth weld design gave favorable results, with lifetimes ranging from 8 to 240 hours. All of the girth weld capsules failed in the center of the weld. The stress rupture model equation for determining test life using base metal properties does not predict the time to failure for the girth weld design under the accident scenario environment. © 1995American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.47170

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

The Sixty Watt Heat Source is a nonvented heat source designed to provide 60 thermal watts of power. The unit incorporates a plutonium‐238 fuel pellet encapsulated in a hot isostatically pressed General Purpose Heat Source (GPHS) iridium clad vent set. A molybdenum liner sleeve and support components isolate the fueled iridium clad from the T‐111 strength member. This strength member serves as the pressure vessel and fulfills the impact and hydrostatic strength requirements. The shell is manufactured from HastelloySwhich prevents the internal components from being oxidized. Conventional drawing operations were used to simplify processing and utilize existing equipment. The deep drawing reqirements for the molybdenum, T‐111, and HastelloySwere developed from past heat source hardware fabrication experiences. This resulted in multiple step drawing processes with intermediate heat treatments between forming steps. The molybdenum processing included warm forming operations. This paper describes the fabrication of these components and the multiple draw tooling developed to produce hardware to the desired specifications. © 1995American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.47171

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

The metallurgical integrity of frit vent assemblies produced by Martin Marietta Energy Systems, Inc. (Energy Systems) were compared to those produced G‐Mound Applied Technologies, Inc. (EG&G‐MAT). Frit vent assemblies were metallographically prepared and examined at magnifications from 50X to 1000X. Scanning electron microscope (SEM) examinations were made of the diffusion bonded powder in finished frit vent assemblies produced by Energy Systems and EG&G‐MAT. The metallographic and SEM examinations of the particle‐to‐particle and particel‐to‐foil component diffusion bonds indicated that the Energy Systems‐produced and EG&G‐MAT‐produced frit vent assemblies have comparable metallurgical integrity. The Energy Systems production data show that the frit vent manufacturing yield is 91%. © 1995American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.47172

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Martin Marietta Energy Systems, Inc., has successfully produced the iridium‐alloy clad vent sets required for encapsulation of plutonia for the National Aeronautics and Space Administration Cassini mission to Saturn. Numerous improvements were made to the manufacturing process in various areas including dye‐penetrant examination of cups, foil part stamping, chemical analysis, tungsten fixturing for laser welding, and enhanced inspections at high magnification. In addition, systems were initiated to ensure process control, and a detailed quality and technical surveillance program was prepared and followed to detect any incipient production problem early in the process so that corrective action could be taken immediately. The quality of the resulting iridium components has been high, and production yields have been above 90%. During the course of the production campaign for the Cassini mission, worker efficiencies lowered production costs, and further cost reductions are possible if operations are consolidated into a single area and bare‐forming of the iridium alloys cups can be qualified for flight‐quality clad vent sets.

ISSN:0094-243X    

DOI:10.1063/1.47173

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

The purpose of process monitoring using a quality and technical surveillance program was to help ensure that manufactured clad went sets fully met technical and quality requirements established by the manufacturer and the customer and that line and program management were immediately alerted if any aspect of the manufacturing activities drifted out of acceptable limits. The quality and technical surveillance program provided a planned, scheduled approach to monitor key processes and documentation and certification systems to prevent noncompliances or any manufacturing discrepancies. These surveillances illuminated potential problem areas early enough to permit timely corrective actions to reverse negative trends that, if left uncorrected, could have resulted in deficient hardware. Significant schedule and cost impacts were eliminated. © 1995American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.47242

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

The surface electrical conductivity of sapphire in the presence of caesium vapour has been measured for a variety of Cs pressures,PCs, and sample temperaturesTs. Data is presented for Cs pressures in the range 10−4to 1 Torr and sample temperatures ranging from 600 to 820 K. The conductivity dependence onPCsat constant values ofTsis weak over the measured range. The small variations observed have a non‐monotonic dependence onPCs. Experiments whereTsis varied at constantPCsshow that below a critical temperature the conductivity decreases with increasing values ofTs. However above this critical temperature the trend is reversed. © 1995American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.47174

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Selective sampling was conducted on three fuel pellet stacks that were manufactured by the reference process for the TOPAZ‐II reactor. The sampling and inspection of approximately two hundred fuel pellets were jointly conducted by US and Russian specialists. The sampling activity was conducted to evaluate the fuel characterization and sampling methods, and to examine the as‐fabricated characteristics of the fuel. The inspection procedure allowed studies of pellets from various batches of initial powder and from various sintering batches. The following characteristics were evaluated: pellet dimensions, O/U, isotopic composition, impurity content, and macro‐ and micro‐structure. © 1995American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.47175

出版商:AIP    

年代:1995

数据来源: AIP

摘要:

Demonstration tests were conducted using a diagnostic thermionic converter (N597) designed and manufactured at NII NPO LUCH (JV INERTEK). The converter at NII NPO LUCH was a subject of comparative research on mass loss rate of two ceramic materials (aluminium oxide and scandium oxide) at constant sample temperature in various modes of the converter operation. These investigations were continued in NMERI on the modified TISA Rig. Substantial corrosion of Al2O3was revealed after sample exposure in cesium plasma. It was also determined that Sc2O3does not interact with cesium plasma. Sc2O3mass loss rate in all thermionic converter operation modes does not exceed values corresponding to diffusion mode and is by several orders lower than Al2O3mass loss rate. Based on these results the lifetime of TFE electrode spacers was evaluated. © 1995American Institute of Physics

ISSN:0094-243X    

DOI:10.1063/1.47176

出版商:AIP    

年代:1995

数据来源: AIP