The Experts below are selected from a list of 79371 Experts worldwide ranked by ideXlab platform
Rodney C. Ewing - One of the best experts on this subject based on the ideXlab platform.
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Long-term storage of spent Nuclear Fuel
Nature Materials, 2015Co-Authors: Rodney C. EwingAbstract:To design reliable and safe geological repositories it is critical to understand how the characteristics of spent Nuclear Fuel evolve with time, and how this affects the storage environment.
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THE Nuclear Fuel CYCLE versus THE CARBON CYCLE
2015Co-Authors: Rodney C. EwingAbstract:Nuclear power provides approximately 17 % of the world’s electricity, which is equivalent to a reduction in carbon emissions of ~0.5 gigatonnes (Gt) of C/yr. This is a modest reduction as compared with global emissions of carbon, ~7 Gt C/yr. Most analyses suggest that in order to have a signifi cant and timely impact on carbon emissions, carbon-free sources, such as Nuclear power, would have to expand total production of energy by factors of three to ten by 2050. A three-fold increase in Nuclear power capacity would result in a projected reduction in carbon emissions of 1 to 2 Gt C/yr, depending on the type of carbon-based energy source that is displaced. This three-fold increase utilizing present Nuclear technologies would result in 25,000 metric tonnes (t) of spent Nuclear Fuel (SNF) per year, containing over 200 t of plutonium. This is compared to a present global inventory of approxi-mately 280,000 t of SNF and>1,700 t of Pu. A Nuclear weapon can be fashioned from as little as 5 kg of 239Pu. However, there is considerable technological fl exibility in the Nuclear Fuel cycle. There are three types of Nuclear Fuel cycles that might be utilized for the increased production of energy: open, closed, or a symbiotic combination of different types of reactor (such as, thermal and fast neutron reactors). The neutron energy spectrum has a signifi cant effect on the fi ssion product yield, and the consumption of long-lived actinides, by fi ssion, is best achieved by fast neutrons. Within each cycle, the volume and composition of the high-level Nuclear waste and fi ssile material depend on the type of Nuclear Fuel, the amount of burn-up, the extent of radionuclide separation during reprocessing, and the types of materials used to immobilize different radionuclides. As an example, a 232Th-based fue
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Nuclear Fuel cycle environmental impact
Mrs Bulletin, 2008Co-Authors: Rodney C. EwingAbstract:1The last two, weapons and waste, are directly tied to the type of Nuclear Fuel cycle (Figure 4 in the main Nuclear article by Raj et al. in this issue). The different Fuel cycles reflect different strategies for the utilization of fissile nuclides, mainly 235 U and 239 Pu, and these different strategies have important implications for Nuclear waste management and Nuclear weapons proliferation. The “once-through” open cycle treats the spent Fuel as a “waste” without any attempt to reclaim the remaining fissile nuclides, 235 U and newly created 239 Pu, and the spent Nuclear Fuel (SNF) is directly disposed in a geological repository. This is the present strategy in the United States, and its success rests on the opening of the proposed geologic repository at Yucca Mountain in Nevada. A closed Fuel cycle utilizes chemical reprocessing of the used Fuel and retrieves approximately 99% of the fissile nuclides. However, the recovered fissile nuclides are only a supplement to the Nuclear Fuel that is mainly derived from newly mined uranium ore. The highly radioactive waste from reprocessing and the unprocessed SNF are disposed in a geological repository. Other Fuel cycles are possible, such as the breeder reactor cycle, which creates more fissile material in the SNF than in the original Fuel. The breeder reactor cycle envisions multiple cycles of reprocessing in order to extend the uranium resource. One can also develop Fuel cycles based on 232 Th
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Spent Nuclear Fuel
Elements, 2006Co-Authors: Jordi Bruno, Rodney C. EwingAbstract:The primary waste form resulting from Nuclear energy production is spent Nuclear Fuel (SNF). There are a number of different types of Fuel, but they are predominantly uranium based, mainly UO 2 or, in some cases, metallic U. The UO 2 in SNF is a redox-sensitive semiconductor consisting of a fine-grained (5-10 μm), polycrystalline aggregate containing fission-product and transuranium elements in concentrations of 4 to 6 atomic percent. The challenge is to predict the long-term behavior of UO 2 under a range of redox conditions. Experimental results and observations from natural systems, such as the Oklo natural reactors, have been used to assess the long-term performance of SNF.
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the Nuclear Fuel cycle versus the carbon cycle
Canadian Mineralogist, 2005Co-Authors: Rodney C. EwingAbstract:Nuclear power provides approximately 17% of the world’s electricity, which is equivalent to a reduction in carbon emissions of ~0.5 gigatonnes (Gt) of C/yr. This is a modest reduction as compared with global emissions of carbon, ~7 Gt C/yr. Most analyses suggest that in order to have a signifi cant and timely impact on carbon emissions, carbon-free sources, such as Nuclear power, would have to expand total production of energy by factors of three to ten by 2050. A three-fold increase in Nuclear power capacity would result in a projected reduction in carbon emissions of 1 to 2 Gt C/yr, depending on the type of carbon-based energy source that is displaced. This three-fold increase utilizing present Nuclear technologies would result in 25,000 metric tonnes (t) of spent Nuclear Fuel (SNF) per year, containing over 200 t of plutonium. This is compared to a present global inventory of approximately 280,000 t of SNF and >1,700 t of Pu. A Nuclear weapon can be fashioned from as little as 5 kg of 239 Pu. However, there is considerable technological fl exibility in the Nuclear Fuel cycle. There are three types of Nuclear Fuel cycles that might be utilized for the increased production of energy: open, closed, or a symbiotic combination of different types of reactor (such as, thermal and fast neutron reactors). The neutron energy spectrum has a signifi cant effect on the fi ssion product yield, and the consumption of long-lived actinides, by fi ssion, is best achieved by fast neutrons. Within each cycle, the volume and composition of the high-level Nuclear waste and fi ssile material depend on the type of Nuclear Fuel, the amount of burn-up, the extent of radionuclide separation during reprocessing, and the types of materials used to immobilize different radionuclides. As an example, a 232 Th-based Fuel cycle can be used to breed fi ssile 233 U with minimum production of Pu. In this paper, I will contrast the production of excess carbon in the form of CO2 from fossil Fuels with the production of plutonium in a uranium-based Nuclear Fuel cycle, with special emphasis on the “mineralogical solution” for the “sequestration” of Pu into pyrochlore structure-types.
Stephen Herzog - One of the best experts on this subject based on the ideXlab platform.
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the Nuclear Fuel cycle and the proliferation danger zone
Journal for Peace and Nuclear Disarmament, 2020Co-Authors: Stephen HerzogAbstract:Horizontal Nuclear proliferation presents what is sometimes referred to as the “Nth country problem,” or identifying which state could be next to acquire Nuclear weapons. Nuclear Fuel cycle technol...
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the Nuclear Fuel cycle and the proliferation danger zone
Social Science Research Network, 2020Co-Authors: Stephen HerzogAbstract:Horizontal Nuclear proliferation presents what is sometimes referred to as the “Nth country problem,” or identifying which state could be next to acquire Nuclear weapons. Nuclear Fuel cycle technologies can contribute to both Nuclear power generation and weapons development. Consequently, observers often view civilian Nuclear programs with suspicion even as research on Nuclear latency and the technological inputs of proliferation has added nuance to these discussions. To contribute to this debate, I put forth a simple theoretical proposition: En route to developing a civilian Nuclear infrastructure and mastering the Fuel cycle, states pass through a proliferation “danger zone.” States with Fuel cycle capabilities below a certain threshold will likely be unable to proliferate. States that pass through the “danger zone” without proliferating will be unlikely to do so in the future. I support this proposition by introducing preliminary analysis from the Nuclear Fuel Cycle (NFC) Index, a new heuristic tool to complement political assessments of the connection between civilian Nuclear energy development and Nuclear weapons proliferation. I conclude with policy implications for contemporary Iran, Saudi Arabia, Japan, and South Korea. Taken together, this article calls for increased policymaker interaction with historical cases and more sophisticated academic engagement with the Nuclear Fuel cycle.
W I Ko - One of the best experts on this subject based on the ideXlab platform.
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Nuclear Fuel cycle cost estimation and sensitivity analysis of unit costs on the basis of an equilibrium model
Nuclear Engineering and Technology, 2015Co-Authors: W I Ko, Saerom YounAbstract:This paper examines the difference in the value of the Nuclear Fuel cycle cost calculated by the deterministic and probabilistic methods on the basis of an equilibrium model. Calculating using the deterministic method, the direct disposal cost and Pyro-SFR (sodiumcooled fast reactor) Nuclear Fuel cycle cost, including the reactor cost, were found to be 66.41 mills/kWh and 77.82 mills/kWh, respectively (1 mill ¼ one thousand of a dollar, i.e., 10 -3 $). This is because the cost of SFR is considerably expensive. Calculating again using the probabilistic method, however, the direct disposal cost and Pyro-SFR Nuclear Fuel cycle cost, excluding the reactor cost, were found be 7.47 mills/kWh and 6.40 mills/kWh, respectively, on the basis of the most likely value. This is because the Nuclear Fuel cycle cost is significantly affected by the standard deviation and the mean of the unit cost that includes uncertainty. Thus, it is judged that not only the deterministic method, but also the probabilistic method, would also be necessary to evaluate the Nuclear Fuel cycle cost. By analyzing the sensitivity of the unit cost in each phase of the Nuclear Fuel cycle, it was found that the uranium unit price is the most influential factor in determining Nuclear Fuel cycle costs.
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comparative study of different Nuclear Fuel cycle options quantitative analysis on material flow
Energy Policy, 2011Co-Authors: Byung Heung Park, Eun-ha Kwon, W I KoAbstract:As a nation develops its Nuclear strategies, it must consider various aspects of Nuclear energy such as sustainability, environmental-friendliness, proliferation-resistance, economics, technologies, and so on. A Nuclear Fuel cycle study could give convincing answers to many questions in regard to technical aspects. However, one Nuclear Fuel cycle option cannot be superior in all aspects. Therefore a nation must identify its top priority and accordingly evaluate all the possible Nuclear Fuel cycle options. For such a purpose, this paper examined four different Fuel cycle options that are likely to be plausible under situation of Republic of Korea: once-through cycle, DUPIC recycling, thermal recycling using MOX Fuel in PWR (pressurized water reactor), and SFR (sodium cooled fast reactor) employing Fuel recycling by a pyroprocess. The options have been quantitatively compared in terms of resource utilization and waste generation based on 1TWh electricity production at a “steady-state” condition as a basic analysis. This investigation covered from the front-end of the Fuel cycles to the final disposal and showed that the Pyro-SFR recycling appears to be the most competitive from these material quantitative aspects due to the reduction of the required uranium resources and the least amount of waste generation.
Mujid S Kazimi - One of the best experts on this subject based on the ideXlab platform.
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a Nuclear Fuel cycle system dynamic model for spent Fuel storage options
Energy Conversion and Management, 2013Co-Authors: Samuel Brinton, Mujid S KazimiAbstract:Abstract The options for used Nuclear Fuel storage location and affected parameters such as economic liabilities are currently a focus of several high level studies. A variety of Nuclear Fuel cycle system analysis models are available for such a task. The application of Nuclear Fuel cycle system dynamics models for waste management options is important to life-cycle impact assessment. The recommendations of the Blue Ribbon Committee on America’s Nuclear Future led to increased focus on long periods of spent Fuel storage [1] . This motivated further investigation of the location dependency of used Nuclear Fuel in the parameters of economics, environmental impact, and proliferation risk. Through a review of available literature and interactions with each of the programs available, comparisons of post-reactor Fuel storage and handling options will be evaluated based on the aforementioned parameters and a consensus of preferred system metrics and boundary conditions will be provided. Specifically, three options of local, regional, and national storage were studied. The preliminary product of this research is the creation of a system dynamics tool known as the Waste Management Module (WMM) which provides an easy to use interface for education on Fuel cycle waste management economic impacts. Initial results of baseline cases point to positive benefits of regional storage locations with local regional storage options continuing to offer the lowest cost.
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sustainability features of Nuclear Fuel cycle options
Sustainability, 2012Co-Authors: Stefano Passerini, Mujid S KazimiAbstract:The Nuclear Fuel cycle is the series of stages that Nuclear Fuel materials go through in a cradle to grave framework. The Once Through Cycle (OTC) is the current Fuel cycle implemented in the United States; in which an appropriate form of the Fuel is irradiated through a Nuclear reactor only once before it is disposed of as waste. The discharged Fuel contains materials that can be suitable for use as Fuel. Thus, different types of Fuel recycling technologies may be introduced in order to more fully utilize the energy potential of the Fuel, or reduce the environmental impacts and proliferation concerns about the discarded Fuel materials. Nuclear Fuel cycle systems analysis is applied in this paper to attain a better understanding of the strengths and weaknesses of Fuel cycle alternatives. Through the use of the Nuclear Fuel cycle analysis code CAFCA (Code for Advanced Fuel Cycle Analysis), the impact of a number of recycling technologies and the associated Fuel cycle options is explored in the context of the U.S. energy scenario over 100 years. Particular focus is given to the quantification of Uranium utilization, the amount of Transuranic Material (TRU) generated and the economics of the different options compared to the base-line case, the OTC option. It is concluded that LWRs and the OTC are likely to dominate the Nuclear energy supply system for the period considered due to limitations on availability of TRU to initiate recycling technologies. While the introduction of U-235 initiated fast reactors can accelerate their penetration of the Nuclear energy system, their higher capital cost may lead to continued preference for the LWR-OTC cycle.
Yongsik Yang - One of the best experts on this subject based on the ideXlab platform.
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3d finite element analysis of a Nuclear Fuel rod with gap elements between the pellet and the cladding
Journal of Nuclear Science and Technology, 2016Co-Authors: Changhak Kang, Sunguk Lee, Dongyol Yang, Hyochan Kim, Yongsik YangAbstract:Nuclear Fuel rods which comprises an important component of a Nuclear power plant are composed of Nuclear Fuel and cladding. Simulating the Nuclear Fuel rod using a computer program is the universal method to verify its safety. The computer program used for this is called the Fuel performance code. The main objective of this study is to simulate the Nuclear Fuel rod behavior considering the gap conductance using three-dimensional gap elements. Gap elements are used because, unlike other methods, this approach does not require special methods or other variables such as the Lagrange multiplier. In this work, a Nuclear Fuel rod has been simulated and the results are compared with the experimental results.
