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Nuclear heat sources for cryogenic refrigerator applications

Description: Spacecraft cryogenic refrigerators require thermal inputs on the order of 1000 W. First, the characteristics of solar-electric and radioisotope heat source systems for supplying this thermal input are compared. Then the design of a $sup 238$Pu heat source for this application is described, and equipment for shipping and handling the heat source is discussed. (LCL)
Date: June 1, 1975
Creator: Raab, B.; Schock, A.; King, W.G.; Kline, T. & Russo, F.A.
Partner: UNT Libraries Government Documents Department

Nuclear Rocket Facility Decommissioning Project: Controlled Explosive Demolition of Neutron-Activated Shield Wall

Description: Located in Area 25 of the Nevada Test Site (NTS), the Test Cell A (TCA) Facility (Figure 1) was used in the early to mid-1960s for testing of nuclear rocket engines, as part of the Nuclear Rocket Development Program, to further space travel. Nuclear rocket testing resulted in the activation of materials around the reactors and the release of fission products and fuel particles. The TCA facility, known as Corrective Action Unit 115, was decontaminated and decommissioned (D&D) from December 2004 to July 2005 using the Streamlined Approach for Environmental Restoration (SAFER) process, under the Federal Facility Agreement and Consent Order. The SAFER process allows environmental remediation and facility closure activities (i.e., decommissioning) to occur simultaneously, provided technical decisions are made by an experienced decision maker within the site conceptual site model. Facility closure involved a seven-step decommissioning strategy. First, preliminary investigation activities were performed, including review of process knowledge documentation, targeted facility radiological and hazardous material surveys, concrete core drilling and analysis, shield wall radiological characterization, and discrete sampling, which proved to be very useful and cost-effective in subsequent decommissioning planning and execution and worker safety. Second, site setup and mobilization of equipment and personnel were completed. Third, early removal of hazardous materials, including asbestos, lead, cadmium, and oil, was performed ensuring worker safety during more invasive demolition activities. Process piping was to be verified void of contents. Electrical systems were de-energized and other systems were rendered free of residual energy. Fourth, areas of high radiological contamination were decontaminated using multiple methods. Contamination levels varied across the facility. Fixed beta/gamma contamination levels ranged up to 2 million disintegrations per minute (dpm)/100 centimeters squared (cm2) beta/gamma. Removable beta/gamma contamination levels seldom exceeded 1,000 dpm/100 cm2, but, in railroad trenches on the reactor pad containing soil on the concrete pad in ...
Date: June 1, 2008
Creator: Kruzic, Michael R.
Partner: UNT Libraries Government Documents Department

High Temperature Integrated Thermoelectric System and Materials

Description: The final goal of this project is to produce, by the end of Phase II, an all ceramic high temperature thermoelectric module. Such a module design integrates oxide ceramic n-type, oxide ceramic p-type materials as thermoelectric legs and oxide ceramic conductive material as metalizing connection between n-type and p-type legs. The benefits of this all ceramic module are that it can function at higher temperatures (> 700 C), it is mechanically and functionally more reliable and it can be scaled up to production at lower cost. With this all ceramic module, millions of dollars in savings or in new opportunities recovering waste heat from high temperature processes could be made available. A very attractive application will be to convert exhaust heat from a vehicle to reusable electric energy by a thermoelectric generator (TEG). Phase I activities were focused on evaluating potential n-type and p-type oxide compositions as the thermoelectric legs. More than 40 oxide ceramic powder compositions were made and studied in the laboratory. The compositions were divided into 6 groups representing different material systems. Basic ceramic properties and thermoelectric properties of discs sintered from these powders were measured. Powders with different particles sizes were made to evaluate the effects of particle size reduction on thermoelectric properties. Several powders were submitted to a leading thermoelectric company for complete thermoelectric evaluation. Initial evaluation showed that when samples were sintered by conventional method, they had reasonable values of Seebeck coefficient but very low values of electrical conductivity. Therefore, their power factors (PF) and figure of merits (ZT) were too low to be useful for high temperature thermoelectric applications. An unconventional sintering method, Spark Plasma Sintering (SPS) was determined to produce better thermoelectric properties. Particle size reduction of powders also was found to have some positive benefits. Two composition systems, specifically 1.0 SrO ...
Date: June 6, 2011
Creator: Chu, Mike S. H.
Partner: UNT Libraries Government Documents Department

A Summary Review of Mound Laboratory's Experience in D & D of Radioactive Facilities 1949-1973

Description: The objective of Mound Laboratory's Decontamination and Decommissioning (D&D) projects has been the effective termination of radioactive material processing facilities with no significant personnel exposures or environmental releases. This objective must be met with available resources and manpower. Mound has effectively decontaminated and/or decommissioned four major facilities in the 1949 through 1973 time period. Many minor areas were also decontaminated and/or decommissioned during this period. The major D & D projects involved the following isotopes: polonium-210, radium-226, actinium-227, and plutonium-238. To achieve a D & D status, Mound has employed several control and decontamination techniques such as: "Navy Cocooning", entombment, removal, foaming, bagging, tents, chutes, portable exhausters, dry ice, vents, bubble suits, three-zones, fire watches, painting and sealing, in-line cleaning, high pressure water blaster, and chemical cleaning.
Date: June 1, 1974
Creator: Garner, J. M. & Davis, W. P.
Partner: UNT Libraries Government Documents Department