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 Thermal Safety Analyses for the Production of Plutonium 238 at the High Flux Isotope Reactor written by and published by . This book was released on 2016 with total page 104 pages. Available in PDF, EPUB and Kindle. Book excerpt: There has been a considerable effort over the previous few years to demonstrate and optimize the production of plutonium-238 (238Pu) at the High Flux Isotope Reactor (HFIR). This effort has involved resources from multiple divisions and facilities at the Oak Ridge National Laboratory (ORNL) to demonstrate the fabrication, irradiation, and chemical processing of targets containing neptunium-237 (237Np) dioxide (NpO2)/aluminum (Al) cermet pellets. A critical preliminary step to irradiation at the HFIR is to demonstrate the safety of the target under irradiation via documented experiment safety analyses. The steady-state thermal safety analyses of the target are simulated in a finite element model with the COMSOL Multiphysics code that determines, among other crucial parameters, the limiting maximum temperature in the target. Safety analysis efforts for this model discussed in the present report include: (1) initial modeling of single and reduced-length pellet capsules in order to generate an experimental knowledge base that incorporate initial non-linear contact heat transfer and fission gas equations, (2) modeling efforts for prototypical designs of partially loaded and fully loaded targets using limited available knowledge of fabrication and irradiation characteristics, and (3) the most recent and comprehensive modeling effort of a fully coupled thermo-mechanical approach over the entire fully loaded target domain incorporating burn-up dependent irradiation behavior and measured target and pellet properties, hereafter referred to as the production model. These models are used to conservatively determine several important steady-state parameters including target stresses and temperatures, the limiting condition of which is the maximum temperature with respect to the melting point. The single pellet model results provide a basis for the safety of the irradiations, followed by parametric analyses in the initial prototypical designs that were necessary due to the limiting fabrication and irradiation data available. The calculated parameters in the final production target model are the most accurate and comprehensive, while still conservative. Over 210 permutations in irradiation time and position were evaluated, and are supported by the most recent inputs and highest fidelity methodology. The results of these analyses show that the models presented in this report provide a robust and reliable basis for previous, current and future experiment safety analyses. In addition, they reveal an evolving knowledge of the steady-state behavior of the NpO2/Al pellets under irradiation for a variety of target encapsulations and potential conditions.
Download or read book Design and Nuclear Safety Related Simulations of Bare Pellet Test Irradiations for the Production of Pu 238 in the High Flux Isotope Reactor Using COMSOL written by and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The Oak Ridge National Laboratory (ORNL)is developing technology to produce plutonium-238 for the National Aeronautics and Space Administration (NASA) as a power source material for powering vehicles while in deep-space[1]. The High Flux Isotope Reactor (HFIR) of ORNL has been utilized to perform test irradiations of incapsulated neptunium oxide (NpO2) and aluminum powder bare pellets for purposes of understanding the performance of the pellets during irradiation[2]. Post irradiation examinations (PIE) are currently underway to assess the effect of temperature, thermal expansion, swelling due to gas production, fission products, and other phenomena.
Download or read book Summary of Plutonium 238 Production Alternatives Analysis Final Report written by and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The Team implemented a two-phase evaluation process. During the first phase, a wide variety of past and new candidate facilities and processing methods were assessed against the criteria established by DOE for this assessment. Any system or system element selected for consideration as an alternative within the project to reestablish domestic production of Pu-238 must meet the following minimum criteria: Any required source material must be readily available in the United States, without requiring the development of reprocessing technologies or investments in systems to separate material from identified sources. It must be cost, schedule, and risk competitive with existing baseline technology. Any identified facilities required to support the concept must be available to the program for the entire project life cycle (notionally 35 years, unless the concept is so novel as to require a shorter duration). It must present a solution that can generate at least 1.5 Kg of Pu-238 oxide per year, for at least 35 years. It must present a low-risk, near-term solution to the National Aeronautics and Space Administration's urgent mission need. DOE has implemented this requirement by eliminating from project consideration any alternative with key technologies at less than Technology Readiness Level 5. The Team evaluated the options meeting these criteria using a more detailed assessment of the reasonable facility variations and compared them to the preferred option, which consists of target irradiation at the Advanced Test Reactor (ATR) and the High Flux Isotope Reactor (HFIR), target fabrication and chemical separations processing at the ORNL Radiochemical Engineering Development Center, and neptunium 237 storage at the Materials and Fuels Complex at INL. This preferred option is consistent with the Records of Decision from the earlier National Environmental Policy Act (NEPA) documentation.
Download or read book Deterministic Neutron Transport and Multiphysics Experimental Safety Analyses at the High Flux Isotope Reactor written by Christopher James Hurt and published by . This book was released on 2016 with total page 222 pages. Available in PDF, EPUB and Kindle. Book excerpt: The computational ability to accurately predict the conditions in an experiment under irradiation is a valuable tool in the operation of a research reactor whose scientific mission includes isotope production, materials irradiation, and neutron activation analysis. Understanding of different governing physics is required to ascertain satisfactory conditions within the experiment: the neutron transport behavior throughout the reactor and the coupled behavior of heat transfer, structural mechanics and fluid flow. Computational methods and tools were developed for robust numerical analysis of experiment behavior at the Oak Ridge National Laboratory (ORNL) High Flux Isotope Reactor (HFIR), including fully-coupled thermo-mechanics in three plutonium-238 (238Pu) production targets. In addition, a new computational tool was developed that solves neutron transport using the discrete ordinates method on a finite element mesh and offers multiphysics coupling. The thermo-mechanical models of the 238Pu targets are solved using the COMSOL heat transfer and solid mechanics modules with irradiation behavior and thermophysical properties taken from measurements performed at ORNL. The experiments, placed in the permanent beryllium (PB) reflector, consist of neptunium dioxide/aluminum (NpO2/Al) pellets in Al containment, the model taking advantage of axisymmetry in two-dimensional R-Z cylindrical geometry. At times, extended analysis was needed for incomplete data sets and time schedules; however, the thermal-structure models ensured progression through three project phases of target qualification. The neutron transport equation was solved in COMSOL, using the discrete ordinates formulation in the weak form partial differential equation (PDE) interface. Validation studies were performed for the dimensions developed (one-, two- and three- dimensional Cartesian as well as two-dimensional R-Z cylindrical/axi-symmetric) and compared to external deterministic and stochastic codes. The method was then applied to a beginning-of-cycle (BOC) simplified HFIR core, with good comparison to other static solutions of the HFIR, and a time-dependent extension to this tool was created and exhibited for a benchmark problem. The research presented in this dissertation is the continued progress towards creating a comprehensive multiphysics methodology for studying the dynamic behavior of the HFIR core, and shows the capabilities of detailed space-time reactor physics studies and of multiphysics analyses for experiment qualification and safety analyses at a research reactor.
Download or read book Programmatic EIS for Accomplishing Expanded Civilian Nuclear Energy Research and Development and Isotope Production Missions in the United States Including the Role of the Fast Flux Test Facility written by and published by . This book was released on 2000 with total page 470 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 Plutonium 238 Production in Commercial Water Reactors Experimental and Analytical Program written by Kenneth E. Roach and published by . This book was released on 1974 with total page 126 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Improving the Scientific Basis for Managing DOE s Excess Nuclear Materials and Spent Nuclear Fuel written by National Research Council and published by National Academies Press. This book was released on 2003-06-09 with total page 124 pages. Available in PDF, EPUB and Kindle. Book excerpt: The production of nuclear materials for the national defense was an intense, nationwide effort that began with the Manhattan Project and continued throughout the Cold War. Now many of these product materials, by-products, and precursors, such as irradiated nuclear fuels and targets, have been declared as excess by the Department of Energy (DOE). Most of this excess inventory has been, or will be, turned over to DOE's Office of Environmental Management (EM), which is responsible for cleaning up the former production sites. Recognizing the scientific and technical challenges facing EM, Congress in 1995 established the EM Science Program (EMSP) to develop and fund directed, long-term research that could substantially enhance the knowledge base available for new cleanup technologies and decision making. The EMSP has previously asked the National Academies' National Research Council for advice for developing research agendas in subsurface contamination, facility deactivation and decommissioning, high-level waste, and mixed and transuranic waste. For this study the committee was tasked to provide recommendations for a research agenda to improve the scientific basis for DOE's management of its high-cost, high-volume, or high-risk excess nuclear materials and spent nuclear fuels. To address its task, the committee focused its attention on DOE's excess plutonium-239, spent nuclear fuels, cesium-137 and strontium-90 capsules, depleted uranium, and higher actinide isotopes.
Download or read book Hearings Reports and Prints of the Joint Committee on Atomic Energy written by United States. Congress. Joint Committee on Atomic Energy and published by . This book was released on 1966 with total page 1822 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Nuclear Batteries and Radioisotopes written by Mark Prelas and published by Springer. This book was released on 2016-08-04 with total page 363 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book explains the physics of nuclear battery operation. It provides a comprehensive background that allows readers to understand all past and future developments in the field. The supply and cost of radioisotopes for use in applications (focused on nuclear batteries) are covered in the initial sections of the text. The interaction of ionizing radiation with matter is discussed as applied to nuclear batteries. The physics of interfacing the radioisotopes to the transducers which represent the energy conversion mechanism for nuclear batteries are described for possible nuclear battery configurations. Last but not least the efficiencies of nuclear battery configurations are discussed combined with a review of the literature on nuclear battery research.
Download or read book AEC Authorizing Legislation written by United States. Congress. Joint Committee on Atomic Energy and published by . This book was released on 1969 with total page 866 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Production Test IP 805 Irradiation of Neptunium Target Elements written by and published by . This book was released on 1965 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: A sustained demand for large quantities of plutonium 238, a heat generating isotope, formed by irradiation of neptunium 237, is anticipated over the next ten to fifteen years. Plutonium 238 is thus a natural candidate as an alternate product for production reactors. Detailed studies have been completed outlining the advantages and incentives of producing plutonium 238 at Hanford. A primary conclusion of these studies is that more efficient production is possible in Hanford's relatively low neutron fluxes. Under irradiation neptunium 237 captures a neutron, then decays to plutonium 238 by beta emission. The intermediate product, neptunium 238 has a high capture cross section; therefore in a low flux field a greater proportion decays to the desired product. More efficient utilization is an important advantage since the amount of plutonium 238 that can be produced is limited by the availability of target neptunium. The referenced studies and conclusions drawn therefrom are based entirely on analytical calculations. Experimental data are needed to confirm the calculations and demonstrate Hanford's capability. The objective of this production test is to obtain experimental data on plutonium 238 production in Hanford reactors.
Download or read book Hearings and Reports on Atomic Energy written by United States. Congress. Joint Committee on Atomic Energy and published by . This book was released on 1946 with total page 1112 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Proposed Consolidation of Nuclear Operations Related to Production of Radioisotope Power Systems written by and published by . This book was released on 2005 with total page 542 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 1988 with total page 1224 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 1976 with total page 724 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.
