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Two-phase alkali-metal experiments in reduced gravity

Description: Future space missions envision the use of large nuclear reactors utilizing either a single or a two-phase alkali-metal working fluid. The design and analysis of such reactors require state-of-the-art computer codes that can properly treat alkali-metal flow and heat transfer in a reduced-gravity environment. A literature search of relevant experiments in reduced gravity is reported on here, and reveals a paucity of data for such correlations. The few ongoing experiments in reduced gravity are noted. General plans are put forth for the reduced-gravity experiments which will have to be performed, at NASA facilities, with benign fluids. A similar situation exists regarding two-phase alkali-metal flow and heat transfer, even in normal gravity. Existing data are conflicting and indequate for the task of modeling a space reactor using a two-phase alkali-metal coolant. The major features of past experiments are described here. Data from the reduced-gravity experiments with innocuous fluids are to be combined with normal gravity data from the two-phase alkali-metal experiments. Analyses undertaken here give every expectation that the correlations developed from this data base will provide a valid representation of alkali-metal heat transfer and pressure drop in reduced gravity.
Date: June 1, 1986
Creator: Antoniak, Z.I.
Partner: UNT Libraries Government Documents Department

Two-phase reduced gravity experiments for a space reactor design

Description: Future space missions envision the use of large nuclear reactors utilizing either a single or a two-phase alkali-metal working fluid. The design and analysis of such reactors require state-of-the-art computer codes that can properly treat alkali-metal flow and heat transfer in a reduced-gravity environment. New flow regime maps, models, and correlations are required if the codes are to be successfully applied to reduced-gravity flow and heat transfer. General plans are put forth for the reduced-gravity experiments which will have to be performed, at NASA facilities, with benign fluids. Data from the reduced-gravity experiments with innocuous fluids are to be combined with normal gravity data from two-phase alkali-metal experiments. Because these reduced-gravity experiments will be very basic, and will employ small test loops of simple geometry, a large measure of commonality exists between them and experiments planned by other organizations. It is recommended that a committee be formed, to coordinate all ongoing and planned reduced gravity flow experiments.
Date: August 1, 1986
Creator: Antoniak, Z.I.
Partner: UNT Libraries Government Documents Department

Thermoelectric generator and method for the fabrication thereof

Description: A thermoelectric generator using semiconductor elements for responding to a temperature gradient to produce electrical energy with all of the semiconductor elements being of the same type is disclosed. A continuous process for forming substrates on which the semiconductor elements and superstrates are deposited and a process for forming the semiconductor elements on the substrates are also disclosed. The substrates with the semiconductor elements thereon are combined with superstrates to form modules for use as thermoelectric generators.
Date: August 1, 1984
Creator: Benson, D.K. & Tracy, C.E.
Partner: UNT Libraries Government Documents Department

Dynamics analyses of space power systems using the salt code

Description: The dynamic behavior of large space power systems has been identified as a significant technical issue. To date several analyses of reactor kinetics have been reported in the literature, but there have been few (if any) studies of the dynamic response of the entire space power system. The problem is complex and required analytical methods are not generally available. Furthermore, given the conceptual state of current MMW space power systems designs, dynamic models of components are not generally available. We have used the SALT code to perform preliminary analyses of the startup and shutdown transients of several proposed MMW system designs. In this paper we will provide a description of the code methodology and present results of the analyses performed for the NERVA derivative reactor (NDR) system. 3 refs., 3 figs.
Date: January 1, 1989
Creator: Geyer, H.K.; Bhattacharyya, S.K.; Hanan, N.A.; Livingston, J.M. (Argonne National Lab., IL (USA) & Westinghouse Electric Corp., Pittsburgh, PA (USA))
Partner: UNT Libraries Government Documents Department

Milliwatt-generator heat source. Progress report, January-June 1983

Description: Progress is reported in the following: heat source shipments, reimbursable orders, hardware shipments, raw material qualification/procurement, DOE audit and milliwatt generator process review, surveillance capsule evaluations, pressure burst testing, and hardware fabrication and quality. (MHR)
Date: September 20, 1983
Creator: Mershad, E.A.
Partner: UNT Libraries Government Documents Department

Milliwatt generator heat source. Progress report, July-December 1981

Description: As part of the Milliwatt Generator (MWG) Program, a second series of pressure burst capsules welded offsite was tested; the resulting data indicate that the welds are very similar to those in the first series of capsules. Sufficient hardware was fabricated to meet all scheduled commitments. To provide a unit for feasibility testing, a heat source clad with Hastelloy C was reclad with Inconel 600. Forming development tests on Inconel 600 were conducted with favorable results. A QAS-3 survey was conducted and a satisfactory rating was received. Lot 11 qualification began on T-111 materials. The production period ended with an overall process yield of 99.6%, and a dollar percent defective rate of 0.60%.
Date: April 8, 1982
Creator: Mershad, E.A.
Partner: UNT Libraries Government Documents Department

Evaluation of a steady state MPD thruster test facility

Description: The successful development of multimegawatt MPD thrusters depends, to a great extent, on testing them under steady state high altitude space conditions. Steady state testing is required to provide thermal characteristics, life cycle, erosion, and other essential data. the major technical obstacle for ground testing of MPD thrusters in a space simulation facility is the inability of state-of-the-art vacuum systems to handle the tremendous pumping speeds required for multimegawatt MPD thrusters. This is true for other types of electric propulsion devices as well. This paper discusses the results of the first phase of an evaluation of steady state MPD thruster test facilities. The first phase addresses the conceptual design of vacuum systems required to support multimegawatt MPD thruster testing. Three advanced pumping system concepts were evaluated and are presented here.
Date: January 1, 1985
Creator: Reed, C.B.; Carlson, L.W.; Herman, H.; Doss, E.D. & Kilgore, O.
Partner: UNT Libraries Government Documents Department

Molybdenum-base cermet fuel development

Description: Development of a multimegawatt (MMW) space nuclear power system requires identification and resolution of several technical feasibility issues before selecting one or more promising system concepts. Demonstration of reactor fuel fabrication technology is required for cermet-fueled reactor concepts. MMW reactor fuel development activity at Pacific Northwest Laboratory (PNL) is focused on producing a molybdenum-matrix uranium-nitride (UN) fueled cermet. This cermet is to have a high matrix density (greater than or equal to95%) for high strength and high thermal conductance coupled with a high particle (UN) porosity (approx.25%) for retention of released fission gas at high burnup. Fabrication process development involves the use of porous TiN microspheres as surrogate fuel material until porous UN microspheres become available. Process development has been conducted in the areas of microsphere synthesis, particle sealing/coating, and high-energy-rate forming (HERF) and vacuum hot press consolidation techniques. This paper summarizes the status of these activities.
Date: July 1, 1987
Creator: Gurwell, W.E.; Moss, R.W.; Pilger, J.P. & White, G.D.
Partner: UNT Libraries Government Documents Department

Low gravity fluid-thermal experiments

Description: Pacific Northwest Laboratory (PNL) is the lead laboratory for the thermal-hydraulic research in the US Department of Energy Multimegawatt Space Nuclear Power Program. PNL must provide the tools necessary to analyze proposed space reactor concepts, which include single- and two-phase alkali metal and gas-cooled designs. PNL has divided its activities for this task into three basic areas: computer code development, thermal-hydraulic modeling, and experimentation. The subject of this paper is the low-gravity experimental program currently underway at PNL in support of the MMW Program.
Date: June 1, 1987
Creator: Krotiuk, W.J. & Cuta, J.M.
Partner: UNT Libraries Government Documents Department

Fabric space radiators

Description: Future Air Force space missions will require thermal radiators that both survive in the hostile space environment and stow away for minimal bulk during launch. Advances in all aspects of radiator design, construction, and analysis will be necessary to enable such future missions. Currently, the best means for obtaining high strength along with flexibility is through structures known as fabrics. The development of new materials and bonding techniques has extended the application range of fabrics into areas traditionally dominated by monolithic and/or metallic structures. Given that even current spacecraft heat rejection considerations tend to dominate spacecraft design and mass, the larger and more complex designs of the future face daunting challenges in thermal control. Ceramic fabrics bonded to ultra-thin metal liners (foils) have the potential of achieving radiator performance levels heretofore unattainable, and of readily matching the advances made in other branches of spacecraft design. The research effort documented here indicates that both pumped loops and heat pipes constructed in ceramic fabrics stand to benefit in multiple ways. Flexibility and low mass are the main advantages exhibited by fabric radiators over conventional metal ones. We feel that fabric radiators have intrinsic merits not possessed by any other radiator design and need to be researched further. 26 refs., 16 figs., 17 tabs.
Date: January 1, 1988
Creator: Antoniak, Z.I.; Krotiuk, W.J.; Webb, B.J.; Prater, J.T. & Bates, J.M.
Partner: UNT Libraries Government Documents Department

Safety Analysis Report for Packaging (SARP) for USA/5790/BLF (DOE-AL) and USA/5791/BLF (DOE-AL)

Description: This revised Safety Analysis Report for Packaging (SARP) includes discussions of structural integrity, thermal resistance, radiation shielding and radiological safety, nuclear criticality safety, and quality control of shipping containers. Much of the information was previously submitted to AEC/OSD/ALO and the Department of Transportation (DOT) and provided the basis for obtaining special permits DOT-SP-5790 and DOT-SP-5791 as well as the Interim Certificates of Compliance until the original SARP could be prepared and Certificates of Compliance issued by ERDA. This SARP revision incorporates information on certain design changes, the most significant of which relate to the inner container for the type 5790 package. Complete physical and technical descriptions of the packages are presented. Each package consists of a cylindrical steel inner container centered within an insulating steel drum assembly. The contents may be any radioactive materials which satisfy the requirements established in this SARP. A shipment of plutonium-238 in the form of a solid oxide is evaluated in this SARP as an example. The results of the nuclear criticality safety analysis show how much of the fissile isotopes may be shipped as Fissile Class I, II, or III for each container. Design and development considerations, the tests and evaluations required to prove the ability of the containers to withstand normal transportation conditions, and the sequence of four hypothetical accident conditions (free drop, puncture, thermal, and water immersion) are discussed. Tables, graphs, dimensional sketches, photographs, technical references, loading and shipping procedures, Mound Facility experience in using the containers, and copies of the DOE Certificates of Compliance are included. Internal reviews of the original and revised SARP's have been performed in compliance with the requirement of DOEM 5201-Part V.
Date: January 25, 1980
Creator: Roome, L.G.; Watkins, R.A.; Bertram, R.E. & Kreider, H.B.
Partner: UNT Libraries Government Documents Department

Safety-analysis report for packaging (SARP) general-purpose heat-source module 750-Watt shipping container

Description: The SARP includes discussions of structural integrity, thermal resistance, radiation shielding and radiological safety, nuclear criticality safety, and quality control. Extensive tests and evaluations were performed to show that the container will function effectively with respect to all required standards and when subjected to normal transportation conditions and the sequence of four hypothetical accident conditions (free drop, puncture, thermal, and water immersion). In addition, a steady state temperature profile and radiation profile were measured using two heat sources that very closely resemble the GPHS. This gave an excellent representation of the GPHS temperature and radiation profile. A nuclear criticality safety analysis determined that all safety requirements are met.
Date: October 15, 1981
Creator: Whitney, M.A.; Burgan, C.E.; Blauvelt, R.K.; Zocher, R.W. & Bronisz, S.E.
Partner: UNT Libraries Government Documents Department

LPCVD tungsten deposition on Si-Ge alloy

Description: The Radioisotope Thermoelectric Generator (RTG) consists of a heat source, an 80/20 Si-Ge thermopile, MIN-K insulation, and a stainless steel container. The dc diode sputtered tungsten bridges interconnect alternate wafers in the thermopile. The diffusion of silicon into the tungsten interconnects appears to be the cause of a sudden increase in contact resistance after a period of time. The low pressure chemical vapor deposition (LPCVD) technique is compared with sputtering for this reason. LPCVD is found to be simpler than sputtering, self-cleaning, and not prone to damage the surface as does sputtering. Aging profiles are found to tend toward the high end of the acceptance window. (LEW)
Date: January 1, 1984
Creator: Rossmeisl, R.A.; Wells, V.A. & Walko, R.J.
Partner: UNT Libraries Government Documents Department

Advanced nuclear rocket engine mission analysis

Description: The use of a derivative of the NERVA engine developed from 1955 to 1973 was evluated for potential application to Air Force orbital transfer and maneuvering missions in the time period 1995 to 2020. The NERVA stge was found to have lower life cycle costs (LCC) than an advanced chemical stage for performing low earth orbit (LEO) to geosynchronous orbit (GEO0 missions at any level of activity greater than three missions per year. It had lower life cycle costs than a high performance nuclear electric engine at any level of LEO to GEO mission activity. An examination of all unmanned orbital transfer and maneuvering missions from the Space Transportation Architecture study (STAS 111-3) indicated a LCC advantage for the NERVA stage over the advanced chemical stage of fifteen million dollars. The cost advanced accured from both the orbital transfer and maneuvering missions. Parametric analyses showed that the specific impulse of the NERVA stage and the cost of delivering material to low earth orbit were the most significant factors in the LCC advantage over the chemical stage. Lower development costs and a higher thrust gave the NERVA engine an LCC advantage over the nuclear electric stage. An examination of technical data from the Rover/NERVA program indicated that development of the NERVA stage has a low technical risk, and the potential for high reliability and safe operation. The data indicated the NERVA engine had a great flexibility which would permit a single stage to perform all Air Force missions.
Date: December 1, 1987
Creator: Ramsthaler, J.; Farbman, G.; Sulmeisters, T.; Buden, D. & Harris, P.
Partner: UNT Libraries Government Documents Department

Cryogenic explosion environment modeling and testing of space shuttle and light-weight radioisotope heater unit interactions

Description: In order to assess the risk to the world's populace in the event of a Space Shuttle accident when radioisotope-containing heat sources are on board, testing of that system must be performed to determine release point, environments required, and the size distribution of the released fuel. To evaluate the performance of the Light-Weight Radioisotope Heater Unit (LWRHU) (101 of these 1-W items are placed on the Galileo spacecraft which will be launched from the Space Shuttle), some high-velocity impact and flyer plate testing was carried out. The results showed that a bare urania-fueled LWRHU clad (approximately 1-mm thick platinum-30 wt % rhodium alloy) will withstand 1100 m/s flyer plate (3.5-mm thick aluminum) impacts and 330 m/s impacts upon the Space Shuttle floor (approximately 12-mm thick aluminum) without rupture or fuel release. Velocities in the order of 600 m/s on a steel surface will cause clad failure with fuel release. The fuel breakup patterns were characterized as to quantity in a specific size range. These data were employed in the formal Safety Analysis Report for the LWRHU to support the planned 1986 Galileo launch. 19 figs.
Date: October 1, 1985
Creator: Johnson, E.W.
Partner: UNT Libraries Government Documents Department

Post remedial action survey report for Building 003, Santa Susana Field Laboratories, Rockwell International, Ventura County, California, October 1981; April 1982. Surplus Facilities Management Program

Description: Rockwell International's Santa Susana Laboratories in Ventura County, California, have been the site of numerous Federally-funded projects involving the use of radioactive materials. One such project was the System for Nuclear Auxiliary Power (SNAP) Program. Building 003 on the Santa Susana site was used in conjunction with the SNAP Program and contained a highly shielded area designed for remote manipulation of radioactive materials. Such facilities are commonly referred to as hot caves. During the SNAP Program, fuel burnup samples were analyzed and irradiation experiments were evaluated in the Building 003 hot cave. Use of the hot cave facility ended when the SNAP Program was terminated in 1973. Subsequently, the Building 003 facilities were declared excess and were decontaminaed and decommissioned during the first half of calendar year 1975. At that time, the building was given a preliminary release. In 1981, a post-remedial-action (certification) survey of Building 003 was conducted at the request of the Department of Energy. Significant levels of residual contamination were found in various parts of the building. Consequently, additional decontamination was conducted by Rockwell International. A final post-remedial-action survey was conducted during April 1982, and those areas in Building 003 that had been found contaminated in 1981 were now found to be free of detectable radioactive contamination. Sludge samples taken from the sewer sump showed elevated levels of enriched uranium contaminant. Hence, all sewer lines within Building 003 were removed. This permitted unconditional release of the building for unrestricted use. However, the sewer lines exterior to the building, which remain in place, must be considered potentially contaminated and, therefore, subject to restricted use.
Date: October 1, 1983
Creator: Wynveen, R.A.; Smith, W.H.; Sholeen, C.M.; Justus, A.L. & Flynn, K.F.
Partner: UNT Libraries Government Documents Department

Power plant system assessment. Final report. SP-100 Program

Description: The purpose of this assessment was to provide system-level insights into 100-kWe-class space reactor electric systems. Using these insights, Rockwell was to select and perform conceptual design studies on a ''most attractive'' system that met the preliminary design goals and requirements of the SP-100 Program. About 4 of the 6 months were used in the selection process. The remaining 2 months were used for the system conceptual design studies. Rockwell completed these studies at the end of FY 1983. This report summarizes the results of the power plant system assessment and describes our choice for the most attractive system - the Rockwell SR-100G System (Space Reactor, 100 kWe, Growth) - a lithium-cooled UN-fueled fast reactor/Brayton turboelectric converter system.
Date: October 31, 1983
Creator: Anderson, R.V.; Atkins, D.F.; Bost, D.S.; Berman, B.; Clinger, D.A.; Determan, W.R. et al.
Partner: UNT Libraries Government Documents Department

Small space reactor power systems for unmanned solar system exploration missions

Description: A preliminary feasibility study of the application of small nuclear reactor space power systems to the Mariner Mark II Cassini spacecraft/mission was conducted. The purpose of the study was to identify and assess the technology and performance issues associated with the reactor power system/spacecraft/mission integration. The Cassini mission was selected because study of the Saturn system was identified as a high priority outer planet exploration objective. Reactor power systems applied to this mission were evaluated for two different uses. First, a very small 1 kWe reactor power system was used as an RTG replacement for the nominal spacecraft mission science payload power requirements while still retaining the spacecraft's usual bipropellant chemical propulsion system. The second use of reactor power involved the additional replacement of the chemical propulsion system with a small reactor power system and an electric propulsion system. The study also provides an examination of potential applications for the additional power available for scientific data collection. The reactor power system characteristics utilized in the study were based on a parametric mass model that was developed specifically for these low power applications. The model was generated following a neutronic safety and operational feasibility assessment of six small reactor concepts solicited from U.S. industry. This assessment provided the validation of reactor safety for all mission phases and generatad the reactor mass and dimensional data needed for the system mass model.
Date: December 1, 1987
Creator: Bloomfield, H.S.
Partner: UNT Libraries Government Documents Department

SIMS study of compositional changes observed in a PuO/sub 2/ heat source cladding alloy

Description: Secondary ion mass spectrometry (SIMS) has been used to investigate changes that occur in an advanced Ir-0.3W alloy during high temperature aging. This alloy is used to clad /sup 238/PuO/sub 2/ heat sources used in thermoelectric generators for deep space reconnaissance satellites. Long-term direct contact with PuO/sub 2/ at 1400/sup 0/C leads to physical and chemical changes within the cladding alloy that affect its metallurgical properties. SIMS was used to show that Cr, Fe, Ni, and in some cases O, diffuse from the PuO/sub 2/ into the alloy. Thorium and aluminum diffuse out of the alloy in these same regions. This SIMS study suggests that inward O diffusion and subsequent formation of ThO/sub 2/ on grain boundaries may stabilize the alloy against enhanced grain growth.
Date: January 1, 1983
Creator: Christie, W.H.; Taylor, D.H.; Eby, R.E. & Pavone, D.
Partner: UNT Libraries Government Documents Department

Small reactor power systems for manned planetary surface bases

Description: A preliminary feasibility study of the potential application of small nuclear reactor space power systems to manned planetary surface base missions was conducted. The purpose of the study was to identify and assess the technology, performance, and safety issues associated with integration of reactor power systems with an evolutionary manned planetary surface exploration scenario. The requirements and characteristics of a variety of human-rated modular reactor power system configurations selected for a range of power levels from 25 kWe to hundreds of kilowatts is described. Trade-off analyses for reactor power systems utilizing both man-made and indigenous shielding materials are provided to examine performance, installation and operational safety feasibility issues. The results of this study have confirmed the preliminary feasibility of a wide variety of small reactor power plant configurations for growth oriented manned planetary surface exploration missions. The capability for power level growth with increasing manned presence, while maintaining safe radiation levels, was favorably assessed for nominal 25 to 100 kWe modular configurations. No feasibility limitations or technical barriers were identified and the use of both distance and indigenous planetary soil material for human rated radiation shielding were shown to be viable and attractive options.
Date: December 1, 1987
Creator: Bloomfield, H.S.
Partner: UNT Libraries Government Documents Department

Moisture content of PuO/sub 2/ fuel used for the milliwatt generator heat source

Description: The determination of the moisture content of /sup 238/Pu dioxide fuel for use in Milliwatt Generator heat sources was studied in an attempt to more clearly define the production fuel preloading procedures. The study indicated that water was not present or being adsorbed at various steps of the process (or during storage) that could lead to compatibility problems during pretreatment or long-term storage. The moisture content of the plutonium dioxide was analyzed by a commercial moisture analyzer. The moisture content at all steps of the process including storage averaged from 0.002% to 0.005%. The moisture content of the plutonium dioxide exposed to moist atmosphere for 7 days was 0.001%. These values indicated that no significant amount of moisture was adsorbed by the plutonium dioxide fuel charges. The only significant moisture content found was an average of 3.47%, after self-calcination. This was expected since no additional steps, other than self-heating of the fuel, are taken to remove the water.
Date: January 31, 1980
Creator: Zanotelli, W.A.
Partner: UNT Libraries Government Documents Department

Small propulsion reactor design based on particle bed reactor concept

Description: In this paper Particle Bed Reactor (PBR) designs are discussed which use /sup 233/U and /sup 242m/Am as fissile materials. A constant total power of 100MW is assumed for all reactors in this study. Three broad aspects of these reactors is discussed. First, possible reactor designs are developed, second physics calculations are outlined and discussed and third mass estimates of the various candidates reactors are made. It is concluded that reactors with a specific mass of 1 kg/MW can be envisioned of /sup 233/U is used and approximately a quarter of this value can be achieved if /sup 242m/Am is used. If this power level is increased by increasing the power density lower specific mass values are achievable. The limit will be determined by uncertainties in the thermal-hydraulic analysis. 5 refs., 5 figs., 6 tabs.
Date: January 1, 1989
Creator: Ludewig, H.; Lazareth, O.; Mughabghab, S.; Perkins, K. & Powell, J.R.
Partner: UNT Libraries Government Documents Department

Use of nuclear energy for bimodal applications in space

Description: The versatile bimodal nuclear reactor is proposed for producing space station-keeping power of 100's kW and also capable of bursts of power by ramping to 100's MW for short times to operate high power magnetic systems. The particle bed reactor, using half-millimeter diameter fuel particles immersed in coolant, provides the heat transfer capability needed for this power level. The coolant is a gas when directly coupled to a Brayton Cycle and is particularly responsive. The reactor design uses 37 fuel elements in a triangular pattern held in a cylindrical core. The reactor, radiator and turbo-generator are packaged for insertion into the shuttle cargo bay.
Date: January 1, 1986
Creator: Horn, F.L.; Powell, J.R. & Ludewig, H.
Partner: UNT Libraries Government Documents Department

Impact failure of MHW fuel sphere MHFT 65: report on interagency task force investigation and SRL evaluation of failure, November 1979-February 1980

Description: Following a safety verification impact test failure of a Multi-Hundred Watt (MHW) fuel sphere made at Savannah River Plant, from which 2.1 g of /sup 238/PuO/sub 2/ escaped containment, the Department of Energy organized a task force to investigate the cause of the test failure and to assess the failure probability of MHW fuel made at SRP. The task force described a two-part failure mechanism: embrittlement of the iridium containment shell by phosphorus which may have been picked up from the fuel; and large shear strains in the iridium caused by shearing or push-through of large chunks of fuel. Because the likelihood of push-through in this failure model depends on preexisting cracks in the fuel and their orientation to the impact face, the probability of further impact failures could not be easily assessed. From independent analysis of the available data at the Savannah River Laboratory, we concluded that the impact failure was caused by phosphorus embrittlement of the iridium, and breaching during impact of the graphite impact shell surrounding and cushioning the iridium-clad fuel. Excessive strain in the iridium is caused by extrusion of the iridium into the breach. This model predicts that impact failure is essentially independent of pre-existing cracks in the fuel and that SRP fuel, upon impact, should have no more failures than previously used fuel made at Mound Facility. Impact data to date indicate that SRP fuel clad in DOP-26 iridium cladding actually has fewer impact failures than earlier fuel clad in undoped iridium at MF.
Date: June 1, 1981
Creator: Taylor, D.H.
Partner: UNT Libraries Government Documents Department