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Description: Plutonium-238 is used in Radioisotope Thermoelectric Generators (RTGs) to generate electrical power and in Radioisotope Heater Units (RHUs) to produce heat for electronics and environmental control for deep space missions. The domestic supply of Pu-238 consists of scrap material from previous mission production or material purchased from Russia. Currently, the United States has no significant production scale operational capability to produce and separate new Pu-238 from irradiated neptunium-237 targets. The Department of Energy - Nuclear Energy is currently evaluating and developing plans to reconstitute the United States capability to produce Pu-238 from irradiated Np-237 targets. The Savannah River Site had previously produced and/or processed all the Pu-238 utilized in Radioisotope Thermoelectric Generators (RTGs) for deep space missions up to and including the majority of the plutonium for the Cassini Mission. The previous full production cycle capabilities included: Np-237 target fabrication, target irradiation, target dissolution and Np-237 and Pu-238 separation and purification, conversion of Np-237 and Pu-238 to oxide, scrap recovery, and Pu-238 encapsulation. The capability and equipment still exist and could be revitalized or put back into service to recover and purify Pu-238/Np-237 or broken General Purpose Heat Source (GPHS) pellets utilizing existing process equipment in HB-Line Scrap Recovery, and H-anyon Frame Waste Recovery processes. The conversion of Np-237 and Pu-238 to oxide can be performed in the existing HB-Line Phase-2 and Phase-3 Processes. Dissolution of irradiated Np-237 target material, and separation and purification of Np-237 and Pu-238 product streams would be possible at production rates of ~ 2 kg/month of Pu-238 if the existing H-Canyon Frames Process spare equipment were re-installed. Previously, the primary H-Canyon Frames equipment was removed to be replaced: however, the replacement project was stopped. The spare equipment is stored and still available for installation. Out of specification Pu-238 scrap material can be purified and recovered ...
Date: January 9, 2013
Creator: Fuller, K.; Smith, Robert H. Jr. & Goergen, Charles R.
Partner: UNT Libraries Government Documents Department

SNAP 29 power supply system. Ninth quarterly progress report

Description: Progress during the period from Oct. through December 1968 in the development of the SNAP 29 battery, a radioisotope-fueled thermoelectric generator (RTG) system for spacecraft power supplies, is reported. Information is included on: fabrication and testing of RTG components; systems evaluation and integration; reliability analysis and prediction; reentry trajectory and heating rates for various burn-up element configurations; and system safety evaluation. (LCL)
Date: January 1, 1969
Partner: UNT Libraries Government Documents Department

Interaction of $sup 238$PuO$sub 2$ heat sources with terrestrial and aquatic environments

Description: Radioisotope thermoelectric generators used in space missions are designed with a great factor of safety to ensure that they will withstand reentry from orbit and impact with the earth, and safely contain the nuclear fuel until it is recovered. Existing designs, utilizing $sup 238$PuO$sub 2$ fuel, have proved more than adequately safe. More data about the interaction of this material with terrestrial and aquatic environments is continually being sought to predict the behavior of these heat sources in the extremely unlikely contact of these materials with the land or ocean. Terrestrial environments are simulated with large environmental chambers that permit control of temperature, humidity, and rainfall using different kinds of soils. Rain falling on thermally hot chunks of $sup 238$PuO$sub 2$ causes the spallation of the surface of the fuel into extremely fine particles, as small as 50 nm, that are later transported downward through the soil. Some of the plutonia particles become agglomerated with soil particles. Plutonium transport is more significant during winter than during summer because evaporation losses from the soil are less in winter. Aquatic environments are simulated with large aquaria that provide temperature and aeration control. Earlier fuel designs that employed a plutonia-molybdenum cermet showed plutonium release rates of about 10 $mu$Ci/m$sup 2$ - s, referred to the total surface area of the cermet. Present advanced fuels, employing pure plutonium oxide, show release rates of about 20 nCi/m$sup 2$ - s in seawater and about 150 nCi/m$sup 2$ - s in freshwater. The temperature of these more advanced heat sources does not seem to affect the release rate in seawater. (auth)
Date: January 1, 1975
Creator: Patterson, J.H.; Nelson, G.B.; Matlack, G.M. & Waterbury, G.R.
Partner: UNT Libraries Government Documents Department

Direct conversion of nuclear radiation energy

Description: This book presents a comprehensive study of methods for converting nuclear radiationi directly without resorting to a heat cycle. The concepts discussed primarily involve direct collection of charged particles released by radioisotopes and by nuclear and thermonuclear reactors. Areas considered include basic energy conversion, charged-particle transport theory, secondary-electron emission, and leakage currents and associated problems. Applications to both nuclear instrumentaion and power sources are discussed. Problems are also included as an aid to the reader or for classroom use.
Date: January 1, 1970
Creator: Miley, George H.
Partner: UNT Libraries Government Documents Department


Description: Current-voltage characteristics of a cesium-on-tantalum thermionic converter with a collector temperature comparable to that of the emitter were obtained for a variety of electrode temperatures and cesium vapor pressures. The results show that for emitter temperatures in excess of 2000 deg K, power outputs of a few watts per square centimeter can be obtained when the ratio of collector temperature to emitter temperature is as high as 0.75 to 0.80, which is the required range for best performance of a radiation-cooled Carnot engine, and that at temperature ratios above 0.80 the power output is insensitive to changes in electrode spacing for ratios of spacing to electron mean free path greater than 100 at a cesium vapor pressure of 5 torr. (auth)
Date: January 15, 1963
Creator: Blue, E. & Ingold, J.H.
Partner: UNT Libraries Government Documents Department