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Design, Analysis, and Optimization of RTG for Solar Polar Mission

Description: The paper presents the conceptual design of an RTG, employing stacked radioisotope heat source modules and silicon-germanium thermoelectric couples, for use on the joint NASA/ESA International Solar-Polar Mission, to be launched in early 1983. The use of stacked heat source modules in RTGs requires a structural support system which holds the stack together during launch, but allows it to disassemble when the generator housing melts during reentry. This is a much more difficult support problem than in the case of a monolithic heat source. A proposed, light-weight scheme for solving this problem is described and analyzed. A detailed analytical model of the RTG and the spacecraft to which it is attached was constructed, and a NASTRAN analysis was carried out to assess the structural performance of the heat source support scheme under differential thermal expansion and dynamic launch loads, to determine the system's characteristic frequencies, the loads transmitted to the RTG, and the resultant stresses and displacements. There are two versions in the file, a draft copy and a final copy. There are 4 copies of the final copy in the file and also a duplicate copy elsewhere.
Date: June 1, 1979
Creator: Schock, Alfred; Shostak, A. & Sookiazian, H.
Partner: UNT Libraries Government Documents Department

Design Optimization of RTG for Solar-Polar Mission

Description: The paper presents the conceptual design of an RTG, employing stacked radioisotope heat source modules and silicon-germanium thermo-electric couples, for use on the joint NASA/ESA International Solar-Polar Mission. It describes a computer program which, for a given set of assumptions and ground rules, can rapidly examine thousands of design variations and determine the combination of design parameters which will minimize the RTG weight for a given power output. Graphical results are presented to illustrate design trends and clarify the optimization procedure. The generated results lead to interesting and somewhat unexpected conclusions about optimum design parameters, the relative constancy of RTG specific power over a wide power range, comparisons between single and split RTGs, sensitivity to variations in heat source module design, weight comparisons with the MHW RTG, and comparative RTG weights for different housing and radiator fin materials. There are three copies in the file.
Date: August 1, 1979
Creator: Schock, Alfred & Sookiazian, H.
Partner: UNT Libraries Government Documents Department

Use of Modular Heat Source Stack in RTGs

Description: The use of stacked heat source modules in RTGs requires a structural support system which holds the stack together during launch, but allows it to disassemble when the generator housing melts during reentry. This is a much more difficult support problem than in the case of a monolithic heat source. A proposed, light-weight scheme for solving this problem is described, and illustrated with an actual RTG design for a specific mission. A detailed analytical model of the RTG and the spacecraft to which it is attached was constructed, and a NASTRAN analysis was carried out to assess the structural performance of the heat source support scheme under differential thermal expansion and dynamic launch loads, and to determine the system's characteristic frequencies, the loads transmitted to the RTG, and the resultant stresses and displacements. The analytical results presented confirm the structural feasibility of supporting a long heat source stack without intermediate support.
Date: August 1, 1979
Creator: Schock, Alfred & Shostak, A.
Partner: UNT Libraries Government Documents Department

Environmental Development Plan for space applications

Description: The Environmental Development Plan (EDP) identifies the planning and management requirements and schedules needed to evaluate and assess the environmental, health and safety aspects of the Space Applications Program. Environment is defined in its broadest sense to include environmental, health (occupational and public, safety, socioeconomic, legal, and institutional apsects. EDP has been limited to consideration of: (1) space nuclear power system nuclear fuel fabrication; (2) space nuclear power system heat source fabrication; (3) testing of subsystems and assembled systems; (4)research and development (R and D) in support of space nuclear system development; (5) nuclear system responses to launch and reentry accidents: and (6) nuclear system environmental behavior and recovery. (TFD)
Date: September 1, 1979
Partner: UNT Libraries Government Documents Department

DOE/JPL Advanced Thermionic Technology Program. Progress report No. 37, December 1978-January 1979

Description: Continuing research on thermionic converters is described. Topics include thermionic converter plasma studies, low-temperature converter development, component hardware development, and combustion-heated thermionic device. JPL tasks include basic surface experiments, triode converter experiments, design of cylindrical converter, and high-efficiency conversion experiments. Experimental results are reported. (WHK)
Date: January 1, 1979
Partner: UNT Libraries Government Documents Department

Advanced thermionic energy conversion. Joint highlights and status report, April-June 1979

Description: The DOE portion of the effort at Rasor Associates is directed primarily toward terrestrial applications of thermionic energy conversion. It focuses on the development of converters suitable for use with fossil fueled heat sources in power plants. The NASA program is directed at establishing the technical feasibility of an advanced light-weight long-life thermionic conversion system compatible with a remote nuclear or solar heat source. The principal application forseen at this time is in nuclear electric propulsion (NEP) missions in the mid-1990's. Significant accomplishments for the three month period include: (1) devised a blade-type distributed lead design with many advantages compared to the stud-type distributed lead; (2) completed design of Marchuk tube test apparatus; (3) concluded, based on current understanding, that residual hydrogen should not contribute to a negative space charge barrier at the collector; (4) modified THX design program to include series-coupled designs as well as inductively-coupled designs; (5) initiated work on the heat transfer technology, THX test module, output power transfer system, heat transfer system, and conceptual plant design tasks; and (6) reached 2200 hours of operation in JPL-5 cylindrical converter envelope test. (WHK)
Date: January 1, 1979
Partner: UNT Libraries Government Documents Department

DOE/JPL advanced thermionic technology program. Progress report No. 38, February-March 1979

Description: Progress on DOE tasks is reported including (1) surface and plasma investigations (surface characterization chamber experiments, spectroscopic plasma measurements, and converter theory), (2) low temperature converter development (tungsten emitter, lanthanum hexaboride collector and tungsten emitter, tungsten oxide collector), and (3) component hardware development. JPL tasks reported include high-temperature converter evaluation, advanced converter studies, and correlation of design interfaces. (WHK)
Date: January 1, 1979
Partner: UNT Libraries Government Documents Department

Dynamic isotope power system (DIPS) applications study. Volume I. Summary. Final report

Description: The Nuclear Integrated Multimission Spacecraft (NIMS) is designed for communications, surveillance, navigation and meteorelogical missions. This study assesses th attributes of the Dynamic Isotope Power System (DIPS) for this spacecraft. These attributes include cost, system and mission compatibility, and survivability. (LCL)
Date: November 1, 1979
Partner: UNT Libraries Government Documents Department

SNAP 19 Viking Program. Bimonthly technical progress report, October 1979-November 1979

Description: Monitoring and evaluation of Viking 1 Lander power system data continued. The RTG series power range as measured at the PCDA was 65 to 68 watts at fin root temperatures between 280/sup 0/F and 310/sup 0/F. The Mars landed performance history of Viking 1 include both the minimum and maximum data for each of the SOL days. Monitoring and evaluation of Viking 2 Lander power system data continued. The RTG series power range as measured at the PCDA was 71 to 72 watts at fin root temperatures between 230/sup 0/F and 260/sup 0/F. The Mars landed performance history of Viking 2 include both the minimum and maximum data for each of the SOL days. The performance of both power systems continues to be very satisfactory. Power system performance data for Pioneer 10 and Pioneer 11 spacecraft were monitored through the reporting period. The estimated RTG system net power was 116 watts for Pioneer 10 and 118 watts for Pioneer Saturn. The September 1 encounter with Saturn appears to have had no deleterious effect on the RTG's of the spacecraft power system. The telemetry signals from both spacecrafts remain satisfactory.
Date: December 1, 1979
Partner: UNT Libraries Government Documents Department

Selenide isotope generator for the Galileo Mission: SIG thermal insulation evaluaion tests

Description: Since the SIG program required the use of very high performance thermal insulation materials in rather severe thermal and environmental conditions, a thorough screening and testing program was performed. Several types of materials were included in the preliminary survey. Most promising were oxide and carbonaceous fibrous insulations, oxide and carbonaceous foamed materials, and multilayer materials with both powder and cloth spacers. The latter were only viable for the vacuum option. In all, over one hundred materials from more than sixty manufacturers were evaluated from literature and manufacturers' data. The list was pared to eighteen candidates in seven basic types, i.e., fibrous microporous SiO/sub 2/, fibrous SiO/sub 2//Al/sub 2/O/sub 3/, fibrous ZrO/sub 2/, fibrous carbon, foamed SiO/sub 2/, foamed carbon, and multilayer. Test results are presented.
Date: June 1, 1979
Partner: UNT Libraries Government Documents Department

Selenide isotope generator for the Galileo Mission. Program final report

Description: This final report for the Selenide Isotope Generator for the Galileo Mission (SIG/GM) documents the work performed by Teledyne Energy Systems (TES) under US Department of Energy (DOE) Contract No. DE-AC01-78ET33009 (formerly ET-78-C-01-2865) during the period April 10, 1978 to June 30, 1979. Because of technical difficulties with the thermoelectric converter being developed by the 3M Company under separate DOE contract, a Stop Work Order, dated January 29, 1979, was issued by DOE. The TES effort up to the receipt of the Stop Work Order as well as limited technical activities up to the contract conclusion on June 30, 1979 are reported.
Date: June 1, 1979
Partner: UNT Libraries Government Documents Department

General purpose heat source task group. Final report

Description: The results of thermal analyses and impact tests on a modified design of a /sup 238/Pu-fueled general purpose heat source (GPHS) for spacecraft power supplies are presented. This work was performed to establish the safety of a heat source with pyrolytic graphite insulator shells located either inside or outside the graphite impact shell. This safety is dependent on the degree of aerodynamic heating of the heat source during reentry and on the ability of the heat source capsule to withstand impact after reentry. Analysis of wind tunnel and impact test data result in a recommended GPHS design which should meet all temperature and safety requirements. Further wind tunnel tests, drop tests, and impact tests are recommended to verify the safety of this design. (LCL)
Date: September 18, 1979
Partner: UNT Libraries Government Documents Department

DOE/JPL Advanced Thermionic Technology Program. Progress report No. 40, July-August-September 1979

Description: The primary long-term goal of the DOE effort at Thermo Electron Corporation is to improve TEC performance to the level that thermionic topping of fossil fuel steam powerplants becomes technically possible and economically attractive. The focus of the JPL program is to develop thermionic conversion technology appropriate for nuclear electric propulsion (NEP) missions. This report covers progress made during the three-month period from July through September 1979. During this period, significant accomplishments in the DOE program include: (1) Demonstration of 2300 hours of stable operation (Silicon Carbide Converter No. 1) in a combustion environment at emitter temperatures at, or above, 1600 K. This test is continuing. (2) Fabrication of two leaktight composite CVD (SiC/C/W) hot shell-emitter structures two inches in diameter. (3) Reproduction of W(100)/O/Zr emitter work function obtained at the Oregon Graduate Center. (4) Formation of an analytical model of the ignited mode thermionic diode which predicts the operating conditions associated with the onset of a double sheath at the emitter. Significant accomplishments in the JPL program include: (1) Demonstration of oxygen enhancement of a molybdenum emitter from a tungsten oxide collector. (2) Development of a technique for casting sapphire prototypic of NEP thermionic reactor system design. (3) Development of a technique for bonding lanthanum hexaboride to rhenium that was stable for 150 hours at temperatures ranging between 1600 and 1700 K. (4) Formulation of an assembly procedure for fabricating thermionic converters on an emitter heat pipe. (WHK)
Date: January 1, 1979
Partner: UNT Libraries Government Documents Department

DOE/JPL advanced thermionic technology program. Progress report No. 39, April-June 1979. Report No. TE4258/4247-2-80

Description: DOE tasks include surface and plasma investigations (surface characterization, spectroscopic plasma experiments, and converter theory); low-temperature converter development (tungsten emitter, tungsten oxide collector and tungsten emitter, nickel collector); component hardware development (hot shell development); and flame-fired CVD silicon carbide converters. JPL tasks include high temperature and advanced converter studies, postoperational diagnostics, and correlation of design interfaces. Progress on each of these tasks is reported. (WHK)
Date: January 1, 1979
Partner: UNT Libraries Government Documents Department

Dynamic Isotope Power System (DIPS) Applications Study. Volume II. Nuclear Integrated Multimission Spacecraft (NIMS) design definition. Final report

Description: The design requirements for the Nuclear Integrated Multimission Spacecraft. (NIMS) are discussed in detail. The requirements are a function of mission specifications, payload, control system requirements, electric system specifications, and cost limitations. (LCL)
Date: November 1, 1979
Partner: UNT Libraries Government Documents Department

Nuclear powered satellite studies. Annual progress report, July 1, 1978-June 30, 1979

Description: Progress achieved during the period July 1, 1978 to June 30, 1979, on US DOE contract No. EY-76-S-02-4045.A002 is reported. Discussions of several pertinent aspects are included, e.g., schedule, personnel, technology developments, and plans. The reporting period represents the third year of activities of a project which is designed to provide continuing support in the area of nuclear space power technology. Important results have been obtained and communicated to the scientific community via publications and presentations. Project personnel have participated in point design efforts, a NASA Space Power Committee, and periodically provide support to Department of Energy activities as the need arises. The report is intended to summarize activities over the past year and provide a basis for continued project support by US DOE.
Date: June 1, 1979
Creator: Kaplan, M.H.
Partner: UNT Libraries Government Documents Department

LASL fabrication flowsheet for GPHS fuel pellets

Description: The General Purpose Heat Source (GPHS) being developed by the Los Alamos Scienific Laboratory for the Department of Energy, Division of Advanced Nuclear Systems and Projects, consists of a series of graphite modules, each having a thermal power inventory of 62.5 watts. Each module is loaded with four cylindrical 62.5-W /sup 238/PuO/sub 2/ fuel pellets. The report summarizes the specifications for these pellets together with the fabrication flowsheet developed at LASL.
Date: August 1, 1979
Creator: Kent, R.A.
Partner: UNT Libraries Government Documents Department

Selected advances in materials research

Description: Several findings emanating from materials research that should have a beneficial impact on technological advancement in the future are described. The report deals with the GRAPHNOL, a new class of high-temperature brazing alloy for joining refractory components, gel-sphere-pac process for manufacture of nuclear fuel, and noble-metal fuel cladding for service in radioisotope thermoelectric generators designed to provide auxiliary power aboard spacecraft for planetary exploration.
Date: January 1, 1979
Creator: Cunningham, J.E.
Partner: UNT Libraries Government Documents Department

100-kW/sub e/ Nuclear space electric power source

Description: The current 100-kW/sub e/ space nuclear power technology program could provide an electric power source for nuclear electric propulsion. The power plant is relatively compact, light weight, and has the advantages of long life and immunity to degradation while passing through the Van Allen belts. The reactor is a unique design using heat pipes to transfer heat from the reactor core to the thermoelectric converters. The converters are an improved design over those used in the radioisotope space program. The radiator, used to eliminate waste heat to space, also makes use of heat pipes. All single failure points have been eliminated from the power plant design and redundancies are provided to ensure high reliability. The power plant configuration and some key results of the current component experimental program are discussed.
Date: January 1, 1979
Creator: Buden, D.
Partner: UNT Libraries Government Documents Department

General-purpose heat source project and space nuclear safety and fuels program. Progress report

Description: This formal monthly report covers the studies related to the use of /sup 238/PuO/sub 2/ in radioisotopic power systems carried out for the Advanced Nuclear Systems and Projects Division of the Los Alamos Scientific Laboratory. The two programs involved are general-purpose heat source development and space nuclear safety and fuels. Most of the studies discussed hear are of a continuing nature. Results and conclusions described may change as the work continues.
Date: December 1, 1979
Creator: Maraman, W.J. (comp.)
Partner: UNT Libraries Government Documents Department

Two-dimensional electron temperature profiles in thermionic converters. Technical status report No. 79-0003 for the period July 1979

Description: The electron temperature profile solution described by Timothy M. Smith in the report ENCOTH-TM79-0001 is generalized to two dimensions. The equations are written in cartesian coordinates used to solve structured electrode problems. An alaternate two-dimensional cylindrical geometry solution is trivially similar. The latter would be used to study departure from one-dimensional symmetry due to finite size electrodes and radial flows. The numerical method is described. The present work represents a partial solution of a complete two-dimensional transport, the purpose of which is the convergence of the proposed numerical approach. Also, the mathematical formulation of two-dimensional transport in electrical plasmas is given. The equations characterizing the two-dimensional transport and the electric field are selected, and a numerical method is proposed. (WHK)
Date: January 1, 1979
Creator: Smith, D.E.
Partner: UNT Libraries Government Documents Department

Heat source component development program. Quarterly report, January 1979-March 1979

Description: This is the eighth of a series of reports describing the results of several analytical and experimental programs being conducted at Battelle-Columbus Laboratories to develop components for advanced radioisotope heat source applications. The heat sources will for the most part be used in advanced static and dynamic power conversion systems. These reports replace the informal monthly technical letter reports previously prepared and are being utilized so that more cohesive presentations of results can be achieved. The specific efforts in progress during the period covered by this report were in support of the General Purpose Heat Source (GPHS) Development Program that is being led by the Los Alsmos Scientific Laboratory (LASL). These specific efforts were concerned with: analyses of trial designs with emphasis on detailed predictions of the response of Trial Design, including the sensitivity of the response to design and environmental uncertainties, and on comparison of performances of the Trial Design and the Ir Reference Design. It should be noted that considerable reentry thermal analyses have been conducted subsequent to the period covered in this report. In these more recent analyses, significant changes have been made to the heat source properties, and time-dependent boundary conditions. Results of these more recent analyses, as reported in project reviews, differ significantly from some of the results contained in the present report.
Date: August 1, 1979
Creator: Foster, E.L. Jr. (comp.)
Partner: UNT Libraries Government Documents Department

Selenide isotope generator for the Galileo Mission: copper/water axially-grooved heat pipe topical report

Description: This report presents a summary of the major accomplishments for the development, fabrication, and testing of axially-grooved copper/water heat pipes for Selenide Isotopic Generator (SIG) applications. The early development consisted of chemical, physical, and analytical studies to define an axially-grooved tube geometry that could be successfully fabricated and provide the desired long term (up to seven years) performance is presented. Heat pipe fabrication procedures, measured performance and accelerated life testing of heat pipes S/Ns AL-5 and LT-57 conducted at B and K Engineering are discussed. S/N AL-5 was the first axially-grooved copper/water heat pipe that was fabricated with the new internal coating process for cupric oxide (CuO) and the cleaning and water preparation methods developed by Battelle Columbus Laboratories. Heat pipe S/N LT-57 was fabricated along with sixty other axially-grooved heat pipes allocated for life testing at Teledyne Energy Systems. As of June 25, 1979, heat pipes S/Ns AL-5 and LT-57 have been accelerated life tested for 13,310 and 6,292 respectively, at a nominal operating temperature of 225/sup 0/C without any signs of thermal performance degradation. (TFD)
Date: June 30, 1979
Creator: Strazza, N.P.
Partner: UNT Libraries Government Documents Department