Download or read book Radiation Properties of sup 238 Pu Produced for Isotopic Power Generators written by and published by . This book was released on 1965 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Preparation and Development of Medical grade Plutonium 238 Fuels written by and published by . This book was released on 1972 with total page 92 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Studies of Plutonium 238 Production at the High Flux Isotope Reactor written by and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory (ORNL) is a versatile 85 MW{sub th}, pressurized, light water-cooled and -moderated research reactor. The core consists of two fuel elements, an inner fuel element (IFE) and an outer fuel element (OFE), each constructed of involute fuel plates containing high-enriched-uranium (HEU) fuel (H"3 wt% 235U/U) in the form of U3O in an Al matrix and encapsulated in Al-6061 clad. An over-moderated flux trap is located in the center of the core, a large beryllium reflector is located on the outside of the core, and two control elements (CE) are located between the fuel and the reflector. The flux trap and reflector house numerous experimental facilities which are used for isotope production, material irradiation, and cold/thermal neutron scattering. Over the past five decades, the US Department of Energy (DOE) and its agencies have been producing radioisotope power systems used by the National Aeronautics and Space Administration (NASA) for unmanned, long-term space exploration missions. Plutonium-238 is used to power Radioisotope Thermoelectric Generators (RTG) because it has a very long half-life (t12 H"89 yr.) and it generates about 0.5 watts/gram when it decays via alpha emission. Due to the recent shortage and uncertainty of future production, the DOE has proposed a plan to the US Congress to produce 238Pu by irradiating 237Np as early as in fiscal year 2011. An annual production rate of 1.5 to 2.0 kg of 238Pu is expected to satisfy these needs and could be produced in existing national nuclear facilities like HFIR and the Advanced Test Reactor (ATR) at the Idaho National Laboratory (INL). Reactors at the Savannah River Site were used in the past for 238Pu production but were shut down after the last production in 1988. The nation's 237Np inventory is currently stored at INL. A plan for producing 238Pu at US research reactor facilities such as the High Flux Isotope Reactor at ORNL has been initiated by the US DOE and NASA for space exploration needs. Two Monte Carlo-based depletion codes, TRITON (ORNL) and VESTA (IRSN), were used to study the 238Pu production rates with varying target configurations in a typical HFIR fuel cycle. Preliminary studies have shown that approximately 11 grams and within 15 to 17 grams of 238Pu could be produced in the first irradiation cycle in one small and one large VXF facility, respectively, when irradiating fresh target arrays as those herein described. Important to note is that in this study we discovered that small differences in assumptions could affect the production rates of Pu-238 observed. The exact flux at a specific target location can have a significant impact upon production, so any differences in how the control elements are modeled as a function of exposure, will also cause differences in production rates. In fact, the surface plot of the large VXF target Pu-238 production shown in Figure 3 illustrates that the pins closest to the core can potentially have production rates as high as 3 times those of pins away from the core, thus implying that a cycle-to-cycle rotation of the targets may be well advised. A methodology for generating spatially-dependent, multi-group self-shielded cross sections and flux files with the KENO and CENTRM codes has been created so that standalone ORIGEN-S inputs can be quickly constructed to perform a variety of 238Pu production scenarios, i.e. combinations of the number of arrays loaded and the number of irradiation cycles. The studies herein shown with VESTA and TRITON/KENO will be used to benchmark the standalone ORIGEN.
Download or read book Properties and Behavior of 238PU Relevant to Decontamination of Building 235 F written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This report was prepared to document the physical, chemical and radiological properties of plutonium oxide materials that were processed in the Plutonium Fuel Form Facility (PuFF) in building 235-F at the Savannah River Plant (now known as the Savannah River Site) in the late 1970s and early 1980s. An understanding of these properties is needed to support current project planning for the safe and effective decontamination and deactivation (D & D) of PuFF. The PuFF mission was production of heat sources to power Radioisotope Thermoelectric Generators (RTGs) used in space craft. The specification for the PuO2 used to fabricate the heat sources required that the isotopic content of the plutonium be 83 ± 1% Pu-238 due to its high decay heat of 0.57 W/g. The high specific activity of Pu-238 (17.1 Ci/g) due to alpha decay makes this material very difficult to manage. The production process produced micron-sized particles which proved difficult to contain during operations, creating personnel contamination concerns and resulting in the expenditure of significant resources to decontaminate spaces after loss of material containment. This report examines high 238Pu-content material properties relevant to the D & D of PuFF. These relevant properties are those that contribute to the mobility of the material. Physical properties which produce or maintain small particle size work to increase particle mobility. Early workers with 238PuO2 felt that, unlike most small particles, Pu-238 oxide particles would not naturally agglomerate to form larger, less mobile particles. It was thought that the heat generated by the particles would prevent water molecules from binding to the particle surface. Particles covered with bound water tend to agglomerate more easily. However, it is now understood that the self-heating effect is not sufficient to prevent adsorption of water on particle surfaces and thus would not prevent agglomeration of particles. Operational experience at PuFF indicates that the Pu-238 contamination was observed to move along surfaces and through High Efficiency Particulate Air (HEPA) filters over time. Recent research into the phenomenon known as alpha recoil offers a potential explanation for this observed behavior. Momentum is conserved when an alpha particle is ejected from a Pu-238 atom due to radioactive decay. Consequently, the entire particle of which that Pu-238 atom is a constituent experiences a movement similar to the recoil of a gun when a bullet is ejected. Furthermore, the particle often fractures in response to Pu-238 atom disintegration (yielding an alpha particle), with a small particle fragment also being ejected in order to conserve momentum. This process results in the continuous size reduction and transport of particles containing Pu-238 atoms, thus explaining movement of contamination along surfaces and through HEPA filters. A better understanding of the thermal behavior of 238PuO2 particles is needed to inform the planning process for the PuFF D & D project at the 235-F facility. There has been a concern that the surface temperature of individual particles may be high enough to cause problems with decontamination equipment and materials as a result of heat generation due to radioactive decay. A calculation under conservative assumptions shows that the surface temperature of particles less than about 100 [mu]m diameter is not appreciably above ambient. Since most particles in PuFF are on order of 1 [mu]m in diameter, the effect of particle surface temperature on decontamination equipment and materials is expected to be minimal. The result of this calculation also indicates that thermal imaging, which has been under consideration as a method to monitor the progress of system decontamination efforts would not likely be effective. The use of strippable coating was suggested as a possible alternative to other decontamination techniques. One particular system (i.e., Decon Gel 1101) may offer significant advantages over conventional liquid decontamination solutions. Previous trials are discussed and have been used successfully at SRS on various surfaces. Some areas showed minimal improvement, while others presented complete (100%) decontamination. However, small scale testing is recommended prior to the full scale use in the cells of PuFF in building 235-F.
Download or read book Nuclear Science Abstracts written by and published by . This book was released on 1976-04 with total page 912 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Economical Production of Pu 238 written by and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: All space exploration missions traveling beyond Jupiter must use radioisotopic power sources for electrical power. The best isotope to power these sources is plutonium-238. The US supply of Pu-238 is almost exhausted and will be gone within the next decade. The Department of Energy has initiated a production program with a $10M allocation from NASA but the cost is estimated at over $100 M to get to production levels. The Center for Space Nuclear Research has conceived of a potentially better process to produce Pu-238 earlier and for significantly less cost. The new process will also produce dramatically less waste. Potentially, the front end costs could be provided by private industry such that the government only had to pay for the product produced. Under a NASA Phase I NIAC grant, the CSNR has evaluated the feasibility of using a low power, commercially available nuclear reactor to produce at least 1.5 kg of Pu-238 per year. The impact on the neutronics of the reactor have been assessed, the amount of Neptunium target material estimated, and the production rates calculated. In addition, the size of the post-irradiation processing facility has been established. In addition, a new method for fabricating the Pu-238 product into the form used for power sources has been identified to reduce the cost of the final product. In short, the concept appears to be viable, can produce the amount of Pu-238 needed to support the NASA missions, can be available within a few years, and will cost significantly less than the current DOE program.
Download or read book Neptunium 237 Production and Recovery written by Wallace W. Schulz and published by . This book was released on 1972 with total page 100 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1971 with total page 284 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Energy Research Abstracts written by and published by . This book was released on 1984 with total page 1430 pages. Available in PDF, EPUB and Kindle. Book excerpt: Semiannual, with semiannual and annual indexes. References to all scientific and technical literature coming from DOE, its laboratories, energy centers, and contractors. Includes all works deriving from DOE, other related government-sponsored information, and foreign nonnuclear information. Arranged under 39 categories, e.g., Biomedical sciences, basic studies; Biomedical sciences, applied studies; Health and safety; and Fusion energy. Entry gives bibliographical information and abstract. Corporate, author, subject, report number indexes.
Download or read book Radioisotope Power Systems written by National Research Council and published by National Academies Press. This book was released on 2009-08-14 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt: Spacecraft require electrical energy. This energy must be available in the outer reaches of the solar system where sunlight is very faint. It must be available through lunar nights that last for 14 days, through long periods of dark and cold at the higher latitudes on Mars, and in high-radiation fields such as those around Jupiter. Radioisotope power systems (RPSs) are the only available power source that can operate unconstrained in these environments for the long periods of time needed to accomplish many missions, and plutonium-238 (238Pu) is the only practical isotope for fueling them. Plutonium-238 does not occur in nature. The committee does not believe that there is any additional 238Pu (or any operational 238Pu production facilities) available anywhere in the world.The total amount of 238Pu available for NASA is fixed, and essentially all of it is already dedicated to support several pending missions-the Mars Science Laboratory, Discovery 12, the Outer Planets Flagship 1 (OPF 1), and (perhaps) a small number of additional missions with a very small demand for 238Pu. If the status quo persists, the United States will not be able to provide RPSs for any subsequent missions.
Download or read book Government Reports Annual Index written by and published by . This book was released on 1992 with total page 1120 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book ERDA Energy Research Abstracts written by United States. Energy Research and Development Administration and published by . This book was released on 1976 with total page 988 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Isotopes and Radiation Technology written by and published by . This book was released on 1969 with total page 1024 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Government wide Index to Federal Research Development Reports written by and published by . This book was released on 1966 with total page 1058 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Monitoring Nuclear Weapons and Nuclear Explosive Materials written by National Research Council and published by National Academies Press. This book was released on 2005-04-15 with total page 266 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this study, CISAC tackles the technical dimensions of a longstanding controversy: To what extent could existing and plausibly attainable measures for transparency and monitoring make possible the verification of all nuclear weaponsâ€"strategic and nonstrategic, deployed and nondeployedâ€"plus the nuclear-explosive components and materials that are their essential ingredients? The committee's assessment of the technical and organizational possibilities suggests a more optimistic conclusion than most of those concerned with these issues might have expected.
Download or read book Management and Disposition of Excess Weapons Plutonium written by National Academy of Sciences and published by National Academies Press. This book was released on 1995-08-06 with total page 432 pages. Available in PDF, EPUB and Kindle. Book excerpt: Within the next decade, many thousands of U.S. and Russian nuclear weapons are slated to be retired as a result of nuclear arms reduction treaties and unilateral pledges. Hundreds of tons of plutonium and highly enriched uranium will no longer be needed for weapons purposes and will pose urgent challenges to international security. This is the supporting volume to a study by the Committee on International Security and Arms Control which dealt with all phases of the management and disposition of these materials. This technical study concentrates on the option for the disposition of plutonium, looking in detail at the different types of reactors in which weapons plutonium could be burned and at the vitrification of plutonium, and comparing them using economic, security and environmental criteria.
Download or read book Government wide Index to Federal Research Development Reports written by and published by . This book was released on 1966 with total page 980 pages. Available in PDF, EPUB and Kindle. Book excerpt:
