WorldWideScience

Sample records for fuel cycles long-term

  1. Waste transmutation with minimal fuel cycle long-term risk

    Energy Technology Data Exchange (ETDEWEB)

    Slessarev, I.; Salvatores, M.; Uematsu, M. [Direction des Reacteurs Nucleaires, Cadarache (France)

    1995-10-01

    Hybrid systems (source-driven subcritical reactors), are investigated at CEA, mainly from a conceptual point of view, in order to assess their potential to transmute radioactive wastes (mainly long-lived fission products, LLFP) and their potential to insure a minimal long-term radiological risk related both to the fuel inventory inside the system and to the full fuel cycle (mass flows, reprocessing transport, waste disposal). The physics of these systems has been explored and work is in progress both in the field of basic data and INC code validation, in the frame of international collaborations and in the field of conceptual design studies. The most interesting feature of subcritical source-driven system is related to the possibility to obtain an {open_quotes}excess{close_quotes} of neutrons per fission, which can be used to reduce the long-term radiological risk. A specific example will be discussed here.

  2. Long-term global nuclear energy and fuel cycle strategies

    International Nuclear Information System (INIS)

    Krakowski, R.A.

    1997-01-01

    The Global Nuclear Vision Project is examining, using scenario building techniques, a range of long-term nuclear energy futures. The exploration and assessment of optimal nuclear fuel-cycle and material strategies is an essential element of the study. To this end, an established global E 3 (energy/economics/environmental) model has been adopted and modified with a simplified, but comprehensive and multi-regional, nuclear energy module. Consistent nuclear energy scenarios are constructed using this multi-regional E 3 model, wherein future demands for nuclear power are projected in price competition with other energy sources under a wide range of long-term demographic (population, workforce size and productivity), economic (price-, population-, and income-determined demand for energy services, price- and population-modified GNP, resource depletion, world-market fossil energy prices), policy (taxes, tariffs, sanctions), and top-level technological (energy intensity and end-use efficiency improvements) drivers. Using the framework provided by the global E 3 model, the impacts of both external and internal drivers are investigated. The ability to connect external and internal drivers through this modeling framework allows the study of impacts and tradeoffs between fossil- versus nuclear-fuel burning, that includes interactions between cost, environmental, proliferation, resource, and policy issues

  3. Long-term global nuclear energy and fuel cycle strategies

    Energy Technology Data Exchange (ETDEWEB)

    Krakowski, R.A. [Los Alamos National Lab., NM (United States). Technology and Safety Assessment Div.

    1997-09-24

    The Global Nuclear Vision Project is examining, using scenario building techniques, a range of long-term nuclear energy futures. The exploration and assessment of optimal nuclear fuel-cycle and material strategies is an essential element of the study. To this end, an established global E{sup 3} (energy/economics/environmental) model has been adopted and modified with a simplified, but comprehensive and multi-regional, nuclear energy module. Consistent nuclear energy scenarios are constructed using this multi-regional E{sup 3} model, wherein future demands for nuclear power are projected in price competition with other energy sources under a wide range of long-term demographic (population, workforce size and productivity), economic (price-, population-, and income-determined demand for energy services, price- and population-modified GNP, resource depletion, world-market fossil energy prices), policy (taxes, tariffs, sanctions), and top-level technological (energy intensity and end-use efficiency improvements) drivers. Using the framework provided by the global E{sup 3} model, the impacts of both external and internal drivers are investigated. The ability to connect external and internal drivers through this modeling framework allows the study of impacts and tradeoffs between fossil- versus nuclear-fuel burning, that includes interactions between cost, environmental, proliferation, resource, and policy issues.

  4. Effect of long-term storage of LWR spent fuel on Pu-thermal fuel cycle

    International Nuclear Information System (INIS)

    Kurosawa, Masayoshi; Naito, Yoshitaka; Suyama, Kenya; Itahara, Kuniyuki; Suzuki, Katsuo; Hamada, Koji

    1998-01-01

    According to the Long-term Program for Research, Development and Utilization of Nuclear Energy (June, 1994) in Japan, the Rokkasho Reprocessing Plant will be operated shortly after the year 2000, and the planning of the construction of the second commercial plant will be decided around 2010. Also, it is described that spent fuel storage has a positive meaning as an energy resource for the future utilization of Pu. Considering the balance between the increase of spent fuels and the domestic reprocessing capacity in Japan, it can be expected that the long-term storage of UO 2 spent fuels will be required. Then, we studied the effect of long-term storage of spent fuels on Pu-thermal fuel cycle. The burnup calculation were performed on the typical Japanese PWR fuel, and the burnup and criticality calculations were carried out on the Pu-thermal cores with MOX fuel. Based on the results, we evaluate the influence of extending the spent fuel storage term on the criticality safety, shielding design of the reprocessing plant and the core life time of the MOX core, etc. As the result of this work on long-term storage of LWR spent fuels, it becomes clear that there are few demerits regarding the lifetime of a MOX reactor core, and that there are many merits regarding the safety aspects of the fuel cycle facilities. Furthermore, long-term storage is meaningful as energy storage for effective utilization of Pu to be improved by technological innovation in future, and it will allow for sufficient time for the important policymaking of nuclear fuel cycle establishment in Japan. (author)

  5. Long term assurance of supply of back end of fuel cycle facilities and services

    International Nuclear Information System (INIS)

    1978-01-01

    The paper deals with the long-term assurance of supply of the back end of fuel cycle facilities and services. 11 fundamental questions are posed and commented on by representatives of 7 countries. Non-proliferation aspects are not considered as they will be discussed elsewhere

  6. Methodology of fuel cycles long-term safety assessment of SNF/HLW geological disposal

    International Nuclear Information System (INIS)

    Pritrsky, J.

    2008-02-01

    Methodology for the long-term safety assessment of nuclear fuel cycles is given in the presented doctoral thesis. The aim of work was to develop a geological repository model for disposal of spent nuclear fuel (SNF) and high level waste (HLW) using an appropriate software code able to calculate the influence of partitioning and transmutation in advanced fuel cycles. The first step in this process was specifying of indicators which can be used to quantify the radiological impact of each fuel cycle. Indicators such as annual effective dose and radiotoxicity of inventory have been quantitatively analysed to determine the potential risk and radiological consequences associated with production of SNF/HLW. Advanced fuel types bring a number of advantages in comparison to uranium oxide fuel UO 2 used worldwide nowadays in terms of safety improvement due to minor actinides transmutation and non-proliferation aspects as well. Within the scope of work, three different fuel cycles are compared from the point of view of long-term safety of deep geological repository. The first considered fuel cycle is the currently used open fuel cycle (UOX) which uses only U-FA (Uranium Fuel Assembly). The second assessed cycle is a closed fuel cycle (MOX) with MOX-FA (Mixed OXides Fuel Assembly) and the third considered one is a partially closed fuel cycle (IMF) with IMC-FA (Inert Matrix Combined Fuel Assembly). Description and input data of advanced fuel cycles have been gained by participation in the EC project RED-IMPACT. Results were calculated using code AMBER, which is a flexible software tool that allows building dynamic compartmental models to represent the migration and fate of contaminants in a system, for example in the surface and sub-surface environment. Contaminants in solid, liquid and gaseous phases can be considered. AMBER gives the user the flexibility to define any number of compartments; any number of contaminants and associated decays; deterministic, probabilistic and

  7. Methodology of fuel cycles long-term safety assessment of SNF/HLW geological disposal

    International Nuclear Information System (INIS)

    Pritrsky, J.

    2008-01-01

    Methodology for the long-term safety assessment of nuclear fuel cycles is given in the presented doctoral thesis. The aim of work was to develop a geological repository model for disposal of spent nuclear fuel (SNF) and high level waste (HLW) using an appropriate software code able to calculate the influence of partitioning and transmutation in advanced fuel cycles. The first step in this process was specifying of indicators which can be used to quantify the radiological impact of each fuel cycle. Indicators such as annual effective dose and radiotoxicity of inventory have been quantitatively analysed to determine the potential risk and radiological consequences associated with production of SNF/HLW. Advanced fuel types bring a number of advantages in comparison to uranium oxide fuel UO 2 used worldwide nowadays in terms of safety improvement due to minor actinides transmutation and non-proliferation aspects as well. Within the scope of work, three different fuel cycles are compared from the point of view of long-term safety of deep geological repository. The first considered fuel cycle is the currently used open fuel cycle (UOX) which uses only U-FA (Uranium Fuel Assembly). The second assessed cycle is a closed fuel cycle (MOX) with MOX-FA (Mixed OXides Fuel Assembly) and the third considered one is a partially closed fuel cycle (IMF) with IMC-FA (Inert Matrix Combined Fuel Assembly). Description and input data of advanced fuel cycles have been gained by participation in the EC project RED-IMPACT. Results were calculated using code AMBER, which is a flexible software tool that allows building dynamic compartmental models to represent the migration and fate of contaminants in a system, for example in the surface and sub-surface environment. Contaminants in solid, liquid and gaseous phases can be considered. AMBER gives the user the flexibility to define any number of compartments; any number of contaminants and associated decays; deterministic, probabilistic and

  8. Development of nuclear fuel cycle technologies - bases of long-term provision of fuel and environmental safety of nuclear power

    International Nuclear Information System (INIS)

    Solonin, M.I.; Polyakov, A.S.; Zakharkin, B.S.; Smelov, V.S.; Nenarokomov, E.A.; Mukhin, I.V.

    2000-01-01

    To-day nuclear power is one of the options, however, to-morrow it may become the main source of the energy, thus, providing for the stable economic development for the long time to come. The availability of the large-scale nuclear power in the foreseeable future is governed by not only the safe operation of nuclear power plants (NPP) but also by the environmentally safe management of spent nuclear fuel, radioactive waste conditioning and long-term storage. More emphasis is to be placed to the closing of the fuel cycle in view of substantial quantities of spent nuclear fuel arisings. The once-through fuel cycle that is cost effective at the moment cannot be considered to be environmentally safe even for the middle term since the substantial build-up of spent nuclear fuel containing thousands of tons Pu will require the resolution of the safe management problem in the nearest future and is absolutely unjustified in terms of moral ethics as a transfer of the responsibility to future generations. The minimization of radioactive waste arisings and its radioactivity is only feasible with the closed fuel cycle put into practice and some actinides and long-lived fission radionuclides burnt out. The key issues in providing the environmentally safe fuel cycle are efficient processes of producing fuel for NPP, radionuclide after-burning included, a long-term spent nuclear fuel storage and reprocessing as well as radioactive waste management. The paper deals with the problems inherent in producing fuel for NPP with a view for the closed fuel cycle. Also discussed are options of the fuel cycle, its effectiveness and environmental safety with improvements in technologies of spent nuclear fuel reprocessing and long-lived radionuclide partitioning. (authors)

  9. NPP fuel cycle and assessment of possible options for long-term fuel supply

    International Nuclear Information System (INIS)

    Ignatenko, E.I.; Lebedev, V.M.; Davidenko, N.N.

    1999-01-01

    The purpose of this paper is to present some results of the analysis of the possible options for Russian NPPs fuel supply. In the classical consideration these are four fuel cycles: uranium cycle based on natural uranium, this cycle has several economical advantages with the use of CANDU type reactors with a heavy-water moderator; uranium cycle based on enriched uranium, it is a basis for the current and future nuclear power; uranium-thorium fuel cycle with capabilities which are very promising but unfortunately difficult to implement in practice; plutonium-uranium cycle, in terms of its potential capabilities it is an excellent option, but it is extremely difficult to implement it in practice due to a high activity and toxicity of nuclear materials under recycle. The nuclear power of Russia is currently aimed at using the cheapest fuel resources, that is first of all, uranium reprocessed from industrial reactor fuel and slag-heaps accumulated on the past in isotope-separation plant sites. These resources are enough for the Russian large-scale nuclear power to be developed [ru

  10. Introduction of Thorium in the Nuclear Fuel Cycle. Short- to long-term considerations

    International Nuclear Information System (INIS)

    Allibert, M.; Merle-Lucotte, E.; Ghetta, V.; Ault, T.; Krahn, S.; Wymer, R.; Croff, A.; Baron, P.; Chauvin, N.; Eschbach, R.; Rimpault, G.; Serp, J.; Bergeron, A.; Bromley, B.; Floyd, M.; Hamilton, H.; Hyland, B.; Wojtaszek, D.; McDonald, M.; Collins, E.; Cornet, S.; Michel-Sendis, F.; ); Feinberg, O.; Ignatiev, V.; Hesketh, K.; Kelly, J.F.; Porsch, D.; Vidal, J.; Taiwo, T.; Uhlir, J.; Van Den Durpel, L.; Van Den Eynde, G.; Vitanza, C.; Butler, Gregg; Cornet, Stephanie; Dujardin, Thierry; Greneche, Dominique; Nordborg, Claes; Rimpault, Gerald; Van Den Durpel, Luc; Michel-Sendis, Franco

    2015-01-01

    Since the beginning of the nuclear era, significant scientific attention has been given to thorium's potential as a nuclear fuel. Although the thorium fuel cycle has never been fully developed, the opportunities and challenges that might arise from the use of thorium in the nuclear fuel cycle are still being studied in many countries and in the context of diverse international programmes around the world. This report provides a scientific assessment of thorium's potential role in nuclear energy both in the short to longer term, addressing diverse options, potential drivers and current impediments to be considered if thorium fuel cycles are to be pursued. (authors)

  11. Success story: Nuclear production, fuel cycle and high level waste management in France: a contribution to long term energy sustainability

    International Nuclear Information System (INIS)

    Debes, Michel

    2006-01-01

    Nuclear energy, with no CO 2 emission, is a prominent contributor to energy sustainability for long term electricity production, but within a set of major conditions for its continuation and development: - Maintaining both a high level of safety, in accordance with international state of art, and the overall competitiveness of nuclear energy in the long term; - Pursuing the development of credible, efficient and economic solutions for a good management of high level waste issue, while meeting the long term institutional and financial responsibilities; - Maintaining the nuclear option fully open, with long term operation of the existing NPPs, preparation of advanced future LWR and future design (Generation IV); - Providing continued effective proliferation resistance of nuclear energy systems; - Preserving future option for energy resource. This 'success story' will focus on the situation in France for nuclear production, spent fuel and high level waste management and mid term prospective. The paper has the following structure: Introduction; Nuclear industry in France; The current fuel cycle; The current studies for future back end options; Conclusion. In conclusion one underlines that nuclear generation plays a major role in France, as a safe, clean, economic and independent energy resource, and will continue in the long term, while preparing for advanced reactors (EPR and GEN4). The closed fuel cycle strategy implemented in France, involving reprocessing of spent fuel and MOX recycling, has gained an extensive experience feedback and has reached an industrial and mature stage. It brings a robust answer to HLW treatment, with vitrification of high level waste within glass canister, while preserving energy resource for long term and meeting cost effectiveness imperative with existing facilities operated in the long run

  12. MOX fuel cycle technologies for medium and long term deployment. Proceedings

    International Nuclear Information System (INIS)

    2000-01-01

    -based weapons-grade plutonium disposition approaches proposed by the United States of America and the Russian Federation build upon proven commercial MOX fuel technologies. It was noted that a number of technical and institutional improvements were taking place. The purpose of the symposium organized by the International Atomic Energy Agency in co-operation with the OECD Nuclear Energy Agency, was to exchange information on MOX fuel cycle technologies worldwide with focus on how past experience has been or can be used to progress further, either for facing more demanding fabrication and utilization conditions or for extending into new processing or utilization domains. Present technologies of MOX fuel fabrication, fuel design, performance, testing, in-core fuel management, transportation, safety analysis, safeguards and MOX fuel cycle options, including back end, were covered by the invited overview papers describing the worldwide status of the topics. Contributed papers concentrated on the differences between MOX and UO 2 fuels and focused on the future, on the basis of today's perspectives and developments. The place of plutonium recycle in the context of the whole nuclear fuel cycle activity under present conditions of a deregulated electricity market and in the future, and its role in the reduction of separated civil and surplus ex-weapons plutonium stockpiles, were examined further in the discussions by participants and a panel of experts

  13. Contribution to a proposition for a long term development of nuclear energy: the TASSE concept (Thorium based Accelerator driven System with Simplified fuel cycle for long term Energy Production); Contribution a une proposition d'un developpement a long terme de l'energie nucleaire: le concept TASSE (Thorium based Accelerator driven System with Simplified fuel cycle for long term Energy Production)

    Energy Technology Data Exchange (ETDEWEB)

    Berthou, V

    2000-10-30

    Nuclear industry creates waste which are in the middle of the discussion concerning the Nuclear Energy future. At this time, important decisions for the Energy production must be taken, so numerous researches are conducted within the framework of the Bataille law. The goal of these studies is to find a range of solutions concerning the waste management. An innovative system, called TASSE (Thorium based Accelerator driven System with Simplified fuel cycle for long term Energy production), is studied in this thesis. This reactor is included in a long term strategy, and is destined for the renewal of the reactor park. In the first part of this work, the main characteristics of TASSE have been defined. They are commensurate with some specific requirements such as: to insure a large time to the Nuclear Energy, to reduce the waste production in an important way, to eliminate waste already stocked in the present park, to insure the non proliferation, and to be economically competitive. Neutronics studies of TASSE have been done. A calculation procedure has been developed to reach the system equilibrium state. Several types of molten salts as well as a pebble-bed fuel have been studied. Thus, an optimal fuel has been brought out in regard to some parameters such as the burn up level, the spectrum, the waste toxicity, the cycle type. Eventually, various TASSE core layout have been envisaged. (author)

  14. The strategy of the long-term back-end nuclear fuel cycle in the Czech Republic

    International Nuclear Information System (INIS)

    Palagyi, S.; Fajman, V.

    2002-01-01

    The present status of the strategy of the long-term back-end nuclear fuel cycle in the Czech Republic is briefly outlined in this paper. This strategy is based on the once-through option in the use of the nuclear fuel with subsequent interim storage of the spent fuel and its final disposal as a declared high level waste. However, other technologies for the management of the back-end of the nuclear fuel cycle are not excluded at all. Besides the first already existing and the second interim spent fuel storage facility being sited at Dukovany Nuclear Power Plant, an interim spent fuel storage facility at Temelin Nuclear Power Plant is also under the siting process. To cover the total storing needs a central spent nuclear fuel interim storage facility at Skalka in the Czech-Moravian Highlands is also under consideration. These facilities are or will be equipped with dry-storage containers of cask-type placed in the concrete building and cooled by natural air ventilation. Since 1993 there is a joint effort of several governmental organisations and institutions and private companies to study the scientific, technical and economical possibilities of the construction of the deep geological repository for spent nuclear fuel disposal. A horizontal repository facility with vertical access was selected and a reference project has been accepted. A time horizon for construction in about the year of 2035 was scheduled. The necessary legal and administrative basis of the spent fuel and radioactive waste management was laid down by the law No. 18/1997 (Atomic Act) passed in 1997. This basic law with its implementing regulations fully reflects the internationally accepted principles of the provision of nuclear safety and radiation protection in this respect and it also strongly supports the policy and strategy of the back-end of the nuclear fuel cycle. (author)

  15. Nuclear fuel cycle in France: today's situation and long term options

    International Nuclear Information System (INIS)

    Boullis, B.; Drevon, C.; Pays, M.

    2015-01-01

    In France plutonium and uranium are recycled as MOX fuel (used in 22 reactors) and URE (enriched uranium from spent fuel). Fission products and minor actinides, that composed ultimate wastes, are vitrified and cast in stainless steel containers. Fuel recycling has reached industrial maturity and about 30.000 tonnes of spent fuels have been processed. This strategy has allowed France to save about 17% of its annual consumption of uranium and to get a least volume of high-level radioactive wastes. This strategy can be pushed forwards by introducing a multi-recycling option in which plutonium and uranium from spent MOX fuels are recycled. Multi-recycling produces a nuclear fuel that is polluted with remainders of actinides and fission products and to compensate this deterioration of its neutronic properties a higher concentration of fissile materials is required. For safety reasons the concentration of plutonium in MOX fuels is limited to 12% so multi-recycling is not a strategy for a fleet of PWRs only. Fast neutron reactors use uranium and plutonium in a more efficiently way and can be a solution for multi-recycling. The study shows that for a constant output of 420 TWh a year a fleet of PWRs need 7600 tonnes of natural uranium. If mono-recycling is allowed this consumption decreases to 6300 tonnes a year and if multi-recycling is allowed by integrating fast reactors in the proportion of 40% of the fleet, this consumption drops to 2700 tonnes a year. The study also shows the changes in the production of wastes in relation with multi-recycling. (A.C.)

  16. Long term wet spent nuclear fuel storage

    International Nuclear Information System (INIS)

    1987-04-01

    The meeting showed that there is continuing confidence in the use of wet storage for spent nuclear fuel and that long-term wet storage of fuel clad in zirconium alloys can be readily achieved. The importance of maintaining good water chemistry has been identified. The long-term wet storage behaviour of sensitized stainless steel clad fuel involves, as yet, some uncertainties. However, great reliance will be placed on long-term wet storage of spent fuel into the future. The following topics were treated to some extent: Oxidation of the external surface of fuel clad, rod consolidation, radiation protection, optimum methods of treating spent fuel storage water, physical radiation effects, and the behaviour of spent fuel assemblies of long-term wet storage conditions. A number of papers on national experience are included

  17. Contribution to a proposition for a long term development of nuclear energy: the TASSE concept (Thorium based Accelerator driven System with Simplified fuel cycle for long term Energy Production)

    International Nuclear Information System (INIS)

    Berthou, V.

    2000-01-01

    Nuclear industry creates waste which are in the middle of the discussion concerning the Nuclear Energy future. At this time, important decisions for the Energy production must be taken, so numerous researches are conducted within the framework of the Bataille law. The goal of these studies is to find a range of solutions concerning the waste management. An innovative system, called TASSE (Thorium based Accelerator driven System with Simplified fuel cycle for long term Energy production), is studied in this thesis. This reactor is included in a long term strategy, and is destined for the renewal of the reactor park. In the first part of this work, the main characteristics of TASSE have been defined. They are commensurate with some specific requirements such as: to insure a large time to the Nuclear Energy, to reduce the waste production in an important way, to eliminate waste already stocked in the present park, to insure the non proliferation, and to be economically competitive. Neutronics studies of TASSE have been done. A calculation procedure has been developed to reach the system equilibrium state. Several types of molten salts as well as a pebble-bed fuel have been studied. Thus, an optimal fuel has been brought out in regard to some parameters such as the burn up level, the spectrum, the waste toxicity, the cycle type. Eventually, various TASSE core layout have been envisaged. (author)

  18. A decision analysis framework to support long-term planning for nuclear fuel cycle technology research, development, demonstration and deployment

    International Nuclear Information System (INIS)

    Sowder, A.G.; Machiels, A.J.; Dykes, A.A.; Johnson, D.H.

    2013-01-01

    To address challenges and gaps in nuclear fuel cycle option assessment and to support research, develop and demonstration programs oriented toward commercial deployment, EPRI (Electric Power Research Institute) is seeking to develop and maintain an independent analysis and assessment capability by building a suite of assessment tools based on a platform of software, simplified relationships, and explicit decision-making and evaluation guidelines. As a demonstration of the decision-support framework, EPRI examines a relatively near-term fuel cycle option, i.e., use of reactor-grade mixed-oxide fuel (MOX) in U.S. light water reactors. The results appear as a list of significant concerns (like cooling of spent fuels, criticality risk...) that have to be taken into account for the final decision

  19. Factors determining the long term back end nuclear fuel cycle strategy and future nuclear systems. Proceedings of a technical committee meeting

    International Nuclear Information System (INIS)

    2002-05-01

    The Technical Committee Meeting (TCM) was held in Vienna on 8-10 November 1999; it was organized by the International Atomic Energy Agency and attended by 26 participants from 16 Member States. The purpose of the meeting was to exchange information among experts on the back end fuel cycle strategies adopted by Member States; to identify key factors determining the long-term back end fuel cycle strategies; and to assess the applicability of these factors to future nuclear systems. Issues associated with the back end fuel cycle supporting a country's nuclear power programme are technical, economic, institutional and political. This TCM provided an opportunity to address these issues and their impacts to the back end fuel cycles, as well as to identify and assess factors affecting the back end fuel cycle strategies. The discussion was organized ib the following topical sessions: the nuclear fuel cycle; spent fuel management; waste management and repository; plutonium management. This document contains a summary of the meeting and 22 individual papers presented by participants. Each of the papers was indexed separately

  20. Spent fuel, plutonium and nuclear waste: long-term management

    International Nuclear Information System (INIS)

    Collard, G.

    1998-11-01

    Different options for the management of nuclear waste arising from the nuclear fuel cycle are discussed. Special emphasis is on reprocessing followed by geological disposal, geological disposal of reprocessing waste, direct geological disposal of spent nuclear fuel, long term storage. Particular emphasis is on the management of plutonium including recycling, immobilisation and disposal, partitioning and transmutation

  1. ADVANCED NUCLEAR FUEL CYCLE EFFECTS ON THE TREATMENT OF UNCERTAINTY IN THE LONG-TERM ASSESSMENT OF GEOLOGIC DISPOSAL SYSTEMS - EBS INPUT

    Energy Technology Data Exchange (ETDEWEB)

    Sutton, M; Blink, J A; Greenberg, H R; Sharma, M

    2012-04-25

    The Used Fuel Disposition (UFD) Campaign within the Department of Energy's Office of Nuclear Energy (DOE-NE) Fuel Cycle Technology (FCT) program has been tasked with investigating the disposal of the nation's spent nuclear fuel (SNF) and high-level nuclear waste (HLW) for a range of potential waste forms and geologic environments. The planning, construction, and operation of a nuclear disposal facility is a long-term process that involves engineered barriers that are tailored to both the geologic environment and the waste forms being emplaced. The UFD Campaign is considering a range of fuel cycles that in turn produce a range of waste forms. The UFD Campaign is also considering a range of geologic media. These ranges could be thought of as adding uncertainty to what the disposal facility design will ultimately be; however, it may be preferable to thinking about the ranges as adding flexibility to design of a disposal facility. For example, as the overall DOE-NE program and industrial actions result in the fuel cycles that will produce waste to be disposed, and the characteristics of those wastes become clear, the disposal program retains flexibility in both the choice of geologic environment and the specific repository design. Of course, other factors also play a major role, including local and State-level acceptance of the specific site that provides the geologic environment. In contrast, the Yucca Mountain Project (YMP) repository license application (LA) is based on waste forms from an open fuel cycle (PWR and BWR assemblies from an open fuel cycle). These waste forms were about 90% of the total waste, and they were the determining waste form in developing the engineered barrier system (EBS) design for the Yucca Mountain Repository design. About 10% of the repository capacity was reserved for waste from a full recycle fuel cycle in which some actinides were extracted for weapons use, and the remaining fission products and some minor actinides were

  2. Advanced Nuclear Fuel Cycle Effects on the Treatment of Uncertainty in the Long-Term Assessment of Geologic Disposal Systems - EBS Input

    International Nuclear Information System (INIS)

    Sutton, M.; Blink, J.A.; Greenberg, H.R.; Sharma, M.

    2012-01-01

    The Used Fuel Disposition (UFD) Campaign within the Department of Energy's Office of Nuclear Energy (DOE-NE) Fuel Cycle Technology (FCT) program has been tasked with investigating the disposal of the nation's spent nuclear fuel (SNF) and high-level nuclear waste (HLW) for a range of potential waste forms and geologic environments. The planning, construction, and operation of a nuclear disposal facility is a long-term process that involves engineered barriers that are tailored to both the geologic environment and the waste forms being emplaced. The UFD Campaign is considering a range of fuel cycles that in turn produce a range of waste forms. The UFD Campaign is also considering a range of geologic media. These ranges could be thought of as adding uncertainty to what the disposal facility design will ultimately be; however, it may be preferable to thinking about the ranges as adding flexibility to design of a disposal facility. For example, as the overall DOE-NE program and industrial actions result in the fuel cycles that will produce waste to be disposed, and the characteristics of those wastes become clear, the disposal program retains flexibility in both the choice of geologic environment and the specific repository design. Of course, other factors also play a major role, including local and State-level acceptance of the specific site that provides the geologic environment. In contrast, the Yucca Mountain Project (YMP) repository license application (LA) is based on waste forms from an open fuel cycle (PWR and BWR assemblies from an open fuel cycle). These waste forms were about 90% of the total waste, and they were the determining waste form in developing the engineered barrier system (EBS) design for the Yucca Mountain Repository design. About 10% of the repository capacity was reserved for waste from a full recycle fuel cycle in which some actinides were extracted for weapons use, and the remaining fission products and some minor actinides were encapsulated

  3. Development of a Code for the Long Term Radiological Safety Assessment of Radioactive Wastes from Advanced Nuclear Fuel Cycle Facilities in Republic of Korea

    International Nuclear Information System (INIS)

    Hwang, Yong Soo

    2010-01-01

    For the purpose of evaluating annual individual doses from a potential repository disposing of radioactive wastes from the operation of the prospective advanced nuclear fuel cycle facilities in Korea, the new safety assessment code based on the Goldsim has been developed. It was designed to compare the environmental impacts from many fuel cycle options such as direct disposal, wet and dry recycling. The code based on the compartment theory can be applied to assess both normal and what if scenarios

  4. Feeding the nuclear fuel cycle with a long term view; AREVA's front-end business units, uranium mining, UF6 conversion and isotopic enrichment

    International Nuclear Information System (INIS)

    Capus, G.A.P.; Autegert, R.

    2005-01-01

    As a leading provider of technological solutions for nuclear power generation and electricity transmission, the AREVA group has the unique capability of offering a fully integrated fuel supply, when requested by its customers. At the core of the AREVA group, COGEMA Front End Division is an essential part of the overall fuel supply chain. Composed of three Business Units and gathering several subsidiaries and joint 'ventures, this division enjoys several leading positions as shown by its market shares and historical production records. Current Uranium market evolutions put the natural uranium supply under focus. The uranium conversion segment also recently revealed some concerning evolutions. And no doubt, the market pressure will soon be directed also at the enrichment segment. Looking towards the long term, AREVA strongly believes that a nuclear power renewal is needed, especially to help limiting green house effect gas release. Therefore, to address future supplies needed to fuel the existing fleet of nuclear power plants, but also new ones, the AREVA group is planning very significant investments to build new facilities in all the three front-end market segments. As far as uranium mining is concerned, these new mines will be based upon uranium reserves of outstanding quality. As for uranium conversion and enrichment, two large projects will be based on the most advanced technologies. This paper is aimed at recalling COGEMA Front End Division experience, the current status of its plants and operating entities and will provide a detailed overview of its major projects. (authors)

  5. Mesozoic long-term eustatic cycles and their uncertain hierarchy

    Directory of Open Access Journals (Sweden)

    Dmitry A. Ruban

    2015-07-01

    Full Text Available Global sea-level has changed in a cyclic manner through geologic history, but the regularities of these changes are yet to be fully understood. Despite certain (and sometimes significant differences, the available Mesozoic eustatic curves permit the outlining of long-term eustatic cycles, which are provisionally defined as cycles recognizable at the stage level and higher. Interpretation of the Triassic eustatic curves indicates two orders of long-term cycles and a 1st-order sea-level rise throughout the entire period. The Jurassic eustatic curves imply cyclicity of one or two orders, and a 1st-order eustatic rise during the entire period is also evident. Most challenges are interpretations for the Cretaceous; two to four orders of long-term eustatic cycles can be established for this period. Generally, the hierarchy of the long-term eustatic cycles might have changed through the Mesozoic. If so, and if one considers differences of cycles of the same order between the periods of this era, it is difficult to apply “standard” hierarchical classifications to the documented cycles. The hypothetical uncertainty of the hierarchy of the Mesozoic long-term eustatic cycles is an important challenge for modern researchers.

  6. Corrosion of Spent Nuclear Fuel: The Long-Term Assessment

    Energy Technology Data Exchange (ETDEWEB)

    Ewing, Rodney C.

    2003-09-14

    The successful disposal of spent nuclear fuel (SNF) is one of the most serious challenges to the successful completion of the nuclear fuel cycle and the future of nuclear power generation. In the United States, 21 percent of the electricity is generated by 107 commercial nuclear power plants (NPP), each of which generates 20 metric tons of spent nuclear fuel annually. In 1996, the total accumulation of spent nuclear fuel was 33,700 metric tons of heavy metal (MTHM) stored at 70 sites around the country. The end-of-life projection for current nuclear power plants (NPP) is approximately 86,000 MTHM. In the proposed nuclear waste repository at Yucca Mountain over 95% of the radioactivity originates from spent nuclear fuel. World-wide in 1998, approximately 130,000 MTHM of SNF have accumulated, most of it located at 236 NPP in 36 countries. Annual production of SNF is approximately 10,000 MTHM, containing about 100 tons of ''reactor grade'' plutonium. Any reasonable increase in the proportion of energy production by NPP, i.e., as a substitute for hydrocarbon-based sources of energy, will significantly increase spent nuclear fuel production. Spent nuclear fuel is essentially UO{sub 2} with approximately 4-5 atomic percent actinides and fission product elements. A number of these elements have long half-lives hence, the long-term behavior of the UO{sub 2} is an essential concern in the evaluation of the safety and risk of a repository for spent nuclear fuel. One of the unique and scientifically most difficult aspects of the successful disposal of spent nuclear fuel is the extrapolation of short-term laboratory data (hours to years) to the long time periods (10{sup 3} to 10{sup 5} years) as required by the performance objectives set in regulations, i.e. 10 CFR 60. The direct verification of these extrapolations or interpolations is not possible, but methods must be developed to demonstrate compliance with government regulations and to satisfy the

  7. Report on the possibilities of long-term storage of irradiated nuclear fuels

    International Nuclear Information System (INIS)

    2001-01-01

    This report aims at giving a legislative aspect to the many rules that govern the activities of the back-end of the fuel cycle in France. These activities concern the unloading of spent nuclear fuels, their reprocessing, storage, recycling and definitive disposal. The following points are reviewed and commented: the management of non-immediately reprocessed fuels (historical reasons of the 'all wastes reprocessing' initial choice, evolution of the economic and political context, the future reprocessing or the definitive disposal of spent fuels in excess); the inevitable long-term storage of part of the spent fuels (quantities and required properties of long-term stored fuels, the eventuality of a definitive disposal of spent fuels); the criteria that long-term storage facilities must fulfill (confinement measures, reversibility, surveillance and control during the whole duration of the storage); storage concept to be retained (increase of storage pools capacity, long-term storage in pools of reprocessing plants, centralized storage in pools, surface dry-storage on power plant sites, reversible underground storage, subsurface storage and storage/disposal in galleries, surface dry-storage facilities); the preliminary studies for the creation of long-term storage facilities (public information, management by a public French organization, clarifying of the conditions of international circulation of spent fuels); problems linked with the presence of foreign spent fuels in France (downstream of the reprocessing cycle, foreign plutonium and wastes re-shipment); conclusions and recommendations. (J.S.)

  8. Long-term storage of spent nuclear fuel

    International Nuclear Information System (INIS)

    Kempe, T.F.; Martin, A.; Thorne, M.C.

    1980-06-01

    This report presents the results of a study on the storage of spent nuclear fuel, with particular reference to the options which would be available for long-term storage. Two reference programmes of nuclear power generation in the UK are defined and these are used as a basis for the projection of arisings of spent fuel and the storage capacity which might be needed. The characteristics of spent fuel which are relevant to long-term storage include the dimensions, materials and physical construction of the elements, their radioactive inventory and the associated decay heating as a function of time after removal from the reactor. Information on the behaviour of spent fuel in storage ponds is reviewed with particular reference to the corrosion of the cladding. The review indicates that, for long-term storage, both Magnox and AGR fuel would need to be packaged because of the high rate of cladding corrosion and the resulting radiological problems. The position on PWR fuel is less certain. Experience of dry storage is less extensive but it appears that the rate of corrosion of cladding is much lower than in water. Unit costs are discussed. Consideration is given to the radiological impact of fuel storage. (author)

  9. Report on the possibilities of long-term storage of irradiated nuclear fuels; Rapport sur les possibilites d'entreposage a long terme de combustibles nucleaires irradies

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-07-01

    This report aims at giving a legislative aspect to the many rules that govern the activities of the back-end of the fuel cycle in France. These activities concern the unloading of spent nuclear fuels, their reprocessing, storage, recycling and definitive disposal. The following points are reviewed and commented: the management of non-immediately reprocessed fuels (historical reasons of the 'all wastes reprocessing' initial choice, evolution of the economic and political context, the future reprocessing or the definitive disposal of spent fuels in excess); the inevitable long-term storage of part of the spent fuels (quantities and required properties of long-term stored fuels, the eventuality of a definitive disposal of spent fuels); the criteria that long-term storage facilities must fulfill (confinement measures, reversibility, surveillance and control during the whole duration of the storage); storage concept to be retained (increase of storage pools capacity, long-term storage in pools of reprocessing plants, centralized storage in pools, surface dry-storage on power plant sites, reversible underground storage, subsurface storage and storage/disposal in galleries, surface dry-storage facilities); the preliminary studies for the creation of long-term storage facilities (public information, management by a public French organization, clarifying of the conditions of international circulation of spent fuels); problems linked with the presence of foreign spent fuels in France (downstream of the reprocessing cycle, foreign plutonium and wastes re-shipment); conclusions and recommendations. (J.S.)

  10. A long-term view of worldwide fossil fuel prices

    International Nuclear Information System (INIS)

    Shafiee, Shahriar; Topal, Erkan

    2010-01-01

    This paper reviews a long-term trend of worldwide fossil fuel prices in the future by introducing a new method to forecast oil, natural gas and coal prices. The first section of this study analyses the global fossil fuel market and the historical trend of real and nominal fossil fuel prices from 1950 to 2008. Historical fossil fuel price analysis shows that coal prices are decreasing, while natural gas prices are increasing. The second section reviews previously available price modelling techniques and proposes a new comprehensive version of the long-term trend reverting jump and dip diffusion model. The third section uses the new model to forecast fossil fuel prices in nominal and real terms from 2009 to 2018. The new model follows the extrapolation of the historical sinusoidal trend of nominal and real fossil fuel prices. The historical trends show an increase in nominal/real oil and natural gas prices plus nominal coal prices, as well as a decrease in real coal prices. Furthermore, the new model forecasts that oil, natural gas and coal will stay in jump for the next couple of years and after that they will revert back to the long-term trend until 2018. (author)

  11. Spent fuel, plutonium and nuclear waste: long-term management; Le combustible use et le plutonium en tant que dechets nucleaires: gestion a long terme

    Energy Technology Data Exchange (ETDEWEB)

    Collard, G

    1998-11-01

    Different options for the management of nuclear waste arising from the nuclear fuel cycle are discussed. Special emphasis is on reprocessing followed by geological disposal, geological disposal of reprocessing waste, direct geological disposal of spent nuclear fuel, long term storage. Particular emphasis is on the management of plutonium including recycling, immobilisation and disposal, partitioning and transmutation.

  12. Synthesis on the spent fuel long term evolution

    International Nuclear Information System (INIS)

    Ferry, C.; Poinssot, Ch.; Lovera, P.; Poulesquen, A.; Broudic, V.; Cappelaere, Ch.; Desgranges, L.; Garcia, Ph.; Jegou, Ch.; Roudil, D.; Lovera, P.; Poulesquen, A.; Marimbeau, P.; Gras, J.M.; Bouffioux, P.

    2005-01-01

    The French research on spent fuel long term evolution has been performed by CEA (Commissariat a l'Energie Atomique) since 1999 in the PRECCI project with the support of EDF (Electricite de France). These studies focused on the spent fuel behaviour under various conditions encountered in dry storage or in deep geological disposal. Three main types of conditions were discerned: - The evolution in a closed system which corresponds to the normal scenario in storage and to the first confinement phase in disposal; - The evolution in air which corresponds to an incidental loss of confinement during storage or to a rupture of the canister before the site re-saturation in geological disposal; - The evolution in water which corresponds to the normal scenario after the breaching of the canister in repository conditions. This document produced in the frame of the PRECCI project is an overview of the state of knowledge in 2004 concerning the long-term behavior of spent fuel under these various conditions. The state of the art was derived from the results obtained under the PRECCI project as well as from a review of the literature and of data acquired under the European project on Spent Fuel Stability under Repository Conditions. The main results issued from the French research are underlined. (authors)

  13. Synthesis on the spent fuel long term evolution

    Energy Technology Data Exchange (ETDEWEB)

    Ferry, C.; Poinssot, Ch.; Lovera, P.; Poulesquen, A. [CEA Saclay, Dept. de Physico-Chimie (DEN/DPC), 91 - Gif sur Yvette (France); Broudic, V. [CEA Cadarache, Direction des Reacteurs Nucleaires (DRN), 13 - Saint Paul lez Durance (France); Cappelaere, Ch. [CEA Saclay, Dept. des Materiaux pour le Nucleaire(DMN), 91 - Gif-sur-Yvette (France); Desgranges, L. [CEA Cadarache, Direction des Reacteurs Nucleaires (DRN), 13 - Saint-Paul-lez-Durance (France); Garcia, Ph. [CEA Cadarache, Dept. d' Etudes des Combustibles (DEC), 13 - Saint Paul lez Durance (France); Jegou, Ch.; Roudil, D. [CEA Valrho, Dir. de l' Energie Nucleaire (DEN), 30 - Marcoule (France); Lovera, P.; Poulesquen, A. [CEA Saclay, Dept. de Physico-Chimie (DPC), 91 - Gif sur Yvette (France); Marimbeau, P. [CEA Cadarache, Dir. de l' Energie Nucleaire (DEN), 13 - Saint-Paul-lez-Durance (France); Gras, J.M.; Bouffioux, P. [Electricite de France (EDF), 75 - Paris (France)

    2005-07-01

    The French research on spent fuel long term evolution has been performed by CEA (Commissariat a l'Energie Atomique) since 1999 in the PRECCI project with the support of EDF (Electricite de France). These studies focused on the spent fuel behaviour under various conditions encountered in dry storage or in deep geological disposal. Three main types of conditions were discerned: - The evolution in a closed system which corresponds to the normal scenario in storage and to the first confinement phase in disposal; - The evolution in air which corresponds to an incidental loss of confinement during storage or to a rupture of the canister before the site re-saturation in geological disposal; - The evolution in water which corresponds to the normal scenario after the breaching of the canister in repository conditions. This document produced in the frame of the PRECCI project is an overview of the state of knowledge in 2004 concerning the long-term behavior of spent fuel under these various conditions. The state of the art was derived from the results obtained under the PRECCI project as well as from a review of the literature and of data acquired under the European project on Spent Fuel Stability under Repository Conditions. The main results issued from the French research are underlined. (authors)

  14. Corrosion of Spent Nuclear Fuel: The Long-Term Assessment

    International Nuclear Information System (INIS)

    Ewing, Rodney C.

    2004-01-01

    Spent nuclear fuel, essentially U 2 , accounts for over 95% of the total radioactivity of all of the radioactive wastes in the United States that require disposal, disposition or remediation. The UO 2 in SNF is not stable under oxiding conditions and may also be altered under reducing conditions. The alteration of SNF results in the formation of new uranium phases that can cause the release or retardation of actinide and fission product radionuclides. Over the long term, and depending on the extent to which the secondary uranium phases incorporate fission products and actinides, these alteration phases become the near-field source term

  15. Corrosion of Spent Nuclear Fuel: The Long-Term Assessment

    Energy Technology Data Exchange (ETDEWEB)

    Rodney C. Ewing

    2004-10-07

    Spent nuclear fuel, essentially U{sub 2}, accounts for over 95% of the total radioactivity of all of the radioactive wastes in the United States that require disposal, disposition or remediation. The UO{sub 2} in SNF is not stable under oxiding conditions and may also be altered under reducing conditions. The alteration of SNF results in the formation of new uranium phases that can cause the release or retardation of actinide and fission product radionuclides. Over the long term, and depending on the extent to which the secondary uranium phases incorporate fission products and actinides, these alteration phases become the near-field source term.

  16. Spent Fuel Long Term Interim Storage: The Spanish Policy

    International Nuclear Information System (INIS)

    Fernandez-Lopez, Javier

    2014-01-01

    ENRESA is the Spanish organization responsible for long-term management of all categories of radioactive waste and nuclear spent fuel and for decommissioning nuclear installations. It is also in charge of the management of the funds collected from waste producers and electricity consumers. The national policy about radioactive waste management is established at the General Radioactive Waste Plan by the Government upon proposal of the Ministry of Industry, Energy and Tourism. Now the Plan in force is the Sixth Plan approved in 2006. The policy on spent nuclear fuel, after description of the current available options, is set up as a long term interim storage at a Centralized Temporary Storage facility (CTS, or ATC in Spanish acronym) followed by geologic disposal, pending technological development on other options being eligible in the future. After a site selection process launched in 2009, the site for the ATC has been chosen at the end of 2011. The first steps for the implementation of the facility are described in the present paper. (authors)

  17. Systematic long-term observations of the global carbon cycle.

    Science.gov (United States)

    Scholes, R J; Monteiro, P M S; Sabine, C L; Canadell, J G

    2009-08-01

    Imagine a meeting convened to avert a global financial crisis where none of the finance ministers had access to reliable information on changes in the stock market, national gross domestic product or international trade flows. It is hardly conceivable. Yet the infinitely more existence-threatening planetary social and ecological crisis we refer to as 'global change' (comprising the linked issues of biogeochemical, climate, biotic and human system change) is in an analogous situation. Our information on the profound and accelerating changes currently depends to an unacceptable degree on serendipity, individual passion, redirected funding and the largely uncoordinated efforts of a few nations. The thesis of this paper is that navigation of the very narrow 'safe passages' that lie ahead requires a comprehensive and systematic approach to Earth observations, supported by a globally coordinated long-term funding mechanism. We developed the argument based on observations of the carbon cycle, because the issues there are compelling and easily demonstrated, but we believe the conclusions also to be true for many other types of observations relating to the state and management of the biosphere.

  18. Long-term sealability of spent fuel casks

    International Nuclear Information System (INIS)

    Kato, O.; Kosaki, A.; Ito, C.; Ozaki, S.; Iitsuka, S.

    1993-01-01

    This report presents the results of long-term sealability test of full-scale model casks which have been in progress since 1990. (O.Kato and C.Ito 1992) The purpose is to confirm the long-term sealability of the casks. (J.P.N.)

  19. Developing and analyzing long-term fuel management strategies for an advanced Small Modular PWR

    Energy Technology Data Exchange (ETDEWEB)

    Hedayat, Afshin, E-mail: ahedayat@aeoi.org.ir

    2017-03-15

    Highlights: • Comprehensive introduction and supplementary concepts as a review paper. • Developing an integrated long-term fuel management strategy for a SMR. • High reliable 3-D core modeling over fuel pins against the traditional LRM. • Verifying the expert rules of large PWRs for an advanced small PWR. • Investigating large numbers of safety parameters coherently. - Abstract: In this paper, long-term fuel management (FM) strategies are introduced and analyzed for a new advanced Pressurized Light Water Reactor (PWR) type of Small Modular Reactors (SMRs). The FM strategies are developed to be safe and practical for implementation as much as possible. Safety performances, economy of fuel, and Quality Assurance (QA) of periodic equilibrium conditions are chosen as the main goals. Flattening power density distribution over fuel pins is the major method to ensure safety performance; also maximum energy output or permissible discharging burn up indicates economy of fuel fabrication costs. Burn up effects from BOC to EOC have been traced, studied, and highly visualized in both of transport lattice cell calculations and diffusion core calculations. Long-term characteristics are searched to gain periodical equilibrium characteristics. They are fissile changes, neutron spectrum, refueling pattern, fuel cycle length, core excess reactivity, average, and maximum burn up of discharged fuels, radial Power Peaking Factors (PPF), total PPF, radial and axial power distributions, batch effects, and enrichment effects for fine regulations. Traditional linear reactivity model have been successfully simulated and adapted via fine core and burn up calculations. Effects of high burnable neutron poison and soluble boron are analyzed. Different numbers of batches via different refueling patterns have been studied and visualized. Expert rules for large type PWRs have been influenced and well tested throughout accurate equilibrium core calculations.

  20. Managing aging effects on used fuel dry cask for very long-term storage - 59067

    International Nuclear Information System (INIS)

    Chopra, Omesh; Diercks, Dwight; Ma, David; Shah, Vikram; Tam, Shiu-Wing; Fabian, Ralph; Liu, Yung; Nutt, Mark

    2012-01-01

    The cancellation of the Yucca Mountain repository program in the Unites States raises the prospect of very long-term storage (i.e., >120 years) and deferred transportation of used fuel at the nuclear power plant sites. While long-term storage of used nuclear fuel in dry cask storage systems (DCSSs) at Independent Spent Fuel Storage Installations (ISFSIs) is already a standard practice among U.S. utilities, recent rule-making activities of the U.S. Nuclear Regulatory Commission (NRC) indicated additional flexibility for the NRC licensees of ISFSIs and certificate holders of the DCSSs to request initial and renewal terms for up to 40 years. The proposed rule also adds a requirement that renewal applicants must provide descriptions of aging management programs (AMPs) and time-limited aging analyses (TLAAs) to ensure that the structures, systems, and components (SSCs) that are important to safety in the DCSSs will perform as designed under the extended license terms. This paper examines issues related to managing aging effects on DCSSs for very long-term storage (VLTS) of used fuels, capitalizing on the extensive knowledge and experience accumulated from the work on aging research and life cycle management at Argonne National Laboratory (ANL) over the last 30 years. The technical basis for acceptable AMPs and TLAAs is described, as are generic AMPs and TLAAs that are being developed by Argonne under the support of the U.S. Department of Energy (DOE) Used Fuel Disposition Campaign for R and D on extended long-term storage and transportation. (authors)

  1. Long-term tradeoffs between nuclear- and fossil-fuel burning

    Energy Technology Data Exchange (ETDEWEB)

    Krakowski, R.A.

    1996-12-31

    A global energy/economics/environmental (E{sup 3}) model has been adapted with a nuclear energy/materials model to understand better {open_quotes}top-level{close_quotes}, long-term trade offs between civilian nuclear power, nuclear-weapons proliferation, fossil-fuel burning, and global economic welfare. Using a {open_quotes}business-as-usual{close_quotes} (BAU) point-of-departure case, economic, resource, proliferation-risk implications of plutonium recycle in LAIRs, greenhouse-gas-mitigating carbon taxes, and a range of nuclear energy costs (capital and fuel) considerations have been examined. After describing the essential elements of the analysis approach being developed to support the Los Alamos Nuclear Vision Project, preliminary examples of parametric variations about the BAU base-case scenario are presented. The results described herein represent a sampling from more extensive results collected in a separate report. The primary motivation here is: (a) to compare the BAU basecase with results from other studies; (b) to model on a regionally resolved global basis long-term (to year {approximately}2100) evolution of plutonium accumulation in a variety of forms under a limited range of fuel-cycle scenarios; and (c) to illustrate a preliminary connectivity between risks associated with nuclear proliferation and fossil-fuel burning (e.g., greenhouse-gas accumulations).

  2. Long-term tradeoffs between nuclear- and fossil-fuel burning

    International Nuclear Information System (INIS)

    Krakowski, R.A.

    1996-01-01

    A global energy/economics/environmental (E 3 ) model has been adapted with a nuclear energy/materials model to understand better open-quotes top-levelclose quotes, long-term trade offs between civilian nuclear power, nuclear-weapons proliferation, fossil-fuel burning, and global economic welfare. Using a open-quotes business-as-usualclose quotes (BAU) point-of-departure case, economic, resource, proliferation-risk implications of plutonium recycle in LAIRs, greenhouse-gas-mitigating carbon taxes, and a range of nuclear energy costs (capital and fuel) considerations have been examined. After describing the essential elements of the analysis approach being developed to support the Los Alamos Nuclear Vision Project, preliminary examples of parametric variations about the BAU base-case scenario are presented. The results described herein represent a sampling from more extensive results collected in a separate report. The primary motivation here is: (a) to compare the BAU basecase with results from other studies; (b) to model on a regionally resolved global basis long-term (to year ∼2100) evolution of plutonium accumulation in a variety of forms under a limited range of fuel-cycle scenarios; and (c) to illustrate a preliminary connectivity between risks associated with nuclear proliferation and fossil-fuel burning (e.g., greenhouse-gas accumulations)

  3. Fuel cycle

    International Nuclear Information System (INIS)

    Bahm, W.

    1989-01-01

    The situation of the nuclear fuel cycle for LWR type reactors in France and in the Federal Republic of Germany was presented in 14 lectures with the aim to compare the state-of-the-art in both countries. In addition to the momentarily changing fuilds of fuel element development and fueling strategies, the situation of reprocessing, made interesting by some recent developmnts, was portrayed and differences in ultimate waste disposal elucidated. (orig.) [de

  4. Long-Term Cycling of the Magnesium Hydrogen System

    DEFF Research Database (Denmark)

    Pedersen, Allan Schrøder; Kjøller, John; Larsen, Bent

    1984-01-01

    Magnesium powder with a grain size of approximately 50γm was hydrogenated for 30 min and dehydrogenated the same time at 390°C, 515 times. A moderate loss in hydrogen storage capacity was observed and was ascribed to a measured decrease in reaction kinetics as the cycle number increased. The time...

  5. Long term monitoring of landslide: observation gravitational slope cycles

    Science.gov (United States)

    Palis, Edouard; Lebourg, Thomas; Vidal, Maurin

    2016-04-01

    Since several years of studies on landslides, we realized the role and subtle interactions that existed between the structural complexity, masses dynamics and complex internal circulation of fluids. Thus, to gain a better understanding of the processes taking place during the evolution of an unstable slope, an observational study is necessary. In this perspective, our team currently monitors slow moving landslide zones. The aim of such a monitoring is to gain a better knowledge of the links between external forcing (meteorological, seismological) and signals going out of the slope (kinematic, vibrations, electrical resistivity). In December 2000, a dramatic event affected the sandy/clayey landslide in the Southern Alpes Maritimes (France). A 10 meters high scarp appeared at the foot of the landslide and affected private yards nearby. This area then became a major concern for local authorities and understand the processes taking place, a scientific challenge. In order to understand the land-sliding reactivations and to quantify the natural cycles of deformations, we analyse the main factors of this complex system. After 10 years of observation we are now able to highlight some of the complex behaviours by the measurement of physical parameters (geophysical monitoring). A permanent 115 m ERT line (5 meters electrode spacing) has been installed and provides an acquisition daily since 2006. The daily acquisitions are now accompanied by continuous measurements from boreholes (thermometers, piezometers, tiltmeters) and pluviometry. We are able to control the whole monitoring from the lab, and all these data are transmitted in real time. The analysis of these large amounts of data over large time series allows the detection of seasonal cycles of surface activity. The deformation taking place can be assimilated to a near-elastic deformation and show a lateral decoupling on both sides of the fault cutting the landslide. These deformation cycles can be associated with the

  6. Future fuel cycles

    International Nuclear Information System (INIS)

    Archinoff, G.H.

    1980-01-01

    A fuel cycle must offer both financial and resource savings if it is to be considered for introduction into Ontario's nuclear system. The most promising alternative CANDU fuel cycles are examined in the context of both of these factors over a wide range of installed capacity growth rates and economic assumptions, in order to determine which fuel cycle, or cycles, should be introduced, and when. It is concluded that the optimum path for the long term begins with the prompt introduction of the low-enriched-uranium fuel cycle. For a wide range of conditions, this cycle remains the optimum throughout the very long term. Conditions of rapid nuclear growth and very high uranium price escalation rates warrant the supersedure of the low-enriched-uranium cycle by either a plutonium-topped thorium cycle or plutonium recycle, beginning between 2010 and 2025. It is also found that the uranium resource position is sound in terms of both known resources and production capability. Moreover, introduction of the low-enriched-uranium fuel cycle and 1250 MWe reactor units will assure the economic viability of nuclear power until at least 2020, even if uranium prices increase at a rate of 3.5% above inflation. The interrelationship between these two conclusions lies in the tremendous incentive for exploration which will occur if the real uranium price escalation rate is high. From a competitive viewpoint, nuclear power can withstand increases in the price of uranium. However, such increases will likely further expand the resource base, making nuclear an even more reliable energy source. (auth)

  7. Fuel cycle management

    International Nuclear Information System (INIS)

    Herbin, H.C.

    1977-01-01

    The fuel cycle management is more and more dependent on the management of the generation means among the power plants tied to the grid. This is due mainly because of the importance taken by the nuclear power plants within the power system. The main task of the fuel cycle management is to define the refuelling pattern of the new and irradiated fuel assemblies to load in the core as a function of: 1) the differences which exist between the actual conditions of the core and what was expected for the present cycle, 2) the operating constraints and the reactor availability, 3) the technical requirements in safety and the technological limits of the fuel, 4) the economics. Three levels of fuel cycle management can be considered: 1) a long term management: determination of enrichments and expected cycle lengths, 2) a mid term management whose aim corresponds to the evaluation of the batch to load within the core as a function of both: the next cycle length to achieve and the integrated power history of all the cycles up to the present one, 3) a short term management which deals with the updating of the loaded fuel utilisations to take into account the operation perturbations, or with the alteration of the loading pattern of the next batch to respect unexpected conditions. (orig.) [de

  8. Fuel cycle services

    International Nuclear Information System (INIS)

    Gruber, Gerhard J.

    1990-01-01

    TRIGA reactor operators are increasingly concerned about the back end of their Fuel Cycle due to a new environmental policy in the USA. The question how to close the Fuel Cycle will have to be answered by all operators sooner or later. Reprocessing of the TRIGA fuel elements is not available. Only long term storage and final disposal can be considered. But for such a storage or disposal a special treatment of the fuel elements and of course a final depository is necessary. NUKEM plans to undertake efforts to assist the TRIGA operators in this area. For that reason we need to know your special needs for today and tomorrow - so that potential processors can consider whether to offer these services on the market. (orig.)

  9. Canada's plan for the long-term management of used nuclear fuel

    Energy Technology Data Exchange (ETDEWEB)

    Shaver, K. [Nuclear Waste Management Organization, Toronto, ON (Canada)

    2015-07-01

    Our mission is to develop and implement collaboratively with Canadians, a management approach for the long-term care of Canada's used nuclear fuel that is socially acceptable, technically sound, environmentally responsible, and economically feasible. The technical method is for Isolation of used nuclear fuel in deep geological repository with continuous monitoring and potential for retrievability.

  10. Criteria for recladding of spent light water reactor fuel before long term pool storage

    International Nuclear Information System (INIS)

    Pettersson, K.; Jansson, L.

    1979-01-01

    The question of the need for any special treatment of failed fuel elements prior to long term pool storage has been studied. It is concluded that the main problem appears to be hydride embrittlement of failed fuel rods, which may lead to increased damage during handling and transport of the failed fuel. Some mechanisms for the degradation of failed fuel rods have been identified. They can all be considered as relatively improbable, but further experimental evidence is needed before it can be concluded that these degradation mechanisms are insignificant during pool storage. The report also contains a review of methods for identification of leaking fuel bundles and fuel rods. (Auth.)

  11. Criteria for recladding of spent light water reactor fuel before long term pool storage

    International Nuclear Information System (INIS)

    Pettersson, K.; Jansson, L.

    1979-06-01

    The question of the need for any special treatment of failed fuel elements prior to long term pool storage has been studied. It is concluded that the main problem appears to be hydride embrittlement of failed fuel rods, which may lead to increased damage during handling and transport of the failed fuel. Some mechanisms for the degradation of failed fuel rods have been identified. They can all be considered as relatively improbable, but further experimental evidence is needed before it can be concluded that thede degradation mechanisms are insignificant during pool storage. The report also contains a review of methods for identification of leaking fuel bundles and fuel rods.(author)

  12. The fuel cycle

    International Nuclear Information System (INIS)

    2000-01-01

    In this brochure the fuel cycle is presented. The following fuel cycle steps are described: (1) Front of the fuel cycle (Mining and milling; Treatment; Refining, conversion and enrichment; Fuel fabrication); (2) Use of fuel in nuclear reactors; (3) Back end of the fuel cycle (Interim storage of spent fuel; spent fuel reprocessing; Final disposal of spent fuel)

  13. Long term evolution of spent nuclear fuel in long term storage or geological disposal. Status of the French research program PRECCI

    International Nuclear Information System (INIS)

    Poinssot, Ch.; Toulhoat, P.; Gras, J.M.

    2001-01-01

    This paper aims to give a brief overview of the wide research undertaken in France in order to elucidate the potential long term evolution of spent nuclear fuels in long term storage or geological disposal. A particular emphasis is put on the last scientific results obtained and on the major scientific issue on which R and D is currently focused: the fate of helium, the RN migration within the rod (irradiation-induced diffusion) and the cladding long term creep for the closed system evolution, the kinetics of oxidation and the RN source term for the evolution in gaseous atmosphere, and the radiolytic dissolution and RN source term in presence of water. (author)

  14. Effects of oxymetazoline nasal spray on the nasal cycle assessed by long-term rhinoflowmetry.

    Science.gov (United States)

    Braun, Thomas; Rich, Maria; Berghaus, Alexander; Kramer, Matthias F

    2012-12-01

    Long-term rhinoflowmetry assesses bilateral nasal flow over 24 hours. In the present study, we evaluated the effects of a standard dose of oxymetazoline topical nasal spray, a widely used over-the-counter drug, on the nasal cycle, since the exact long-term effects, such as the duration of the decongestive effect, are not yet reported. Thirty healthy volunteers received a portable long-term rhinoflowmetry device and applied 22.5 μg oxymetazoline in each nostril. In 90 % of the probands, effects of the nasal spray application could be seen as changes in nasal flow. A decongestive effect could be seen after 18 minutes on average. We found a mean duration of the maximal decongestive effect of four hours. However, it took more than six hours on average until the nasal cycle resumed its normal condition. We did not find significant differences of the effect between probands with a 'classic,' 'in concert' or impaired nasal cycle. In contrast to a substantial interindividual variability, repeated measurements showed that intraindividual variability of the effect of decongestive nasal spray seems to be rather small. Long-term rhinoflowmetry, yielding reliable results, is a valuable tool in the assessment of the effects of nasal drugs on the nasal cycle.

  15. Fuel cycle oriented approach

    International Nuclear Information System (INIS)

    Petit, A.

    1987-01-01

    The term fuel cycle oriented approach is currently used to designate two quite different things: the attempt to consider all or part of a national fuel cycle as one material balance area (MBA) or to consider individual MBAs existing in a state while designing a unique safeguards approach for each and applying the principle of nondiscrimination to fuel cycles as a whole, rather than to individual facilities. The merits of such an approach are acceptability by the industry and comparison with the contemplated establishment of long-term criteria. The following points concern the acceptability by the industry: (1) The main interest of the industry is to keep an open international market and therefore, to have effective and efficient safeguards. (2) The main concerns of the industry regarding international safeguards are economic burden, intrusiveness, and discrimination. Answers to these legitimate concerns, which retain the benefits of a fuel cycle oriented approach, are needed. More specifically, the problem of reimbursing the operator the costs that he has incurred for the safeguards must be considered

  16. Long-term storage of spent fuel from the Rossendorf research reactor

    International Nuclear Information System (INIS)

    Hieronymus, W.

    1983-01-01

    Long-term dry storage is in preparation for the Rossendorf Research Reactor (RFR) spent fuel with an average burnup of about 150,000 MWd/t U. Considering the situation at the RFR, drywell storage is obviously favourable. Problems of decay heat removal, radiation protection, and critical safety are discussed. (author)

  17. The long-term storage of spent nuclear fuel from the Rossendorf Research Reactor

    International Nuclear Information System (INIS)

    Hieronymus, W.

    1990-07-01

    Long-term dry storage is being prepared for the spent nuclear fuel of the Rossendorf Research Reactor (RFR) with an average burn-up of 150,000 M W d/t. With regard to the situation at RFR dry shaft storage is advantageous. The problems of after-heat removal, protection from radiation and criticality safety are discussed. (author)

  18. Long-term capital planning considering nuclear plant life-cycle management

    International Nuclear Information System (INIS)

    Negin, C.A.; Simpson, J.M.; Hostetler, D.R.

    1992-09-01

    The creation of a Life Cycle Management (LCM) group at utilities to evaluate the long term capital refurbishment needs is gaining favor. Among the functions of such groups can be the responsibility for recommending long term capital planning projects based on results of evaluations of systems, structures, and components that are not only essential to achieving the full current license term of operation, but also to extend the service life of the plant. Making such recommendations, in content and timing, requires the ability to view all recommendations in the context of an overall capital budget and long range outage impacts. This report illustrates an approach for creating a Long-Term Capital Plan with methods for deciding on, compiling, integrating, and presenting projects from the perspective of an LCM program for a nuclear power plant. It also addresses a rationale for capitalization of LCM program activities that would not be allowed under current accounting treatment

  19. MTR spent fuel back-end - Cogema's long-term commitment

    International Nuclear Information System (INIS)

    Thomasson, J.

    1998-01-01

    MTR spent fuel back end has been subject to many reversal and uncertainties in the past 10 years. Until the end of 1988, US obligated materials were subject to the Off site Fuels Policy (OFP). Under this policy, spent fuels were returned to USA, and were reprocessed there. This OFP took end the 31th of December 1988, and Research Reactor's operators had to implement others solutions: On site storage or Reprocessing in Europe. Meanwhile the RERTR Program was leading to a new LEU fuel to replace HEU aluminide. This new silicide fuel has one main drawback: it cannot be reprocessed in working plants without some process main line modifications. Fortunately, a new Research Reactors spent fuels return policy has been set up by the US in the early 1996. This new policy applies to all reactors converted or that have agreed to convert to LEU, and reactors operating with HEU for which no suitable LEU is available. It covers all the spent fuels discharged until 2006/05/12. But after that period of time, each reactor will be fully responsible for its spent fuels. Since the end of 1996, COGEMA is proposing reprocessing services for Aluminides spent fuels, based on the La Hague capability. This COGEMA answer is for the long term, as the La Hague plant has a good load for the coming years, including the first decade of the next century. Further, this activity benefits from a strong R and D support, that allowed fulfilling the evolutive needs of our customers, and gives us the ability to adapt the plant to the future market. Taking advantage of this flexibility, COGEMA offers Research Reactors' operators a long-term commitment. Already two reactors' operators have chosen to contract with COGEMA for the whole life of their reactors. The contracts execution is under progress and the first transportation will take place soon. Beside today's services, COGEMA is involved in R and D activities to support new fuels development enhancing present LEU performances and having the ability to

  20. The long term storage of advanced gas-cooled reactor (AGR) fuel

    International Nuclear Information System (INIS)

    Standring, P.N.

    1999-01-01

    The approach being taken by BNFL in managing the AGR lifetime spent fuel arisings from British Energy reactors is given. Interim storage for up to 80 years is envisaged for fuel delivered beyond the life of the Thorp reprocessing plant. Adopting a policy of using existing facilities, to comply with the principles of waste minimisation, has defined the development requirements to demonstrate that this approach can be undertaken safely and business issues can be addressed. The major safety issues are the long term integrity of both the fuel being stored and structure it is being stored in. Business related issues reflect long term interactions with the rest of the Sellafield site and storage optimisation. Examples of the development programme in each of these areas is given. (author)

  1. Synthesis on the long term behavior of spent nuclear fuel. Vol.1,2

    International Nuclear Information System (INIS)

    Poinssot, Ch.; Toulhoat, P.; Grouiller, J.P.; Pavageau, J.; Piron, J.P.; Pelletier, M.; Dehaudt, Ph.; Cappelaere, Ch.; Limon, R.; Desgranges, L.; Jegou, Ch.; Corbel, C.; Maillard, S.; Faure, M.H.; Cicariello, J.C.; Masson, M.

    2001-01-01

    The aim of this report is to present the major objectives, the key scientific issues, and the preliminary results of the research conducted in France in the framework of the third line of the 1991 Law, on the topic of the long term behavior of spent nuclear fuel in view of long term storage or geological disposal. Indeed, CEA launched in 1998 the Research Program on the Long Term Behavior of Spent Nuclear Fuel (abbreviated and referred to as PRECCI in French; Poinssot, 1998) the aim of which is to study and assess the ability of spent nuclear fuel packages to keep their initially allocated functions in interim storage and geological disposal: total containment and recovery functions for duration up to hundreds of years (long term or short-term interim storage and/or first reversible stages of geological disposal) and partial confinement function (controlled fluxes of RN) for thousands of years in geological disposal. This program has to allow to obtain relevant and reliable data concerning the long term behavior of the spent fuel packages so that feasibility of interim storage and/or geological disposal can be assessed and demonstrated as well as optimized. Within this framework, this report presents for every possible scenario of evolution (closed system, in Presence of water in presence of gases) what are estimated to be the most relevant evolution mechanism. For the most relevant scientific issues hence defined, a complete scientific review of the best state of knowledge is subsequently here given thus allowing to draw a clear guideline of the major R and D issues for the next years. (authors)

  2. Long-term variations in the geomagnetic activity level Part II: Ascending phases of sunspot cycles

    Directory of Open Access Journals (Sweden)

    V. Mussino

    1994-08-01

    Full Text Available Monthly averages of the Helsinki Ak-values have been reduced to the equivalent aa-indices to extend the aa-data set back to 1844. A periodicity of about five cycles was found for the correlation coefficient (r between geomagnetic indices and sunspot numbers for the ascending phases of sunspot cycles 9 to 22, confirming previous findings based on a minor number of sunspot cycles. The result is useful to researchers in topics related to solar-terrestrial physics, particularly for the interpretation of long-term trends in geomagnetic activity during the past, and to forecast geomagnetic activity levels in the future.

  3. Long term performance degradation analysis and optimization of anode supported solid oxide fuel cell stacks

    International Nuclear Information System (INIS)

    Parhizkar, Tarannom; Roshandel, Ramin

    2017-01-01

    Highlights: • A degradation based optimization framework is developed. • The cost of electricity based on degradation of solid oxide fuel cells is minimized. • The effects of operating conditions on degradation mechanisms are investigated. • Results show 7.12% lower cost of electricity in comparison with base case. • Degradation based optimization is a beneficial concept for long term analysis. - Abstract: The main objective of this work is minimizing the cost of electricity of solid oxide fuel cell stacks by decelerating degradation mechanisms rate in long term operation for stationary power generation applications. The degradation mechanisms in solid oxide fuel cells are caused by microstructural changes, reactions between lanthanum strontium manganite and electrolyte, poisoning by chromium, carburization on nickel particles, formation of nickel sulfide, nickel coarsening, nickel oxidation, loss of conductivity and crack formation in the electrolyte. The rate of degradation mechanisms depends on the cell operating conditions (cell voltage and fuel utilization). In this study, the degradation based optimization framework is developed which determines optimum operating conditions to achieve a minimum cost of electricity. To show the effectiveness of the developed framework, optimization results are compared with the case that system operates at its design point. Results illustrate optimum operating conditions decrease the cost of electricity by 7.12%. The performed study indicates that degradation based optimization is a beneficial concept for long term performance degradation analysis of energy conversion systems.

  4. Integrated scheme of long-term for spent fuel management of power nuclear reactors

    International Nuclear Information System (INIS)

    Ramirez S, J. R.; Palacios H, J. C.; Martinez C, E.

    2015-09-01

    After of irradiation of the nuclear fuel in the reactor core, is necessary to store it for their cooling in the fuel pools of the reactor. This is the first step in a processes series before the fuel can reach its final destination. Until now there are two options that are most commonly accepted for the end of the nuclear fuel cycle, one is the open nuclear fuel cycle, requiring a deep geological repository for the fuel final disposal. The other option is the fuel reprocessing to extract the plutonium and uranium as valuable materials that remaining in the spent fuel. In this study the alternatives for the final part of the fuel cycle, which involves the recycling of plutonium and the minor actinides in the same reactor that generated them are shown. The results shown that this is possible in a thermal reactor and that there are significant reductions in actinides if they are recycled into reactor fuel. (Author)

  5. Thorium fuel cycle management

    International Nuclear Information System (INIS)

    Zajac, R.; Darilek, P.; Breza, J.; Necas, V.

    2010-01-01

    In this presentation author deals with the thorium fuel cycle management. Description of the thorium fuels and thorium fuel cycle benefits and challenges as well as thorium fuel calculations performed by the computer code HELIOS are presented.

  6. Long Term Performance Study of a Direct Methanol Fuel Cell Fed with Alcohol Blends

    Directory of Open Access Journals (Sweden)

    Eleuterio Mora

    2013-01-01

    Full Text Available The use of alcohol blends in direct alcohol fuel cells may be a more environmentally friendly and less toxic alternative to the use of methanol alone in direct methanol fuel cells. This paper assesses the behaviour of a direct methanol fuel cell fed with aqueous methanol, aqueous ethanol and aqueous methanol/ethanol blends in a long term experimental study followed by modelling of polarization curves. Fuel cell performance is seen to decrease as the ethanol content rises, and subsequent operation with aqueous methanol only partly reverts this loss of performance. It seems that the difference in the oxidation rate of these alcohols may not be the only factor affecting fuel cell performance.

  7. Effects of Radiation and Long-Term Thermal Cycling on EPC 1001 Gallium Nitride Transistors

    Science.gov (United States)

    Patterson, Richard L.; Scheick, Leif; Lauenstein, Jean-Marie; Casey, Megan; Hammoud, Ahmad

    2012-01-01

    Electronics designed for use in NASA space missions are required to work efficiently and reliably under harsh environment conditions. These include radiation, extreme temperatures, and thermal cycling, to name a few. Data obtained on long-term thermal cycling of new un-irradiated and irradiated samples of EPC1001 gallium nitride enhancement-mode transistors are presented. This work was done by a collaborative effort including GRC, GSFC, and support the NASA www.nasa.gov 1 JPL in of Electronic Parts and Packaging (NEPP) Program

  8. The sunspot cycle no. 24 in relation to long term solar activity variation.

    Science.gov (United States)

    Komitov, Boris; Kaftan, Vladimir

    2013-05-01

    The solar minimum between solar cycles 23 and 24 during the period 2007-2009 has been the longest and deepest one at least since for the last 100 years. We suggest that the Sun is going to his next supercenturial minimum. The main aim of this paper is to tell about arguments concerning this statement. They are based on series of studies, which have been provided during the period since 1997 up to 2010. The progress of solar cycle 24 since its minimum at the end of 2008 up to the end of October 2011 in the light of long term solar activity dynamics is analyzed.

  9. The ability to pay for long-term care in the Netherlands : A life-cycle perspective

    NARCIS (Netherlands)

    Hussem, Arjen; van Ewijk, Casper; ter Rele, Harry; Wong, Albert

    This paper uses synthetic life-cycle paths at the individual level to analyze the distribution of long-term care expenditures in the Netherlands. Using a comprehensive set of administrative data 20,000 synthetic life-cycle paths of household income and long-term care costs are constructed using the

  10. Parametric Analysis of PWR Spent Fuel Depletion Parameters for Long-Term-Disposal Criticality Safety

    International Nuclear Information System (INIS)

    DeHart, M.D.

    1999-01-01

    Utilization of burnup credit in criticality safety analysis for long-term disposal of spent nuclear fuel allows improved design efficiency and reduced cost due to the large mass of fissile material that will be present in the repository. Burnup-credit calculations are based on depletion calculations that provide a conservative estimate of spent fuel contents (in terms of criticality potential), followed by criticality calculations to assess the value of the effective neutron multiplication factor (k(sub)eff) for the a spent fuel cask or a fuel configuration under a variety of probabilistically derived events. In order to ensure that the depletion calculation is conservative, it is necessary to both qualify and quantify assumptions that can be made in depletion models

  11. Criticality safety evaluation for long term storage of FFTF fuel in interim storage casks

    International Nuclear Information System (INIS)

    Richard, R.F.

    1995-01-01

    It has been postulated that a degradation phenomenon, referred to as ''hot cell rot'', may affect irradiated FFTF mixed plutonium-uranium oxide (MOX) fuel during dry interim storage. ''Hot cell rot'' refers to a variety of phenomena that degrade fuel pin cladding during exposure to air and inert gas environments. It is thought to be a form of caustic stress corrosion cracking or environmentally assisted cracking. Here, a criticality safety analysis was performed to address the effect of the ''hot cell rot'' phenomenon on the long term storage of irradiated FFTF fuel in core component containers. The results show that seven FFTF fuel assemblies or six Ident-69 pin containers stored in core component containers within interim storage casks will remain safely subcritical

  12. Risk assessment in long-term storage of spent nuclear fuel

    International Nuclear Information System (INIS)

    Ahn, T.; Guttmann, J.; Mohseni, A.

    2013-01-01

    This paper presents probabilistic risk-informed approaches that the Nuclear Regulatory Commission (NRC) staff is planning to consider in preparing regulatory bases for long-term storage of spent nuclear fuel (SNF) for up to 300 years. Due to uncertainties associated with long-term SNF storage, the NRC is considering a probabilistic risk-informed approach as well as a deterministic design-based approach. The uncertainties considered here are primarily associated with materials aging of the canister and SNF in the cask system during long-term storage of SNF. This paper discusses some potential risk contributors involved in long-term SNF storage. Methods of performance evaluation are presented that assess the various types of risks involved. They include deterministic evaluation, probabilistic evaluation, and consequence assessment under normal conditions and the conditions of accidents and natural hazards. Some potentially important technical issues resulting from the consideration of a probabilistic risk-informed evaluation of the cask system performance are discussed for the canister and SNF integrity. These issues are also discussed in comparison with the deterministic approach for comparison purposes, as appropriate. Probabilistic risk-informed methods can provide insights that deterministic methods may not capture. Two specific examples include stress corrosion cracking of the canister and hydrogen-induced cladding failure. These examples are discussed in more detail, in terms of their effects on radionuclide release and nuclear subcriticality associated with the failure. The plan to consider the probabilistic risk-informed approaches is anticipated to provide helpful regulatory insights for long-term storage of SNF that provide reasonable assurance for public health and safety. (authors)

  13. LOSCAR: Long-term Ocean-atmosphere-Sediment CArbon cycle Reservoir Model

    Science.gov (United States)

    Zeebe, R. E.

    2011-06-01

    The LOSCAR model is designed to efficiently compute the partitioning of carbon between ocean, atmosphere, and sediments on time scales ranging from centuries to millions of years. While a variety of computationally inexpensive carbon cycle models are already available, many are missing a critical sediment component, which is indispensable for long-term integrations. One of LOSCAR's strengths is the coupling of ocean-atmosphere routines to a computationally efficient sediment module. This allows, for instance, adequate computation of CaCO3 dissolution, calcite compensation, and long-term carbon cycle fluxes, including weathering of carbonate and silicate rocks. The ocean component includes various biogeochemical tracers such as total carbon, alkalinity, phosphate, oxygen, and stable carbon isotopes. We have previously published applications of the model tackling future projections of ocean chemistry and weathering, pCO2 sensitivity to carbon cycle perturbations throughout the Cenozoic, and carbon/calcium cycling during the Paleocene-Eocene Thermal Maximum. The focus of the present contribution is the detailed description of the model including numerical architecture, processes and parameterizations, tuning, and examples of input and output. Typical CPU integration times of LOSCAR are of order seconds for several thousand model years on current standard desktop machines. The LOSCAR source code in C can be obtained from the author by sending a request to loscar.model@gmail.com.

  14. Long term fuel price elasticity: effects on mobility tool ownership and residential location choice - Final report

    Energy Technology Data Exchange (ETDEWEB)

    Erath, A.; Axhausen, K. W.

    2010-04-15

    This comprehensive final report for the Swiss Federal Office of Energy (SFOE) examines the long-term effects of fuel price elasticity. The study analyses how mobility tool usage and ownership as well as residence location choice are affected by rising fuel costs. Based on econometric models, long-term fuel price elasticity is derived. The authors quote that the demand reactions to higher fuel prices mainly observed are the reduction of mileage and the consideration of smaller-engined and diesel-driven cars. As cars with natural gas powered engines and electric drives were hardly considered in the survey, the results of the natural gas model can, according to the authors, only serve as a trend. No stable model could be estimated for the demand and usage of electric cars. A literature overview is presented and the design of the survey is discussed, whereby socio-demographical variables and the effects of price and residence changes are discussed. Modelling of mobility tool factors and results obtained are looked at. Finally, residence choice factors are modelled and discussed. Several appendices complete the report.

  15. Towards Support for Long-Term Digital Preservation in Product Life Cycle Management

    Directory of Open Access Journals (Sweden)

    Wolfgang Wilkes

    2011-03-01

    Full Text Available Important legal and economic motivations exist for the design and engineering industry to address and integrate digital long-term preservation into product life cycle management (PLM. Investigations revealed that it is not sufficient to archive only the product design data which is created in early PLM phases, but preservation is needed for data that is produced during the entire product lifecycle including early and late phases. Data that is relevant for preservation consists of requirements analysis documents, design rationale, data that reflects experiences during product operation and also metadata like social collaboration context. In addition, also the engineering environment itself that contains specific versions of all tools and services is a candidate for preservation. This paper takes a closer look at engineering preservation use case scenarios as well as PLM characteristics and workflows that are relevant for long-term preservation. Resulting requirements for a long-term preservation system lead to an OAIS (Open Archival Information System based system architecture and a proposed preservation service interface that respects the needs of the engineering industry.

  16. International long-term interim storage for spent fuel. An independent storage service investor model

    International Nuclear Information System (INIS)

    Leister, P.

    1999-01-01

    Thinking globally the obvious world-wide demands for large storage capacities for spent fuel within the next decades and the newly arising demands for long-term interim storage of spent fuel urges to respond by international interim storage facilities of high capacity. Low cost storage can be achieved only by arranging the storage facility underground in a suitable host rock formation and by selecting the geographical are by an international competition under those countries, who are willing to offer their land. The investor and operator of an international storage facility selected and realised by a competition on the free market as well as the country where the storage is built are both bound by two different kinds of contacts. The main contract is between the offering country/region and the independent operator. The independent operator has in addition a series of contracts with various utilities, which are interested to have their spent fuel stored for a longer period

  17. Advanced surveillance technologies for used fuel long-term storage and transportation - 59032

    International Nuclear Information System (INIS)

    Tsai, Hanchung; Liu, Yung Y.; Nutt, Mark; Shuler, James

    2012-01-01

    Utilities worldwide are using dry-cask storage systems to handle the ever-increasing number of discharged fuel assemblies from nuclear power plants. In the United States and possibly elsewhere, this trend will continue until an acceptable disposal path is established. The recent Fukushima nuclear power plant accident, specifically the events with the storage pools, may accelerate the drive to relocate more of the used fuel assemblies from pools into dry casks. Many of the newer cask systems incorporate dual-purpose (storage and transport) or multiple-purpose (storage, transport, and disposal) canister technologies. With the prospect looming for very long term storage - possibly over multiple decades - and deferred transport, condition- and performance-based aging management of cask structures and components is now a necessity that requires immediate attention. From the standpoint of consequences, one of the greatest concerns is the rupture of a substantial number of fuel rods that would affect fuel retrievability. Used fuel cladding may become susceptible to rupture due to radial-hydride-induced embrittlement caused by water-side corrosion during the reactor operation and subsequent drying/transfer process, through early stage of storage in a dry cask, especially for high burnup fuels. Radio frequency identification (RFID) is an automated data capture and remote-sensing technology ideally suited for monitoring sensitive assets on a long-term, continuous basis. One such system, called ARG-US, has been developed by Argonne National Laboratory for the U.S. Department of Energy's Packaging Certification Program for tracking and monitoring drums containing sensitive nuclear and radioactive materials. The ARG-US RFID system is versatile and can be readily adapted for dry-cask monitoring applications. The current built-in sensor suite consists of seal, temperature, humidity, shock, and radiation sensors. With the universal asynchronous receiver/transmitter interface in

  18. Decay heat power of spent nuclear fuel of power reactors with high burnup at long-term storage

    Science.gov (United States)

    Ternovykh, Mikhail; Tikhomirov, Georgy; Saldikov, Ivan; Gerasimov, Alexander

    2017-09-01

    Decay heat power of actinides and fission products from spent nuclear fuel of power VVER-1000 type reactors at long-term storage is calculated. Two modes of storage are considered: mode in which single portion of actinides or fission products is loaded in storage facility, and mode in which actinides or fission products from spent fuel of one VVER reactor are added every year in storage facility during 30 years and then accumulated nuclides are stored without addition new nuclides. Two values of fuel burnup 40 and 70 MW·d/kg are considered for the mode of storage of single fuel unloading. For the mode of accumulation of spent fuel with subsequent storage, one value of burnup of 70 MW·d/kg is considered. Very long time of storage 105 years accepted in calculations allows to simulate final geological disposal of radioactive wastes. Heat power of fission products decreases quickly after 50-100 years of storage. The power of actinides decreases very slow. In passing from 40 to 70 MW·d/kg, power of actinides increases due to accumulation of higher fraction of 244Cm. These data are important in the back end of fuel cycle when improved cooling system of the storage facility will be required along with stronger radiation protection during storage, transportation and processing.

  19. Decay heat power of spent nuclear fuel of power reactors with high burnup at long-term storage

    Directory of Open Access Journals (Sweden)

    Ternovykh Mikhail

    2017-01-01

    Full Text Available Decay heat power of actinides and fission products from spent nuclear fuel of power VVER-1000 type reactors at long-term storage is calculated. Two modes of storage are considered: mode in which single portion of actinides or fission products is loaded in storage facility, and mode in which actinides or fission products from spent fuel of one VVER reactor are added every year in storage facility during 30 years and then accumulated nuclides are stored without addition new nuclides. Two values of fuel burnup 40 and 70 MW·d/kg are considered for the mode of storage of single fuel unloading. For the mode of accumulation of spent fuel with subsequent storage, one value of burnup of 70 MW·d/kg is considered. Very long time of storage 105 years accepted in calculations allows to simulate final geological disposal of radioactive wastes. Heat power of fission products decreases quickly after 50-100 years of storage. The power of actinides decreases very slow. In passing from 40 to 70 MW·d/kg, power of actinides increases due to accumulation of higher fraction of 244Cm. These data are important in the back end of fuel cycle when improved cooling system of the storage facility will be required along with stronger radiation protection during storage, transportation and processing.

  20. Long-term climate policy implications of phasing out fossil fuel subsidies

    International Nuclear Information System (INIS)

    Schwanitz, Valeria Jana; Piontek, Franziska; Bertram, Christoph; Luderer, Gunnar

    2014-01-01

    It is often argued that fossil fuel subsidies hamper the transition towards a sustainable energy supply as they incentivize wasteful consumption. We assess implications of a subsidy phase-out for the mitigation of climate change and the low-carbon transformation of the energy system, using the global energy–economy model REMIND. We compare our results with those obtained by the International Energy Agency (based on the World Energy Model) and by the Organization for Economic Co-Operation and Development (OECD-Model ENV-Linkages), providing the long-term perspective of an intertemporal optimization model. The results are analyzed in the two dimensions of subsidy phase-out and climate policy scenarios. We confirm short-term benefits of phasing-out fossil fuel subsidies as found in prior studies. However, these benefits are only sustained to a small extent in the long term, if dedicated climate policies are weak or nonexistent. Most remarkably we find that a removal of fossil fuel subsidies, if not complemented by other policies, can slow down a global transition towards a renewable based energy system. The reason is that world market prices for fossil fuels may drop due to a removal of subsidies. Thus, low carbon alternatives would encounter comparative disadvantages. - Highlights: • We assess implications of phasing out fossil fuel subsidies on the mitigation of climate change. • The removal of subsidies leads to a net-reduction in the use of energy. • Emission reductions contribute little to stabilize greenhouse gases at 450 ppm if not combined with climate policies. • Low carbon alternatives may encounter comparative disadvantages due to relative price changes at world markets

  1. Biogeochemical Cycling and Environmental Stability of Pu Relevant to Long-Term Stewardship of DOE Sites

    Energy Technology Data Exchange (ETDEWEB)

    Honeyman, Bruce D.

    2006-06-01

    The overall objective of this proposed research is to understand the biogeochemical cycling of Pu in environments of interest to long-term DOE stewardship issues. Central to Pu cycling (transport initiation to immobilization) is the role of microorganisms. The hypothesis underlying this proposal is that microbial activity is the causative agent in initiating the mobilization of Pu in near-surface environments: through the transformation of Pu associated with solid phases, production of extracellular polymeric substances (EPS) carrier phases, and the creation of microenvironments. Also, microbial processes are central to the immobilization of Pu species, through the metabolism of organically complexed Pu species and Pu associated with extracellular carrier phases and the creation of environments favorable for Pu transport retardation.

  2. Biogeochemical Cycling and Environmental Stability of Pu Relevant to Long-Term Stewardship of DOE Sites

    Energy Technology Data Exchange (ETDEWEB)

    Francis, Arokiasamy J.; Santschi, Peter H.; Honeyman, Bruce D.

    2005-06-01

    The overall objective of this proposed research is to understand the biogeochemical cycling of Pu in environments of interest to long-term DOE stewardship issues. Central to Pu cycling (transport initiation to immobilization) is the role of microorganisms. The hypothesis underlying this proposal is that microbial activity is the causative agent in initiating the mobilization of Pu in near-surface environments: through the transformation of Pu associated with solid phases, production of extracellular polymeric substances (EPS) carrier phases, and the creation of microenvironments. Also, microbial processes are central to the immobilization of Pu species, through the metabolism of organically complexed Pu species and Pu associated with extracellular carrier phases and the creation of environments favorable for Pu transport retardation.

  3. Diesel fuel long term storage and treatment- recommended tests and practices (U)

    Energy Technology Data Exchange (ETDEWEB)

    Gross, R. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2009-06-05

    The Clean Air Act (1970) is the comprehensive federal law that regulates air emissions from stationary and mobile sources. Among other things, this law authorized the Environmental Protection Agency (EPA) to establish National Ambient Air Quality Standards to protect public health and public welfare and to regulate emissions of hazardous air pollutants. In recent years, EPA regulations have forced oil refineries into producing a very low sulfur diesel fuel and incentives for adding up to 5% bio-diesel. These changes to the fuel oil formulation are beneficial to air quality and to energy conservation, but adversely impact heat content, long term storage stability, engine power, and injection system reliability. Diesel engines typically have a high incidence of injector failure resulting from poor diesel fuel quality. Since standby diesel engines do not run continuously it is necessary to implement periodic surveillance's to ensure the quality of diesel fuel is acceptable for reliable operation when a loss of power occurs. The information contained in this document is a compilation of best practices to be used as a guide for maintenance of a reliable diesel fuel system.

  4. Optimization of the fuel cycle

    International Nuclear Information System (INIS)

    Kidd, S.W.; Balu, K.; Boczar, P.G.; Krebs, W.D.

    1999-01-01

    The nuclear fuel cycle can be optimized subject to a wide range of criteria. Prime amongst these are economics, sustainability of resources, environmental aspects, and proliferation-resistance of the fuel cycle. Other specific national objectives will also be important. These criteria, and their relative importance, will vary from country to country, and with time. There is no single fuel cycle strategy that is optimal for all countries. Within the short term, the industry is attached to dominant thermal reactor technologies, which themselves have two main variants, a cycle closed by reprocessing of spent fuel and subsequent recycling and a once through one where spent fuel is stored in advance of geological disposal. However, even with current technologies, much can be done to optimize the fuel cycles to meet the relevant criteria. In the long term, resource sustainability can be assured for centuries through the use of fast breeder reactors, supporting high-conversion thermal reactors, possibly also utilizing the thorium cycle. These must, however, meet the other key criteria by being both economic and safe. (author)

  5. DEMONSTRATION OF LONG-TERM STORAGE CAPABILITY FOR SPENT NUCLEAR FUEL IN L BASIN

    Energy Technology Data Exchange (ETDEWEB)

    Sindelar, R.; Deible, R.

    2011-04-27

    The U.S. Department of Energy decisions for the ultimate disposition of its inventory of used nuclear fuel presently in, and to be received and stored in, the L Basin at the Savannah River Site, and schedule for project execution have not been established. A logical decision timeframe for the DOE is following the review of the overall options for fuel management and disposition by the Blue Ribbon Commission on America's Nuclear Future (BRC). The focus of the BRC review is commercial fuel; however, the BRC has included the DOE fuel inventory in their review. Even though the final report by the BRC to the U.S. Department of Energy is expected in January 2012, no timetable has been established for decisions by the U.S. Department of Energy on alternatives selection. Furthermore, with the imminent lay-up and potential closure of H-canyon, no ready path for fuel disposition would be available, and new technologies and/or facilities would need to be established. The fuel inventory in wet storage in the 3.375 million gallon L Basin is primarily aluminum-clad, aluminum-based fuel of the Materials Test Reactor equivalent design. An inventory of non-aluminum-clad fuel of various designs is also stored in L Basin. Safe storage of fuel in wet storage mandates several high-level 'safety functions' that would be provided by the Structures, Systems, and Components (SSCs) of the storage system. A large inventory of aluminum-clad, aluminum-based spent nuclear fuel, and other nonaluminum fuel owned by the U.S. Department of Energy is in wet storage in L Basin at the Savannah River Site. An evaluation of the present condition of the fuel, and the Structures, Systems, or Components (SSCs) necessary for its wet storage, and the present programs and storage practices for fuel management have been performed. Activities necessary to validate the technical bases for, and verify the condition of the fuel and the SSCs under long-term wet storage have also been identified. The

  6. High-level radioactive wastes storage characterization and behaviour of spent fuels in long-term

    International Nuclear Information System (INIS)

    Diaz Arocas, P.; Cobos, J.; Quinones, J.; Rodriguez Almazan, J. L.; Serrano, J.

    2001-01-01

    In order to understand the long term spent fuel dissolution under repository this report shows the study performed by considering spent fuel as a part of the multi barriers containment system. The study takes into account that the oxidative alteration/dissolution of spent fuel matrix is influenced by the intrinsic spent fuel physicochemical characteristics and the repository environmental parameters. Experimental and modelling results for granite and saline repositories are reported. Parameters considered in this work were pH, pCO 2 , S/V ratio, redox conditions and the influence of the container material in the redox conditions. The influence of alpha, beta and gamma radiation and the resulting radiolytic products formed remains as one of the main uncertainties to quantify the spent fuel behaviour under repository conditions. It was studied in a first approach through dose calculations, modelling of radiolytic products formation and leaching experiments in the presence of external gamma irradiation source and leaching experiments of alpha doped UO 2 pellets. Materials considered are LWR spent fuel (UO 2 and MOX fuel) and their chemical analogues non irradiated UO 2 , SIMFUEL and alpha doped UO 2 . Lea chants were granite groundwater, synthetic granite groundwater, synthetic granite groundwater saturated in bentonite, and high concentrated saline solutions. The matrix dissolution rate and release rate of key radionuclides (i. e. actinides and fission products) obtained through the several experimental techniques and methodologies (dissolution, co-dissolution, precipitation and co-precipitation) together with modelling studies supported in geochemical codes are proposed. Moreover, secondary phases formed that could control release and retention of key nuclides are identified. Maximum concentration values for these radionuclides are reported. The data provided by this study were used in ENRESA-2000 performance assessment. (Author)

  7. Measuring brain activity cycling (BAC) in long term EEG monitoring of preterm babies

    International Nuclear Information System (INIS)

    Stevenson, Nathan J; Palmu, Kirsi; Wikström, Sverre; Hellström-Westas, Lena; Vanhatalo, Sampsa

    2014-01-01

    Measuring fluctuation of vigilance states in early preterm infants undergoing long term intensive care holds promise for monitoring their neurological well-being. There is currently, however, neither objective nor quantitative methods available for this purpose in a research or clinical environment. The aim of this proof-of-concept study was, therefore, to develop quantitative measures of the fluctuation in vigilance states or brain activity cycling (BAC) in early preterm infants. The proposed measures of BAC were summary statistics computed on a frequency domain representation of the proportional duration of spontaneous activity transients (SAT%) calculated from electroencephalograph (EEG) recordings. Eighteen combinations of three statistics and six frequency domain representations were compared to a visual interpretation of cycling in the SAT% signal. Three high performing measures (band energy/periodogram: R = 0.809, relative band energy/nonstationary frequency marginal: R = 0.711, g-statistic/nonstationary frequency marginal: R = 0.638) were then compared to a grading of sleep wake cycling based on the visual interpretation of the amplitude-integrated EEG trend. These measures of BAC are conceptually straightforward, correlate well with the visual scores of BAC and sleep wake cycling, are robust enough to cope with the technically compromised monitoring data available in intensive care units, and are recommended for further validation in prospective studies. (paper)

  8. Post-Irradiation Examinations for Resolving Fuel Issues in Long Term Storage

    International Nuclear Information System (INIS)

    Karlsson, Joakim K.H.; Alvarez Holston, Anna-Maria

    2014-01-01

    In many countries extended long term dry storage is the solution for storage of spent nuclear fuel for the foreseeable future. The expected storage times have increased over the last years and today storage times of up to 300 years is anticipated. With such long storage times, requirements on transportability and retrievability of the fuel have become more important. Hitherto most investigations on fuel behaviour during dry storage have been focused on cladding creep and the impact of hydrogen and hydrides in the cladding. Creep data gives input to creep models and creep to rupture data helps to set criteria for maximum allowable internal rod pressure. Hydrides lower the ductility of the cladding and this is more pronounced with radially oriented hydrides. As the temperature decreases over time in a dry storage cask dissolved hydrogen will precipitate forming hydrides in addition to hydrides already present. Assuming there is sufficient hoop stress in the cladding, the new hydrides would be radially oriented. Together with lost ductility Delayed Hydride Cracking (DHC) could be a potential mechanism for rod failure over tens of years of dry storage as the temperature drops from about 350 deg. C to 150 deg. C. Hydride embrittlement and the DHC mechanism have been studied in the first Studsvik Cladding Integrity Project (SCIP), although the focus in this program has mainly been on higher temperatures relevant for operating conditions rather than on dry storage conditions. In addition to the mechanisms mentioned there are other failure mechanisms that could potentially threaten the cladding fuel integrity and retrievability. In case there is residual water or moisture available in the cask, or even in the fuel due to existing fuel failures, radiolysis gives free hydrogen and oxygen. In failed fuel this may cause fuel oxidation and swelling affecting fuel integrity. The hydrogen gas pressure will not threaten the cask but be available for cladding uptake. Furthermore

  9. The role of tectonic uplift, climate, and vegetation in the long-term terrestrial phosphorous cycle

    Directory of Open Access Journals (Sweden)

    C. Buendía

    2010-06-01

    Full Text Available Phosphorus (P is a crucial element for life and therefore for maintaining ecosystem productivity. Its local availability to the terrestrial biosphere results from the interaction between climate, tectonic uplift, atmospheric transport, and biotic cycling. Here we present a mathematical model that describes the terrestrial P-cycle in a simple but comprehensive way. The resulting dynamical system can be solved analytically for steady-state conditions, allowing us to test the sensitivity of the P-availability to the key parameters and processes. Given constant inputs, we find that humid ecosystems exhibit lower P availability due to higher runoff and losses, and that tectonic uplift is a fundamental constraint. In particular, we find that in humid ecosystems the biotic cycling seem essential to maintain long-term P-availability. The time-dependent P dynamics for the Franz Josef and Hawaii chronosequences show how tectonic uplift is an important constraint on ecosystem productivity, while hydroclimatic conditions control the P-losses and speed towards steady-state. The model also helps describe how, with limited uplift and atmospheric input, as in the case of the Amazon Basin, ecosystems must rely on mechanisms that enhance P-availability and retention. Our novel model has a limited number of parameters and can be easily integrated into global climate models to provide a representation of the response of the terrestrial biosphere to global change.

  10. Copper current collectors reduce long-term fouling of air cathodes in microbial fuel cells

    KAUST Repository

    Myung, Jaewook

    2018-02-05

    Long-term operation of wastewater-fed, microbial fuel cells (MFCs) with cathodes made of activated carbon and stainless steel (SS) current collectors can result in decreased performance due to cathode fouling. Copper has good antimicrobial properties, and it is more electrically conductive than SS. To demonstrate that a copper current collector could produce a more fouling resistant cathode, MFCs with air cathodes using either SS or copper current collectors were operated using domestic wastewater for 27 weeks. The reduction in biofouling over time was shown by less biofilm formation on the copper cathode surface compared to SS cathodes, due to the antimicrobial properties of copper. Maximum power densities from 17–27 weeks were 440 ± 38 mW/m2 using copper and 370 ± 21 mW/m2 using SS cathodes. The main difference in the microbial community was a nitrifying community on the SS cathodes, which was not present on the copper cathodes.

  11. Advanced Fuel Cycle Cost Basis

    Energy Technology Data Exchange (ETDEWEB)

    D. E. Shropshire; K. A. Williams; W. B. Boore; J. D. Smith; B. W. Dixon; M. Dunzik-Gougar; R. D. Adams; D. Gombert; E. Schneider

    2009-12-01

    This report, commissioned by the U.S. Department of Energy (DOE), provides a comprehensive set of cost data supporting a cost analysis for the relative economic comparison of options for use in the Advanced Fuel Cycle Initiative (AFCI) Program. The report describes the AFCI cost basis development process, reference information on AFCI cost modules, a procedure for estimating fuel cycle costs, economic evaluation guidelines, and a discussion on the integration of cost data into economic computer models. This report contains reference cost data for 25 cost modules—23 fuel cycle cost modules and 2 reactor modules. The cost modules were developed in the areas of natural uranium mining and milling, conversion, enrichment, depleted uranium disposition, fuel fabrication, interim spent fuel storage, reprocessing, waste conditioning, spent nuclear fuel (SNF) packaging, long-term monitored retrievable storage, near surface disposal of low-level waste (LLW), geologic repository and other disposal concepts, and transportation processes for nuclear fuel, LLW, SNF, transuranic, and high-level waste.

  12. Advanced Fuel Cycle Cost Basis

    Energy Technology Data Exchange (ETDEWEB)

    D. E. Shropshire; K. A. Williams; W. B. Boore; J. D. Smith; B. W. Dixon; M. Dunzik-Gougar; R. D. Adams; D. Gombert; E. Schneider

    2008-03-01

    This report, commissioned by the U.S. Department of Energy (DOE), provides a comprehensive set of cost data supporting a cost analysis for the relative economic comparison of options for use in the Advanced Fuel Cycle Initiative (AFCI) Program. The report describes the AFCI cost basis development process, reference information on AFCI cost modules, a procedure for estimating fuel cycle costs, economic evaluation guidelines, and a discussion on the integration of cost data into economic computer models. This report contains reference cost data for 25 cost modules—23 fuel cycle cost modules and 2 reactor modules. The cost modules were developed in the areas of natural uranium mining and milling, conversion, enrichment, depleted uranium disposition, fuel fabrication, interim spent fuel storage, reprocessing, waste conditioning, spent nuclear fuel (SNF) packaging, long-term monitored retrievable storage, near surface disposal of low-level waste (LLW), geologic repository and other disposal concepts, and transportation processes for nuclear fuel, LLW, SNF, transuranic, and high-level waste.

  13. Advanced Fuel Cycle Cost Basis

    Energy Technology Data Exchange (ETDEWEB)

    D. E. Shropshire; K. A. Williams; W. B. Boore; J. D. Smith; B. W. Dixon; M. Dunzik-Gougar; R. D. Adams; D. Gombert

    2007-04-01

    This report, commissioned by the U.S. Department of Energy (DOE), provides a comprehensive set of cost data supporting a cost analysis for the relative economic comparison of options for use in the Advanced Fuel Cycle Initiative (AFCI) Program. The report describes the AFCI cost basis development process, reference information on AFCI cost modules, a procedure for estimating fuel cycle costs, economic evaluation guidelines, and a discussion on the integration of cost data into economic computer models. This report contains reference cost data for 26 cost modules—24 fuel cycle cost modules and 2 reactor modules. The cost modules were developed in the areas of natural uranium mining and milling, conversion, enrichment, depleted uranium disposition, fuel fabrication, interim spent fuel storage, reprocessing, waste conditioning, spent nuclear fuel (SNF) packaging, long-term monitored retrievable storage, near surface disposal of low-level waste (LLW), geologic repository and other disposal concepts, and transportation processes for nuclear fuel, LLW, SNF, and high-level waste.

  14. Testing causes for long-term changes in carbon cycling and climate during the early Paleogene

    Science.gov (United States)

    Komar, N.; Zeebe, R. E.; Dickens, G. R.

    2013-12-01

    The late Paleocene to the early Eocene (˜58-52 Ma) was marked by significant changes in global climate and carbon cycling. Among the evidence for these changes, stable isotope records reveal a prominent decrease of δ13C and δ18O (in both surface and deep ocean), indicating a reorganization in the long-term global carbon cycle and a long-term warming trend (˜4°C), respectively. Concurrently, deep-sea carbonate records at several sites indicate a deepening of the calcite compensation depth (CCD). Here, we investigate possible causes (e.g., increased volcanic degassing, decreased net organic burial, and accelerated dissociation of gas hydrate) for these observations, but from a new perspective. The basic model employed is a modified version of GEOCARB III. However, we have coupled this well-known geochemical model to LOSCAR, a model that enables simulation of seawater carbonate chemistry, the CCD, and ocean δ13C. We have also added a gas hydrate capacitor that can account for the storage and release of methane from the seafloor over millions of years. We further consider accurate input data (e.g., δ13C of carbonate) on a currently accepted time scale that spans an interval much longer than the perturbation. Several different scenarios are investigated with the goal of consistency amongst inferred changes in temperature, the CCD, and surface ocean and deep ocean δ13C. The results strongly suggest that a decrease in net organic carbon burial drove carbon cycle changes during the late Paleocene and early Eocene, although an increase in volcanic activity might have contributed. Importantly, a drop in net organic carbon burial may represent increased oxidation of previously deposited organic carbon, such as stored in peat or gas hydrates. The model successfully recreates trends in Earth surface warming, as inferred from δ18O records, the CCD, and δ13C. At the moment, however, our coupled modeling effort cannot reproduce the magnitude of change in all these

  15. Solar Cycle Response and Long-Term Trends in the Mesospheric Metal Layers

    Science.gov (United States)

    Dawkins, E. C. M.; Plane, J. M. C.; Chipperfield, M.; Feng, W.; Marsh, D. R.; Hoffner, J.; Janches, D.

    2016-01-01

    The meteoric metal layers (Na, Fe, and K) which form as a result of the ablation of incoming meteors act as unique tracers for chemical and dynamical processes that occur within the upper mesosphere lower thermosphere region. In this work, we examine whether these metal layers are sensitive Fe indicators of decadal long-term changes within the upper atmosphere. Output from a whole-atmosphere climate model is used to assess the response of the Na, K, and Fe layers across a 50 year period (1955-2005). At short timescales, the K layer has previously been shown to exhibit a very different seasonal behavior compared to the other metals. Here we show that this unusual behavior is also exhibited at longer time scales (both the 11 year solar cycle and 50 year periods), where K displays a much more pronounced response to atmospheric temperature changes than either Na or Fe. The contrasting solar cycle behavior of the K and Na layers predicted by the model is confirmed using satellite and lidar observations for the period 2004-2013.

  16. Long-term effects of fuel treatments on aboveground biomass accumulation in ponderosa pine forests of the northern Rocky Mountains

    Science.gov (United States)

    Kate A. Clyatt; Christopher R. Keyes; Sharon M. Hood

    2017-01-01

    Fuel treatments in ponderosa pine forests of the northern Rocky Mountains are commonly used to modify fire behavior, but it is unclear how different fuel treatments impact the subsequent production and distribution of aboveground biomass, especially in the long term. This research evaluated aboveground biomass responses 23 years after treatment in two silvicultural...

  17. Long term storage effects of irradiated fuel elements on power distribution and reactivity

    Energy Technology Data Exchange (ETDEWEB)

    Ponzoni Filho, P.; Sato, Sadakatu; Santos, Teresinha Ipojuca Cardoso T.I.C.; Fernandes Vanderlei Borba [FURNAS, Rio de Janeiro, RJ (Brazil); Fetterman, R.J. [Westinghouse Electric Corp., Pittsburgh, PA (United States)

    1995-12-31

    The ALPHA/PHOENIX-P/ANC (APA) code package was used to calculate the pin by pin power distribution and reactivity for Angra 1 Power Plant, Cycle 5. The Angra 1 Cycle 5 core was loaded with several irradiated fuel elements which were stored in the Spent Fuel Pool (SFP) for more than 8 years. Generally, neutronic codes take into account the buildup and depletion of just a few key fission, products such as Sm-149. In this paper it is shown that the buildup effects of other fission products must be considered for fuel which has been out of the core for significant periods of time. Impacts of these other fission products can change core reactivity and power distribution. (author). 3 refs, 4 figs, 4 tabs.

  18. CRP on Demonstrating Performance of Spent Fuel and Related Storage Systems beyond the Long Term

    International Nuclear Information System (INIS)

    Bevilacqua, Arturo

    2014-01-01

    At the initial Coordinated Research Project (CRP) planning meeting held in August 2011, international experts in spent fuel performance confirmed the value of further coordination and development of international efforts to demonstrate the performance of spent fuel and related storage system components as durations extend. Furthermore, in recognition that the Extended Storage Collaboration Program (ESCP) managed by the Electric Power Research Institute (EPRI) in the USA, from now on ESCP, provided a broad context for the research and development work to be performed in the frame of this CRP, it was agreed that its objectives should target specific ESCP needs in order to make a relevant contribution. Accordingly, the experts examined on-going gap analyses - gaps between anticipated technical needs and existing technical data - for identify the specific research objectives. Additionally, during the planning meeting it was pointed out the need to coordinate and cooperate with the OECD/NEA counterparts involved in the organization of the International Workshop planned in autumn 2013 and with the on-going third phase of the CRP on Spent Fuel Performance Assessment and Research (SPAR-III). Given the importance to assess the performance of spent fuel and related important storage system components in order to confirm the viability of very long term storage for supporting the need to extend or renew licenses for storage facilities the CRP was approved by the IAEA in November 2011. While a full range of spent fuel types and storage conditions are deployed around the world, this CRP is focused on existing systems and, more specifically, water reactor fuel in dry storage with the overall research objective to support the technical basis for water reactor spent fuel management as dry storage durations extend. In March 2012 the group of international experts who participated at the initial CRP planning meeting in August 2011 evaluated and recommended for approval 9 research

  19. An assessment method for long-term management of Canada's used nuclear fuel

    International Nuclear Information System (INIS)

    Leiss, W.

    2006-01-01

    The nine-member Assessment Team, assembled by the Nuclear Waste Management Organization in early 2004, reported the results of its work in the NWMO document, 'Assessing the Options: Future Management of Used Nuclear Fuel in Canada (June 2004). The team was responding to the challenge to develop a rigorous and credible evaluation of multiple options, and one which would also satisfy a complex set of objectives: a solution that would be 'socially acceptable, technically sound, environmentally responsible, and economically feasible.' This paper describes the special challenges faced by the Assessment Team in seeking to respond to this multifaceted assignment. I open by discussing the implications of the institutional and legal framework inherited by the NWMO from the Seaborn Panel (including the government's response to the Seaborn Panel report), which in effect set a new standard for the practice of risk management decision making in Canada. I then review the highlights of the Assessment Team's report, including its chosen method, namely, multi-objective utility analysis. I conclude with a discussion of the longer term implications of the assessment work done to date for the next stages in the process of finding a credible solution for the long-term management of used nuclear fuel in Canada. (author)

  20. High level radioactive wastes storage characterization and long-term behaviour of spent fuels

    International Nuclear Information System (INIS)

    Diaz Arocas, P.P.; Garcia Serrano, J.; Mendez Martin, F.J.; Quinones Diez, J.; Rodriguez Almazan, J.L.; Serrano Agejas, J.A.; Esteban Hernandez, J.A.

    1997-04-01

    The knowledge of long term spent fuel behaviour in a repository is one of the main goals in the waste management assessment due to its influence on repository design topics and on the performance assessment. At the moment, Spain has not selected a geological formation for a final repository. Therefore, R AND D activities are performed by considering granite, salt and clay as candidate options. This report summarises the activities carried out in CIEMAT from 1991 to 1995 in the frame of the Agreement between CIEMAT and ENRESA in the Area of spent fuel direct disposed. Experimental activities include leaching experiments of spent fuel, UO 2 and SIMFUEL and co-precipitation/solubility experiments of relevant secondary solid phases expected under repository conditions. The objective of leaching studies is to understand the processes which will occur when the underground water accede to the source term and to provide leaching rates of spent fuel and the influence of several variables as pH, Eh, etc. The co-precipitation/solubility experiments are focused on the knowledge of the formation conditions of relevant secondary phases, to characterise these phases and to determine their solubility, which could control the leaching of spent fuel. One of the main items to carry out the objectives before indicated in both leaching and co-precipitation/solubility experiments is to perform a extensive solid phases characterisation in order to facilitate the understanding of the processes involved. This report is structured in three parts, the first include experimental procedures, characterisation techniques and solid and solution analyses. The second shows the leaching results obtained by considering the effect of pH, complex formation, redox conditions, surface/volume ratio, etc. The third supply the results of the co-precipitation/solubility studies. The conclusions obtained in this work are considered as the start point of going on and more extensive studies on the mechanisms

  1. Long-term warming amplifies shifts in the carbon cycle of experimental ponds

    Science.gov (United States)

    Yvon-Durocher, Gabriel; Hulatt, Chris J.; Woodward, Guy; Trimmer, Mark

    2017-02-01

    Lakes and ponds cover only about 4% of the Earth’s non-glaciated surface, yet they represent disproportionately large sources of methane and carbon dioxide. Indeed, very small ponds (for example, <0.001 km2) may account for approximately 40% of all CH4 emissions from inland waters. Understanding how greenhouse gas emissions from aquatic ecosystems will respond to global warming is therefore vital for forecasting biosphere-carbon cycle feedbacks. Here, we present findings on the long-term effects of warming on the fluxes of GHGs and rates of ecosystem metabolism in experimental ponds. We show that shifts in CH4 and CO2 fluxes, and rates of gross primary production and ecosystem respiration, observed in the first year became amplified over seven years of warming. The capacity to absorb CO2 was nearly halved after seven years of warmer conditions. The phenology of greenhouse gas fluxes was also altered, with CO2 drawdown and CH4 emissions peaking one month earlier in the warmed treatments. These findings show that warming can fundamentally alter the carbon balance of small ponds over a number of years, reducing their capacity to sequester CO2 and increasing emissions of CH4; such positive feedbacks could ultimately accelerate climate change.

  2. Long-term storage life of light source modules by temperature cycling accelerated life test

    International Nuclear Information System (INIS)

    Sun Ningning; Tan Manqing; Li Ping; Jiao Jian; Guo Xiaofeng; Guo Wentao

    2014-01-01

    Light source modules are the most crucial and fragile devices that affect the life and reliability of the interferometric fiber optic gyroscope (IFOG). While the light emitting chips were stable in most cases, the module packaging proved to be less satisfactory. In long-term storage or the working environment, the ambient temperature changes constantly and thus the packaging and coupling performance of light source modules are more likely to degrade slowly due to different materials with different coefficients of thermal expansion in the bonding interface. A constant temperature accelerated life test cannot evaluate the impact of temperature variation on the performance of a module package, so the temperature cycling accelerated life test was studied. The main failure mechanism affecting light source modules is package failure due to solder fatigue failure including a fiber coupling shift, loss of cooling efficiency and thermal resistor degradation, so the Norris-Landzberg model was used to model solder fatigue life and determine the activation energy related to solder fatigue failure mechanism. By analyzing the test data, activation energy was determined and then the mean life of light source modules in different storage environments with a continuously changing temperature was simulated, which has provided direct reference data for the storage life prediction of IFOG. (semiconductor devices)

  3. The long-term seismic cycle at subduction thrusts: benchmarking geodynamic numerical simulations and analogue models

    Science.gov (United States)

    van Dinther, Y.; Gerya, T.; Corbi, F.; Funiciello, F.; Mai, P. M.; Dalguer, L. A.

    2011-12-01

    The physics governing the long-term seismic cycle in subduction zones remains elusive, largely due to its spatial inaccessibility, complex tectonic and geometric setting, and the short observational time span. To improve our understanding of the physics governing this seismic cycle, we benchmark a geodynamic numerical approach with a novel laboratory model. In this work we quantify and compare periodicity and source parameters of slip events (earth-quakes and gel-quakes) as a function of fault rheology (i.e. frictional properties), subduction velocity, slab dip, and seismogenic zone width. Our fluid-dynamic numerical method involves a plane-strain finite-difference scheme with marker-in-cell technique to solve the conservation of momentum, mass, and energy for a visco-elasto-plastic rheology. The simulated gelatin laboratory setup constitutes a triangular, visco-elastic crustal wedge on top of a straight subducting slab that includes a seismogenic zone. Numerical and analogue results show a regular and roughly comparable periodicity of short, rapid wedge velocity reversals. Ruptures nucleating mainly around the bottom of the seismogenic zone, and propagating upward, cause a distinct and rapid drop in stress within the wedge. To mimic the short duration, high speed and regularity of the analogue results, the numerical method requires a form of steady-state velocity-weakening friction for acceleration, and healing. The necessity of including a variable state component into the numerical simulations is subject of ongoing work. Finally, we extend this analysis by observing the role of different friction laws in large-scale, geometrically more realistic models.

  4. Long-term α-hazard of high activity waste from nuclear fuel reprocessing

    International Nuclear Information System (INIS)

    Girardi, F.; Bertozzi, G.

    1974-01-01

    The concentration and decay of α-emitters in high activity waste arising from spent nuclear fuel reprocessing was calculated under specified reference conditions. An attempt to evaluate the long-term hazard of such waste is being made by applying the ''barrier'' approach derived from reactor safety studies. Four barriers were identified, which could be evaluated in a probabilistic way by taking into account the great uncertainties present in each of them. The barriers are: 1) quality of the segregation afforded by deep geological formations, 2) stability of conditioned waste (chemical and physical), 3) retention by immediate surrounding, 4) distribution pattern of actinides in the environment. The analysis of a fictional accident showed that the uncertainties connected with the evaluation of the barriers' value are rather large. Additional studies particularly on the stability of conditioned waste and ecological properties of the environment towards actinides, would considerably improve our knowledge of the value of the barrier system. Chemical separation of actinides from high activity waste would be an additional option of undoubted value for the disposal of high activity waste. Its value for the overall safety of the entire waste inventory depends on many factors which need better evaluation, such as safety of the disposal of the separated actinides and the amount and quality of the additional waste generated by the separation process. An analysis of various levels of possible separations suggests that a reasonable target might be: Pu, Am and Cm, decontamination factor 10 3 ; Np, coextraction with U and Pu with a 90% yield

  5. 77 FR 74788 - Long-Term Cooling and Unattended Water Makeup of Spent Fuel Pools

    Science.gov (United States)

    2012-12-18

    .... Comment NEI-5 The Petition presents a Probabilistic Risk Assessment to conclude a long term loss of off... Petitioner offers no data to support the conclusion that a long term loss of off-site power event due to...-like event, is not known with certainty. However, based on the NRC's review of the existing data, the...

  6. Long-term shifts in life-cycle energy efficiency and carbon intensity.

    Science.gov (United States)

    Yeh, Sonia; Mishra, Gouri Shankar; Morrison, Geoff; Teter, Jacob; Quiceno, Raul; Gillingham, Kenneth; Riera-Palou, Xavier

    2013-03-19

    The quantity of primary energy needed to support global human activity is in large part determined by how efficiently that energy is converted to a useful form. We estimate the system-level life-cycle energy efficiency (EF) and carbon intensity (CI) across primary resources for 2005-2100. Our results underscore that although technological improvements at each energy conversion process will improve technology efficiency and lead to important reductions in primary energy use, market mediated effects and structural shifts toward less efficient pathways and pathways with multiple stages of conversion will dampen these efficiency gains. System-level life-cycle efficiency may decrease as mitigation efforts intensify, since low-efficiency renewable systems with high output have much lower GHG emissions than some high-efficiency fossil fuel systems. Climate policies accelerate both improvements in EF and the adoption of renewable technologies, resulting in considerably lower primary energy demand and GHG emissions. Life-cycle EF and CI of useful energy provide a useful metric for understanding dynamics of implementing climate policies. The approaches developed here reiterate the necessity of a combination of policies that target efficiency and decarbonized energy technologies. We also examine life-cycle exergy efficiency (ExF) and find that nearly all of the qualitative results hold regardless of whether we use ExF or EF.

  7. Nuclear fuel cycle

    International Nuclear Information System (INIS)

    Niedrig, T.

    1987-01-01

    Nuclear fuel supply is viewed as a buyer's market of assured medium-term stability. Even on a long-term basis, no shortage is envisaged for all conceivable expansion schedules. The conversion and enrichment facilities developed since the mid-seventies have done much to stabilize the market, owing to the fact that one-sided political decisions by the USA can be counteracted efficiently. In view of the uncertainties concerning realistic nuclear waste management strategies, thermal recycling and mixed oxide fuel elements might increase their market share in the future. Capacities are being planned accordingly. (orig.) [de

  8. The nuclear fuel cycle

    International Nuclear Information System (INIS)

    Jones, P.M.S.

    1987-01-01

    This chapter explains the distinction between fissile and fertile materials, examines briefly the processes involved in fuel manufacture and management, describes the alternative nuclear fuel cycles and considers their advantages and disadvantages. Fuel management is usually divided into three stages; the front end stage of production and fabrication, the back end stage which deals with the fuel after it is removed from the reactor (including reprocessing and waste treatment) and the stage in between when the fuel is actually in the reactor. These stages are illustrated and explained in detail. The plutonium fuel cycle and thorium-uranium-233 fuel cycle are explained. The differences between fuels for thermal reactors and fast reactors are explained. (U.K.)

  9. The plutonium fuel cycles

    International Nuclear Information System (INIS)

    Pigford, T.H.; Ang, K.P.

    1975-01-01

    The quantities of plutonium and other fuel actinides have been calculated for equilibrium fuel cycles for 1000-MW water reactors fueled with slightly enriched uranium, water reactors fueled with plutonium and natural uranium, fast-breder reactors, gas-cooled reactors fueled with thorium and highly enriched uranium, and gas-cooled reactors fueled with thorium, plutonium and recycled uranium. The radioactivity quantities of plutonium, americium and curium processed yearly in these fuel cycles are greatest for the water reactors fueled with natural uranium and recycled plutonium. The total amount of actinides processed is calculated for the predicted future growth of the U.S. nuclear power industry. For the same total installed nuclear power capacity, the introduction of the plutonium breeder has little effect upon the total amount of plutonium in this century. The estimated amount of plutonium in the low-level process wastes in the plutonium fuel cycles is comparable to the amount of plutonium in the high-level fission product wastes. The amount of plutonium processed in the nuclear fuel cycles can be considerably reduced by using gas-cooled reactors to consume plutonium produced in uranium-fueled water reactors. These, and other reactors dedicated for plutonium utilization, could be co-located with facilities for fuel reprocessing ad fuel fabrication to eliminate the off-site transport of separated plutonium. (author)

  10. On the Properties and Long-Term Stability of Infiltrated Lanthanum Cobalt Nickelates (LCN) in Solid Oxide Fuel Cell Cathodes

    DEFF Research Database (Denmark)

    Kiebach, Wolff-Ragnar; Zielke, Philipp; Veltzé, Sune

    2017-01-01

    Infiltration as a fabrication method for solid oxide fuel cells (SOFC) electrodes is offering significant improvements in cell performance at reduced materials and fabrication costs, especially when combined with co-sintering. However, important questions regarding the long-term performance and m...

  11. How plants changed the world: Using qualitative reasoning to explain plant macroevolution's effect on the long-term carbon cycle

    NARCIS (Netherlands)

    Kansou, K.; Nuttle, T.; Farnsworth, K.; Bredeweg, B.

    2013-01-01

    We present a qualitative reasoning model of how plant colonization of land during the mid Paleozoic era (450–300 million years ago) altered the long-term carbon cycle resulting in a dramatic decrease in global atmospheric carbon dioxide levels. This model is aimed at facilitating learning and

  12. A Paleogene Silicon Stable Isotope Record: Long-Term Carbon and Silicon Cycling Interaction Revealed By Sponges and Radiolarians

    Science.gov (United States)

    Fontorbe, G.; De La Rocha, C. L.; Hendry, K. R.; Frings, P.; Conley, D. J.

    2014-12-01

    Silicon and carbon cycling are related both on short time scales via the uptake of carbon dioxide and dissolved silica (DSi) by diatoms, and on geological time scales via weathering of silicate rocks consuming carbon dioxide. Long-term changes in oceanic silicon cycling and DSi concentration have been mostly attributed to the evolution of siliceous organisms, especially the colonization of the surface waters by diatoms and their diversification. Thus, impacts of geological mechanisms and changes in carbon cycling have been, in our opinion, overlooked. During the past decade, progress has been made in using silicon isotopes in marine archives to investigate the paleo-silicon cycle. Silicon isotope fractionation in siliceous sponges is closely related to ambient DSi concentration. It follows from this relationship that sponge spicules from marine sediment cores provide a good proxy for reconstructing the paleo-DSi concentration and isotopic composition. The Paleogene period (65.5 to 23Ma) is highly relevant for studying the long-term silicon and carbon cycling relationship due to radiance of diatoms, high variability in the carbon cycle and initiation of the Himalayan orogeny. Here, we will present a sponge spicules and radiolarian silicon isotopes record from ODP Leg 171B (Blake Nose, Western North Atlantic) spanning most of the Paleogene. Our data show similar patterns in both foraminiferal carbon and spicule silicon stable isotopes, providing information on the mechanisms coupling the long-term silicon and carbon cycle.

  13. Durability and efficiency tests for direct methanol fuel cell's long-term performance assessment

    International Nuclear Information System (INIS)

    Yeh, Pulin; Chang, Chu Hsiang; Shih, Naichien; Yeh, Naichia

    2016-01-01

    This research assessed the long-term performance of direct methanol fuel cells. The experiment was performed at room temperature using 0.51 mol/L ∼0.651 mol/L methanol with a fuel consumption rate of 0.8 ± 0.1 cc/Wh at stack temperature of 60 °C–70 °C. DuPont Nafion115 proton exchange membrane was used as the base material of MEA (membrane electrode assembly), which is then examined via a series of processes that include I−V curve test, humidity cycle test, load cycle test, and hydrogen penetration test. The study employs membrane modification and cell structure adjustment approaches to reduce the methanol crossover in the cathode and identify the cell performance effect of the carbon paper gas diffusion layer. The test results indicated an efficiency of 25% can be achieved with a three-piece MEA assembly. According to the durability test, the stack power-generation efficiency has maintained at 15%–25% level. With such efficiency, the stack voltage output has been able to stay above 7.8-V for over 5000 h. This result is in line with industry standard. - Highlights: • Assess DMFC performance under non-optimal conditions for production readiness. • Output of 26-cell DMFC stack stays beyond 7.8v after 5000 operation hours. • Power-generation efficiency of 26-cell DMFC stack maintains between 15%–20%.

  14. Nuclear fuel cycle

    International Nuclear Information System (INIS)

    1993-01-01

    Status of different nuclear fuel cycle phases in 1992 is discussed including the following issues: uranium exploration, resources, supply and demand, production, market prices, conversion, enrichment; reactor fuel technology; spent fuel management, as well as trends of these phases development up to the year 2010. 10 refs, 11 figs, 15 tabs

  15. Carbonate-silicate cycle models of the long-term carbon cycle, carbonate accumulation in the oceans, and climate

    International Nuclear Information System (INIS)

    Caldeira, K.G.

    1991-01-01

    Several models of the long-term carbon cycle, incorporating models of the carbonate-silicate cycle, were developed and utilized to investigate issues relating to global climate and the causes and consequences of changes in calcium carbonate accumulation in the oceans. Model results indicate that the marked mid-Cretaceous (120 Ma) global warming could be explained by increased rates of release of carbon dioxide from subduction-zone metamorphism and mid-ocean-ridges, in conjunction with paleogeographic factors. Since the mid-Cretaceous, the primary setting for calcium carbonate accumulation in the oceans has shifted from shallow-water to deep-water environments. Model results suggest that this shift could have major consequences for the carbonate-silicate cycle and climate, and lead to significant increases in the flux of metamorphic carbon dioxide to the atmosphere. Increases in pelagic carbonate productivity, and decreases in tropical shallow-water area available for neritic carbonate accumulation, have both been proposed as the primary cause of this shift. Two lines of evidence developed here (one involving a statistical analysis of Tertiary carbonate-accumulation and oxygen-isotope data, and another based on modeling the carbonate-silicate cycle and ocean chemistry) suggest that a decrease in tropical shallow-water area was more important than increased pelagic productivity in explaining this shift. Model investigations of changes in ocean chemistry at the Cretaceous/Tertiary (K/T) boundary (66 Ma) indicate that variations in deep-water carbonate productivity may affect shallow-water carbonate accumulation rates through a mechanism involving surface-water carbonate-ion concentration. In the aftermath of the K/T boundary event, deep-water carbonate production and accumulation were significantly reduced as a result of the extinction of calcareous plankton

  16. Study on component interface evolution of a solid oxide fuel cell stack after long term operation

    Science.gov (United States)

    Yang, Jiajun; Huang, Wei; Wang, Xiaochun; Li, Jun; Yan, Dong; Pu, Jian; Chi, Bo; Li, Jian

    2018-05-01

    A 5-cell solid oxide fuel cell (SOFC) stack with external manifold structure is assembled and underwent a durability test with an output of 250 W for nearly 4400 h when current density and operating temperature are 355 mA/cm2 and 750 °C. Cells used in the stack are anode-supported cells (ASC) with yttria-stabilized zirconia (YSZ) electrolytes, Ni/YSZ hydrogen electrodes, and YSZ based composite cathode. The dimension of the cell is 150 × 150 mm (active area: 130 × 130 mm). Ceramic-glass sealant is used in the stack to keep the gas tightness between cells, interconnects and manifolds. Pure hydrogen and dry air are used as fuel and oxidant respectively. The stack has a maximum output of 340 W at 562 mA/cm2 current density at 750 °C. The stack shows a degradation of 1.5% per 1000 h during the test with 2 thermal cycles to room temperature. After the test, the stack was dissembled and examined. The relationship between microstructure changes of interfaces and degradation in the stack are discussed. The microstructure evolution of interfaces between electrode, contact material and current collector are unveiled and their relationship with the degradation is discussed.

  17. Increased fuel burn-up and fuel cycle equilibrium

    International Nuclear Information System (INIS)

    Debes, M.

    2001-01-01

    Improvement of nuclear competitiveness will rely mainly on increased fuel performance, with higher burn-up, and reactors sustained life. Regarding spent fuel management, the EDF current policy relies on UO 2 fuel reprocessing (around 850 MTHM/year at La Hague) and MOX recycling to ensure plutonium flux adequacy (around 100 MTHM/year, with an electricity production equivalent to 30 TWh). This policy enables to reuse fuel material, while maintaining global kWh economy with existing facilities. It goes along with current perspective to increase fuel burn-up up to 57 GWday/t mean in 2010. The following presentation describes the consequences of higher fuel burn-up on fuel cycle and waste management and implementation of a long term and global equilibrium for decades in spent fuel management resulting from this strategy. (author)

  18. Fuel cycle studies

    International Nuclear Information System (INIS)

    Anon.

    1978-01-01

    Programs are being conducted in the following areas: advanced solvent extraction techniques, accident consequences, fuel cycles for nonproliferation, pyrochemical and dry processes, waste encapsulation, radionuclide transport in geologic media, hull treatment, and analytical support for LWBR

  19. Life’s Critical Role in the Long-term Carbon Cycle: the Biotic Enhancement of Weathering

    Directory of Open Access Journals (Sweden)

    David W. Schwartzman

    2017-06-01

    Full Text Available The biotic enhancement of weathering (BEW has important implications for the long-term carbon cycle, in particular as a driver of climatic cooling. The BEW factor is defined as how much faster the silicate weathering carbon sink is under biotic conditions than under abiotic conditions at the same atmospheric pCO2 level and surface temperature. The BEW factor and its evolution over geological time can potentially be inferred from consideration of empirical and theoretical weathering studies. Estimates of the global magnitude of the BEW are presented, drawing from laboratory, field, watershed data and models of the long-term carbon cycle, with values ranging from one to two orders of magnitude.

  20. IFR fuel cycle

    International Nuclear Information System (INIS)

    Battles, J.E.; Miller, W.E.; Lineberry, M.J.; Phipps, R.D.

    1992-01-01

    The next major milestone of the IFR program is engineering-scale demonstration of the pyroprocess fuel cycle. The EBR-II Fuel Cycle Facility has just entered a startup phase, which includes completion of facility modifications and installation and cold checkout of process equipment. This paper reviews the development of the electrorefining pyroprocess, the design and construction of the facility for the hot demonstration, the design and fabrication of the equipment, and the schedule and initial plan for its operation

  1. Institutional framework for long term management of high level waste and/or spent nuclear fuel

    International Nuclear Information System (INIS)

    2002-12-01

    The objective of this publication is to provide information on the institutional framework that has been, or is being, established for the long term management of HLW and/or SNF in the selected Member States, and to provide this information to all interested Member States. Information on the amounts of HLW and SNF that are expected to be generated, and on the geological repositories that are being considered for disposal of this waste is also provided to help put the institutional framework into perspective (e.g. regarding the scale of the programmes). The scope of this publication includes the institutional and financial arrangements that have to be used for the long term management of HLW and/or SNF. For the purpose of this report, the institutional framework for the long term management of HLW and/or SNF is defined to include the following elements: A consistent set of requirements for the technical and legal infrastructure including: funding, liability, institutional control, records management, and research activities; An organizational structure with clearly defined responsibilities; and Provisions for participation by interested parties in decisions and outcomes. The focus of this publication is on geological disposal of HLW and/or SNF from commercial nuclear power reactors. Nevertheless, in cases where national programmes include plans for geological disposal of HLW and/or SNF from sources other than commercial nuclear power generation (e.g. research, defence, medicine, industry, agriculture), information pertaining to long term management of the waste from such activities is also included. The TECDOC is divided into two main parts: a summary overview and comparison of the approaches selected by Member States for the HLW and/or SNF long term management in their countries, and an Annex presenting more detailed information on the status of institutional development in the participating Member States. The Annex items with information on twenty individual

  2. ESTIMATION OF LONG-TERM INVESTMENT PROJECTS WITH ENERGY-EFFICIENT SOLUTIONS BASED ON LIFE CYCLE COSTS INDICATOR

    Directory of Open Access Journals (Sweden)

    Bazhenov Viktor Ivanovich

    2015-09-01

    Full Text Available The starting stage of the tender procedures in Russia with the participation of foreign suppliers dictates the feasibility of the developments for economical methods directed to comparison of technical solutions on the construction field. The article describes the example of practical Life Cycle Cost (LCC evaluations under respect of Present Value (PV determination. These create a possibility for investor to estimate long-term projects (indicated as 25 years as commercially profitable, taking into account inflation rate, interest rate, real discount rate (indicated as 5 %. For economic analysis air-blower station of WWTP was selected as a significant energy consumer. Technical variants for the comparison of blower types are: 1 - multistage without control, 2 - multistage with VFD control, 3 - single stage double vane control. The result of LCC estimation shows the last variant as most attractive or cost-effective for investments with economy of 17,2 % (variant 1 and 21,0 % (variant 2 under adopted duty conditions and evaluations of capital costs (Cic + Cin with annual expenditure related (Ce+Co+Cm. The adopted duty conditions include daily and seasonal fluctuations of air flow. This was the reason for the adopted energy consumption as, kW∙h: 2158 (variant 1,1743...2201 (variant 2, 1058...1951 (variant 3. The article refers to Europump guide tables in order to simplify sophisticated factors search (Cp /Cn, df, which can be useful for economical analyses in Russia. Example of evaluations connected with energy-efficient solutions is given, but this reference involves the use of materials for the cases with resource savings, such as all types of fuel. In conclusion follows the assent to use LCC indicator jointly with the method of determining discounted cash flows, that will satisfy the investor’s need for interest source due to technical and economical comparisons.

  3. The impact of inter-annual variability of annual cycle on long-term memory in long historical temperature records

    Science.gov (United States)

    Deng, Qimin; Fu, Zuntao

    2017-04-01

    Changes in the estimation of long-term correlation induced by inter-annual variability of annual cycle have been investigated by means of detrended fluctuation analysis (DFA). In a consequence of the intrinsic nonlinearity of the climate system, the annual cycle suffers from both amplitude and phase fluctuations. How does this changing annual cycle affect the fluctuation of temperature anomalies? A recently developed adaptive data analysis tool, the Nonlinear Mode Decomposition (NMD), is used to extract and remove time-varying annual cycle. We compared the differences of the long-term correlation calculated by removing different annual cycle, time-varying and stationary. The study was based on long historical temperature records around the North Atlantic Ocean. The traditional climatology annual cycle which lack characteristic of inter-annual fluctuation would lead to: (1) the estimation of Hurst exponent (2) how to choose scaling range and (3) the goodness of fit. Especially removing steady climatology annual cycle would introduce an artificial crossover around one-year period in the DFA curve. The conclusion is verified by generating deterministic time series through Monte Carlo simulations.

  4. 1. round table - Spent fuels composition. Back-end of the fuel cycle and reprocessing, plutonium and other nuclear materials management. 2. round table - Separation-transmutation. 3. round table - Scenarios for a long term inventory of nuclear materials and wastes

    International Nuclear Information System (INIS)

    2005-01-01

    The law from December 30, 1991, precisely defines 3 axes of researches for the management of high level and long-lived radioactive wastes: separation/transmutation, surface storage and underground disposal. A global evaluation report about these researches is to be supplied in 2006 by the French government to the Parliament. A first synthesis of the knowledge gained after 14 years of research has led the national commission of the public debate (CNDP) to organize a national debate about the general options of management of high-level and long-lived radioactive wastes before the 2006 date line. The debate comprises 4 public hearings (September 2005: Bar-le-Duc, Saint-Dizier, Pont-du-Gard, Cherbourg), 12 round-tables (October and November 2005: Paris, Joinville, Caen, Nancy, Marseille), a synthesis meeting (December 2005, Dunkerque) and a closing meeting (January 2006, Lyon). This document is the synthesis of the round table debates which took place at Paris on the reprocessing of spent fuels. Three aspects are discussed: the risks linked with the recovery of valorizable materials, the economical viability of the separation/transmutation option, and the future of the nuclear option in the French energy policy. Six presentations (transparencies) are attached with these proceedings which treat of: the reprocessing/recycling to the test, perspectives of future wastes, present day wastes/valorizable materials and future scenarios, critical analysis scenarios, why reprocessing spent fuels?, processing of spent fuels and recycling, separation and transmutation of long-lived radioactive wastes, thorium-uranium cycle. (J.S.)

  5. The nuclear fuel cycle

    International Nuclear Information System (INIS)

    Vernaz, Etienne

    2015-10-01

    The author proposes an overview of the different steps of the nuclear fuel cycle: uranium mining (applied processes, formation of Yellow Cake), conversion into uranium hexafluoride (UF 6 ) for enrichment purposes, enrichment (physical methods and plants), nuclear fuel fabrication (description of a fuel assembly), physical, chemical and radiological evolution of the nuclear fuel in the reactor, spent fuel warehousing, spent fuel processing (dissolution, methods of liquid/liquid extraction, output products), effluents and by-products, recycling of valuable materials (URE, MOX, RNR and others), waste containment for the different waste types regarding their radioactivity level and lifetime (vitrification, shell compacting, cementation, and other processes). The author also presents the French policy and choices regarding spent fuel processing and waste management

  6. Alternative fuel cycles

    International Nuclear Information System (INIS)

    Penn, W.J.

    1979-05-01

    Uranium resource utilization and economic considerations provide incentives to study alternative fuel cycles as future options to the PHWR natural uranium cycle. Preliminary studies to define the most favourable alternatives and their possible introduction dates are discussed. The important and uncertain components which influence option selection are reviewed, including nuclear capacity growth, uranium availability and demand, economic potential, and required technological developments. Finally, a summary of Ontario Hydro's program to further assess cycle selection and define development needs is given. (auth)

  7. The nuclear fuel cycle

    International Nuclear Information System (INIS)

    1998-05-01

    After a short introduction about nuclear power in the world, fission physics and the French nuclear power plants, this brochure describes in a digest way the different steps of the nuclear fuel cycle: uranium prospecting, mining activity, processing of uranium ores and production of uranium concentrates (yellow cake), uranium chemistry (conversion of the yellow cake into uranium hexafluoride), fabrication of nuclear fuels, use of fuels, reprocessing of spent fuels (uranium, plutonium and fission products), recycling of energetic materials, and storage of radioactive wastes. (J.S.)

  8. A review of the main parameters influencing long-term performance and durability of PEM fuel cells

    Science.gov (United States)

    Schmittinger, Wolfgang; Vahidi, Ardalan

    This paper presents an overview of issues affecting the life and the long-term performance of proton exchange membrane fuel cells based on a survey of existing literature. We hope that this brief overview provides the engineers and researchers in the field with a perspective of the important issues that should be addressed to extend the life of next-generation fuel cells. Causes and fundamental mechanisms of cell degradation and their influence on long-term performance of fuel cells are discussed. Current research shows that main causes of short life and performance degradation are poor water management, fuel and oxidant starvation, corrosion and chemical reactions of cell components. Poor water management can cause dehydration or flooding, operation under dehydrated condition could damage the membrane whereas flooding facilitates corrosion of the electrodes, the catalyst layers, the gas diffusion media and the membrane. Corrosion products and impurities from outside can poison the cell. Thermal management is particularly important when the fuel cell is operated at sub-zero and elevated temperatures and is key at cold start-ups as well as when subjected to freezing conditions.

  9. An Integrated Multicriteria Decision-Making Approach for Evaluating Nuclear Fuel Cycle Systems for Long-term Sustainability on the Basis of an Equilibrium Model: Technique for Order of Preference by Similarity to Ideal Solution, Preference Ranking Organization Method for Enrichment Evaluation, and Multiattribute Utility Theory Combined with Analytic Hierarchy Process

    Directory of Open Access Journals (Sweden)

    Saerom Yoon

    2017-02-01

    Full Text Available The focus on the issues surrounding spent nuclear fuel and lifetime extension of old nuclear power plants continues to grow nowadays. A transparent decision-making process to identify the best suitable nuclear fuel cycle (NFC is considered to be the key task in the current situation. Through this study, an attempt is made to develop an equilibrium model for the NFC to calculate the material flows based on 1 TWh of electricity production, and to perform integrated multicriteria decision-making method analyses via the analytic hierarchy process technique for order of preference by similarity to ideal solution, preference ranking organization method for enrichment evaluation, and multiattribute utility theory methods. This comparative study is aimed at screening and ranking the three selected NFC options against five aspects: sustainability, environmental friendliness, economics, proliferation resistance, and technical feasibility. The selected fuel cycle options include pressurized water reactor (PWR once-through cycle, PWR mixed oxide cycle, or pyroprocessing sodium-cooled fast reactor cycle. A sensitivity analysis was performed to prove the robustness of the results and explore the influence of criteria on the obtained ranking. As a result of the comparative analysis, the pyroprocessing sodium-cooled fast reactor cycle is determined to be the most competitive option among the NFC scenarios.

  10. An integrated multicriteria decision-making approach for evaluating nuclear fuel cycle systems for long-term sustainability on the basis of an equilibrium model: Technique for order of preference by similarity to ideal solution, preference ranking organization method for enrichment evaluation, and multiattribute utility theory combined with analytic hierarchy process

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Sae Rom [Dept of Quantum Energy Chemical Engineering, Korea University of Science and Technology (KUST), Daejeon (Korea, Republic of); Choi, Sung Yeol [Ulsan National Institute of Science and Technology, Ulju (Korea, Republic of); Ko, Wonil [Nonproliferation System Development Division, Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2017-02-15

    The focus on the issues surrounding spent nuclear fuel and lifetime extension of old nuclear power plants continues to grow nowadays. A transparent decision-making process to identify the best suitable nuclear fuel cycle (NFC) is considered to be the key task in the current situation. Through this study, an attempt is made to develop an equilibrium model for the NFC to calculate the material flows based on 1 TWh of electricity production, and to perform integrated multicriteria decision-making method analyses via the analytic hierarchy process technique for order of preference by similarity to ideal solution, preference ranking organization method for enrichment evaluation, and multiattribute utility theory methods. This comparative study is aimed at screening and ranking the three selected NFC options against five aspects: sustainability, environmental friendliness, economics, proliferation resistance, and technical feasibility. The selected fuel cycle options include pressurized water reactor (PWR) once-through cycle, PWR mixed oxide cycle, or pyroprocessing sodium-cooled fast reactor cycle. A sensitivity analysis was performed to prove the robustness of the results and explore the influence of criteria on the obtained ranking. As a result of the comparative analysis, the pyroprocessing sodium-cooled fast reactor cycle is determined to be the most competitive option among the NFC scenarios.

  11. Long-Term Charge/Discharge Cycling Stability of MnO2 Aqueous Supercapacitor under Positive Polarization

    KAUST Repository

    Ataherian, Fatemeh

    2011-01-01

    The long-term charge/discharge cycling stability of MnO 2 electrode under positive polarization in aqueous KCl electrolyte has been studied over different potential windows spanning from the open circuit potential to varied higher-end potential limited by O 2 evolution. Cycling up to 1.2 V (vs Ag/AgCl (aq)) causes partial (35) capacitance fading to a plateau value within the initial cycles, accompanied by morphological reconstruction, reduction of surface Mn ions and oxygen evolution. The surface Mn-ion reduction has been attributed to a two-step oxidation-reduction mechanism involving OH oxidation in electrolyte, based on electrochemical analysis. When cycling potential extends to 1.4 V, extensive oxygen evolution takes place. The combination of surface passivation of current collector and extensive gas bubbling, which deteriorates electrical contact among the constituent particles within the electrode, results in further monotonic capacitance reduction. © 2011 The Electrochemical Society.

  12. Long-term trends in nitrogen isotope composition and nitrogen concentration in brazilian rainforest trees suggest changes in nitrogen cycle.

    Science.gov (United States)

    Hietz, Peter; Dünisch, Oliver; Wanek, Wolfgang

    2010-02-15

    Direct or indirect anthropogenic effects on ecosystem nitrogen cycles are important components of global change. Recent research has shown that N isotopes in tree rings reflect changes in ecosystem nitrogen sources or cycles and can be used to study past changes. We analyzed trends in two tree species from a remote and pristine tropical rainforest in Brazil, using trees of different ages to distinguish between the effect of tree age and long-term trends. Because sapwood differed from heartwood in delta(15)N and N concentration and N can be translocated between living sapwood cells, long-term trends are best seen in dead heartwood. Heartwood delta(15)N in Spanish cedar (Cedrela odorata) and big-leaf mahogany (Swietenia macrophylla) increased with tree age, and N concentrations increased with age in Cedrela. Controlling for tree age, delta(15)N increased significantly during the past century even when analyzing only heartwood and after removing labile N compounds. In contrast to northern temperate and boreal forests where wood delta(15)N often decreased, the delta(15)N increase in a remote rainforest is unlikely to be a direct signal of changed N deposition. More plausibly, the change in N isotopic composition indicates a more open N cycle, i.e., higher N losses relative to internal N cycling in the forest, which could be the result of changed forest dynamics.

  13. LOSCAR: Long-term Ocean-atmosphere-Sediment CArbon cycle Reservoir Model v2.0.4

    Directory of Open Access Journals (Sweden)

    R. E. Zeebe

    2012-01-01

    Full Text Available The LOSCAR model is designed to efficiently compute the partitioning of carbon between ocean, atmosphere, and sediments on time scales ranging from centuries to millions of years. While a variety of computationally inexpensive carbon cycle models are already available, many are missing a critical sediment component, which is indispensable for long-term integrations. One of LOSCAR's strengths is the coupling of ocean-atmosphere routines to a computationally efficient sediment module. This allows, for instance, adequate computation of CaCO3 dissolution, calcite compensation, and long-term carbon cycle fluxes, including weathering of carbonate and silicate rocks. The ocean component includes various biogeochemical tracers such as total carbon, alkalinity, phosphate, oxygen, and stable carbon isotopes. LOSCAR's configuration of ocean geometry is flexible and allows for easy switching between modern and paleo-versions. We have previously published applications of the model tackling future projections of ocean chemistry and weathering, pCO2 sensitivity to carbon cycle perturbations throughout the Cenozoic, and carbon/calcium cycling during the Paleocene-Eocene Thermal Maximum. The focus of the present contribution is the detailed description of the model including numerical architecture, processes and parameterizations, tuning, and examples of input and output. Typical CPU integration times of LOSCAR are of order seconds for several thousand model years on current standard desktop machines. The LOSCAR source code in C can be obtained from the author by sending a request to loscar.model@gmail.com.

  14. LOSCAR: Long-term Ocean-atmosphere-Sediment CArbon cycle Reservoir Model v2.0.4

    Science.gov (United States)

    Zeebe, R. E.

    2012-01-01

    The LOSCAR model is designed to efficiently compute the partitioning of carbon between ocean, atmosphere, and sediments on time scales ranging from centuries to millions of years. While a variety of computationally inexpensive carbon cycle models are already available, many are missing a critical sediment component, which is indispensable for long-term integrations. One of LOSCAR's strengths is the coupling of ocean-atmosphere routines to a computationally efficient sediment module. This allows, for instance, adequate computation of CaCO3 dissolution, calcite compensation, and long-term carbon cycle fluxes, including weathering of carbonate and silicate rocks. The ocean component includes various biogeochemical tracers such as total carbon, alkalinity, phosphate, oxygen, and stable carbon isotopes. LOSCAR's configuration of ocean geometry is flexible and allows for easy switching between modern and paleo-versions. We have previously published applications of the model tackling future projections of ocean chemistry and weathering, pCO2 sensitivity to carbon cycle perturbations throughout the Cenozoic, and carbon/calcium cycling during the Paleocene-Eocene Thermal Maximum. The focus of the present contribution is the detailed description of the model including numerical architecture, processes and parameterizations, tuning, and examples of input and output. Typical CPU integration times of LOSCAR are of order seconds for several thousand model years on current standard desktop machines. The LOSCAR source code in C can be obtained from the author by sending a request to loscar.model@gmail.com.

  15. Fuel cycle based safeguards

    International Nuclear Information System (INIS)

    De Montmollin, J.M.; Higinbotham, W.A.; Gupta, D.

    1985-07-01

    In NPT safeguards the same model approach and absolute-quantity inspection goals are applied at present to all similar facilities, irrespective of the State's fuel cycle. There is a continuing interest and activity on the part of the IAEA in new NPT safeguards approaches that more directly address a State's nuclear activities as a whole. This fuel cycle based safeguards system is expected to a) provide a statement of findings for the entire State rather than only for individual facilities; b) allocate inspection efforts so as to reflect more realistically the different categories of nuclear materials in the different parts of the fuel cycle and c) provide more timely and better coordinated information on the inputs, outputs and inventories of nuclear materials in a State. (orig./RF) [de

  16. The thorium fuel cycle

    International Nuclear Information System (INIS)

    Merz, E.R.

    1977-01-01

    The utilization of the thorium fuel cycle has long since been considered attractive due to the excellent neutronic characteristics of 233 U, and the widespread and cheap thorium resources. Although the uranium ore as well as the separative work requirements are usually lower for any thorium-based fuel cycle in comparison to present uranium-plutonium fuel cycles of thermal water reactors, interest by nuclear industry has hitherto been marginal. Fast increasing uranium prices, public reluctance against widespread Pu-recycling and expected retardations for the market penetration of fast breeders have led to a reconsideration of the thorium fuel cycle merits. In addition, it could be learned in the meantime that problems associated with reprocessing and waste handling, but particularly with a remote refabrication of 233 U are certainly not appreciably more difficult than for Pu-recycling. This may not only be due to psychological constraints but be based upon technological as well as economical facts, which have been mostly neglected up till now. In order to diversify from uranium as a nuclear energy source it seems to be worthwhile to greatly intensify efforts in the future for closing the Th/ 233 U fuel cycle. HTGR's are particularly promising for economic application. However, further R and D activites should not be solely focussed on this reactor type alone. Light and heavy-water moderated reactors, as well as even fast breeders later on, may just as well take advantage of a demonstrated thorium fuel cycle. A summary is presented of the state-of-the-art of Th/ 233 U-recycling technology and the efforts still necessary to demonstrate this technology all the way through to its industrial application

  17. Activity release from the damaged spent VVER-fuel during long-term wet storage

    Energy Technology Data Exchange (ETDEWEB)

    Slonszki, E.; Hozer, Z. [Hungarian Academy of Sciences, KFKI Atomic Energy Research Inst., Budapest (Hungary); Pinter, T.; Baracska Varju, I. [Nuclear Power Plant Paks, Paks (Hungary)

    2010-07-01

    An ex-core fuel damage incident took place at Unit 2 of Paks Nuclear Power Plant in Hungary on the 10{sup th} April 2003. After this event the damaged fuel assemblies were stored under water for four years. During wet storage a continuous activity release was observed. The evaluation of the measured activity concentration showed that the UO{sub 2} mass released from the fuel into the coolant was {approx} 1.8% of the total fuel mass. Furthermore this paper contains the calculation methods and the calculated activity release of the main analysed isotopes. (orig.)

  18. Activity release from the damaged spent VVER-fuel during long-term wet storage

    International Nuclear Information System (INIS)

    Slonszki, E.; Hozer, Z.; Pinter, T.; Baracska Varju, I.

    2010-01-01

    An ex-core fuel damage incident took place at Unit 2 of Paks Nuclear Power Plant in Hungary on the 10 th April 2003. After this event the damaged fuel assemblies were stored under water for four years. During wet storage a continuous activity release was observed. The evaluation of the measured activity concentration showed that the UO 2 mass released from the fuel into the coolant was ∼ 1.8% of the total fuel mass. Furthermore this paper contains the calculation methods and the calculated activity release of the main analysed isotopes. (orig.)

  19. New Methods for Evaluation of Spent Fuel Condition during Long-Term Storage in Slovakia

    Directory of Open Access Journals (Sweden)

    M. Mikloš

    2009-01-01

    Full Text Available Experiences with an advanced spent nuclear fuel management in Slovakia are presented in this paper. The evaluation and monitoring procedures are based on practices at the Slovak wet interim spent fuel storage facility in NPP Jaslovské Bohunice. Since 1999, leak testing of WWER-440 fuel assemblies are provided by special leak tightness detection system “Sipping in pool” delivered by Framatomeanp with external heating for the precise defects determination. In 2006, a new inspection stand “SVYP-440” for monitoring of spent nuclear fuel condition was inserted. This stand has the possibility to open WWER-440 fuel assemblies and examine fuel elements. Optimal ways of spent fuel disposal and monitoring of nuclear fuel condition were designed. With appropriate approach of conservativeness, new factor for specifying spent fuel leak tightness is introduced in the paper. By using computer simulations (based on SCALE 4.4a code for fission products creation and measurements by system “Sipping in pool,” the limit values of leak tightness were established.

  20. HTGR fuel and fuel cycle technology

    International Nuclear Information System (INIS)

    Lotts, A.L.; Coobs, J.H.

    1976-08-01

    The status of fuel and fuel cycle technology for high-temperature gas-cooled reactors (HTGRs) is reviewed. The all-ceramic core of the HTGRs permits high temperatures compared with other reactors. Core outlet temperatures of 740 0 C are now available for the steam cycle. For advanced HTGRs such as are required for direct-cycle power generation and for high-temperature process heat, coolant temperatures as high as 1000 0 C may be expected. The paper discusses the variations of HTGR fuel designs that meet the performance requirements and the requirements of the isotopes to be used in the fuel cycle. Also discussed are the fuel cycle possibilities, which include the low-enrichment cycle, the Th- 233 U cycle, and plutonium utilization in either cycle. The status of fuel and fuel cycle development is summarized

  1. Development of nuclear fuel cycle technologies

    International Nuclear Information System (INIS)

    Suzuoki, Akira; Matsumoto, Takashi; Suzuki, Kazumichi; Kawamura, Fumio

    1995-01-01

    In the long term plan for atomic energy that the Atomic Energy Commission decided the other day, the necessity of the technical development for establishing full scale fuel cycle for future was emphasized. Hitachi Ltd. has engaged in technical development and facility construction in the fields of uranium enrichment, MOX fuel fabrication, spent fuel reprocessing and so on. In uranium enrichment, it took part in the development of centrifuge process centering around Power Reactor and Nuclear Fuel Development Corporation (PNC), and took its share in the construction of the Rokkasho uranium enrichment plant of Japan Nuclear Fuel Service Co., Ltd. Also it cooperates with Laser Enrichment Technology Research Association. In Mox fuel fabrication, it took part in the construction of the facilities for Monju plutonium fuel production of PNC, for pellet production, fabrication and assembling processes. In spent fuel reprocessing, it cooperated with the technical development of maintenance and repair of Tokai reprocessing plant of PNC, and the construction of spent fuel stores in Rokkasho reprocessing plant is advanced. The centrifuge process and the atomic laser process of uranium enrichment are explained. The high reliability of spent fuel reprocessing plants and the advancement of spent fuel reprocessing process are reported. Hitachi Ltd. Intends to exert efforts for the technical development to establish nuclear fuel cycle which increases the importance hereafter. (K.I.)

  2. Long Term Aggresome Accumulation Leads to DNA Damage, p53-dependent Cell Cycle Arrest, and Steric Interference in Mitosis.

    Science.gov (United States)

    Lu, Meng; Boschetti, Chiara; Tunnacliffe, Alan

    2015-11-13

    Juxtanuclear aggresomes form in cells when levels of aggregation-prone proteins exceed the capacity of the proteasome to degrade them. It is widely believed that aggresomes have a protective function, sequestering potentially damaging aggregates until these can be removed by autophagy. However, most in-cell studies have been carried out over a few days at most, and there is little information on the long term effects of aggresomes. To examine these long term effects, we created inducible, single-copy cell lines that expressed aggregation-prone polyglutamine proteins over several months. We present evidence that, as perinuclear aggresomes accumulate, they are associated with abnormal nuclear morphology and DNA double-strand breaks, resulting in cell cycle arrest via the phosphorylated p53 (Ser-15)-dependent pathway. Further analysis reveals that aggresomes can have a detrimental effect on mitosis by steric interference with chromosome alignment, centrosome positioning, and spindle formation. The incidence of apoptosis also increased in aggresome-containing cells. These severe defects developed gradually after juxtanuclear aggresome formation and were not associated with small cytoplasmic aggregates alone. Thus, our findings demonstrate that, in dividing cells, aggresomes are detrimental over the long term, rather than protective. This suggests a novel mechanism for polyglutamine-associated developmental and cell biological abnormalities, particularly those with early onset and non-neuronal pathologies. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  3. Long-term performance of a plant microbial fuel cell with Spartina anglica

    NARCIS (Netherlands)

    Timmers, R.A.; Strik, D.P.B.T.B.; Hamelers, H.V.M.; Buisman, C.J.N.

    2010-01-01

    The plant microbial fuel cell is a sustainable and renewable way of electricity production. The plant is integrated in the anode of the microbial fuel cell which consists of a bed of graphite granules. In the anode, organic compounds deposited by plant roots are oxidized by electrochemically active

  4. BIO-ETHANOL FUELS: SHORT-TERM SOLUTIONS, LONG-TERM DISASTERS

    Science.gov (United States)

    Ethanol derived from bio-mass is often advocated as a significant contributor to possible solutions to our need for a sustainable transportation fuel. Substituting bio-ethanol for conventional fuel immediately addresses the issue of reducing our use of non-renewable resources (f...

  5. The role of long-term geologic changes in the regulation of the Canadian nuclear fuel waste management program

    International Nuclear Information System (INIS)

    Flavelle, P.

    1996-01-01

    It is recognized that the geosphere is a dynamic system over the long time frames of nuclear fuel waste disposal. This paper describes how consideration of a dynamic geosphere has impacted upon the evolving regulatory environment in Canada, and how the approach taken to comply with the regulatory requirements can affect the evaluation of long-term geologic changes. AECB staff opinion is that if the maximum possible effect of geologic changes can be demonstrated to have negligible impact on the safety of a nuclear fuel waste repository, then further consideration of a dynamic geosphere is unnecessary for the current review of the Canadian Nuclear Fuel Waste Management Program. (authors). 7 refs., 4 figs

  6. Investigation of Long Term Cycle Stability - First Results of Metal Hydride Composites

    OpenAIRE

    Dieterich, Mila; Bürger, Inga; Linder, Marc; Wörner, Antje

    2014-01-01

    Reversible reactions of solid powders and hydrogen can be used for hydrogen storage as well as for thermal applications like heat storages or heat conversion systems. For all applications, one of the fundamental prerequisites is the cycle stability of the reaction material and - if required - its bulk structure. At the Institute of Technical Thermodynamics at the German Aerospace Center a test bench to investigate the cycle stability of reversible gas/solid-reactions has been developed and...

  7. The French program on the spent nuclear fuel long term evolution: Major results, uncertainties and new requirements

    International Nuclear Information System (INIS)

    Ferry, Cecile; Poinssot, Christophe; Gras, Jean-Marie

    2006-01-01

    The 1991 Radioactive Waste Management Act established a framework in France for research activities on nuclear waste. Within this context, the Commissariat a l'Energie Atomique initiated a research program in 1999 to investigate the long-term behaviour of commercial spent nuclear fuel under the PRECCI project (from the French acronym for Research Project on Long-Term Evolution of Spent Fuel Packages), supported by the French electrical utility EDF and partially by FRAMATOME ANP. The scientific and technical studies performed within the project aim to address the operational issues of the spent fuel end-of-life. Within the context of the law which ends in 2006, the major part of the studies focused on the behaviour of the spent fuel (SF) in interim long-term dry storage and deep geological disposal. The operational questions initially identified concern (i) the retrievability of spent fuel assemblies at the end of the interim period of storage, (ii) the feasibility of treatment after the period of storage, (iii) the radionuclide source terms for SF in storage and geological disposal and (iv) the compatibility between storage and a subsequent geological disposal. Therefore the long-term evolution of the irradiated fuel is studied under the various boundary conditions encountered during storage and geological disposal: - in a closed system; this condition corresponds to the nominal scenario during storage and to the first confinement phase in disposal conditions (with a duration of 10,000 years in the reference scenario); - it consists in assessing the effects of the residual temperature and high radioactivity on the chemical and physical properties of the spent fuel pellets; - some of the studies are also dedicated to the mechanical behaviour of the cladding and structural materials of the assemblies; - in air, it refers to an incidental loss of confinement during storage or to a breaching of the canister before the site re-saturation in geological disposal

  8. Long-term performance of a plant microbial fuel cell with Spartina anglica

    OpenAIRE

    Timmers, Ruud A.; Strik, David P. B. T. B.; Hamelers, Hubertus V. M.; Buisman, Cees J. N.

    2010-01-01

    The plant microbial fuel cell is a sustainable and renewable way of electricity production. The plant is integrated in the anode of the microbial fuel cell which consists of a bed of graphite granules. In the anode, organic compounds deposited by plant roots are oxidized by electrochemically active bacteria. In this research, salt marsh species Spartina anglica generated current for up to 119?days in a plant microbial fuel cell. Maximum power production was 100?mW?m?2 geometric anode area, hi...

  9. Long-term performance of a plant microbial fuel cell with Spartina anglica

    OpenAIRE

    Timmers, R.A.; Strik, D.P.B.T.B.; Hamelers, H.V.M.; Buisman, C.J.N.

    2010-01-01

    The plant microbial fuel cell is a sustainable and renewable way of electricity production. The plant is integrated in the anode of the microbial fuel cell which consists of a bed of graphite granules. In the anode, organic compounds deposited by plant roots are oxidized by electrochemically active bacteria. In this research, salt marsh species Spartina anglica generated current for up to 119 days in a plant microbial fuel cell. Maximum power production was 100 mW m-2 geometric anode area, hi...

  10. Fuel cycle centres

    International Nuclear Information System (INIS)

    Hagen, M.

    1977-01-01

    The concept of co-locating and integrating fuel cycle facilities at one site is discussed. This concept offers considerable advantages, especially in minimizing the amount of radioactive material to be transported on public roads. Safeguards and physical protection as relating to such an integrated system of facilities are analysed in detail, also industrial and commercial questions. An overall risk-benefit evaluation turns out to be in favour of fuel cycle centres. These centres seem to be specifically attractive with regard to the back end of the fuel cycle, including on-site disposal of radioactive wastes. The respective German approach is presented as an example. Special emphasis is given to the site selection procedures in this case. Time scale and cost for the implementation of this concept are important factors to be looked at. Since participation of governmental institutions in these centres seems to be indispensable their respective roles as compared to industry must be clearly defined. The idea of adjusting fuel cycle centres to regional rather than national use might be an attractive option, depending on the specific parameters in the region, though results of existing multinational ventures are inconclusive in this respect. Major difficulties might be expected e.g. because of different national safety regulations and standards as well as commercial conditions among partner countries. Public acceptance in the host country seems to be another stumbling block for the realization of this type of multinational facilities

  11. Long-term performance of a plant microbial fuel cell with Spartina anglica

    Energy Technology Data Exchange (ETDEWEB)

    Timmers, Ruud A.; Strik, David P.B.T.B.; Hamelers, Hubertus V.M.; Buisman, Cees J.N. [Wageningen Univ. (Netherlands). Sub-dept. of Environmental Technology

    2010-04-15

    The plant microbial fuel cell is a sustainable and renewable way of electricity production. The plant is integrated in the anode of the microbial fuel cell which consists of a bed of graphite granules. In the anode, organic compounds deposited by plant roots are oxidized by electrochemically active bacteria. In this research, salt marsh species Spartina anglica generated current for up to 119 days in a plant microbial fuel cell. Maximum power production was 100 mW m{sup -2} geometric anode area, highest reported power output for a plant microbial fuel cell. Cathode overpotential was the main potential loss in the period of oxygen reduction due to slow oxygen reduction kinetics at the cathode. Ferricyanide reduction improved the kinetics at the cathode and increased current generation with a maximum of 254%. In the period of ferricyanide reduction, the main potential loss was transport loss. This research shows potential application of microbial fuel cell technology in salt marshes for bio-energy production with the plant microbial fuel cell. (orig.)

  12. INTERIM STORAGE AND LONG TERM DISPOSAL OF RESEARCH REACTOR SPENT FUEL

    Energy Technology Data Exchange (ETDEWEB)

    Vinson, D

    2006-08-22

    Aluminum clad research reactor spent nuclear fuel (SNF) is currently being consolidated in wet storage basins (pools). Approximately 20 metric tons (heavy metal) of aluminum-based spent nuclear fuel (Al-SNF) is being consolidated for treatment, packaging, interim storage, and preparation for ultimate disposal in a geologic repository. The storage and disposal of Al-SNF are subject to requirements that provide for safety and acceptable radionuclide release. The options studied for interim storage of SNF include wet storage and dry storage. Two options have also been studied to develop the technical basis for the qualification and repository disposal of aluminum spent fuel. The two options studied include Direct Disposal and Melt-Dilute treatment. The implementation of these options present relative benefits and challenges. Both the Direct Disposal and the Melt-Dilute treatment options have been developed and their technical viability assessed. Adaptation of the melt-dilute technology for the treatment of spent fuel offers the benefits of converting the spent fuel into a proliferation resistant form and/or significantly reducing the volume of the spent fuel. A Mobile Melt-Dilute system concept has emerged to realize these benefits and a prototype system developed. The application of the melt-dilute technology for the treatment of legacy nuclear materials has been evaluated and also offers the promise for the safe disposal of these materials.

  13. Synthesis on the long term behavior of spent nuclear fuel. Vol.1,2; Synthese sur l'evolution a long terme des colis de combustibles irradies. Tome 1,2

    Energy Technology Data Exchange (ETDEWEB)

    Poinssot, Ch.; Toulhoat, P.; Grouiller, J.P.; Pavageau, J.; Piron, J.P.; Pelletier, M.; Dehaudt, Ph.; Cappelaere, Ch.; Limon, R.; Desgranges, L.; Jegou, Ch.; Corbel, C.; Maillard, S.; Faure, M.H.; Cicariello, J.C.; Masson, M. [CEA Saclay, DEN/DDIN/DPRGD, 91 - Gif sur Yvette (France)

    2001-07-01

    The aim of this report is to present the major objectives, the key scientific issues, and the preliminary results of the research conducted in France in the framework of the third line of the 1991 Law, on the topic of the long term behavior of spent nuclear fuel in view of long term storage or geological disposal. Indeed, CEA launched in 1998 the Research Program on the Long Term Behavior of Spent Nuclear Fuel (abbreviated and referred to as PRECCI in French; Poinssot, 1998) the aim of which is to study and assess the ability of spent nuclear fuel packages to keep their initially allocated functions in interim storage and geological disposal: total containment and recovery functions for duration up to hundreds of years (long term or short-term interim storage and/or first reversible stages of geological disposal) and partial confinement function (controlled fluxes of RN) for thousands of years in geological disposal. This program has to allow to obtain relevant and reliable data concerning the long term behavior of the spent fuel packages so that feasibility of interim storage and/or geological disposal can be assessed and demonstrated as well as optimized. Within this framework, this report presents for every possible scenario of evolution (closed system, in Presence of water in presence of gases) what are estimated to be the most relevant evolution mechanism. For the most relevant scientific issues hence defined, a complete scientific review of the best state of knowledge is subsequently here given thus allowing to draw a clear guideline of the major R and D issues for the next years. (authors)

  14. Durability and regeneration of activated carbon air-cathodes in long-term operated microbial fuel cells

    Science.gov (United States)

    Zhang, Enren; Wang, Feng; Yu, Qingling; Scott, Keith; Wang, Xu; Diao, Guowang

    2017-08-01

    The performance of activated carbon catalyst in air-cathodes in microbial fuel cells was investigated over one year. A maximum power of 1722 mW m-2 was produced within the initial one-month microbial fuel cell operation. The air-cathodes produced a maximum power >1200 mW m-2 within six months, but gradually became a limiting factor for the power output in prolonged microbial fuel cell operation. The maximum power decreased by 55% when microbial fuel cells were operated over one year due to deterioration in activated carbon air-cathodes. While salt/biofilm removal from cathodes experiencing one-year operation increased a limiting performance enhancement in cathodes, a washing-drying-pressing procedure could restore the cathode performance to its original levels, although the performance restoration was temporary. Durable cathodes could be regenerated by re-pressing activated carbon catalyst, recovered from one year deteriorated air-cathodes, with new gas diffusion layer, resulting in ∼1800 mW m-2 of maximum power production. The present study indicated that activated carbon was an effective catalyst in microbial fuel cell cathodes, and could be recovered for reuse in long-term operated microbial fuel cells by simple methods.

  15. Impact of long-term climate change on a deep geological repository for spent nuclear fuel

    International Nuclear Information System (INIS)

    Boulton, G.S.; Kautsky, U.; Moren, L.; Wallroth, T.

    2001-05-01

    The radioactivity of spent nuclear fuel will decay over a period of time (100,000 years or longer) in which we expect major environmental change. Climatically driven changes such as glaciation, permafrost and changes in sea level will affect the subsurface environment and must therefore be considered in performance and safety assessments. We regard the state of climate to be determined by the climate system, comprising the atmosphere, the biosphere, the oceans, the ice sheets and the surface of the lithosphere. Climate can change as a consequence of external forcing or as a consequence of the internal dynamics. The changes in the past show a complex cyclical pattern with repetitive periodicities and magnitudes of change. On the relatively long time scale which is of concern in this report climate changes are believed to be triggered by changes in insolation due to cyclical changes in the earth's orbit around the sun. This is referred to as the Milankovitch theory or the astronomical climate theory. A brief review of our knowledge of the climate system, proxy records and observations of past climate change is presented in the report. The most extreme departures from modern environmental conditions in Sweden have occurred during the cold, glacial cycles with ice sheets covering the whole of Sweden. As part of SKB's palaeohydrogeological research programme a time-dependent, thermo-mechanically coupled model of ice sheet behaviour has been developed in order to simulate past fluctuations of the Scandinavian ice sheet and forecast its future. The ice sheet model can calculate the temperature field and isostatic response of the underlying bedrock, subglacial and proglacial permafrost and the subglacial melt rates. By connecting the glaciation model with hydrogeological and rock mechanical models, the response of the subsurface to climate change can be investigated. In this report the climate-driven environmental changes are represented as a series of successive climate

  16. Impact of long-term climate change on a deep geological repository for spent nuclear fuel

    Energy Technology Data Exchange (ETDEWEB)

    Boulton, G.S. [Edinburgh Univ. (United Kingdom); Kautsky, U.; Moren, L. [Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden); Wallroth, T. [Bergab Consulting Geologists (Sweden)

    2001-05-01

    The radioactivity of spent nuclear fuel will decay over a period of time (100,000 years or longer) in which we expect major environmental change. Climatically driven changes such as glaciation, permafrost and changes in sea level will affect the subsurface environment and must therefore be considered in performance and safety assessments. We regard the state of climate to be determined by the climate system, comprising the atmosphere, the biosphere, the oceans, the ice sheets and the surface of the lithosphere. Climate can change as a consequence of external forcing or as a consequence of the internal dynamics. The changes in the past show a complex cyclical pattern with repetitive periodicities and magnitudes of change. On the relatively long time scale which is of concern in this report climate changes are believed to be triggered by changes in insolation due to cyclical changes in the earth's orbit around the sun. This is referred to as the Milankovitch theory or the astronomical climate theory. A brief review of our knowledge of the climate system, proxy records and observations of past climate change is presented in the report. The most extreme departures from modern environmental conditions in Sweden have occurred during the cold, glacial cycles with ice sheets covering the whole of Sweden. As part of SKB's palaeohydrogeological research programme a time-dependent, thermo-mechanically coupled model of ice sheet behaviour has been developed in order to simulate past fluctuations of the Scandinavian ice sheet and forecast its future. The ice sheet model can calculate the temperature field and isostatic response of the underlying bedrock, subglacial and proglacial permafrost and the subglacial melt rates. By connecting the glaciation model with hydrogeological and rock mechanical models, the response of the subsurface to climate change can be investigated. In this report the climate-driven environmental changes are represented as a series of successive

  17. A risk-based monitoring framework for the long term management of used fuel

    International Nuclear Information System (INIS)

    Garisto, N.C.

    2006-01-01

    The Nuclear Waste Management Organization has a mandate from the Government of Canada to consult with the public and to recommend an approach for managing Canada's used nuclear fuel. Three main fuel management methods are being explored and evaluated by the Nuclear Waste Management Organization: disposal in a Deep Geological Repository (DGR); reactor-site extended storage (RES); and centralized extended storage (CES), either above ground or below ground. The used nuclear fuel management system, whether a DGR or an extended storage system will require monitoring. In this study, a risk-based monitoring framework was developed for the used fuel management program. The proposed approach addresses the unique challenges of used fuel management being implemented in a multi-stakeholder process, including: (i) the complexity of the facilities; (ii) the need to consider both science-based risk and perceived risk in the monitoring plans; and (iii) the difficulty in conducting 'invasive' measurements of sealed systems, particularly over a very long time frame. (author)

  18. Long-term cycle stability of metal hydride-graphite composites

    OpenAIRE

    Dieterich, Mila; Pohlmann, Carsten; Bürger, Inga; Linder, Marc; Röntzsch, Lars

    2015-01-01

    Recently, metal hydride composites (MHC) have been proposed which consist of a hydride forming metal alloy and a highly heat conduction secondary phase such as expanded natural graphite (ENG) in order to improve the thermal conductivity of metal hydride powder beds. However, only little data is available in the literature on the effects of extensive cycling on technically relevant properties of MHC. In this paper, hydrogenation characteristics, thermal conductivity and geometrical stability o...

  19. Evaluating the Long-term Water Cycle Trends at a Global-scale using Satellite and Assimilation Datasets

    Science.gov (United States)

    Kim, H.; Lakshmi, V.

    2017-12-01

    Global-scale soil moisture and rainfall products retrieved from remotely sensed and assimilation datasets provide an effective way to monitor near surface soil moisture content and precipitation with sub-daily temporal resolution. In the present study, we employed the concept of the stored precipitation fraction Fp(f) in order to examine the long-term water cycle trends at a global-scale. The analysis was done for Fp(f) trends with the various geophysical aspects such as climate zone, land use classifications, amount of vegetation, and soil properties. Furthermore, we compared a global-scale Fp(f) using different microwave-based satellite soil moisture datasets. The Fp(f) is calculated by utilized surface soil moisture dataset from Soil Moisture Active Passive (SMAP), Soil Moisture and Ocean Salinity, Advanced Scatterometer, Advanced Microwave Scanning Radiometer 2, and precipitation information from Global Precipitation Measurement Mission and Global Land Data Assimilation System. Different results from microwave-based soil moisture dataset showed discordant results particularly over arid and highly vegetated regions. The results of this study provide us new insights of the long-term water cycle trends over different land surface areas. Thereby also highlighting the advantages of the recently available GPM and SMAP datasets for the uses in various hydrometeorological applications.

  20. Long-term effects of storage and thermal cycling on the marginal adaptation of provisional resin crowns: a pilot study.

    Science.gov (United States)

    Ehrenberg, David; Weiner, Gabriel I; Weiner, Saul

    2006-03-01

    Provisional resin crowns may be used for an extended period while complex treatments are completed. The crowns function intraorally; therefore, moisture absorption and thermal cycling may affect the physical properties of acrylic resin, causing a change in marginal gap size. The purpose of this pilot study was to examine the effect of long-term water absorption and thermal cycling on marginal gap size of polymethyl methacrylate copolymer and bis-acrylic composite resin crowns. Specimens (n = 10) were fabricated from 2 acrylic resins: a polymethyl methacrylate (Alike) and a bis-acrylic composite resin (Provitec). Specimens were first fabricated on a metal master die. Custom die stems were fabricated for each specimen from a low-fusing alloy (Cerroblend) to eliminate the factor of polymerization shrinkage. Specimens were then fitted to assure a standardized, pre-experimental marginal gap range of Provisional crowns made from either a bis-acrylic resin composite or a polymethyl methacrylate copolymer demonstrated loss of marginal adaptation during a simulated long-term period of service.

  1. Long-term ocean oxygen depletion in response to carbon dioxide emissions from fossil fuels

    DEFF Research Database (Denmark)

    Shaffer, G.; Olsen, S.M.; Pedersen, Jens Olaf Pepke

    2009-01-01

    Ongoing global warming could persist far into the future, because natural processes require decades to hundreds of thousands of years to remove carbon dioxide from fossil-fuel burning from the atmosphere(1-3). Future warming may have large global impacts including ocean oxygen depletion and assoc......Ongoing global warming could persist far into the future, because natural processes require decades to hundreds of thousands of years to remove carbon dioxide from fossil-fuel burning from the atmosphere(1-3). Future warming may have large global impacts including ocean oxygen depletion...... solubility from surface-layer warming accounts for most of the enhanced oxygen depletion in the upper 500 m of the ocean. Possible weakening of ocean overturning and convection lead to further oxygen depletion, also in the deep ocean. We conclude that substantial reductions in fossil-fuel use over the next...

  2. Lanthanide based conversion coatings for long term wet storage of aluminium-clad spent fuel

    International Nuclear Information System (INIS)

    Fernandes, S.M.C.; Correa, O.V.; De Souza, J.A.; Ramanathan, L.V.

    2010-01-01

    Spent fuels from research reactors are stored in basins with water of less than desirable quality at many facilities around the world and instances of cladding failure caused by pitting corrosion have been reported. Conversion coatings have been used in many industries to protect different metals, including aluminium alloys. This paper presents the results of an ongoing investigation in which the corrosion resistance of lanthanide (cerium, lanthanum and praseodymium) based conversion coated RR fuel cladding alloys has been studied. Electrochemical tests in the laboratory revealed higher corrosion resistance of CeO 2 , La 2 O 3 and Pr 2 O 3 coated AA 1100 and AA 6061 alloys in NaCl solutions. Uncoated and CeO 2 coated coupons of these alloys exposed for 50 days to the spent fuel basin of the IEA-R1 research reactor in IPEN, Brazil, revealed marked reductions in the extent of pitting corrosion. (author)

  3. Long-term operation of double chambered microbial fuel cell for bio-electro denitrification.

    Science.gov (United States)

    Oon, Yoong-Sin; Ong, Soon-An; Ho, Li-Ngee; Wong, Yee-Shian; Oon, Yoong-Ling; Lehl, Harvinder Kaur; Thung, Wei-Eng

    2016-06-01

    The main aim of this study is to investigate the performance of organic oxidation and denitrification of the system under long-term operation. The MFC reactor was operated in continuous mode for 180 days. Nitrate was successfully demonstrated as terminal electron acceptor, where nitrate was reduced at the cathode using electron provided by acetate oxidation at the anode. The removal efficiencies of chemical oxygen demand (COD) and nitrate were higher in the closed circuit system than in open circuit system. Both COD and nitrate reduction improved with the increase of organic loading and subsequently contributed to higher power output. The maximum nitrate removal efficiency was 88 ± 4 % (influent of 141 ± 14 mg/L). The internal resistant was 50 Ω, which was found to be low for a double chambered MFC. The maximum power density was 669 mW/m(3) with current density of 3487 mA/m(3).

  4. Compact approach to long-term monitored retrievable storage of spent fuel

    International Nuclear Information System (INIS)

    Muir, D.W.

    1986-01-01

    We examine a new approach to monitored retrievable storage (MRS) that is extremely compact in terms of total land use and may offer increased security and reduced environmental impact, relative to current designs. This approach involves embedding the spent fuel assemblies in monolithic blocks of metallic aluminum. While this would clearly require increased effort in the spent-fuel packaging phase, it would offer in return the above-mentioned environmental advantages, plus the option of easily extending the surface-storage time scale from several years to several decades if a need for longer storage times should arise in the future

  5. Fuel and nuclear fuel cycle

    International Nuclear Information System (INIS)

    Prunier, C.

    1998-01-01

    The nuclear fuel is studied in detail, the best choice and why in relation with the type of reactor, the properties of the fuel cans, the choice of fuel materials. An important part is granted to the fuel assembly of PWR type reactor and the performances of nuclear fuels are tackled. The different subjects for research and development are discussed and this article ends with the particular situation of mixed oxide fuels ( materials, behavior, efficiency). (N.C.)

  6. Nuclear Fuel Cycle; (USA)

    Energy Technology Data Exchange (ETDEWEB)

    Cason, D.L.; Hicks, S.C. (eds.)

    1991-01-01

    Nuclear Fuel Cycle (NFC) announces on a monthly basis the current worldwide information available from the open literature on all aspects of the fuel cycle except in-reactor properties and performance of fuels. More information related to radioactive waste and to the transport and storage of spent fuel is included in the current awareness publication, Radioactive Waste Management. This publication contains the abstracts of DOE reports, journal articles, conference papers, patents, theses, and monographs added to the Energy Science and Technology Database (EDB) during the past month. Also included are other US information obtained through acquisition programs or interagency agreements and international information obtained through the International Energy Agency's Technology Data Exchange, the International Atomic Energy Agency's International Nuclear Information System, or government-to-government agreements. The digests in NFC on nuclear fuel back to 1948 are available for online searching and retrieval in EDB and Nuclear Science Abstracts (NSA) database. Current information, added daily to EDB, is available to DOE and its contractors through the DOE Integrated Technical Information System. Customized profiles can be developed to provide current information to meet each user's needs.

  7. Long-term soil warming and Carbon Cycle Feedbacks to the Climate System

    Energy Technology Data Exchange (ETDEWEB)

    Melillo, Jerry M.

    2014-04-30

    The primary objective of the proposed research was to quantify and explain the effects of a sustained in situ 5oC soil temperature increase on net carbon (C) storage in a northeastern deciduous forest ecosystem. The research was done at an established soil warming experiment at the Harvard Forest in central Massachusetts – Barre Woods site established in 2001. In the field, a series of plant and soil measurements were made to quantify changes in C storage in the ecosystem and to provide insights into the possible relationships between C-storage changes and nitrogen (N) cycling changes in the warmed plots. Field measurements included: 1) annual woody increment; 2) litterfall; 3) carbon dioxide (CO2) efflux from the soil surface; 4) root biomass and respiration; 5) microbial biomass; and 6) net N mineralization and net nitrification rates. This research was designed to increase our understanding of how global warming will affect the capacity of temperate forest ecosystems to store C. The work explored how soil warming changes the interactions between the C and N cycles, and how these changes affect land-atmosphere feedbacks. This core research question framed the project – What are the effects of a sustained in situ 5oC soil temperature increase on net carbon (C) storage in a northeastern deciduous forest ecosystem? A second critical question was addressed in this research – What are the effects of a sustained in situ 5{degrees}C soil temperature increase on nitrogen (N) cycling in a northeastern deciduous forest ecosystem?

  8. Do Business Cycles Have Long-Term Impact for Particular Cohorts?

    DEFF Research Database (Denmark)

    Andersen, Torben M.; Maibom, Jonas; Svarer, Michael

    Will the current employment crisis produce lost generations with permanently lower labour market attachment? Taking an explicit cohort perspective and based on Danish data we do not find strong persistence in employment rates at the cohort level. Younger workers tend to be more exposed to business...... cycle fluctuations than older workers, but importantly they recover more quickly from such set-backs than older workers for whom persistence is stronger. Moreover, no cohorts have been disproportionately affected by exposure to a sequence of adverse shocks. An explicit account of overlapping cohorts...

  9. Averaging business cycles vs. myopia: Do we need a long term vision when developing IRP?

    Energy Technology Data Exchange (ETDEWEB)

    McDonald, C. [Synergic Resources Corporation, Bala Cynwyd, PA (United States); Gupta, P.C. [Synergic Resources Corp., Oakland, CA (United States)

    1995-05-01

    Utility demand forecasting is inherently imprecise due to the number of uncertainties resulting from business cycles, policy making, technology breakthroughs, national and international political upheavals and the limitations of the forecasting tools. This implies that revisions based primarily on recent experience could lead to unstable forecasts. Moreover, new planning tools are required that provide an explicit consideration of uncertainty and lead to flexible and robust planning tools are required that provide an explicit consideration of uncertainty and lead to flexible and robust planning decisions.

  10. Cryoprotectants are metabolic fuels during long term frost exposure in the earthworm Dendrobaena octaedra

    DEFF Research Database (Denmark)

    Jørgensen, S.; Overgaard, J.; Holmstrup, M.

    2008-01-01

    Ectothermic animals that live in the subarctic and temperate regions must have strategies to deal with periods of frost during winter. The earthworm Dendrobaena octaedra is a freeze tolerant species that accumulates large concentrations of the cryoprotectant glucose upon ice formation in the extr...... as anaerobic fuel source than as a cryoprotectant....

  11. Long-Term Effects of Repeated Cycles of Intrathecal Triamcinolone Acetonide on Spasticity in MS Patients.

    Science.gov (United States)

    Rommer, Paulus Stefan; Kamin, Frank; Abu-Mugheisib, Mazen; Koehler, Wolfgang; Hoffmann, Frank; Winkelmann, Alexander; Benecke, Reiner; Zettl, Uwe Klaus

    2016-01-01

    Spasticity is a common feature in patients with multiple sclerosis (MS). Although options have broadened over the last years, there are still patients with no response to common therapeutic agents. Intrathecal administered triamcinolone acetonide (TCA) has been tested for spasticity in patients with MS. However, the long run effects are not known so far. The aim of this study was to evaluate the effects of repeated cycles of intrathecal TCA instillations on clinical parameters. A total of 54 patients with clinically definite MS and no response to commonly utilized antispastic drugs were enrolled. TCA was administered every 3 months for a period of 9 months. Clinical assessments including spasticity, disability (EDSS), mobility (walking distance, and timed 25-foot walk), bladder function, and quality of life were carried out prior to and at the end of each treatment cycle. Repeated TCA treatment led to repeated effects on spasticity (P spasticity or EDSS was not shown at end of the study. Effects diminished over 3 months. Repeated TCA instillations led to replicable effects on spasticity; subgroup analyses suggest that higher spasticity, more frequent treatments, and higher EDSS may lead to pronounced effects on spasticity and EDSS. Intrathecal TCA treatment was safe and no severe side effects occurred. We hypothesize a significant time dependence of re-administration of TCA and that an interval of 3 months between the treatments might be too long. © 2015 John Wiley & Sons Ltd.

  12. Long term behaviour and seasonal cycling of Cs-137 in a eutrophic lake in Southern Germany

    Energy Technology Data Exchange (ETDEWEB)

    Klemt, E.; Knaus, J.; Putyrskaya, V.; Ries, T. [Hochschule Ravensburg-Weingarten (Germany)

    2014-07-01

    Lake Vorsee is a small and shallow eutrophic lake with a swampy watershed about 25 km north of Lake Constance in southern Germany which is intensely used for fishing by local fishermen. It is completely overgrown by watermilfoil (Myriophyllum spicatum) which produces thick watery organic sediment layers when it decomposes in late autumn and winter. In 1986 the watershed of Lake Vorsee had a Cs-137 Chernobyl inventory of about 30 kBq/m{sup 2}. The Cs-137 activity concentration in the water was monitored for more than 25 years and it can be well described by a sum of two exponential functions superimposed by some seasonal cycling. To analyze the seasonal cycling of the Cs-137 activity concentration in water and in suspended matter, samples were collected with a Large Volume Water Sampler (Midiya-System) on a monthly base and measured gamma-spectrometrically by HPGe-detectors. Also the Cs-137 distribution coefficient kD was determined. Additionally, in the lake water the concentration of the competing ions K{sup +} and NH{sub 4}{sup +} was determined by ion-chromatography, total organic carbon (TOC) with a combustion catalytic oxidation / NDIR detection method as well as the dissolved O{sub 2}-concentration and the pH and temperature of the water by hand-held probes. Information on the amount of precipitation was taken from nearby weather stations. In this project the following hypothesis will be checked: In late autumn the decomposing watermilfoil produces NH{sub 4}{sup +}-ions which exchange Cs{sup +}-ions from their binding places, thereby increasing the Cs-137 activity concentration in the water. In spring the watermilfoil starts growing which leads to a larger O{sub 2}-concentration in the water and helps to disintegrate the NH{sub 4}{sup +}-ions in this way decreasing the Cs-137 concentration again. A possible influence of the other measured parameters on the seasonal cycling will also be discussed. Document available in abstract form only. (authors)

  13. Long Term Planetary Habitability and the Carbonate-Silicate Cycle: The Effect of Planet Size

    Science.gov (United States)

    Rushby, A. J.; Johnson, M.; Mills, B.; Watson, A. J.; Claire, M.

    2017-12-01

    The potential habitability of exoplanets is traditionally assessed by determining whether or not its orbit falls within the circumstellar `habitable zone' of its star [1]. However, this metric does not readily account readily for changes in the abundance of greenhouse gases and their associated radiative forcing as a result of the action of the carbonate-silicate cycle. We develop a model of the carbon cycle on Earth, coupled with a stellar evolution model and a 1-D radiative-convective climate model with an Earth-like atmospheric water vapour profile [1], to explore the potential changes in the CO2 greenhouse under conditions of varying planet size (0.5 - 2 R⊕) and stellar flux (0.75 to 1.25 S⊕).We find that likely changes in global topography, tectonic outgassing and uplift, and the hydrological cycle on larger planets results in proportionally greater surface temperatures and pCO2 for a given incident flux. For planets between 0.5 and 2 R⊕ the effect of these changes results in average global surface temperature deviations of up to 15 K, which suggests that these relationships be considered in future studies of planetary habitability.Furthermore, by coupling this model with the stellar evolution scheme presented in [2] and setting an upper temperature limit of 343 K, the habitable period of the Earth-sized world around the Sun can be quantified. For a 1 R⊕ planet, this limit is approximately 6.35 Gyr after planet formation, or 1.81 Gyr from present day. Additionally, atmospheric CO2 falls below the limit at which C3 and C4 plants can effectively photosynthesize after 5.38 Gyr and 6.1 Gyr respectively, which may initiate a significant reorganization of the biosphere of the planet well before average surface temperatures render it uninhabitable.References: [1] Kopparapu et al. (2013) The Astrophysical Journal 765(2) [2] Rushby et al. (2013) Astrobiology, 13(9), 833-849.

  14. Scientific reference on the long time evolution of spent fuels; Referentiel scientifique sur l'evolution a long terme des combustibles uses

    Energy Technology Data Exchange (ETDEWEB)

    Ferry, C.; Poinssot, Ch.; Broudic, V.; Jegou, Ch.; Roudil, D.; Poulesquen, A.; Miserque, F. [CEA Saclay, Dept. de Physico-Chimie, 91 - Gif sur Yvette (France); Cappelaere, Ch. [CEA Saclay, Dept. des Materiaux pour le Nucleaire, 91 - Gif-sur-Yvette (France); Desgranges, L.; Garcia, Ph.; Piron, J.P. [CEA Cadarache, 13 - Saint-Paul-lez-Durance (France). Dept. d' Etudes des Combustibles; Lovera, P.; Marimbeau, P. [CEA Cadarache, 13 - Saint Paul lez Durance (France). Dept. d' Etudes des Reacteurs; Corbel, C. [CEA Saclay, Dept. de Recherche sur l' Etat Condense, les Atomes et les Molecules, 91 - Gif sur Yvette (France)

    2005-03-15

    This report is published in the framework of the 1991 French law for the nuclear waste management. The state of the art reported here concerns the long term evolution of spent fuel in the various environmental conditions corresponding to dry storage and geological disposal: closed system, air and water saturated medium. This review is based on the results of the french PRECCI project (Research Program on Long term Evolution of Spent Nuclear Fuel) and on literature data. (authors)

  15. Long-term kinetic effects and colloid formations in dissolution of LWR spent fuels

    International Nuclear Information System (INIS)

    Ahn, T.M.

    1996-11-01

    This report evaluates continuous dissolution and colloid formation during spent-fuel performance under repository conditions in high-level waste disposal. Various observations suggest that reprecipitated layers formed on spent-fuel surfaces may not be protective. This situation may lead to continuous dissolution of highly soluble radionuclides such as C-14, Cl-36, Tc-99, I-129, and Cs-135. However, the diffusion limits of various species involved may retard dissolution significantly. For low-solubility actinides such as Pu-(239+240) or Am-(241+243), various processes regarding colloid formation have been analyzed. The processes analyzed are condensation, dispersion, and sorption. Colloid formation may lead to significant releases of low-solubility actinides. However, because there are only limited data available on matrix dissolution, colloid formation, and solubility limits, many uncertainties still exist. These uncertainties must be addressed before the significance of radionuclide releases can be determined. 118 refs

  16. Potential long-term impacts of changes in US vehicle fuel efficiency standards

    International Nuclear Information System (INIS)

    Bezdek, Roger H.; Wendling, Robert M.

    2005-01-01

    Changes in corporate average fuel economy (CAFE) standards have not been made due, in part, to concerns over their negative impact on the economy and jobs. This paper simulates the effects of enhanced CAFE standards through 2030 and finds that such changes could increase GDP and create 300,000 jobs distributed widely across states, industries, and occupations. In addition, enhanced CAFE standards could, each year, reduce US oil consumption by 30 billion gallons, save drivers $40 billion, and reduce US greenhouse gas emissions by 100 million tons. However, there is no free lunch. There would be widespread job displacement within many industries, occupations, and states, and increased CAFE standards require that fuel economy be given priority over other vehicle improvements, increase the purchase price of vehicles, require manufacturers to produce vehicles that they otherwise would not, and require consumers to purchase vehicles that would not exist except for CAFE

  17. Short and long-term carbon balance of bioenergy electricity production fueled by forest treatments

    OpenAIRE

    Kelsey, Katharine C; Barnes, Kallie L; Ryan, Michael G; Neff, Jason C

    2014-01-01

    Background Forests store large amounts of carbon in forest biomass, and this carbon can be released to the atmosphere following forest disturbance or management. In the western US, forest fuel reduction treatments designed to reduce the risk of high severity wildfire can change forest carbon balance by removing carbon in the form of biomass, and by altering future potential wildfire behavior in the treated stand. Forest treatment carbon balance is further affected by the fate of this biomass ...

  18. A long term radiological risk model for plutonium-fueled and fission reactor space nuclear system

    International Nuclear Information System (INIS)

    Bartram, B.W.; Dougherty, D.K.

    1987-01-01

    This report describes the optimization of the RISK III mathematical model, which provides risk assessment for the use of a plutonium-fueled, fission reactor in space systems. The report discusses possible scenarios leading to radiation releases on the ground; distinctions are made for an intact reactor and a dispersed reactor. Also included are projected dose equivalents for various accident situations. 54 refs., 31 figs., 11 tabs

  19. HTGR fuel cycle

    International Nuclear Information System (INIS)

    1987-08-01

    In the spring of 1987, the HTGR fuel cycle project has been existing for ten years, and for this reason a status seminar has been held on May 12, 1987 in the Juelich Nuclear Research Center, that gathered the participants in this project for a discussion on the state of the art in HTGR fuel element development, graphite development, and waste management. The papers present an overview of work performed so far and an outlook on future tasks and goals, and on taking stock one can say that the project has been very successful so far: The HTGR fuel element now available meets highest requirements and forms the basis of today's HTGR safety philosophy; research work on graphite behaviour in a high-temperature reactor has led to complete knowledge of the temperature or neutron-induced effects, and with the concept of direct ultimate waste disposal, the waste management problem has found a feasible solution. (orig./GL) [de

  20. Long-term change of the atmospheric energy cycles and weather disturbances

    Science.gov (United States)

    Kim, WonMoo; Choi, Yong-Sang

    2017-11-01

    Weather disturbances are the manifestation of mean atmospheric energy cascading into eddies, thus identifying atmospheric energy structure is of fundamental importance to understand the weather variability in a changing climate. The question is whether our observational data can lead to a consistent diagnosis on the energy conversion characteristics. Here we investigate the atmospheric energy cascades by a simple framework of Lorenz energy cycle, and analyze the energy distribution in mean and eddy fields as forms of potential and kinetic energy. It is found that even the widely utilized independent reanalysis datasets, NCEP-DOE AMIP-II Reanalysis (NCEP2) and ERA-Interim (ERA-INT), draw different conclusions on the change of weather variability measured by eddy-related kinetic energy. NCEP2 shows an increased mean-to-eddy energy conversion and enhanced eddy activity due to efficient baroclinic energy cascade, but ERA-INT shows relatively constant energy cascading structure between the 1980s and the 2000s. The source of discrepancy mainly originates from the uncertainties in hydrological variables in the mid-troposphere. Therefore, much efforts should be made to improve mid-tropospheric observations for more reliable diagnosis of the weather disturbances as a consequence of man-made greenhouse effect.

  1. Short and long-term carbon balance of bioenergy electricity production fueled by forest treatments.

    Science.gov (United States)

    Kelsey, Katharine C; Barnes, Kallie L; Ryan, Michael G; Neff, Jason C

    2014-01-01

    Forests store large amounts of carbon in forest biomass, and this carbon can be released to the atmosphere following forest disturbance or management. In the western US, forest fuel reduction treatments designed to reduce the risk of high severity wildfire can change forest carbon balance by removing carbon in the form of biomass, and by altering future potential wildfire behavior in the treated stand. Forest treatment carbon balance is further affected by the fate of this biomass removed from the forest, and the occurrence and intensity of a future wildfire in this stand. In this study we investigate the carbon balance of a forest treatment with varying fates of harvested biomass, including use for bioenergy electricity production, and under varying scenarios of future disturbance and regeneration. Bioenergy is a carbon intensive energy source; in our study we find that carbon emissions from bioenergy electricity production are nearly twice that of coal for the same amount of electricity. However, some emissions from bioenergy electricity production are offset by avoided fossil fuel electricity emissions. The carbon benefit achieved by using harvested biomass for bioenergy electricity production may be increased through avoided pyrogenic emissions if the forest treatment can effectively reduce severity. Forest treatments with the use of harvested biomass for electricity generation can reduce carbon emissions to the atmosphere by offsetting fossil fuel electricity generation emissions, and potentially by avoided pyrogenic emissions due to reduced intensity and severity of a future wildfire in the treated stand. However, changes in future wildfire and regeneration regimes may affect forest carbon balance and these climate-induced changes may influence forest carbon balance as much, or more, than bioenergy production.

  2. Solid TRU fuels and fuel cycle technology

    International Nuclear Information System (INIS)

    Ogawa, Toru; Suzuki, Yasufumi

    1997-01-01

    Alloys and nitrides are candidate solid fuels for transmutation. However, the nitride fuels are preferred to the alloys because they have more favorable thermal properties which allows to apply a cold-fuel concept. The nitride fuel cycle technology is briefly presented

  3. Long-term management of Canada's spent nuclear fuel: the nuclear waste management organizations recommendation to government

    International Nuclear Information System (INIS)

    Shaver, K.

    2006-01-01

    Full text: Like many countries with nuclear power programs, Canada is in the process of addressing the long-term management of its spent fuel. The Nuclear Waste Management Organization (NWMO) was tasked through federal legislation to conduct a three-year study of approaches for the long-term management of spent fuel, and to recommend a preferred approach to the Government of Canada. Legislation required NWMO to compare at least three approaches -approaches based on deep geological disposal in the Canadian Shield, storage at nuclear reactor sites, and centralized storage either above or below ground. In assessing the options, NWMO sought a recommendation that would be socially acceptable, technically sound, environmentally responsible and economically feasible. The study drew on a vast base of social, technical, engineering, and financial research, and included an extensive engagement program with the public and Aboriginal peoples. The recommendation emerged from a collaborative dialogue with specialists and citizens, for an approach that is built on sound science and technology and responsive to citizen values. NWMO submitted its completed options study, with recommendation, to the Government in November 2005. NWMO has proposed an alternative approach, Adaptive Phased Management, which has as its key attributes: central containment and isolation of spent fuel in a deep repository, in an appropriate geological formation; contingency provision for central shallow storage; monitoring and retrievability; and a staged, adaptive process of concept implementation, reflecting the complex nature of the task and the desire of citizens to proceed through cautious, deliberate steps of technical demonstration and social acceptance. This paper will review: 1) the development of the assessment framework for comparing the technical options, which incorporated social and ethical considerations expressed by citizens; 2) findings of the assessment; and 3) features of the proposed

  4. Nuclear Fuel Cycle Objectives

    International Nuclear Information System (INIS)

    2013-01-01

    . The four Objectives publications include Nuclear General Objectives, Nuclear Power Objectives, Nuclear Fuel Cycle Objectives, and Radioactive Waste management and Decommissioning Objectives. This publication sets out the objectives that need to be achieved in the area of the nuclear fuel cycle to ensure that the Nuclear Energy Basic Principles are satisfied. Within each of these four Objectives publications, the individual topics that make up each area are addressed. The five topics included in this publication are: resources; fuel engineering and performance; spent fuel management and reprocessing; fuel cycles; and the research reactor nuclear fuel cycle

  5. The effects of hybrid cycle training in inactive people with long-term spinal cord injury: design of a multicentre randomized controlled trial

    NARCIS (Netherlands)

    Bakkum, A.J.T.; De Groot, S.; van der Woude, L.H.V.; Janssen, T.W.J.

    2013-01-01

    Purpose: Physical activity in people with long-term spinal cord injury (SCI) is important to stay fit and healthy. The purpose of this study is to evaluate the effects of hybrid cycle training (hand cycling in combination with functional electrical stimulation-induced leg cycling) on fitness,

  6. The effects of hybrid cycle training in inactive people with long-term spinal cord injury : design of a multicenter randomized controlled trial

    NARCIS (Netherlands)

    Bakkum, Arjan J. T.; de Groot, Sonja; van der Woude, Lucas H. V.; Janssen, Thomas W. J.

    2013-01-01

    Purpose: Physical activity in people with long-term spinal cord injury (SCI) is important to stay fit and healthy. The purpose of this study is to evaluate the effects of hybrid cycle training (hand cycling in combination with functional electrical stimulation-induced leg cycling) on fitness,

  7. Nuclear power generation and fuel cycle report 1996

    International Nuclear Information System (INIS)

    1996-10-01

    This report presents the current status and projections through 2015 of nuclear capacity, generation, and fuel cycle requirements for all countries using nuclear power to generate electricity for commercial use. It also contains information and forecasts of developments in the worldwide nuclear fuel market. Long term projections of U.S. nuclear capacity, generation, and spent fuel discharges for two different scenarios through 2040 are developed. A discussion on decommissioning of nuclear power plants is included

  8. Nuclear power generation and fuel cycle report 1996

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-10-01

    This report presents the current status and projections through 2015 of nuclear capacity, generation, and fuel cycle requirements for all countries using nuclear power to generate electricity for commercial use. It also contains information and forecasts of developments in the worldwide nuclear fuel market. Long term projections of U.S. nuclear capacity, generation, and spent fuel discharges for two different scenarios through 2040 are developed. A discussion on decommissioning of nuclear power plants is included.

  9. Fast breeder fuel cycle

    International Nuclear Information System (INIS)

    1978-07-01

    This contribution is prepared for the answer to the questionnaire of working group 5, subgroup B. B.1. is the short review of the fast breeder fuel cycles based on the reference large commercial Japanese LMFBR. The LMFBRs are devided into two types. FBR-A is the reactor to be used before 2000, and its burnup and breeding ratio are relatively low. The reference fuel cycle requirement is calculated based on the FBR-A. FBR-B is the one to be used after 2000, and its burnup and breeding ratio are relatively high. B.2. is basic FBR fuel reprocessing scheme emphasizing the differences with LWR reprocessing. This scheme is based on the conceptual design and research and development work on the small scale LMFBR reprocessing facility of Japan. The facility adopts a conventional PUREX process except head end portions. The report also describes the effects of technical modifications of conventional reprocessing flow sheets, and the problems to be solved before the adoption of these alternatives

  10. Long-term cathode performance and the microbial communities that develop in microbial fuel cells fed different fermentation endproducts

    KAUST Repository

    Kiely, Patrick D.

    2011-01-01

    To better understand how cathode performance and substrates affected communities that evolved in these reactors over long periods of time, microbial fuel cells were operated for more than 1year with individual endproducts of lignocellulose fermentation (acetic acid, formic acid, lactic acid, succinic acid, or ethanol). Large variations in reactor performance were primarily due to the specific substrates, with power densities ranging from 835±21 to 62±1mW/m3. Cathodes performance degraded over time, as shown by an increase in power of up to 26% when the cathode biofilm was removed, and 118% using new cathodes. Communities that developed on the anodes included exoelectrogenic families, such as Rhodobacteraceae, Geobacteraceae, and Peptococcaceae, with the Deltaproteobacteria dominating most reactors. Pelobacter propionicus was the predominant member in reactors fed acetic acid, and it was abundant in several other MFCs. These results provide valuable insights into the effects of long-term MFC operation on reactor performance. © 2010 Elsevier Ltd.

  11. Long term immersion test of aluminum alloy AA 6061 used for fuel cladding in MTR type reactors

    International Nuclear Information System (INIS)

    Linardi, Evelina M.; Rodriguez, Sebastian; Haddad, Roberto; Lanzani, Liliana

    2009-01-01

    In this work we present the results of long term immersion tests performed in the aluminum alloy AA 6061, used for fuel cladding in MTR type reactors. The tests were performed at open circuit potential in high purity water (ρ = 18.2 MΩ.cm) and in 10 -3 M NaCl solution. Two kinds of assemblies were studied: simple sheets and artificial crevices, immersed during 6, 12 and 18 months at room temperature. In both media and both assemblies, the aluminum hydroxide phases crystalline bayerite and bohemite were identified. It was found that a kind of localized attack named alkaline attack occurs around the iron-rich intermetallics. These particles were confirmed to control the corrosion of the AA 6061 alloy in an aerated medium. Immersion times for up to 18 months did not increase the oxide growth or the alkaline attack on the AA 6061 alloy. (author)

  12. Engaging aboriginal peoples in Canada's plan for the long-term management of used nuclear fuel

    International Nuclear Information System (INIS)

    Patton, P.

    2011-01-01

    The interests and concerns of Aboriginal peoples are integral to development and implementation of Canada's plans for the long-term management of used nuclear fuel. The Nuclear Waste Management Organization (NWMO) has an ongoing statutory obligation and a commitment to active and meaningful participation with Aboriginal peoples. The organization has worked with Aboriginal organizations and individuals to develop long-term engagement and dialogue processes that respect traditional Aboriginal practices, culture, protocols and approaches to decision-making. Aboriginal peoples were significant participants in the 2003-2005 study that resulted in the recommendation for Adaptive Phased Management (APM). After the Canadian government agreed to proceed with APM, Aboriginal peoples provided valuable input into development of the process for selecting a site for a deep geological repository (DGR) for the long-term management of Canada's used nuclear fuel. The involvement of Aboriginal stakeholders continues to be important as Canada moves into the siting process. Engagement of Aboriginal peoples is guided by principles that respond to the unique interests, perspectives and culture of Aboriginal peoples. These principles recognize and honour the special relationship that Aboriginal peoples have with the natural environment, their unique stewardship responsibilities, and the fact that Aboriginal peoples are holders of Aboriginal Traditional Knowledge (ATK), which brings value to planning processes. The NWMO has been working with Aboriginal Elders and others to learn about ATK and to interweave this knowledge into its work. ATK includes important knowledge about the land, ecology and intergenerational decision-making. The NWMO and Aboriginal peoples have given life to engagement principles and the wisdom of ATK by collaboratively developing a number of programs including agreements with national, regional and local Aboriginal organizations. Additionally, the NWMO has

  13. From the seismic cycle to long-term deformation: linking seismic coupling and Quaternary coastal geomorphology along the Andean megathrust

    Science.gov (United States)

    Saillard, M.; Audin, L.; Rousset, B.; Avouac, J. P.; Chlieh, M.; Hall, S. R.; Husson, L.; Farber, D.

    2017-12-01

    Measurement of interseismic strain along subduction zones reveals the location of both locked asperities, which might rupture during megathrust earthquakes, and creeping zones, which tend to arrest such seismic ruptures. The heterogeneous pattern of interseismic coupling presumably relates to spatial variations of frictional properties along the subduction interface and may also show up in the fore-arc morphology. To investigate this hypothesis, we compiled information on the extent of earthquake ruptures for the last 500 yrs and uplift rates derived from dated marine terraces along the South American coastline from central Peru to southern Chile. We additionally calculated a new interseismic coupling model for that same area based on a compilation of GPS data. We show that the coastline geometry, characterized by the distance between the coast and the trench; the latitudinal variations of long-term uplift rates; and the spatial pattern of interseismic coupling are correlated. Zones of faster and long-term permanent coastal uplift, evidenced by uplifted marine terraces, coincide with peninsulas and also with areas of creep on the megathrust where slip is mostly aseismic and tend to arrest seismic ruptures. This correlation suggests that these areas prevent elastic strain buildup and inhibit lateral seismic rupture propagation. Correlation between the location of these regions across and along strike of convergence and the long-term morphology of the subduction margin suggests that the barrier effect might be due to rheology, namely rate-strengthening friction, although geometric effects might also play a secondary role. Higher shear stress along creeping segments of the megathrust than along segments dominated by recurring large earthquakes would favor more rapid viscoplastic (permanent) deformation of the fore arc and thus uplift. Marine terrace sequences attest to frictional properties along the megathrust persisting for million-year time scales. Peninsulas are

  14. The fuel cycle scoping system

    International Nuclear Information System (INIS)

    Dooley, G.D.; Malone, J.P.

    1986-01-01

    The Fuel Cycle Scoping System (FCSS) was created to fill the need for a scoping tool which provides the utilities with the ability to quickly evaluate alternative fuel management strategies, tails assay choices, fuel fabrication quotes, fuel financing alternatives, fuel cycle schedules, and other fuel cycle perturbations. The FCSS was specifically designed for PC's that support dBASE-III(TM), a relational data base software system by Ashton-Tate. However, knowledge of dBASE-III is not necessary in order to utilize the FCSS. The FCSS is menu driven and can be utilized as a teaching tool as well as a scoping tool

  15. Candu reactors with thorium fuel cycles

    International Nuclear Information System (INIS)

    Hopwood, J.M.; Fehrenbach, P.; Duffey, R.; Kuran, S.; Ivanco, M.; Dyck, G.R.; Chan, P.S.W.; Tyagi, A.K.; Mancuso, C.

    2006-01-01

    Over the last decade and a half AECL has established a strong record of delivering CANDU 6 nuclear power plants on time and at budget. Inherently flexible features of the CANDU type reactors, such as on-power fuelling, high neutron economy, fuel channel based heat transport system, simple fuel bundle configuration, two independent shut down systems, a cool moderator and a defence-in-depth based safety philosophy provides an evolutionary path to further improvements in design. The immediate milestone on this path is the Advanced CANDU ReactorTM** (ACRTM**), in the form of the ACR-1000TM**. This effort is being followed by the Super Critical Water Reactor (SCWR) design that will allow water-cooled reactors to attain high efficiencies by increasing the coolant temperature above 550 0 C. Adaptability of the CANDU design to different fuel cycles is another technology advantage that offers an additional avenue for design evolution. Thorium is one of the potential fuels for future reactors due to relative abundance, neutronics advantage as a fertile material in thermal reactors and proliferation resistance. The Thorium fuel cycle is also of interest to China, India, and Turkey due to local abundance that can ensure sustainable energy independence over the long term. AECL has performed an assessment of both CANDU 6 and ACR-1000 designs to identify systems, components, safety features and operational processes that may need to be modified to replace the NU or SEU fuel cycles with one based on Thorium. The paper reviews some of these requirements and the associated practical design solutions. These modifications can either be incorporated into the design prior to construction or, for currently operational reactors, during a refurbishment outage. In parallel with reactor modifications, various Thorium fuel cycles, either based on mixed bundles (homogeneous) or mixed channels (heterogeneous) have been assessed for technical and economic viability. Potential applications of a

  16. Dry Storage at long term of nuclear fuels: Influence of the fuel design and commercial irradiation conditions

    International Nuclear Information System (INIS)

    Marino, Armando C

    2009-01-01

    The BaCo code was applied to simulate the behaviour for a PHWR fuel under storage conditions showing a strong dependence on the original design of the fuel and the irradiation history. In particular, the results of the statistical analysis of BaCo indicate that the integrity of the fuel is influenced by the manufacture tolerances and the solicitations during the NPP irradiation. The main conclusion of the present study is that the fuel temperature of the device should be carefully controlled in order to ensure safe storage conditions. [es

  17. Part 5. Fuel cycle options

    International Nuclear Information System (INIS)

    Lineberry, M.J.; McFarlane, H.F.; Amundson, P.I.; Goin, R.W.; Webster, D.S.

    1980-01-01

    The results of the FBR fuel cycle study that supported US contributions to the INFCE are presented. Fuel cycle technology is reviewed from both generic and historical standpoints. Technology requirements are developed within the framework of three deployment scenarios: the reference international, the secured area, and the integral cycle. Reprocessing, fabrication, waste handling, transportation, and safeguards are discussed for each deployment scenario. Fuel cycle modifications designed to increase proliferation defenses are described and assessed for effectiveness and technology feasibility. The present status of fuel cycle technology is reviewed and key issues that require resolution are identified

  18. Survey of nuclear fuel-cycle codes

    International Nuclear Information System (INIS)

    Thomas, C.R.; de Saussure, G.; Marable, J.H.

    1981-04-01

    A two-month survey of nuclear fuel-cycle models was undertaken. This report presents the information forthcoming from the survey. Of the nearly thirty codes reviewed in the survey, fifteen of these codes have been identified as potentially useful in fulfilling the tasks of the Nuclear Energy Analysis Division (NEAD) as defined in their FY 1981-1982 Program Plan. Six of the fifteen codes are given individual reviews. The individual reviews address such items as the funding agency, the author and organization, the date of completion of the code, adequacy of documentation, computer requirements, history of use, variables that are input and forecast, type of reactors considered, part of fuel cycle modeled and scope of the code (international or domestic, long-term or short-term, regional or national). The report recommends that the Model Evaluation Team perform an evaluation of the EUREKA uranium mining and milling code

  19. Effect of Gaseous Impurities on Long-Term Thermal Cycling and Aging Properties of Complex Hydrides for Hydrogen Storage

    Energy Technology Data Exchange (ETDEWEB)

    Chandra, Dhanesh [Primary Contact; Lamb, Joshua; Chien, Wen-Ming; Talekar, Anjali; and Pal, Narendra

    2011-03-28

    This program was dedicated to understanding the effect of impurities on Long-Term Thermal Cycling and aging properties of Complex Hydrides for Hydrogen Storage. At the start of the program we found reversibility between Li2NH+LiH LiH+LiNH2 (yielding ~5.8 wt.%H capacity). Then we tested the effect of impurity in H2 gas by pressure cycling at 255°C; first with industrial gas containing ppm levels of O2 and H2O as major impurities. Both these impurities had a significant impact on the reversibility and decreased the capacity by 2.65 wt.%H. Further increase in number of cycles from 500 to 1100 showed only a 0.2 wt%H more weight loss, showing some capacity is still maintained after a significant number of cycles. The loss of capacity is attributed to the formation of ~55 wt% LiH and ~30% Li2O, as major contaminant phases, along with the hydride Li2NH phase; suggesting loss of nitrogen during cycling. The effect of 100 ppm H2O in H2 also showed a decrease of ~2.5 wt.%H (after 560 cycles), and 100ppm O2 in H2; a loss of ~4.1 wt.%. Methane impurity (100 ppm, 100cycles), showed a very small capacity loss of 0.9 wt.%H under similar conditions. However, when Li3N was pressure cycled with 100ppmN2-H2 there were beneficial effects were observed (255oC); the reversible capacity increased to 8.4wt.%H after 853 cycles. Furthermore, with 20 mol.%N2-H2 capacity increased to ~10 wt.%H after 516 cycles. We attribute this enhancement to the reaction of nitrogen with liquid lithium during cycling as the Gibbs free energy of formation of Li3N (Go = -98.7 kJ/mol) is more negative than that of LiH (Go = -50.3 kJ/mol). We propose that the mitigation of hydrogen capacity losses is due to the destabilization of the LiH phase that tends to accumulate during cycling. Also more Li2NH phase was found in the cycled product. Mixed Alanates (3LiNH2:Li3AlH6) showed that 7 wt% hydrogen desorbed under dynamic vacuum. Equilibrium experiments (maximum 12 bar H2) showed up to 4wt% hydrogen reversibly

  20. HTGR fuel and fuel cycle technology

    International Nuclear Information System (INIS)

    Lotts, A.L.; Homan, F.J.; Balthesen, E.; Turner, R.F.

    1977-01-01

    Significant advances have occurred in the development of HTGR fuel and fuel cycle. These accomplishments permit a wide choice of fuel designs, reactor concepts, and fuel cycles. Fuels capable of providing helium outlet temperatures of 750 0 C are available, and fuels capable of 1000 0 C outlet temperatures may be expected from extension of present technology. Fuels have been developed for two basic HTGR designs, one using a spherical (pebble bed) element and the other a prismatic element. Within each concept a number of variations of geometry, fuel composition, and structural materials are permitted. Potential fuel cycles include both low-enriched and high-enriched Th- 235 U, recycle Th- 233 U, and Th-Pu or U-Pu cycles. This flexibility offered by the HTGR is of great practical benefit considering the rapidly changing economics of power production. The inflation of ore prices has increased optimum conversion ratios, and increased the necessity of fuel recycle at an early date. Fuel element makeup is very similar for prismatic and spherical designs. Both use spherical fissile and fertile particles coated with combinations of pyrolytic carbon and silicon carbide. Both use carbonaceous binder materials, and graphite as the structural material. Weak-acid resin (WAR) UO 2 -UC 2 fissile fuels and sol-gel-derived ThO 2 fertile fuels have been selected for the Th- 233 U cycle in the prismatic design. Sol-gel-derived UO 2 UC 2 is the reference fissile fuel for the low-enriched pebble bed design. Both the United States and Federal Republic of Germany are developing technology for fuel cycle operations including fabrication, reprocessing, refabrication, and waste handling. Feasibility of basic processes has been established and designs developed for full-scale equipment. Fuel and fuel cycle technology provide the basis for a broad range of applications of the HTGR. Extension of the fuels to higher operating temperatures and development and commercial demonstration of fuel

  1. Investigation of nuclide importance to functional requirements related to transport and long-term storage of LWR spent fuel

    International Nuclear Information System (INIS)

    Broadhead, B.L.; DeHart, M.D.; Ryman, J.C.; Tang, J.S.; Parks, C.V.

    1995-06-01

    This study investigates the relative importances of the various actinide, fission-product, and light-element isotopes associated with LWR spent fuel with respect to five analysis areas: criticality safety (absorption fractions), shielding (dose rate fractions), curies (fractional curies levels), decay heat (fraction of total watts), and radiological toxicity (fraction of potential committed effective dose equivalent). These rankings are presented for up to six different burnup/enrichment scenarios and at decay times from 2 to 100,000 years. Ranking plots for each of these analysis areas are given in an Appendix for completeness, as well as summary tables in the main body of the report. Summary rankings are presented in terms of high (greater than 10% contribution to the total), medium (between 1% and 10% contribution), and low (less than 1% contribution) for both short- and long-term cooling. When compared with the expected measurement accuracies, these rankings show that most of the important isotopes can be characterized sufficiently for the purpose of radionuclide generation/depletion code validation in each of the analysis areas. Because the main focus of this work is on the relative importances of isotopes associated with L at sign spent fuel, some conclusions may not be applicable to similar areas such as high-level waste (HLW) and nonfuel-bearing components (NFBC)

  2. Long-term cycling of mantle Pb: A trace element study of the major mantle mineral phases in abyssal peridotites

    Science.gov (United States)

    D'Errico, M. E.; Warren, J. M.; Godard, M.; Ildefonse, B.

    2012-12-01

    Peridotites from ultraslow-spreading ridges preserve signatures of the depleted mantle, while also reflecting the fine scale compositional variability present in the mantle. Traditional analyses of these depleted rocks have focused on clinopyroxene, the main trace element host in spinel peridotites. However, key isotopic systems, such as lead and osmium, are hosted in other phases at low but significant concentration levels. The amount of lead contained within mantle mineral phases is of critical importance to understanding the long-term evolution of the Earth, because the radiogenic isotopes of lead are sensitive to past material cycling and melt-rock interaction. Sulfides have long been suggested as the main host for lead (Pb) in the mantle, but recent studies have demonstrated that Pb is not exclusively hosted in this trace phase. Therefore, the Pb contents of the major peridotite mineral phases (olivine, orthopyroxene, and clinopyroxene) need to be reassessed. Lead concentration data is available for orogenic and xenolith peridotite samples, which are typically more enriched than abyssal peridotites, but these do not provide direct information on the oceanic upper mantle. Direct measurement of Pb in abyssal peridotites has so far been limited because of its extremely low concentration (often spreading Gakkel and Southwest Indian Ridges (SWIR), with samples coming from segments with full spreading rates Gakkel and SWIR samples are relatively unaltered (Gakkel. A total of five Gakkel and six SWIR peridotites were analyzed by LA-ICP-MS, with a subset of samples also analyzed for bulk rock trace elements by solution ICP-MS. Combined with mineral modal data, this study provides a direct comparison of measured and calculated bulk rock Pb concentrations to determine a comprehensive assessment of the distribution of Pb among upper mantle phases Results indicate that all three of the main mantle mineral phases have similar Pb concentrations, ranging from 2-20 ppb, which

  3. Future fuel cycle and reactor strategies

    International Nuclear Information System (INIS)

    Meneley, D.A.

    1999-01-01

    Within the framework of the 1997 IAEA Symposium 'Future Fuel Cycle and Reactor Strategies Adjusting to New Realities', Working Group No.3 produced a Key Issues paper addressing the title of the symposium. The scope of the Key Issues paper included those factors that are expected to remain or become important in the time period from 2015 to 2050, considering all facets of nuclear energy utilization from ore extraction to final disposal of waste products. The paper addressed the factors influencing the choice of reactor and fuel cycle. It then addressed the quantitatively largest category of reactor types expected to be important during the period; that is, thermal reactors burning uranium and plutonium fuel. The fast reactor then was discussed both as a stand-alone technology and as might be used in combination with thermal reactors. Thorium fuel use was discussed briefly. The present paper includes of a digest of the Key Issues Paper. Some comparisons arc made between the directions suggested in that paper and those indicated by the Abstracts of this Technical Committee Meeting- Recommendations are made for work which might be undertaken in the short and medium time frames, to ensure that fuel cycle technologies and processes established by the year 2050 will support the continuation of nuclear energy applications in the long term. (author)

  4. Nuclear Energy, Long Term Requirements

    International Nuclear Information System (INIS)

    Knapp, V.

    2006-01-01

    status of the intermediate and long-term issues will be discussed, with special attention to the nuclear proliferation issue in view of unfavourable recent development, such as failure of 2005 NPT renewal conference and the Iran and North Korea cases. It will be argued that nuclear proliferation threat is the only really serious obstacle to the large-scale use of nuclear energy. In positive political environment solution of this problem could be possible on the lines of the very early US proposal (so called Baruch plan, UN 1946). Present political developments appear to demand renewed attempt to internationalize proliferation sensitive fuel cycle installations. Reasons will be discussed for a conviction that prospects for this may be better than in 1946. (author)

  5. Future electricity generation: An economic and environmental life cycle perspective on near-, mid- and long-term technology options and policy implications

    Science.gov (United States)

    Bergerson, Joule Andrea

    This thesis evaluates the cost and environmental tradeoffs of current and future electricity generation options from a life cycle perspective. Policy and technology options are considered for each critical time horizon (near-, mid-, and long-term). The framework developed for this analysis is a hybrid life cycle analysis which integrates several models and frameworks including process and input-output life cycle analysis, an integrated environmental control model, social costing, forecasting and future energy scenario analysis. The near-term analysis shows that several recent LCA studies of electricity options have contributed to our understanding of the technologies available and their relative environmental impacts. Several promising options could satisfy our electricity demands. Other options remain unproven or too costly to encourage investment in the near term but show promise for future use (e.g. photovoltaic, fuel cells). Public concerns could impede the use of some desirable technologies (e.g. hydro, nuclear). Finally, less tangible issues such as intermittency of some renewable technologies, social equity and visual and land use impacts, while difficult to quantify, must be considered in the investment decision process. In the mid-term analysis, this thesis explores alternative methods for transport of coal energy. A hybrid life cycle analysis is critical for evaluating the cost, efficiency and environmental tradeoffs of the entire system. If a small amount of additional coal is to be shipped, current rail infrastructure should be used where possible. If entirely new infrastructure is required, the mine mouth generation options are cheaper but have increased environmental impact due to the increased generation required to compensate for transmission line losses. Gasifying the coal to produce methane also shows promise in terms of lowering environmental emissions. The long-term analysis focuses on the implications of a high coal use future. This scenario

  6. Biogeochemical cycles of Chernobyl-born radionuclides in the contaminated forest ecosystems: long-term dynamics of the migration processes

    Science.gov (United States)

    Shcheglov, Alexey; Tsvetnova, Ol'ga; Klyashtorin, Alexey

    2013-04-01

    Biogeochemical migration is a dominant factor of the radionuclide transport through the biosphere. In the early XX century, V.I. Vernadskii, a Russian scientist known, noted about a special role living things play in transport and accumulation of natural radionuclide in various environments. The role of biogeochemical processes in migration and redistribution of technogenic radionuclides is not less important. In Russia, V. M. Klechkovskii and N.V. Timofeev-Ressovskii showed some important biogeochemical aspects of radionuclide migration by the example of global fallout and Kyshtym accident. Their followers, R.M. Alexakhin, M.A. Naryshkin, N.V. Kulikov, F.A. Tikhomirov, E.B. Tyuryukanova, and others also contributed a lot to biogeochemistry of radionuclides. In the post-Chernobyl period, this area of knowledge received a lot of data that allowed building the radioactive element balance and flux estimation in various biogeochemical cycles [Shcheglov et al., 1999]. Regrettably, many of recent radioecological studies are only focused on specific radionuclide fluxes or pursue some applied tasks, missing the holistic approach. Most of the studies consider biogeochemical fluxes of radioactive isotopes in terms of either dose estimation or radionuclide migration rates in various food chains. However, to get a comprehensive picture and develop a reliable forecast of environmental, ecological, and social consequences of radioactive pollution in a vast contaminated area, it is necessary to investigate all the radionuclide fluxes associated with the biogeochemical cycles in affected ecosystems. We believe such an integrated approach would be useful to study long-term environmental consequences of the Fukushima accident as well. In our long-term research, we tried to characterize the flux dynamics of the Chernobyl-born radionuclides in the contaminated forest ecosystems and landscapes as a part of the integrated biogeochemical process. Our field studies were started in June of

  7. Alternative fuel cycle options: performance characteristics and impact on nuclear power growth potential

    International Nuclear Information System (INIS)

    Chang, Y.I.; Till, C.E.; Rudolph, R.R.; Deen, J.R.; King, M.J.

    1977-09-01

    The fuel utilization characteristics for LWR, SSCR, CANDU and LMFBR reactor concepts are quantified for various fuel cycle options, including once-through cycles, thorium cycles, and denatured cycles. The implications of various alternative reactor deployment strategies on the long-term nuclear power growth potential are then quantified in terms of the maximum nuclear capacity that can be achieved and the growth pattern over time, subject to the constraint of a fixed uranium-resource base. The overall objective of this study is to shed light on any large differences in the long-term potential that exist between various alternative reactor/fuel cycle deployment strategies

  8. The impact of inter-annual variability of annual cycle on long-term persistence of surface air temperature in long historical records

    Science.gov (United States)

    Deng, Qimin; Nian, Da; Fu, Zuntao

    2018-02-01

    Previous studies in the literature show that the annual cycle of surface air temperature (SAT) is changing in both amplitude and phase, and the SAT departures from the annual cycle are long-term correlated. However, the classical definition of temperature anomalies is based on the assumption that the annual cycle is constant, which contradicts the fact of changing annual cycle. How to quantify the impact of the changing annual cycle on the long-term correlation of temperature anomaly variability still remains open. In this paper, a recently developed data adaptive analysis tool, the nonlinear mode decomposition (NMD), is used to extract and remove time-varying annual cycle to reach the new defined temperature anomalies in which time-dependent amplitude of annual cycle has been considered. By means of detrended fluctuation analysis, the impact induced by inter-annual variability from the time-dependent amplitude of annual cycle has been quantified on the estimation of long-term correlation of long historical temperature anomalies in Europe. The results show that the classical climatology annual cycle is supposed to lack inter-annual fluctuation which will lead to a maximum artificial deviation centering around 600 days. This maximum artificial deviation is crucial to defining the scaling range and estimating the long-term persistence exponent accurately. Selecting different scaling range could lead to an overestimation or underestimation of the long-term persistence exponent. By using NMD method to extract the inter-annual fluctuations of annual cycle, this artificial crossover can be weakened to extend a wider scaling range with fewer uncertainties.

  9. Orbit-related long-term climate cycles revealed in a 12-Myr continental record from Lake Baikal.

    Science.gov (United States)

    Kashiwaya, K; Ochiai, S; Sakai, H; Kawai, T

    2001-03-01

    Quaternary records of climate change from terrestrial sources, such as lake sediments and aeolian sediments, in general agree well with marine records. But continuous records that cover more than the past one million years were essentially unavailable until recently, when the high-sedimentation-rate site of Lake Baikal was exploited. Because of its location in the middle latitudes, Lake Baikal is highly sensitive to insolation changes and the entire lake remained uncovered by ice sheets throughout the Pleistocene epoch, making it a valuable archive for past climate. Here we examine long sediment cores from Lake Baikal that cover the past 12 million years. Our record reveals a gradual cooling of the Asian continental interior, with some fluctuations. Spectral analyses reveal periods of about 400 kyr, 600 kyr and 1,000 kyr, which may correspond to Milankovitch periods (reflecting orbital cycles). Our results indicate that changes in insolation were closely related to long-term environmental variations in the deep continental interior, over the past 12 million years.

  10. Analysis of environmental friendliness of DUPIC fuel cycle

    International Nuclear Information System (INIS)

    Ko, Won Il; Kim, Ho Dong

    2001-07-01

    Some properties of irradiated DUPIC fuels are compared with those of other fuel cycles. It was indicated that the toxicity of the DUPIC option based on 1 GWe-yr is much smaller than those of other fuel cycle options, and is just about half the order of magnitude of other fuel cycles. From the activity analysis of 99 Tc and 237 Np, which are important to the long-term transport of fission products stored in geologic media, the DUPIC option, was being contained only about half of those other options. It was found from the actinide content estimation that the MOX option has the lowest plutonium arising based on 1 GWe-year and followed by the DUPIC option. However, fissile Pu content generated in the DUPIC fuel was the lowest among the fuel cycle options. From the analysis of radiation barrier in proliferation resistance aspect, the fresh DUPIC fuel can play a radiation barrier part, better than CANDU spent fuels as well as fresh MOX fuel. It is indicated that the DUPIC fuel cycle has the excellent resistance to proliferation, compared with an existing reprocessing option and CANDU once-through option. In conclusions, DUPIC fuel cycle would have good properties on environmental effect and proliferation resistance, compared to other fuel cycle cases

  11. Identification of a subset of patients with acute myeloid leukemia characterized by long-term in vitro proliferation and altered cell cycle regulation of the leukemic cells.

    Science.gov (United States)

    Hatfield, Kimberley Joanne; Reikvam, Håkon; Bruserud, Øystein

    2014-11-01

    The malignant cell population of acute myeloid leukemia (AML) includes a small population of stem/progenitor cells with long-term in vitro proliferation. We wanted to compare long-term AML cell proliferation for unselected patients, investigate the influence of endothelial cells on AML cell proliferation and identify biological characteristics associated with clonogenic capacity. Cells were cultured in medium supplemented with recombinant growth factors FMS-like tyrosine kinase-3 ligand, stem cell factor, IL-3, G-CSF and thrombopoietin. The colony-forming unit assay was used to estimate the number of progenitors in AML cell populations after 35 days of culture, and microarray was used to study global gene expression profiles between AML patients. Long-term cell proliferation was observed in 7 of 31 patients, whereas 3 additional patients showed long-term proliferation after endothelial cell coculture. Patient-specific differences in constitutive cytokine release were maintained during cell culture. Patients with long-term proliferation showed altered expression in six cell cycle-related genes (HMMR, BUB1, NUSAP1, AURKB, CCNF, DLGAP5), two genes involved in DNA replication (TOP2A, RFC3) and one gene with unknown function (LHFPL2). We identified a subset of AML patients characterized by long-term in vitro cell proliferation and altered expression of cell cycle regulators that may be potential candidates for treatment of AML.

  12. Differential response of carbon cycling to long-term nutrient input and altered hydrological conditions in a continental Canadian peatland

    Science.gov (United States)

    Berger, Sina; Praetzel, Leandra S. E.; Goebel, Marie; Blodau, Christian; Knorr, Klaus-Holger

    2018-02-01

    Peatlands play an important role in global carbon cycling, but their responses to long-term anthropogenically changed hydrologic conditions and nutrient infiltration are not well known. While experimental manipulation studies, e.g., fertilization or water table manipulations, exist on the plot scale, only few studies have addressed such factors under in situ conditions. Therefore, an ecological gradient from the center to the periphery of a continental Canadian peatland bordering a eutrophic water reservoir, as reflected by increasing nutrient input, enhanced water level fluctuations, and increasing coverage of vascular plants, was used for a case study of carbon cycling along a sequence of four differently altered sites. We monitored carbon dioxide (CO2) and methane (CH4) surface fluxes and dissolved inorganic carbon (DIC) and CH4 concentrations in peat profiles from April 2014 through September 2015. Moreover, we studied bulk peat and pore-water quality and we applied δ13C-CH4 and δ13C-CO2 stable isotope abundance analyses to examine dominant CH4 production and emission pathways during the growing season of 2015. We observed differential responses of carbon cycling at the four sites, presumably driven by abundances of plant functional types and vicinity to the reservoir. A shrub-dominated site in close vicinity to the reservoir was a comparably weak sink for CO2 (in 1.5 years: -1093 ± 794, in 1 year: +135 ± 281 g CO2 m-2; a net release) as compared to two graminoid-moss-dominated sites and a moss-dominated site (in 1.5 years: -1552 to -2260 g CO2 m-2, in 1 year: -896 to -1282 g CO2 m-2). Also, the shrub-dominated site featured notably low DIC pore-water concentrations and comparably 13C-enriched CH4 (δ13C- CH4: -57.81 ± 7.03 ‰) and depleted CO2 (δ13C-CO2: -15.85 ± 3.61 ‰) in a more decomposed peat, suggesting a higher share of CH4 oxidation and differences in predominant methanogenic pathways. In comparison to all other sites, the graminoid

  13. Lessons from the use of a long-term energy model for consequential life cycle assessment: the BTL case

    International Nuclear Information System (INIS)

    Menten, Fabio; Tchung-Ming, Stephane; Lorne, Daphne; Bouvart, Frederique

    2013-11-01

    The main objective of this study is to develop a methodology adapted to the prospective environmental evaluation of actions in the energy sector. It describes how a bottom-up long-term energy model can be used in a life cycle assessment (LCA) framework. The proposed methodology is applied in a case study about the global warming impacts occurring as a consequence of the future production of synthetic diesel from biomass 'biomass to liquids' - BTL), a second generation biofuel, in France. The results show a high sensitivity of the system-wide GHG balance to (i) the policy context and to (ii) the economic environment. Both influence the substitutions occurring within the system due to the production of BTL. Under the specific conditions of this study, the consequences of introducing BTL are not clear-cut. Therefore, we focus on the lessons from the detailed analysis of the results more than in the precise-looking projections, illustrating how this type of models can be used for strategic planning (industry and policy makers). TIMES-type models allow a detailed description of the numerous technologies affected by BTL production and how these vary under different policy scenarios. Moreover, some recommendations are presented, which should contribute for a proper systematization of consequential and prospective LCA methodologies. We provide argumentation on how to define a functional unit and system boundaries that are better linked with the goal of the study. Other crucial methodological issues are also discussed: how to treat temporal aspects in such environmental evaluation and how to increase the consistency of life cycle assessments. (authors)

  14. Improvement of the long term stability in the high temperature solid oxide fuel cell using functional layers

    Energy Technology Data Exchange (ETDEWEB)

    Brueckner, B.; Guenther, C.; Ruckdaeschel, R. [Siemens AG, Erlangen (Germany)] [and others

    1996-12-31

    In the planar Siemens design of the solid oxide fuel cell a metallic interconnector is used to seperate the ceramic single cells. A disadvantage of the metallic bipolar plate which consists of a chromium alloy is the formation of high volatile Cr-oxides and hydroxides at the surface at the cathode side. The reaction products evaporate and are reduced at the cathode/electrolyte interface to form new crystalline phases. This process gives rise to long term cell degradation. Protective coatings might be successful in preventing the chromium oxide evaporation. The required properties of the protective layers are (I) high electrical conductivity, (II) similar coefficients of thermal expansion to the bipolar plate (III), chemical compatibility to the bipolar plate and cathode material, (IV) a low diffusion coefficient of Cr and (V) chemical stability up to 1223K under oxygen atmosphere. Furthermore, during operation at 1223K an electrical contact between the metallic plate and the electrodes has to be maintained. This problem could be solved using ceramic layer between the metallic plate and the single cells.

  15. A review on durability issues and restoration techniques in long-term operations of direct methanol fuel cells

    Science.gov (United States)

    Mehmood, Asad; Scibioh, M. Aulice; Prabhuram, Joghee; An, Myung-Gi; Ha, Heung Yong

    2015-11-01

    Direct methanol fuel cells (DMFCs) remain attractive among advanced energy conversion technologies due to their high energy density and simple system configuration. Although they made an early market entry but failed to attain a large-scale commercialization mainly because of their inferior performance sustainment in lifetime operations and high production costs. There have been lots of R&D efforts made to upgrade the long-term durability of DMFCs to a commercially acceptable standard. These rigorous efforts have been useful in gaining insights about various degradation mechanisms and their origins. This review first briefly describes the recent progress in lifetime enhancement of DMFC technology reported by various groups in academia and industry. Then, it is followed by comprehensive discussions on the major performance degradation routes and associated physico-chemical origins, and influence of operational parameters, together with the methods which have been employed to alleviate and restore the performance losses. Finally, a brief summary of the presented literature survey is provided in conjunction with some possible future research directions.

  16. Long-term performance of activated carbon air cathodes with different diffusion layer porosities in microbial fuel cells

    KAUST Repository

    Zhang, Fang

    2011-08-01

    Activated carbon (AC) air-cathodes are inexpensive and useful alternatives to Pt-catalyzed electrodes in microbial fuel cells (MFCs), but information is needed on their long-term stability for oxygen reduction. AC cathodes were constructed with diffusion layers (DLs) with two different porosities (30% and 70%) to evaluate the effects of increased oxygen transfer on power. The 70% DL cathode initially produced a maximum power density of 1214±123mW/m 2 (cathode projected surface area; 35±4W/m 3 based on liquid volume), but it decreased by 40% after 1 year to 734±18mW/m 2. The 30% DL cathode initially produced less power than the 70% DL cathode, but it only decreased by 22% after 1 year (from 1014±2mW/m 2 to 789±68mW/m 2). Electrochemical tests were used to examine the reasons for the degraded performance. Diffusion resistance in the cathode was found to be the primary component of the internal resistance, and it increased over time. Replacing the cathode after 1 year completely restored the original power densities. These results suggest that the degradation in cathode performance was due to clogging of the AC micropores. These findings show that AC is a cost-effective material for oxygen reduction that can still produce ~750mW/m 2 after 1 year. © 2011 Elsevier B.V.

  17. Long-Term Performance of Chemically and Physically Modified Activated Carbons in Air Cathodes of Microbial Fuel Cells

    KAUST Repository

    Zhang, Xiaoyuan

    2014-07-31

    © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Activated carbon (AC) is a low-cost and effective catalyst for oxygen reduction in air cathodes of microbial fuel cells (MFCs), but its performance must be maintained over time. AC was modified by three methods: 1)pyrolysis with iron ethylenediaminetetraacetic acid (AC-Fe), 2)heat treatment (AC-heat), and 3)mixing with carbon black (AC-CB). The maximum power densities after one month with these AC cathodes were 35% higher with AC-Fe (1410±50mW m-2) and AC-heat (1400±20mW m-2), and 16% higher with AC-CB (1210±30mW m-2) than for plain AC (1040±20mW m-2), versus 1270±50mW m-2 for a Pt control. After 16months, the Pt cathodes produced only 250±10mW m-2. However, the AC-heat and AC-CB cathodes still produced 960-970mW m-2, whereas plain AC produced 860±60mW m-2. The performance of the AC cathodes was restored to >85% of the initial maximum power densities by cleaning with a weak acid solution. Based on cost considerations among the AC materials, AC-CB appears to be the best choice for long-term performance.

  18. Long-term safety of radioactive waste disposal. Radioactive analysis of samples from spent fuel leaching experiments

    International Nuclear Information System (INIS)

    Geckeis, H.; Degering, D.; Goertzen, A.; Geyer, F.W.; Dressler, P.

    1995-09-01

    In order to assess the long-term performance of spent fuel during direct disposal, high burnup fuel (50 MWd/kg U) has been exposed to non-buffered brine solutions and to deionized water under static anaerobic conditions at 25 C. The leaching behaviour of several radionuclides has been observed over periods of approximately 500 d. Currently used radiometric methods (α-, β-, γ-spectrometry) were applied to the analysis of sample solutions. Due to its low specific activity, uranium was determined using ICP-mass-spectrometry (ICP-MS) or laser induced fluorescence spectrometry (LFS). In order to determine radionuclide concentrations without interferences a preceeding radiochemical separation by ion-exchange, solvent-extraction or extraction chromatography was necessary in most cases. The Sc-isotopes 134/137, which are present in a high excess over other γ-emitting nuclides, were separated using the inorganic ion exchanger ammonium molybdato phosphate (AMP). This step allowed the subsequent γ-spectrometric determination of Am-241, Ag-110m, Ru-106, Sb-125 and Eu-154/155. Activity concentrations of pure β-emitters like Sr-90, Tc-99, I-129 and Pu-241 were determined by liquid scintillation counting (LSC) after selective separation using extraction chromatography or solvent extraction. The actinides Am-241, Cm-242/244, Pu-238/239/240 and Np-237 were analysed by α-spectrometry again after selective separation. The direct analysis of uranium by LFS or ICP-MS was hampered by high salt concentrations. Therefore a separation by extraction chromatography turned out to be necessary, too. The analytical procedures used throughout this work are described in detail. (orig.) [de

  19. Long term storage of spent nuclear fuel -- Survey and recommendations. Final report of a co-ordinated research project 1994-1997

    International Nuclear Information System (INIS)

    2002-05-01

    Two Technical Committee meetings were held at the IAEA in Vienna to share the experiences of Member States with regard to extended of long term storage of spent nuclear fuel. Potential technological, regulatory and societal concerns and impacts associated with storage were discussed. Participants presented papers during these two meetings covering all the relevant issues. Smaller discussion groups were formed which enabled the participants to provide detailed information within the context of four general subjects: 1. Long term behaviour of spent fuel; 2. Long term behaviour of dry storage systems; 3. Wet spent fuel storage facilities; and 4. Regulatory concerns related to long term spent fuel storage. The nuclear industry worldwide has accumulated significant fuel storage operating experience over the past decades. This experience, however, is largely based on safe and effective wet storage and the effect of time on structures and materials during this limited period of time. The new challenges are to extend the life of existing and new wet and dry storage facilities and guarantee their safe performance for much longer periods of time. Participants in each group have therefore reflected on past experience in order to define the issues and questions, which should to be addresses through future research and development. This document summarizes their contributions

  20. Innovative Stirling-Cycle Cryocooler for Long Term In-Space Storage of Cryogenic Liquid Propellants, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Numerous studies have concluded that increasing effectiveness of long-term storage of cryogenic liquid propellants, primarily LO2 and LH2, offers the largest single...

  1. Constraining Silicate Weathering Processes in an Active Volcanic Complex: Implications for the Long-term Carbon Cycle

    Science.gov (United States)

    Washington, K.; West, A. J.; Hartmann, J.; Amann, T.; Hosono, T.; Ide, K.

    2017-12-01

    While analyzing geochemical archives and carbon cycle modelling can further our understanding of the role of silicate weathering as a sink in the long-term carbon cycle, it is necessary to study modern weathering processes to inform these efforts. A recent compilation of data from rivers draining basaltic catchments estimates that rock weathering in active volcanic fields (AVFs) consumes atmospheric CO2 approximately three times faster than in inactive volcanic fields (IVFs), suggesting that the eruption and subsequent weathering of large igneous provinces likely played a major role in the carbon cycle in the geologic past [1]. The study demonstrates a significant correlation between catchment mean annual temperature (MAT) and atmospheric CO2 consumption rate for IVFs. However CO2 consumption due to weathering of AVFs is not correlated with MAT as the relationship is complicated by variability in hydrothermal fluxes, reactive surface area, and groundwater flow paths. To investigate the controls on weathering processes in AVFs, we present data for dissolved and solid weathering products from Mount Aso Caldera, Japan. Aso Caldera is an ideal site for studying the how the chemistry of rivers draining an AVF is impacted by high-temperature water/rock interactions, volcanic ash weathering, and varied groundwater flow paths and residence times. Samples were collected over five field seasons from two rivers and their tributaries, cold groundwater springs, and thermal springs. These samples capture the region's temperature and precipitation seasonality. Solid samples of unaltered volcanic rocks, hydrothermally-altered materials, volcanic ash, a soil profile, and suspended and bedload river sediments were also collected. The hydrochemistry of dissolved phases were analyzed at the University of Hamburg, while the mineralogy and geochemical compositions of solid phases were analyzed at the Natural History Museum of Los Angeles. This work will be discussed in the context of

  2. World nuclear capacity and fuel cycle requirements, November 1993

    Energy Technology Data Exchange (ETDEWEB)

    1993-11-30

    This analysis report presents the current status and projections of nuclear capacity, generation, and fuel cycle requirements for all countries in the world using nuclear power to generate electricity for commercial use. Long-term projections of US nuclear capacity, generation, fuel cycle requirements, and spent fuel discharges for three different scenarios through 2030 are provided in support of the Department of Energy`s activities pertaining to the Nuclear Waste Policy Act of 1982 (as amended in 1987). The projections of uranium requirements also support the Energy Information Administration`s annual report, Domestic Uranium Mining and Milling Industry: Viability Assessment.

  3. World nuclear capacity and fuel cycle requirements, November 1993

    International Nuclear Information System (INIS)

    1993-01-01

    This analysis report presents the current status and projections of nuclear capacity, generation, and fuel cycle requirements for all countries in the world using nuclear power to generate electricity for commercial use. Long-term projections of US nuclear capacity, generation, fuel cycle requirements, and spent fuel discharges for three different scenarios through 2030 are provided in support of the Department of Energy's activities pertaining to the Nuclear Waste Policy Act of 1982 (as amended in 1987). The projections of uranium requirements also support the Energy Information Administration's annual report, Domestic Uranium Mining and Milling Industry: Viability Assessment

  4. Investigation of a methanol reformer concept considering the particular impact of dynamics and long-term stability for use in a fuel-cell-powered passenger car

    Science.gov (United States)

    Peters, R.; Düsterwald, H. G.; Höhlein, B.

    A methanol reformer concept including a reformer, a catalytic burner, a gas cleaning unit, a PEMFC and an electric motor for use in fuel-cell-powered passenger cars was investigated. Special emphasis was placed on the dynamics and the long-term stability of the reformer. Experiments on a laboratory scale were performed in a methanol steam reformer consisting of four different reactor tubes, which were separately balanced. Due to the endothermy of the steam reforming reaction of methanol, a sharp drop in the reaction temperature of about 50 K occurs at the beginning of the catalyst bed. This agrees well with the high catalytic activity at the entrance of the catalyst bed. Forty-five percent of the methanol was converted within the first 10 cm of the catalyst bed where 12.6 g of the CuO/ZnO catalyst was located. Furthermore, CO formation during methanol steam reforming strongly depends on methanol conversion. Long-term measurements for more than 700 h show that the active reaction zone moved through the catalyst bed. Calculations, on the basis of these experiments, revealed that 63 g of reforming catalyst was necessary for mobile PEMFC applications, in this case for 400 W el at a system efficiency of 42% and a theoretical specific hydrogen production of 5.2 m 3n/(h kg Cat). This amount of catalyst was assumed to maintain a hydrogen production of at least 80% of the original amount over an operating range of 3864 h. Cycled start-up and shut-down processes of the methanol steam reformer under nitrogen and hydrogen atmospheres did not harm the catalytic activity. The simulation of the breakdown of the heating system, in which a liquid water/methanol mixture was in close contact with the catalyst, did not reveal any deactivation of the catalytic activity.

  5. Chemistry for fast reactor fuel cycle

    International Nuclear Information System (INIS)

    Vasudeva Rao, P.R.

    2011-01-01

    The fuel cycle for the fast reactors poses several challenging chemistry issues. The use of fuels with high plutonium content, the variety of fuel matrices (oxides, carbides, metal alloys), the high burn-up to which the fuel is driven and the need to close the fuel cycle with minimum out-of-pile inventory are examples of special features of fast reactors. The need to reduce waste generation and the need to identify matrices for safe long term disposal of waste are additional issues that need a chemist's attention. As a chemist, the subject of actinide separations has been very stimulating to me, with a myriad of interesting possibilities and at the same time, demanding careful attention to the unique chemistry of the actinides including multiplicity of oxidation states. The presence of high concentrations of plutonium in the reprocessing streams introduces issues such as third phase formation, which provides an incentive for the development of candidates for solvent extraction as alternatives to tri-n-butyl phosphate, currently used for the Purex reprocessing scheme. With the advent of supercritical fluid extraction as a tool for actinide recovery from a variety of matrices, and the potential of room temperature ionic liquids to offer significant advantages in actinide processing, actinide separations is an element of fast reactor fuel cycle that is full of opportunities and challenges. The need to process metallic alloy fuels using molten salt electrorefining as the route, adds further to the challenges. The presentation will highlight some of the recent progress achieved in this area at IGCAR. (author)

  6. Advanced nuclear fuel cycles - Main challenges and strategic choices

    International Nuclear Information System (INIS)

    Le Biez, V.; Machiels, A.; Sowder, A.

    2013-01-01

    A graphical conceptual model of the uranium fuel cycles has been developed to capture the present, anticipated, and potential (future) nuclear fuel cycle elements. The once-through cycle and plutonium recycle in fast reactors represent two basic approaches that bound classical options for nuclear fuel cycles. Chief among these other options are mono-recycling of plutonium in thermal reactors and recycling of minor actinides in fast reactors. Mono-recycling of plutonium in thermal reactors offers modest savings in natural uranium, provides an alternative approach for present-day interim management of used fuel, and offers a potential bridging technology to development and deployment of future fuel cycles. In addition to breeder reactors' obvious fuel sustainability advantages, recycling of minor actinides in fast reactors offers an attractive concept for long-term management of the wastes, but its ultimate value is uncertain in view of the added complexity in doing so,. Ultimately, there are no simple choices for nuclear fuel cycle options, as the selection of a fuel cycle option must reflect strategic criteria and priorities that vary with national policy and market perspectives. For example, fuel cycle decision-making driven primarily by national strategic interests will likely favor energy security or proliferation resistance issues, whereas decisions driven primarily by commercial or market influences will focus on economic competitiveness

  7. Kinetic and thermodynamic studies of uranium minerals. Assessment of the long-term evolution of spent nuclear fuel

    International Nuclear Information System (INIS)

    Casas, I.; Bruno, J.; Cera, E.; Finch, R.J.; Ewing, R.C.

    1994-10-01

    We have studied the dissolution behavior of uraninite, becquerelite, schoepite and uranophane. The information obtained under a variety of experimental conditions has been combined with extensive solid phase characterizations, performed in both leached and unleached samples. The overall objective is to construct a thermodynamic and kinetic model for the long-term oxidation alteration of UO 2 (s), as an analogy of the spent nuclear fuel matrix. We have determined the solubility product for becquerelite (logK s0 32.7±1.3) and uranophane (logK s0 = 7.8±0.8). In some experiments, the reaction progress has shown initial dissolution of uranophane followed by precipitation of a secondary solid phase, characterized as soddyite. The solubility production for this phase has been determined (logK s0 = 3.0±2.9). We have studied the kinetics of dissolution of uraninite, uranophane and schoepite under oxidizing conditions in synthetic granitic groundwater. BET measurements have been performed for uraninite and uranophane. For schoepite, the measurement has not been performed due to lack of sufficient amount of sample. The normalized rates of dissolution of uraninite and uranophane have been calculated referred to the uranium release, as 1.97x10 -8 moles h -1 m -2 and 4.0x 10 -9 moles h -1 m -2 , respectively. For schoepite, the dissolution process has shown two different rates, with a relatively fast initial dissolution rate of 1.97x10 -8 moles h -1 followed, after approximately 1000 hours, by a slower one of 1.4x10 -9 moles h -1 . No formation of secondary phases has been observed in those experiments, although final uranium concentrations have in all cases exceeded the solubility of uranophane, the thermodynamically more stable phase under the experimental conditions. 24 refs, 45 figs

  8. Fuel cycles using adulterated plutonium

    International Nuclear Information System (INIS)

    Brooksbank, R.E.; Bigelow, J.E.; Campbell, D.O.; Kitts, F.G.; Lindauer, R.B.

    1978-01-01

    Adjustments in the U-Pu fuel cycle necessitated by decisions made to improve the nonproliferation objectives of the US are examined. The uranium-based fuel cycle, using bred plutonium to provide the fissile enrichment, is the fuel system with the highest degree of commercial development at the present time. However, because purified plutonium can be used in weapons, this fuel cycle is potentially vulnerable to diversion of that plutonium. It does appear that there are technologically sound ways in which the plutonium might be adulterated by admixture with 238 U and/or radioisotopes, and maintained in that state throughout the fuel cycle, so that the likelihood of a successful diversion is small. Adulteration of the plutonium in this manner would have relatively little effect on the operations of existing or planned reactors. Studies now in progress should show within a year or two whether the less expensive coprocessing scheme would provide adequate protection (coupled perhaps with elaborate conventional safeguards procedures) or if the more expensive spiked fuel cycle is needed as in the proposed civex pocess. If the latter is the case, it will be further necessary to determine the optimum spiking level, which could vary as much as a factor of a billion. A very basic question hangs on these determinations: What is to be the nature of the recycle fuel fabrication facilities. If the hot, fully remote fuel fabrication is required, then a great deal of further development work will be required to make the full cycle fully commercial

  9. ITER fuel cycle systems layout

    International Nuclear Information System (INIS)

    Kveton, O.K.

    1990-10-01

    The ITER fuel cycle building (FCB) will contain the following systems: fuel purification - permeator based; fuel purification - molecular sieves; impurity treatment; waste water storage and treatment; isotope separation; waste water tritium extraction; tritium extraction from solid breeder; tritium extraction from test modules; tritium storage, shipping and receiving; tritium laboratory; atmosphere detritiation systems; fuel cycle control centre; tritiated equipment maintenance space; control maintenance space; health physics laboratory; access, access control and facilities. The layout of the FCB and the requirements for these systems are described. (10 figs.)

  10. Logistics of the research reactor fuel cycle: AREVA solutions

    International Nuclear Information System (INIS)

    Ohayon, David; Halle, Laurent; Naigeon, Philippe; Falgoux, Jean-Louis; Franck Obadia, Franck; Auziere, Philippe

    2005-01-01

    The AREVA Group Companies offer comprehensive solutions for the entire fuel cycle of Research Reactors comply with IAEA standards. CERCA and Cogema Logistics have developed a full partnership in the front end cycle. In the field of uranium CERCA and Cogema Logistics have the long term experience of the shipment from Russia, USA to the CERCA plant.. Since 1960, CERCA has manufactured over 300,000 fuel plates and 15,000 fuel elements of more than 70 designs. These fuel elements have been delivered to 40 research reactors in 20 countries. For the Back-End stage, Cogema and Cogema Logistics propose customised solutions and services for international shipments. Cogema Logistics has developed a new generation of packaging to meet the various needs and requirements of the Laboratories and Research Reactors all over the world, and complex regulatory framework. Comprehensive assistance dedicated, services, technical studies, packaging and transport systems are provided by AREVA for every step of research reactor fuel cycle. (author)

  11. New technology and fuel cycles

    International Nuclear Information System (INIS)

    Mooradian, A.J.

    1979-06-01

    The means of improving uranium utilization in nuclear power reactors are reviewed with respect to economic considerations, assurance of adequate fuel supplies and risk of weapons proliferation. Reference is made to what can be done to improve fuel economy in existing reactor systems operating on a once-through fuel cycle and the potential for improvement offered by fuel recycle in those systems. The state of development of new reactor systems that offer significant savings in uranium utilization is also reviewed and conclusions are made respecting the policy implications of the search for fuel economy. (author)

  12. Proliferation resistance fuel cycle technology

    Energy Technology Data Exchange (ETDEWEB)

    Lee, J. S.; Ko, W. I

    1999-02-01

    The issues of dual use in nuclear technology are analysed for nuclear fuel cycle with special focus on uranium enrichment and spent fuel reprocessing which are considered as the most sensitive components in terms of vulnerability to diversion. Technical alternatives to mitigrate the vulnerability, as has been analysed in depth during the NASAP and INFCE era in the late seventies, are reviewed to characterize the DUPIC fuel cycle alternative. On the other hand, the new realities in nuclear energy including the disposition of weapon materials as a legacy of cold war are recast in an angle of nuclear proliferation resistance and safeguards with a discussion on the concept of spent fuel standard concept and its compliance with the DUPIC fuel cycle technology. (author)

  13. CANDU fuel-cycle vision

    International Nuclear Information System (INIS)

    Boczar, P.G.

    1999-01-01

    The fuel-cycle path chosen by a particular country will depend on a range of local and global factors. The CANDU reactor provides the fuel-cycle flexibility to enable any country to optimize its fuel-cycle strategy to suit its own needs. AECL has developed the CANFLEX fuel bundle as the near-term carrier of advanced fuel cycles. A demonstration irradiation of 24 CANFLEX bundles in the Point Lepreau power station, and a full-scale critical heat flux (CHF) test in water are planned in 1998, before commercial implementation of CANFLEX fuelling. CANFLEX fuel provides a reduction in peak linear element ratings, and a significant enhancement in thermalhydraulic performance. Whereas natural uranium fuel provides many advantages, the use of slightly enriched uranium (SEU) in CANDU reactors offers even lower fuel-cycle costs and other benefits, such as uprating capability through flattening the channel power distribution across the core. Recycled uranium (RU) from reprocessing spent PWR fuel is a subset of SEU that has significant economic promise. AECL views the use of SEU/RU in the CANFLEX bundle as the first logical step from natural uranium. High neutron economy enables the use of low-fissile fuel in CANDU reactors, which opens up a spectrum of unique fuel-cycle opportunities that exploit the synergism between CANDU reactors and LWRs. At one end of this spectrum is the use of materials from conventional reprocessing: CANDU reactors can utilize the RU directly without re-enrichment, the plutonium as conventional Mixed-oxide (MOX) fuel, and the actinide waste mixed with plutonium in an inert-matrix carrier. At the other end of the spectrum is the DUPIC cycle, employing only thermal-mechanical processes to convert spent LWR fuel into CANDU fuel, with no purposeful separation of isotopes from the fuel, and possessing a high degree of proliferation resistance. Between these two extremes are other advanced recycling options that offer particular advantages in exploiting the

  14. Nuclear fuel cycle and reactor strategies: Adjusting to new realities. Key issue papers

    International Nuclear Information System (INIS)

    1997-01-01

    The international symposium ''Nuclear Fuel Cycle and Reactor Strategy: Adjusting to new Realities'' was organized to face the new realities in the nuclear fuel cycle and to consider options on how these new realities could be addressed. The Key Issue Papers treat the various subjects from both short and long term perspectives. In so doing, they address the likely development of all aspects concerning the nuclear fuel cycle up to the year 2050

  15. Sustainability of advanced fuel cycles

    International Nuclear Information System (INIS)

    Vasudeva Rao, P.R.

    2013-01-01

    Features of Sustainability: • Minimisation of fuel fabrication & reprocessing by enhancing burn-up; • Minimisation of waste volume; • Reduced toxicity of waste; • Enhanced safety in operations; • Economy: operation of fuel cycle facilities at name plate capacity, enhanced plant life; • Reduced exposure to operators

  16. The assessment of the long-term evolution of the spent nuclear fuel matrix by kinetic, thermodynamic and spectroscopic studies of uranium minerals

    International Nuclear Information System (INIS)

    Bruno, J.; Casas, I.; Cera, E.; Ewing, R.C.; Finch, R.J.

    1995-01-01

    The long term behavior of spent nuclear fuel is discussed in the light of recent thermodynamic and kinetic data on mineralogical analogues related to the key phases in the oxidative alteration of uraninite. The implications for the safety assessment of a repository of the established oxidative alteration sequence of the spent fuel matrix are illustrated with Pagoda calculations. The application to the kinetic and thermodynamic data to source term calculations indicates that the appearance and duration of the U(VI) oxyhydroxide transient is critical for the stability of the fuel matrix

  17. Nuclear fuel cycle techniques

    International Nuclear Information System (INIS)

    Pecqueur, Michel; Taranger, Pierre

    1975-01-01

    The production of fuels for nuclear power plants involves five principal stages: prospecting of uranium deposits (on the ground, aerial, geochemical, geophysical, etc...); extraction and production of natural uranium from the deposits (U content of ores is not generally high and a chemical processing is necessary to obtain U concentrates); production of 235 U enriched uranium for plants utilizing this type of fuel (a description is given of the gaseous diffusion process widely used throughout the world and particularly in France); manufacture of suitable fuel elements for the different plants; reprocessing of spent fuels for the purpose of not only recovering the fissile materials but also disposing safely of the fission products and other wastes [fr

  18. Current Comparison of Advanced Fuel Cycle Options

    International Nuclear Information System (INIS)

    Steven J. Piet; B. W. Dixon; A. Goldmann; R. N. Hill; J. J. Jacobson; G. E. Matthern; J. D. Smith; A. M. Yacout

    2006-01-01

    The nuclear fuel cycle includes mining, enrichment, nuclear power plants, recycling (if done), and residual waste disposition. The U.S. Advanced Fuel Cycle Initiative (AFCI) has four program objectives to guide research on how best to glue these pieces together, as follows: waste management, proliferation resistance, energy recovery, and systematic management/economics/safety. We have developed a comprehensive set of metrics to evaluate fuel cycle options against the four program objectives. The current list of metrics is long-term heat, long-term dose, radiotoxicity and weapons usable material. This paper describes the current metrics and initial results from comparisons made using these metrics. The data presented were developed using a combination of ''static'' calculations and a system dynamic model, DYMOND. In many cases, we examine the same issue both dynamically and statically to determine the robustness of the observations. All analyses are for the U.S. reactor fleet. This work aims to clarify many of the issues being discussed within the AFCI program, including Inert Matrix Fuel (IMF) versus Mixed Oxide (MOX) fuel, single-pass versus multi-pass recycling, thermal versus fast reactors, and the value of separating cesium and strontium. The results from a series of dynamic simulations evaluating these options are included in this report. The model interface includes a few ''control knobs'' for flying or piloting the fuel cycle system into the future. The results from the simulations show that the future is dark (uncertain) and that the system is sluggish with slow time response times to changes (i.e., what types of reactors are built, what types of fuels are used, and the capacity of separation and fabrication plants). Piloting responsibilities are distributed among utilities, government, and regulators, compounding the challenge of making the entire system work and respond to changing circumstances. We identify four approaches that would increase our chances

  19. Sulfur poisoning of Ni/Gadolinium-doped ceria anodes: A long-term study outlining stable solid oxide fuel cell operation

    Science.gov (United States)

    Riegraf, Matthias; Zekri, Atef; Knipper, Martin; Costa, Rémi; Schiller, Günter; Friedrich, K. Andreas

    2018-03-01

    This work presents an analysis of the long-term behavior of nickel/gadolinium-doped ceria (CGO) anode-based solid oxide fuel cells (SOFC) under sulfur poisoning conditions. A parameter study of sulfur-induced irreversible long-term degradation of commercial, high-performance single cells was carried out at 900 °C for different H2/N2/H2S fuel gas atmospheres, current densities and Ni/CGO anodes. The poisoning periods of the cells varied from 200 to 1500 h. The possibility of stable long-term Ni/CGO anode operation under sulfur exposure is established and the critical operating regime is outlined. Depending on the operating conditions, two degradation phenomena can be observed. Small degradation of the ohmic resistance was witnessed for sulfur exposure times of approximately 1000 h. Moreover, degradation of the anode charge transfer resistance was observed to be triggered by the combination of a small anodic potential step and high sulfur coverage on Ni. The microstructural evolution of altered Ni/CGO anodes was examined post-mortem by means of SEM and FIB/SEM, and is correlated to the anode performance degradation under critical operating conditions, establishing Ni depletion, porosity increase and a tripe phase boundary density decrease in the anode functional layer. It is shown that short-term sulfur poisoning behavior can be used to assess long-term stability.

  20. Effect of Long-Term Freezing and Freeze–Thaw Cycles on Indigenous and Inoculated Microorganisms in Dewatered Blackwater

    DEFF Research Database (Denmark)

    Gunnarsdottir, Ragnhildur; Müller, Karoline; Jensen, Pernille Erland

    2012-01-01

    coliforms, fecal streptococci, and antibiotic-resistant (AR) bacteria, and inoculated Salmonella Enteriditis and E. coli bacteriophage ΦX174 in dewatered blackwater. At the end of the long-term freezing experiment (10 months), an MPN recovery study was done, including the microbial groups that had shown...... the largest reduction, using tryptone soy broth at incubation temperatures of 10 and 20 °C overnight for the coliforms and AR bacteria, and buffered peptone water at incubation temperature of 37 °C for 18–20 h for Salmonella. Fecal streptococci were more resistant to long-term freezing than the coliform group....... Total number of AR bacteria decreased slowly but constantly over the 10-month freezing period. Salmonella rapidly decreased and were nondetectable within a week but exhibited some recovery after 10 months of freezing, whereas limited or no recovery of coliforms and AR-bacteria was detected...

  1. High polymer composites for containers for the long-term storage of spent nuclear fuel and high level radioactive waste

    International Nuclear Information System (INIS)

    Bonin, H.W.; Vui, V.T.; Legault, J.-F.

    1997-01-01

    The feasibility of using polymeric composite materials as an alternative to metals in the design of a nuclear waste disposal container was examined. The disposal containers would be stored in deep underground vaults in plutonic rock formations within the Canadian Shield for several thousands of years. The conditions of disposal considered in the evaluation of the polymeric composite materials were based on the long-term disposal concept proposed by Atomic Energy of Canada Limited. Four different composites were considered for this work, all based on boron fibre as reinforcing material, imbedded in polymeric matrices made of polystyrene (PS), polymethyl methacrylate (PMMA), Devcon 10210 epoxy, and polyetheretherketone (PEEK). Both PS and PMMA were determined as unsuitable for use in the fabrication of the storage container because of thermal failure. This was determined following thermal analysis of the materials in which heat transfer calculations yielded the temperature of the container wall and of the surroundings resulting from the heat generated by the spent nuclear fuel stored inside the container. In the case of the PS, the temperature of the container, the buffer and the backfill would exceed the 100 degrees C imposed in the AECL's proposal as the maximum allowable. In the case of the PMMA, the 100 degrees temperature is too close to the glass transition temperature of this material (105 degrees C) and would cause structural degradation of the container wall. The other two materials present acceptable thermal characteristics for this application. An important concern for polymeric materials in such use is their resistance to radiations. The Devcon 10210 epoxy has been the object of research at the Royal Military College in the past years and fair, but limited, resistance to both neutrons and gamma radiation has been demonstrated, with the evidence of increased mechanical strength when subjected to moderate doses. Provided that the container wall could be

  2. Characteristics of fuel cycle waste

    International Nuclear Information System (INIS)

    Aquilina, C.A.; Everette, S.E.

    1982-01-01

    The Low-Level Waste Management System started in 1979 to describe and model the existing commercial low-level waste management system. The system description produced is based on the identification of the different elements making up both the fuel and non-fuel cycle and their relationships to each other. A systems model based on the system description can accurately reflect the flow of low-level waste from generator to disposal site and is only limited by the reliability of the information it uses. For both the fuel cycle and non-fuel cycle large quantities of information is required in order to allow the system to operate at its full potential. Work is ongoing to collect this information. Significant progress is being made in the fuel cycle area primarily because the majority of fuel cycle low-level radioactive waste is produced by commercial power reactor plant operations. The Low-Level Waste Management system is only beginning to derive the benefits to be obtained from an accurate low-level waste management information system. As data is verified and analyzed, results on a national as well as individual organization level will be gained. Comparisons to previous studies will be made. Accurate projections of waste volumes and activities to be produced, projected impacts of waste streams of treatment or management changes are only examples of information to be produced. 1 figure, 1 table

  3. Answering Key Fuel Cycle Questions

    International Nuclear Information System (INIS)

    Piet, S.J.; Dixon, B.W.; Bennett, R.G.; Smith, J.D.; Hill, R.N.

    2004-01-01

    Given the range of fuel cycle goals and criteria, and the wide range of fuel cycle options, how can the set of options eventually be narrowed in a transparent and justifiable fashion? It is impractical to develop all options. We suggest an approach that starts by considering a range of goals for the Advanced Fuel Cycle Initiative (AFCI) and then posits seven questions, such as whether Cs and Sr isotopes should be separated from spent fuel and, if so, what should be done with them. For each question, we consider which of the goals may be relevant to eventually providing answers. The AFCI program has both ''outcome'' and ''process'' goals because it must address both waste already accumulating as well as completing the fuel cycle in connection with advanced nuclear power plant concepts. The outcome objectives are waste geologic repository capacity and cost, energy security and sustainability, proliferation resistance, fuel cycle economics, and safety. The process objectives are rea diness to proceed and adaptability and robustness in the face of uncertainties

  4. Globalisation of the nuclear fuel cycle - impact of developments on fuel management

    International Nuclear Information System (INIS)

    Durpel, L. van den; Bertel, E.

    2000-01-01

    Nuclear energy will have to cope more and more with a rapid changing environment due to economic competitive pressure and the deregulatory progress. In current economic environment, utilities will have to focus strongly on the reduction of their total generation costs, covering the fuel cycle costs, which are only partly under their control. Developments in the fuel cycle will be in the short-term rather evolutionary addressing the current needs of utilities. However, within the context of sustainable development and more and more inclusion of externalities in energy generation costs, more performing developments in the fuel cycle could become important and feasible. A life-cycle design approach of the fuel cycle will be requested in order to cover all factors in order to decrease significantly the nuclear energy generation cost to complete with other alternative fuels in the long-term. This paper will report on some of the trends one could distinguish in the fuel cycle with emphasis on cost reduction. OECD/NEA is currently conducting a study on the fuel cycle aiming to assess current and future nuclear fuel cycles according to the potential for further improvement of the full added-value chain of these cycles from a mainly technological and economic perspective including environmental and social considerations. (orig.) [de

  5. Utilization of Plutonium and Higher Actinides in the HTGR as Possibility to Maintain Long-Term Operation on One Fuel Loading

    International Nuclear Information System (INIS)

    Tsvetkova, Galina V.; Peddicord, Kenneth L.

    2002-01-01

    Promising existing nuclear reactor concepts together with new ideas are being discussed worldwide. Many new studies are underway in order to identify prototypes that will be analyzed and developed further as systems for Generation IV. The focus is on designs demonstrating full inherent safety, competitive economics and proliferation resistance. The work discussed here is centered on a modularized small-size High Temperature Gas-cooled Reactor (HTGR) concept. This paper discusses the possibility of maintaining long-term operation on one fuel loading through utilization of plutonium and higher actinides in the small-size pebble-bed reactor (PBR). Acknowledging the well-known flexibility of the PBR design with respect to fuel composition, the principal limitations of the long-term burning of plutonium and higher actinides are considered. The technological challenges and further research are outlined. The results allow the identification of physical features of the PBR that significantly influence flexibility of the design and its applications. (authors)

  6. Fuel-cycle greenhouse gas emissions impacts of alternative transportation fuels and advanced vehicle technologies

    International Nuclear Information System (INIS)

    Wang, M. Q.

    1998-01-01

    At an international conference on global warming, held in Kyoto, Japan, in December 1997, the United States committed to reduce its greenhouse gas (GHG) emissions by 7% over its 1990 level by the year 2012. To help achieve that goal, transportation GHG emissions need to be reduced. Using Argonne's fuel-cycle model, I estimated GHG emissions reduction potentials of various near- and long-term transportation technologies. The estimated per-mile GHG emissions results show that alternative transportation fuels and advanced vehicle technologies can help significantly reduce transportation GHG emissions. Of the near-term technologies evaluated in this study, electric vehicles; hybrid electric vehicles; compression-ignition, direct-injection vehicles; and E85 flexible fuel vehicles can reduce fuel-cycle GHG emissions by more than 25%, on the fuel-cycle basis. Electric vehicles powered by electricity generated primarily from nuclear and renewable sources can reduce GHG emissions by 80%. Other alternative fuels, such as compressed natural gas and liquefied petroleum gas, offer limited, but positive, GHG emission reduction benefits. Among the long-term technologies evaluated in this study, conventional spark ignition and compression ignition engines powered by alternative fuels and gasoline- and diesel-powered advanced vehicles can reduce GHG emissions by 10% to 30%. Ethanol dedicated vehicles, electric vehicles, hybrid electric vehicles, and fuel-cell vehicles can reduce GHG emissions by over 40%. Spark ignition engines and fuel-cell vehicles powered by cellulosic ethanol and solar hydrogen (for fuel-cell vehicles only) can reduce GHG emissions by over 80%. In conclusion, both near- and long-term alternative fuels and advanced transportation technologies can play a role in reducing the United States GHG emissions

  7. Fuel-cycle greenhouse gas emissions impacts of alternative transportation fuels and advanced vehicle technologies.

    Energy Technology Data Exchange (ETDEWEB)

    Wang, M. Q.

    1998-12-16

    At an international conference on global warming, held in Kyoto, Japan, in December 1997, the United States committed to reduce its greenhouse gas (GHG) emissions by 7% over its 1990 level by the year 2012. To help achieve that goal, transportation GHG emissions need to be reduced. Using Argonne's fuel-cycle model, I estimated GHG emissions reduction potentials of various near- and long-term transportation technologies. The estimated per-mile GHG emissions results show that alternative transportation fuels and advanced vehicle technologies can help significantly reduce transportation GHG emissions. Of the near-term technologies evaluated in this study, electric vehicles; hybrid electric vehicles; compression-ignition, direct-injection vehicles; and E85 flexible fuel vehicles can reduce fuel-cycle GHG emissions by more than 25%, on the fuel-cycle basis. Electric vehicles powered by electricity generated primarily from nuclear and renewable sources can reduce GHG emissions by 80%. Other alternative fuels, such as compressed natural gas and liquefied petroleum gas, offer limited, but positive, GHG emission reduction benefits. Among the long-term technologies evaluated in this study, conventional spark ignition and compression ignition engines powered by alternative fuels and gasoline- and diesel-powered advanced vehicles can reduce GHG emissions by 10% to 30%. Ethanol dedicated vehicles, electric vehicles, hybrid electric vehicles, and fuel-cell vehicles can reduce GHG emissions by over 40%. Spark ignition engines and fuel-cell vehicles powered by cellulosic ethanol and solar hydrogen (for fuel-cell vehicles only) can reduce GHG emissions by over 80%. In conclusion, both near- and long-term alternative fuels and advanced transportation technologies can play a role in reducing the United States GHG emissions.

  8. Nuclear fuel cycle studies

    International Nuclear Information System (INIS)

    Anon.

    1980-01-01

    For the metal-matrix encapsulation of radioactive waste, brittle-fracture, leach-rate, and migration studies are being conducted. For fuel reprocessing, annular and centrifugal contactors are being tested and modeled. For the LWBR proof-of-breeding project, the full-scale shear and the prototype dissolver were procured and tested. 5 figures

  9. Assessment of the long-term risk of a meteorite impact on a hypothetical Canadian nuclear fuel waste disposal vault deep in plutonic rock

    International Nuclear Information System (INIS)

    Wuschke, D.M.; Whitaker, S.H.; Goodwin, B.W.; Rasmussen, L.R.

    1995-06-01

    This report describes an assessment of the long-term radiological risk to an individual of the critical group that would result from a meteorite impact on a hypothetical reference disposal vault for used fuel, located 500 m below the Earth's surface. The purpose of the assessment was to determine if this radiological risk could exceed or approach the AECB risk criterion. (author). 47 refs., 5 tabs., 6 figs

  10. Nuclear energy and its fuel cycle, prospects to 2025

    International Nuclear Information System (INIS)

    1987-01-01

    Nuclear power will supply an increasing share of the world's electricity but will expand more slowly than had been expected, and no shortages of uranium or other fuel cycle services are foreseen before the end of the century. While exploration for new uranium deposits should continue to ensure long-term supplies, advances in reactor design and enrichment and reprocessing techniques could achieve reductions in uranium demand

  11. Closing the fuel cycle: A superior option for India

    International Nuclear Information System (INIS)

    Balu, K.; Purushotham, D.S.C.; Kakodkar, A.

    1999-01-01

    The closed fuel cycle option with reprocessing and recycle of uranium and plutonium (U and Pu) for power generation allows better utilization of the uranium resources. On its part, plutonium is a unique energy source. During the initial years of nuclear fuel cycle activities, reprocessing and recycle of uranium and plutonium for power generation was perceived by many countries to be among the best of long term strategies for the management of spent fuel. But, over the years, some of the countries have taken a position that once-through fuel cycle is both economical and proliferation-resistant. However, such perceptions do vary as a function of economic growth and energy security of a given country. This paper deals with techno-economic perspectives of reprocessing and recycling in the Indian nuclear power programme. Experience of developing Mixed Oxide UO 2 -PuO 2 (MOX) fuel and its actual use in a power reactor (BWR) is presented. The paper further deals with the use of MOX in PHWRs in the future and current thinking, in the Indian context, in respect of advanced fuel cycles for the future. From environmental safety considerations, the separation of long-lived isotopes and minor actinides from high level waste (HLW) would enhance the acceptability of reprocessing and recycle option. The separated actinides are suitable for recycling with MOX fuel. However, the advanced fuel cycles with such recycling of Uranium and transuranium elements call for additional sophisticated fuel cycle activities which are yet to be mastered. India is interested in both uranium and thorium fuel cycles. This paper describes the current status of the Indian nuclear power scenario with reference to the program on reactors, reprocessing and radioactive waste management, plutonium recycle options, thorium-U233 fuel cycle studies and investigations on partitioning of actinides from Purex HLW as relevant to PHWR spent fuels. (author)

  12. The challenge of long-term participatory repository governance. Lessons learned for high level radioactive waste and spent fuel

    International Nuclear Information System (INIS)

    Landstroem, Catharina

    2012-01-01

    Voluntaristic siting procedures for deep geological repositories are becoming increasingly common; they reconfigure the relationship of repositories and society in ways that have implications for the long-term governance of these facilities. This paper identifies three challenges emerging in relation to this question: principles of monitoring, repository content, and facility closure. This paper discusses them in a comparison with similar challenges being addressed in Belgian partnerships founded to facilitate the siting and design of a low- and intermediate level short lived waste repository. The empirical exploration confirms the importance of securing stakeholder engagement throughout the repository lifecycle, for which there is a need to develop knowledge about how to encourage long-term democratic governance systems.

  13. Energy conversion with solid oxide fuel cell systems: A review of concepts amd outlooks for the short- and long-term

    Energy Technology Data Exchange (ETDEWEB)

    Adams, II, Thomas A. [McMaster University; Nease, Jake [McMaster University; Tucker, David [U.S DOE; Barton, Paul I. [MIT

    2013-01-01

    A review of energy conversion systems which use solid oxide fuel cells (SOFCs) as their primary electricity generation component is presented. The systems reviewed are largely geared for development and use in the short- and long-term future. These include systems for bulk power generation, distributed power generation, and systems integrated with other forms of energy conversion such as fuel production. The potential incorporation of CO{sub 2} capture and sequestration technologies and the influences of potential government policies are also discussed.

  14. From the seismic cycle to long-term deformation: linking seismic coupling and Quaternary coastal geomorphology along the Andean megathrust

    Science.gov (United States)

    Saillard, M.; Audin, L.; Rousset, B.; Avouac, J.-P.; Chlieh, M.; Hall, S. R.; Husson, L.; Farber, D. L.

    2017-02-01

    Measurement of interseismic strain along subduction zones reveals the location of both locked asperities, which might rupture during megathrust earthquakes, and creeping zones, which tend to arrest such seismic ruptures. The heterogeneous pattern of interseismic coupling presumably relates to spatial variations of frictional properties along the subduction interface and may also show up in the fore-arc morphology. To investigate this hypothesis, we compiled information on the extent of earthquake ruptures for the last 500 years and uplift rates derived from dated marine terraces along the South American coastline from central Peru to southern Chile. We additionally calculated a new interseismic coupling model for that same area based on a compilation of GPS data. We show that the coastline geometry, characterized by the distance between the coast and the trench; the latitudinal variations of long-term uplift rates; and the spatial pattern of interseismic coupling are correlated. Zones of faster and long-term permanent coastal uplift, evidenced by uplifted marine terraces, coincide with peninsulas and also with areas of creep on the megathrust where slip is mostly aseismic and tend to arrest seismic ruptures. We conclude that spatial variations of frictional properties along the megathrust dictate the tectono-geomorphological evolution of the coastal zone and the extent of seismic ruptures along strike.

  15. Australia and the nuclear fuel cycle

    International Nuclear Information System (INIS)

    Alder, K; Australian Atomic Energy Commission, Lucas Heights; Reynolds, J.; Western Mining Corporation, Western Australia

    2010-01-01

    The nuclear electricity industry based on uranium fuel is now well established in 31 countries. Nuclear's ability to provide large scale base load power at costs competitive with available and politically favoured alternatives is causing it to be increasingly selected for new capacity. The World Nuclear Association data shows that current new construction together with that planned and proposed as of December 2009, will bring world nuclear electricity generating capacity from the present 373 000 MW to 876 000 MWm an increase of 112 per cent. By comparison Australia's total generating capacity (mainly from coal) is 47 000 MW, or one eighth of existing world nuclear capacity. Nuclear growth can be expected to increase further, due to continuing world-wide energy supply security issues and politically driven climate change concerns. Australia has been mining uranium for 60 eventful years, much influenced by government policy changes. Australia's un-mined resources are now the largest in the world and it is already a major supplier to the nuclear fueld cycle, in a growing market. This situation offers long term opportunities for Australia to benefit more fully and at the same time contribute to global security by further participation in the uranium-based nuclear electricity industry fuel cycle

  16. Impact of Total Ionizing Dose Radiation Testing and Long-Term Thermal Cycling on the Operation of CMF20120D Silicon Carbide Power MOSFET

    Science.gov (United States)

    Patterson, Richard L.; Scheidegger, Robert J.; Lauenstein, Jean-Marie; Casey, Megan; Scheick, Leif; Hammoud, Ahmad

    2013-01-01

    Power systems designed for use in NASA space missions are required to work reliably under harsh conditions including radiation, thermal cycling, and extreme temperature exposures. Silicon carbide devices show great promise for use in future power electronics systems, but information pertaining to performance of the devices in the space environment is very scarce. A silicon carbide N-channel enhancement-mode power MOSFET called the CMF20120 is of interest for use in space environments. Samples of the device were exposed to radiation followed by long-term thermal cycling to address their reliability for use in space applications. The results of the experimental work are presentd and discussed.

  17. Advanced Nuclear Fuel Cycle Options

    Energy Technology Data Exchange (ETDEWEB)

    Roald Wigeland; Temitope Taiwo; Michael Todosow; William Halsey; Jess Gehin

    2010-06-01

    A systematic evaluation has been conducted of the potential for advanced nuclear fuel cycle strategies and options to address the issues ascribed to the use of nuclear power. Issues included nuclear waste management, proliferation risk, safety, security, economics and affordability, and sustainability. The two basic strategies, once-through and recycle, and the range of possibilities within each strategy, are considered for all aspects of the fuel cycle including options for nuclear material irradiation, separations if needed, and disposal. Options range from incremental changes to today’s implementation to revolutionary concepts that would require the development of advanced nuclear technologies.

  18. Fuel cycle and quality control

    International Nuclear Information System (INIS)

    Stoll, W.

    1979-01-01

    The volume of the fuel cycle is described in its economic importance and its through put, as it is envisaged for the Federal Republic of Germany. Definitions are given for quality continuing usefulness of an object and translated into quality criteria. Requirements on performance of fuel elements are defined. The way in which experimental results are translated into mass production of fuel rods, is described. The economic potential for further quality effort is derived. Future ways of development for quality control organisation and structure are outlined. (Auth.)

  19. Long-term superelastic cycling at nano-scale in Cu-Al-Ni shape memory alloy micropillars

    Energy Technology Data Exchange (ETDEWEB)

    San Juan, J., E-mail: jose.sanjuan@ehu.es; Gómez-Cortés, J. F. [Dpto. Física Materia Condensada, Facultad de Ciencia y Tecnología, Univ. del País Vasco UPV/EHU, Apdo. 644, 48080 Bilbao (Spain); López, G. A.; Nó, M. L. [Dpto. Física Aplicada II, Facultad de Ciencia y Tecnología, Univ. del País Vasco UPV/EHU, Apdo. 644, 48080 Bilbao (Spain); Jiao, C. [FEI, Achtseweg Noord 5, 5651 GG Eindhoven (Netherlands)

    2014-01-06

    Superelastic behavior at nano-scale has been studied along cycling in Cu-Al-Ni shape memory alloy micropillars. Arrays of square micropillars were produced by focused ion beam milling, on slides of [001] oriented Cu-Al-Ni single crystals. Superelastic behavior of micropillars, due to the stress-induced martensitic transformation, has been studied by nano-compression tests during thousand cycles, and its evolution has been followed along cycling. Each pillar has undergone more than thousand cycles without any detrimental evolution. Moreover, we demonstrate that after thousand cycles they exhibit a perfectly reproducible and completely recoverable superelastic behavior.

  20. Hybrid reactors. [Fuel cycle

    Energy Technology Data Exchange (ETDEWEB)

    Moir, R.W.

    1980-09-09

    The rationale for hybrid fusion-fission reactors is the production of fissile fuel for fission reactors. A new class of reactor, the fission-suppressed hybrid promises unusually good safety features as well as the ability to support 25 light-water reactors of the same nuclear power rating, or even more high-conversion-ratio reactors such as the heavy-water type. One 4000-MW nuclear hybrid can produce 7200 kg of /sup 233/U per year. To obtain good economics, injector efficiency times plasma gain (eta/sub i/Q) should be greater than 2, the wall load should be greater than 1 MW.m/sup -2/, and the hybrid should cost less than 6 times the cost of a light-water reactor. Introduction rates for the fission-suppressed hybrid are usually rapid.

  1. Temperature regime of solonetzic meadow-chernozemic permafrost-affected soil in a long-term cycle

    Science.gov (United States)

    Desyatkin, R. V.; Desyatkin, A. R.

    2017-11-01

    The characteristics of temperature dynamics in a solonetzic meadow-chernozemic soil of alas depression in Central Yakutia are described on the basis of long-term (2005-2014) stationary studies. Quick changes in weather conditions accompanied by changes in the soil temperature regime were observed during that period. Thus, the beginning of soil thawing in the spring shifted to earlier dates, and the beginning of soil freezing in the fall shifted to later dates. Temperature trends demonstrate an increase in the mean annual soil temperatures at all the depths. In total, the period of the frozen state of the soil became considerably shorter: in the middle-profile horizons, by 30-39 days. The obtained results attest to the high dynamism in temperature parameters of meadow soils in alas depressions of Central Yakutia under conditions of global climate changes.

  2. Long Term Care

    Science.gov (United States)

    ... us! Living with HD Long-Term Care Long Term Care Click here to download Long-Term Care for HD, (part of HDSA’s Family Guide ... on patient and family issues related to long-term HD care. For many caregivers of people with ...

  3. Identification and understanding the factors affecting the public and political acceptance of long term storage of spent fuel and high-level radioactive wastes

    International Nuclear Information System (INIS)

    Gorea, Valica

    2006-01-01

    In the end of 2004, according to the information available to the IAEA, there were 440 nuclear reactors operating worldwide, with a total net capacity of 366.3 GW(e), 6 of them being connected to the grid in 2004 ( 2 in Ukraine, one each in China, Japan and the Russian Federation and a reconnection in Canada) by comparison with 2 connections and 2 re-connections in 2003. Also, in the end of 2004, 26 nuclear power plants were under construction with a total net capacity of 20.8 GW(e). The conclusion accepted by common consent is that the nuclear power is still in progress and represents one of the options for power security on long and middle term. If we refer to the nuclear fusion which will produce commercial electric power, over 30 - 40 years, in practically unlimited quantities, the above underlining becomes even more evident. Fortunately, besides the beneficent characteristics, such as: clean, stable as engendering and price, has also a negative characteristic, which generally breathes fear into the people: radioactive waste. A classification of the radioactive waste is not the target of this presentation. I just want to point that a nuclear power plant produces during the time spent fuel - long life high radioactive, generating heat. Another high radioactive waste have similar characteristics (HLW = High Level Waste) for which reason these two categories of wastes are treated together. The spent fuel and the High Level Waste are interim stored for cooling, for around 50 years, afterwards it is transferred to the final repository where it will be kept for hundreds of years, in the case of an open fuel cycle and this is also the case of Cernavoda NPP. Taking into consideration that the Cernavoda Unit 1 reaches the age of 10 years of commercial running during December 2006, it results that the issue of the final disposal is not such urgent as it looks. The objectives of long term management of radioactive waste are public health and protection of the environment

  4. Nuclear Fuel Cycle Introductory Concepts

    International Nuclear Information System (INIS)

    Karpius, Peter Joseph

    2017-01-01

    The nuclear fuel cycle is a complex entity, with many stages and possibilities, encompassing natural resources, energy, science, commerce, and security, involving a host of nations around the world. This overview describes the process for generating nuclear power using fissionable nuclei.

  5. Nuclear fuel cycle. V. 2

    International Nuclear Information System (INIS)

    1984-01-01

    Nuclear fuel cycle information in some countries that develop, supply or use nuclear energy is presented. Data about Argentina, Australia, Belgium, Netherlands, Italy, Denmarmark, Norway, Sweden, Switzerland, Finland, Spain and India are included. The information is presented in a tree-like graphic way. (C.S.A.) [pt

  6. Nuclear fuel cycle. V. 1

    International Nuclear Information System (INIS)

    1983-01-01

    Nuclear fuel cycle information in the main countries that develop, supply or use nuclear energy is presented. Data about Japan, FRG, United Kingdom, France and Canada are included. The information is presented in a tree-like graphic way. (C.S.A.) [pt

  7. Nuclear Fuel Cycle Introductory Concepts

    Energy Technology Data Exchange (ETDEWEB)

    Karpius, Peter Joseph [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-02-02

    The nuclear fuel cycle is a complex entity, with many stages and possibilities, encompassing natural resources, energy, science, commerce, and security, involving a host of nations around the world. This overview describes the process for generating nuclear power using fissionable nuclei.

  8. Fuel cycles for the 80's

    International Nuclear Information System (INIS)

    1980-01-01

    Papers presented at the American Nuclear Society's topical meeting on the fuel cycle are summarized. Present progress and goals in the areas of fuel fabrication, fuel reprocessing, spent fuel storage, accountability, and safeguards are reported. Present governmental policies which affect the fuel cycle are also discussed. Individual presentations are processed for inclusion in the Energy Data Base

  9. Nonproliferation and safeguards aspects of the DUPIC fuel cycle concept

    Energy Technology Data Exchange (ETDEWEB)

    Persiani, P. K. [Argonne National Lab., IL (United States)

    1997-07-01

    The purpose of the study is to comment on the proliferation characteristic profiles of some of the proposed fuel cycle alternatives to help ensure that nonproliferation concerns are introduced into the early stages of a fuel cycle concept development program, and to perhaps aid in the more effective implementation of the international nonproliferation regime initiative and safeguards systems. Alternative recycle concepts proposed by several countries involve the recycle of spent fuel without the separation of plutonium from uranium and fission products. The concepts are alternatives to either the direct long-term storage deposition of or the purex reprocessing of the spent fuels. The alternate fuel cycle concepts reviewed include: the dry-recycle processes such as the direct use of reconfigured PWR spent fuel assemblies into CANDU reactors(DUPIC); low-decontamination, single-cycle co-extraction of fast reactor fuels in a wet-purex type of reprocessing; and on a limited scale the thorium-uranium fuel cycle. The nonproliferation advantages usually associated with the above non-separation processes are: the highly radioactive spent fuel presents a barrier to the physical diversion of the nuclear material; avoid the need to dissolve and chemically separate the plutonium from the uranium and fission products; and that the spent fuel isotopic quality of the plutonium vector is further degraded. Although the radiation levels and the need for reprocessing may be perceived as barriers to the terrorist or the subnational level of safeguards, the international level of nonproliferation concerns is addressed primarily by material accountancy and verification activities. On the international level of nonproliferation concerns, the non-separation fuel cycle concepts involved have to be evaluated on the bases of the impact the processes may have on nuclear materials accountancy. (author).

  10. Innovative Stirling-Cycle Cryocooler for Long Term In-Space Storage of Cryogenic Liquid Propellants, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Under this Phase II SBIR project we will build and test a stirling-cycle cryocooler and coolant circulating subsystem for use with broad area cooling (BAC) systems...

  11. Design and operation of an anaerobic digester for waste management and fuel generation during long term lunar mission

    Science.gov (United States)

    Dhoble, Abhishek S.; Pullammanappallil, Pratap C.

    2014-10-01

    Waste treatment and management for manned long term exploratory missions to moon will be a challenge due to longer mission duration. The present study investigated appropriate digester technologies that could be used on the base. The effect of stirring, operation temperature, organic loading rate and reactor design on the methane production rate and methane yield was studied. For the same duration of digestion, the unmixed digester produced 20-50% more methane than mixed system. Two-stage design which separated the soluble components from the solids and treated them separately had more rapid kinetics than one stage system, producing the target methane potential in one-half the retention time than the one stage system. The two stage system degraded 6% more solids than the single stage system. The two stage design formed the basis of a prototype digester sized for a four-person crew during one year exploratory lunar mission.

  12. Isoprene emission, photosynthesis, and growth in sweetgum (Liquidambar styraciflua) seedlings exposed to short- and long-term drying cycles.

    Science.gov (United States)

    Fang, C; Monson, R K; Cowling, E B

    1996-04-01

    Isoprene emissions were studied in one-year old sweetgum (Liquidambar styraciflua L.) seedlings during nine drying-rewatering cycles extending over five months. Each drying cycle lasted to the point of leaf wilting. Growth was essentially stopped in response to the first drying cycle, though seedling survival and capacity to recover turgor on rewatering remained high throughout the entire nine cycles. Photosynthetic rates of leaves were inhibited by the drying treatments. Under severe drought, isoprene emission rates of leaves were also inhibited, though isoprene emission was generally less sensitive to drought than photosynthesis. The lower drought sensitivity of isoprene emission compared with photosynthesis resulted in a higher percentage of fixed carbon lost as isoprene as seedlings became more stressed. During the recovery phase of the drying-rewatering cycles, isoprene emission rates in several seedlings were higher than in well-watered control seedlings. Following the ninth drying-rewatering cycle, sustained daily watering resulted in recovery of isoprene emission rates to control values within four days. Photosynthetic rates only recovered to 50% of control values after seven days. We conclude that the mechanisms regulating photosynthetic rate and isoprene emission rate are differentially influenced by limited water supplies. The results are consistent with past studies that predict a protective role for isoprene emission during stress, particularly protection from excessive leaf temperatures during drought.

  13. Development and use of long-term, global data records of forest, water, and urban change for terrestrial ecology and carbon cycle science

    Science.gov (United States)

    Sexton, J. O.

    2015-12-01

    Earth's human population has risen over the last century from less than 2 billion to over 7 billion people. The current "Anthropocene Era" has brought changes in Earth's landforms, climate, biodiversity, atmosphere, and hydrologic and biogeochemical cycles, as well as the expansion and intensification of human land use. As the emerging nexus of the physical, biological, and social sciences, measurements of Earth's natural and anthropogenic land cover are needed to understand and manage the coupled dynamics of human and natural systems. In recent years, NASA-sponsored efforts have produced global, time-serial estimates of tree cover using the MOderate-resolution Imaging Spectroradiometer (MODIS) and the world's first global, Landsat-based datasets representing tree and forest cover change from 1990 to 2010. These data are fueling global and national estimates of the rate and acceleration of deforestation as well as international commitments to conserve forest ecosystems. Likewise, Landsat-based datasets documenting Earth's inland surface waters are enabling the world's first global, high-resolution estimates of water cover based on repeatable satellite measurements. Meanwhile, long-term, time-serial estimates of impervious surface cover are being used to model the effect of urbanization on storm-water runoff, watershed health, and stream biodiversity. MODIS-based records of plant phenology are depicting the vulnerability and resilience of ecosystems to drought and are informing land managers of the sensitivity of wildlife to climate and plant phenology. Natural ecosystems are complex and potentially chaotic even in the absence of anthropogenic influence, and so understanding these interactions between physical, biological, and social systems is increasingly crucial under escalating human impacts. Globally consistent, locally accurate, and publicly available records spanning multiple decades at high frequency are the living legacy of the NASA Earth Science Programs

  14. Nuclear reactors and fuel cycle

    International Nuclear Information System (INIS)

    2014-01-01

    to contribute in improving the quality of life of the Brazilian people. The nuclear fuel cycle is a series of steps involved in the production and use of fuel for nuclear reactors. The Laboratories of Chemistry and Environmental Diagnosis Center, CQMA, support the demand of Nuclear Fuel Cycle Program providing chemical characterization of uranium compounds and other related materials. In this period the Research Reactor Center (CRPq) concentrated efforts on improving equipment and systems to enable the IEA-R1 research reactor to operate at higher power, increasing the capacity of radioisotopes production, samples irradiation, tests and experiments. (author)

  15. Advanced Fuel Cycle Cost Basis – 2017 Edition

    Energy Technology Data Exchange (ETDEWEB)

    Dixon, B. W. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Ganda, F. [Argonne National Lab. (ANL), Argonne, IL (United States); Williams, K. A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Hoffman, E. [Argonne National Lab. (ANL), Argonne, IL (United States); Hanson, J. K. [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2017-09-29

    This report, commissioned by the U.S. Department of Energy (DOE) Office of Nuclear Energy (NE), provides a comprehensive set of cost data supporting a cost analysis for the relative economic comparison of options for use in the DOE Nuclear Technology Research and Development (NTRD) Program (previously the Fuel Cycle Research and Development (FCRD) and the Advanced Fuel Cycle Initiative (AFCI)). The report describes the NTRD cost basis development process, reference information on NTRD cost modules, a procedure for estimating fuel cycle costs, economic evaluation guidelines, and a discussion on the integration of cost data into economic computer models. This report contains reference cost data for numerous fuel cycle cost modules (modules A-O) as well as cost modules for a number of reactor types (R modules). The fuel cycle cost modules were developed in the areas of natural uranium mining and milling, thorium mining and milling, conversion, enrichment, depleted uranium disposition, fuel fabrication, interim spent fuel storage, reprocessing, waste conditioning, spent nuclear fuel (SNF) packaging, long-term monitored retrievable storage, managed decay storage, recycled product storage, near surface disposal of low-level waste (LLW), geologic repository and other disposal concepts, and transportation processes for nuclear fuel, LLW, SNF, transuranic, and high-level waste. Since its inception, this report has been periodically updated. The last such internal document was published in August 2015 while the last external edition was published in December of 2009 as INL/EXT-07-12107 and is available on the Web at URL: www.inl.gov/technicalpublications/Documents/4536700.pdf. This current report (Sept 2017) is planned to be reviewed for external release, at which time it will replace the 2009 report as an external publication. This information is used in the ongoing evaluation of nuclear fuel cycles by the NE NTRD program.

  16. Nuclear fuel cycle activities with an utility

    International Nuclear Information System (INIS)

    Schwarz, E.

    1977-01-01

    The lecture will deal with the following topics: Fuel requirements: establishing fuel requirements - first core - reloads. Calculation of required uranium and separation work: reload planning - long term - short term - during refuelling; exactness of calculations: contracts: 1) Uranium and conversion; 2) Enrichment services; 3) Fuel elements; 4) Ownership; 5) Accidential loss of material; 6) Flexibility in time and amounts; 7) Specifications, surcharges; 8) Terms of payment; 9) Fuel containers, ownership, retransport; fuel reserves: 1) Natural uranium (concentrates or reserves in the ground); 2) Enriched uranium; 3) Fuel elements; 4) Cost of reserves; 5) Exchange in case of need. Handling of contracts: 1) Schedule for deliveries; Notes for deliveries; 3) Fuel accounting and balance; 4) Formalities (export and import licenses, customs etc.). Fuel cost: 1) Prices; 2) Fuel cost calculations for comparison of bids and cost forecast. (orig.) [de

  17. Increased susceptibility to repeated freeze-thaw cycles in Escherichia coli following long-term evolution in a benign environment

    Directory of Open Access Journals (Sweden)

    Lenski Richard E

    2006-12-01

    Full Text Available Abstract Background In order to study the dynamics of evolutionary change, 12 populations of E. coli B were serially propagated for 20,000 generations in minimal glucose medium at constant 37°C. Correlated changes in various other traits have been previously associated with the improvement in competitive fitness in the selective environment. This study examines whether these evolved lines changed in their ability to tolerate the stresses of prolonged freezing and repeated freeze-thaw cycles during adaptation to a benign environment. Results All 12 lines that evolved in the benign environment for 20,000 generations are more sensitive to freeze-thaw cycles than their ancestor. The evolved lines have an average mortality rate of 54% per daily cycle, compared to the ancestral rate of 34%. By contrast, there was no significant difference between the evolved lines and their ancestor in mortality during prolonged freezing. There was also some variability among the evolved lines in susceptibility to repeated freeze-thaw cycles. Those lines that had evolved higher competitive fitness in the minimal glucose medium at 37°C also had higher mortality during freeze-thaw cycles. This variability was not associated, however, with differences among lines in DNA repair functionality and mutability. Conclusion The consistency of the evolutionary declines in freeze-thaw tolerance, the correlation between fitness in glucose medium at 37°C and mortality during freeze-thaw cycles, and the absence of greater declines in freeze-thaw survival among the hypermutable lines all indicate a trade-off between performance in minimal glucose medium at 37°C and the capacity to tolerate this stress. Analyses of the mutations that enhance fitness at 37°C may shed light on the physiological basis of this trade-off.

  18. Non-proliferation aspects of long term assurance of supply

    International Nuclear Information System (INIS)

    1978-01-01

    The meetings in this section deal with the non-proliferation aspects of long-term assurance of supply of the nuclear fuel cycle. A list of 12 fundamental questions concerning the observation and application of the non-proliferation regulations is followed by the comments made by representatives of 10 countries

  19. Fuel cycle problems in fusion reactors

    International Nuclear Information System (INIS)

    Hickman, R.G.

    1976-01-01

    Fuel cycle problems of fusion reactors evolve around the breeding, recovery, containment, and recycling of tritium. These processes are described, and their implications and alternatives are discussed. Technically, fuel cycle problems are solvable; economically, their feasibility is not yet known

  20. Long-term variations in the South Asian monsoon annual cycle: the role of regional anthropogenic aerosol forcing

    Science.gov (United States)

    Bollasina, Massimo; Ming, Yi

    2013-04-01

    Detection and attribution of long-term variations of the South Asian monsoon is of extreme importance. Indeed, even small changes in the onset and duration of the monsoon season or in the spatial distribution of the seasonal mean precipitation may severely impact agriculture, health, water availability, ecosystems, and economy for a substantial fraction of the world's population. In the past decades emissions of aerosols have dramatically increased over South Asia due to rapid urbanization and population growth. As a result, the study of the impact of anthropogenic aerosols on the monsoon has recently emerged as one of the topics of highest priority in the scientific community. This study makes use of a state-of-the-art coupled climate model, the GFDL CM3, to investigate two aspects of the aerosol influence on the 20th-century changes in the monsoon. The model has fully-interactive aerosols and a representation of both direct and indirect effects. Aerosols are responsible for the advancement of the monsoon onset over India, leading, in agreement with observations, to enhanced precipitation in June over most parts of the subcontinent. Our experiments show that the earlier onset is preceded in early spring by a strong aerosol forcing over the Bay of Bengal and Indonesia and associated atmospheric circulation anomalies. The latter triggers thermodynamical changes over the northwestern part of the Subcontinent in May and June, including enhanced surface heating, which in turn drive the movement of the monsoon to the west. We also performed historical experiments with time-evolving radiative forcings aimed at isolating the contribution of regional versus remote anthropogenic aerosol emissions on the observed 20th century widespread drying of the Indian monsoon. Indian-only aerosol sources are found to play a predominant role in generating suppressed rainfall over the subcontinent, especially during early summer. Remote aerosols contribute, although in a minor way, to

  1. Nuclear power and its fuel cycle

    International Nuclear Information System (INIS)

    Wymer, R.G.

    1986-01-01

    A series of viewgraphs describes the nuclear fuel cycle and nuclear power, covering reactor types, sources of uranium, enrichment of uranium, fuel fabrication, transportation, fuel reprocessing, and radioactive wastes

  2. Spent fuel transport in fuel cycle

    International Nuclear Information System (INIS)

    Labrousse, M.

    1977-01-01

    The transport of radioactive substances is a minor part of the fuel cycle because the quantities of matter involved are very small. However the length and complexity of the cycle, the weight of the packing, the respective distances between stations, enrichment plants and reprocessing plants are such that the problem is not negligible. In addition these transports have considerable psychological importance. The most interesting is spent fuel transport which requires exceptionally efficient packaging, especially where thermal and mechanical resistance are concerned. To meet the safety criteria necessary for the protection of both public and users it was decided to use the maximum capacity consistent with rail transport and to avoid coolant fluids under pressure. Since no single type of packing is suitable for all existing stations an effort has been made to standardise handling accessories, and future trands are towards maximum automation. A discussion on the various technical solutions available for the construction of these packing systems is followed by a description of those used for the two types of packaging ordered by COGEMA [fr

  3. The long-term life cycle private and external costs of high coal usage in the US

    International Nuclear Information System (INIS)

    Bergerson, Joule; Lave, Lester

    2007-01-01

    Using four times as much coal in 2050 for electricity production need not degrade air quality or increase greenhouse gas emissions. Current SO x and NO x emissions from the power sector could be reduced from 12 to less than 1 and from 5 to 2 million tons annually, respectively, using advanced technology. While direct CO 2 emissions from new power plants could be reduced by over 87%, life cycle emissions could increase by over 25% due to the additional coal that is required to be mined and transported to compensate for the energy penalty of the carbon capture and storage technology. Strict environmental controls push capital costs of pulverized coal (PC) and integrated coal gasification combined cycle (IGCC) plants to $1500-1700/kW and $1600-2000/kW, respectively. Adding carbon capture and storage (CCS) increases costs to $2400-2700/kW and $2100-3000/kW (2005 dollars), respectively. Adding CCS reduces the 40-43% efficiency of the ultra-supercritical PC plant to 31-34%; adding CCS reduces the 32-38% efficiency of the GE IGCC plant to 27-33%. For IGCC, PC, and natural gas combined cycle (NGCC) plants, the carbon dioxide tax would have to be $53, $74, and $61, respectively, to make electricity from a plant with CCS cheaper. Capturing and storing 90% of the CO 2 emissions increases life cycle costs from 5.4 to 11.6 cents/kWh. This analysis shows that 90% CCS removal efficiency, although being a large improvement over current electricity generation emissions, results in life cycle emissions that are large enough that additional effort is required to achieve significant economy-wide reductions in the US for this large increase in electricity generation using either coal or natural gas

  4. OPTIMIZATION OF THE CATHODE LONG TERM STABILITY IN MOLTEN CARBONATE FUEL CELLS: EXPERIMENTAL STUDY AND MATHEMATICAL MODELING

    Energy Technology Data Exchange (ETDEWEB)

    Anand Durairajan; Bala Haran; Branko N. Popov; Ralph E. White

    2000-05-01

    The cathode materials for molten carbonate fuel cells (MCFCs) must have low dissolution rate, high structural strength and good electrical conductivity. Currently available cathodes are made of lithiated NiO which have acceptable structural strength and conductivity. However a study carried out by Orfeld et al. and Shores et al. indicated that the nickel cathodes dissolved, then precipitated and reformed as dendrites across the electrolyte matrix. This results in a decrease in cell utilization and eventually leads to shorting of the cell. The solubility of NiO was found to depend upon the acidity/basicity of the melt (basicity is directly proportional to log P{sub CO2}), carbonate composition, H{sub 2}O partial pressure and temperature. Urushibata et al. found that the dissolution of the cathode is a primary life limiting constraint of MCFCs, particularly in pressurized operation. With currently available NiO cathodes, the goal of 40,000 hours for the lifetime of MCFC appears achievable with cell operation at atmospheric pressure. However, the cell life at 10 atm and higher cell pressures is in the range between 5,000 to 10,000 hours. The overall objective of this research is to develop a superior cathode for MCFC's with improved catalytic ability, enhanced corrosion resistance with low ohmic losses, improved electronic conductivity. We also plan to understand the corrosion processes occurring at the cathode/molten carbonate interface. The following cathode materials will be subjected to detailed electrochemical, performance, structural and corrosion studies. (i) Passivated NiO alloys using chemical treatment with yttrium ion implantation and anodic yttrium molybdate treatment; (ii) Novel composite materials based on NiO and nanosized Ce, Yt, Mo; (iii) Co doped LiNiO{sub 2} LiNiO{sub 2} doped with 10 to 20% Co (LiCo{sub 0.2}NiO{sub 2}) and NiO cathodes; and (iv) CoO as a replacement for NiO. Passivation treatments will inhibit corrosion and increase the

  5. World nuclear capacity and fuel cycle requirements 1992

    International Nuclear Information System (INIS)

    1992-12-01

    This analysis report presents the current status and projections of nuclear capacity, generation, and fuel cycle requirements for all countries in the world using nuclear power to generate electricity for commercial use. Long-term projections of US nuclear capacity, generation, fuel cycle requirements, and spent fuel discharges for three different scenarios through 2030 are provided in support of the Department of Energy's activities pertaining to the Nuclear Waste Policy Act of 1982 (as amended in 1987). The projections of uranium requirements also support the Energy Information Administration's annual report, Domestic Uranium Mining and Milling Industry: Viability Assessment for the Lower and Upper Reference case scenarios were obtained from the Office of Integrated Analysis and Forecasting, Energy Information Administration. Most of these projections were developed using the World Integrated Nuclear Evaluation System (WINES) model

  6. Implementation of thorium fuel cycle in Indian nuclear programme

    International Nuclear Information System (INIS)

    Krishnani, P.D.; Srivenkatesan, R.

    2004-01-01

    To ensure long term availability of nuclear energy in a sustainable manner, taking cognisance of its resource position, India has followed a closed fuel cycle option and chalked out a three-stage nuclear power programme based on uranium and thorium. The three stages of this programme comprise: - Natural uranium fuelled Pressurized Heavy Water Reactors - Fast Breeder Reactors utilising plutonium based fuel - Advanced nuclear power systems for utilization of thorium The technology for the first stage has already reached a level of maturity, and a commercial fast breeder reactor programme, comprising of the second stage, is due to start soon with the construction of Prototype Fast Breeder Reactor (Pbr). A large amount of research and development is going on for utilizing thorium. In this respect, an Advanced Heavy Water Reactor (A HWR) is being designed in India. The R and D work on thorium fuel cycle is discussed

  7. Aspects of the fast reactors fuel cycle

    International Nuclear Information System (INIS)

    Zouain, D.M.

    1982-06-01

    The fuel cycle for fast reactors, is analysed, regarding the technical aspects of the developing of the reprocessing stages and the fuel fabrication. The environmental impact of LMFBRs and the waste management of this cycle are studied. The economic aspects of the fuel cycle, are studied too. Some coments about the Brazilian fast reactors programs are done. (E.G.) [pt

  8. Rational Functionalization of Perylene Diimide for Stable Capacity and Long-term Cycling Performance for Li-ion Batteries

    International Nuclear Information System (INIS)

    M, Veerababu; R, Kothandaraman

    2017-01-01

    Perylene based dilithium salt of N,N'-bis (glycinyl) perylene diimide (Li 2 -PDI) was synthesized and studied as an electrode material for lithium-ion batteries. The −CH 2 −COOLi functionalization of perylene diimide is a simple strategy to mitigate the dissolution of the monomer in the electrolyte. The Li 2 -PDI electrode exhibits excellent capacity retention behaviour and delivers a stable specific capacity of 101 mAh g −1 after 100 cycles at a current density of 17 mA g −1 , which is 98% of theoretical specific capacity. A remarkably stable capacity of 87 mAh g −1 was observed even after 1000 cycles with 100% coulombic efficiency at a current density of 200 mA g −1 . The reversible electrochemical lithiation/delithiation mechanism of Li 2 -PDI was studied by ex-situ XRD and FT-IR spectroscopic techniques.

  9. Finite element modeling of copper coated used fuel containers for long-term storage in a deep geological repository

    International Nuclear Information System (INIS)

    Boyle, C.; Meguid, S.A.

    2014-01-01

    The Nuclear Waste Management Organization (NWMO) is developing a Used Fuel Container (UFC) optimized for CANDU fuel with an integrally bonded copper coating corrosion barrier. This paper demonstrates a validated finite element coating model, which can accurately predict the response of the UFC's steel-copper coating composite. Tensile, adhesion, and three-point bend tests were conducted for copper cold spray and electrodeposited coatings. The nonlinear finite element model accurately predicted the response of three different coating types, including cracking and delamination failure mechanisms, beyond the design basis loadings. The model will further be utilized to evaluate alternative UFC designs under anticipated repository conditions to assess safety margins. (author)

  10. VISION: Verifiable Fuel Cycle Simulation Model

    Energy Technology Data Exchange (ETDEWEB)

    Jacob J. Jacobson; Abdellatif M. Yacout; Gretchen E. Matthern; Steven J. Piet; David E. Shropshire

    2009-04-01

    The nuclear fuel cycle is a very complex system that includes considerable dynamic complexity as well as detail complexity. In the nuclear power realm, there are experts and considerable research and development in nuclear fuel development, separations technology, reactor physics and waste management. What is lacking is an overall understanding of the entire nuclear fuel cycle and how the deployment of new fuel cycle technologies affects the overall performance of the fuel cycle. The Advanced Fuel Cycle Initiative’s systems analysis group is developing a dynamic simulation model, VISION, to capture the relationships, timing and delays in and among the fuel cycle components to help develop an understanding of how the overall fuel cycle works and can transition as technologies are changed. This paper is an overview of the philosophy and development strategy behind VISION. The paper includes some descriptions of the model and some examples of how to use VISION.

  11. Perspective of nuclear fuel cycle for sustainable nuclear energy

    International Nuclear Information System (INIS)

    Fukuda, K.; Bonne, A.; Kagramanian, V.

    2001-01-01

    Nuclear power, on a life-cycle basis, emits about the same level of carbon per unit of electricity generated as wind and solar power. Long-term energy demand and supply analysis projects that global nuclear capacities will expand substantially, i.e. from 350 GW today to more than 1,500 GW by 2050. Uranium supply, spent fuel and waste management, and a non-proliferation nuclear fuel cycle are essential factors for sustainable nuclear power growth. An analysis of the uranium supply up to 2050 indicates that there is no real shortage of potential uranium available if based on the IIASA/WEC scenario on medium nuclear energy growth, although its market price may become more volatile. With regard to spent fuel and waste management, the short term prediction foresees that the amount of spent fuel will increase from the present 145,000 tHM to more than 260,000 tHM in 2015. The IPCC scenarios predicted that the spent fuel quantities accumulated by 2050 will vary between 525 000 tHM and 3 210 000 tHM. Even according to the lowest scenario, it is estimated that spent fuel quantity in 2050 will be double the amount accumulated by 2015. Thus, waste minimization in the nuclear fuel cycle is a central tenet of sustainability. The proliferation risk focusing on separated plutonium and resistant technologies is reviewed. Finally, the IAEA Project INPRO is briefly introduced. (author)

  12. Long term radiotoxicity

    International Nuclear Information System (INIS)

    Slessarev, I.

    2001-01-01

    A major issue to secure the development of nuclear energy in future is the radioactive waste minimization, both inside the fuel cycle and in a deep geological storage. The aim of this paper is to establish the physical principles which provide an inherent minimization of the radioactive wastes. A new concept is introduced to characterize the radiotoxicity associated to various nuclei families in equilibrium state. The analysis shows the potential of evolutionary nuclear systems, mostly based on known technologies and the potential of more futuristic systems, like accelerator-driven systems and Th-fuel cycle. Several groups of the toxicity sources are object of the studies: Actinides as a part of the nuclear fuel which is remaining unusable after irradiation in nuclear power plants; long-lived fission products as the inevitable result of nuclear energy production; Lanthanides as an important part of fission products which separation from Actinides is technologically difficult because of similar chemical properties

  13. Homogeneous Thorium Fuel Cycles in Candu Reactors

    International Nuclear Information System (INIS)

    Hyland, B.; Dyck, G.R.; Edwards, G.W.R.; Magill, M.

    2009-01-01

    The CANDU R reactor has an unsurpassed degree of fuel-cycle flexibility, as a consequence of its fuel-channel design, excellent neutron economy, on-power refueling, and simple fuel bundle [1]. These features facilitate the introduction and full exploitation of thorium fuel cycles in Candu reactors in an evolutionary fashion. Because thorium itself does not contain a fissile isotope, neutrons must be provided by adding a fissile material, either within or outside of the thorium-based fuel. Those same Candu features that provide fuel-cycle flexibility also make possible many thorium fuel-cycle options. Various thorium fuel cycles can be categorized by the type and geometry of the added fissile material. The simplest of these fuel cycles are based on homogeneous thorium fuel designs, where the fissile material is mixed uniformly with the fertile thorium. These fuel cycles can be competitive in resource utilization with the best uranium-based fuel cycles, while building up a 'mine' of U-233 in the spent fuel, for possible recycle in thermal reactors. When U-233 is recycled from the spent fuel, thorium-based fuel cycles in Candu reactors can provide substantial improvements in the efficiency of energy production from existing fissile resources. The fissile component driving the initial fuel could be enriched uranium, plutonium, or uranium-233. Many different thorium fuel cycle options have been studied at AECL [2,3]. This paper presents the results of recent homogeneous thorium fuel cycle calculations using plutonium and enriched uranium as driver fuels, with and without U-233 recycle. High and low burnup cases have been investigated for both the once-through and U-233 recycle cases. CANDU R is a registered trademark of Atomic Energy of Canada Limited (AECL). 1. Boczar, P.G. 'Candu Fuel-Cycle Vision', Presented at IAEA Technical Committee Meeting on 'Fuel Cycle Options for LWRs and HWRs', 1998 April 28 - May 01, also Atomic Energy of Canada Report, AECL-11937. 2. P

  14. ORIGEN-based Nuclear Fuel Inventory Module for Fuel Cycle Assessment: Final Project Report

    Energy Technology Data Exchange (ETDEWEB)

    Skutnik, Steven E. [Univ. of Tennessee, Knoxville, TN (United States). Dept. of Nuclear Engineering

    2017-06-19

    The goal of this project, “ORIGEN-based Nuclear Fuel Depletion Module for Fuel Cycle Assessment" is to create a physics-based reactor depletion and decay module for the Cyclus nuclear fuel cycle simulator in order to assess nuclear fuel inventories over a broad space of reactor operating conditions. The overall goal of this approach is to facilitate evaluations of nuclear fuel inventories for a broad space of scenarios, including extended used nuclear fuel storage and cascading impacts on fuel cycle options such as actinide recovery in used nuclear fuel, particularly for multiple recycle scenarios. The advantages of a physics-based approach (compared to a recipe-based approach which has been typically employed for fuel cycle simulators) is in its inherent flexibility; such an approach can more readily accommodate the broad space of potential isotopic vectors that may be encountered under advanced fuel cycle options. In order to develop this flexible reactor analysis capability, we are leveraging the Origen nuclear fuel depletion and decay module from SCALE to produce a standalone “depletion engine” which will serve as the kernel of a Cyclus-based reactor analysis module. The ORIGEN depletion module is a rigorously benchmarked and extensively validated tool for nuclear fuel analysis and thus its incorporation into the Cyclus framework can bring these capabilities to bear on the problem of evaluating long-term impacts of fuel cycle option choices on relevant metrics of interest, including materials inventories and availability (for multiple recycle scenarios), long-term waste management and repository impacts, etc. Developing this Origen-based analysis capability for Cyclus requires the refinement of the Origen analysis sequence to the point where it can reasonably be compiled as a standalone sequence outside of SCALE; i.e., wherein all of the computational aspects of Origen (including reactor cross-section library processing and interpolation, input and output

  15. Advanced Fuel Cycle Economic Sensitivity Analysis

    Energy Technology Data Exchange (ETDEWEB)

    David Shropshire; Kent Williams; J.D. Smith; Brent Boore

    2006-12-01

    A fuel cycle economic analysis was performed on four fuel cycles to provide a baseline for initial cost comparison using the Gen IV Economic Modeling Work Group G4 ECON spreadsheet model, Decision Programming Language software, the 2006 Advanced Fuel Cycle Cost Basis report, industry cost data, international papers, the nuclear power related cost study from MIT, Harvard, and the University of Chicago. The analysis developed and compared the fuel cycle cost component of the total cost of energy for a wide range of fuel cycles including: once through, thermal with fast recycle, continuous fast recycle, and thermal recycle.

  16. Contribution of Heavy Water Board in nuclear fuel cycle technologies. Contributed Paper IT-03

    International Nuclear Information System (INIS)

    Mohanty, P.R.

    2014-01-01

    The three stage Indian nuclear power programme envisages use of closed nuclear fuel cycle and thorium utilization as its mainstay for long term energy security on sustainable basis. India is committed to realize this objective through the development and deployment of frontier technologies pertaining to all aspects of a closed nuclear fuel cycle. Comprehensive indigenous capabilities have been developed in all aspects of nuclear power and associated fuel cycles. Heavy Water Board (HWB), with its abiding objective of fulfilling demand of heavy water for India's flourishing nuclear power program, is one of the frontrunner in Nuclear Fuel Cycle Technology. HWB is now engaged in wide spectrum of activities in various facets of fuel cycle covering all the three stages of Indian Nuclear Power Programme. HWB is contributing to Nuclear Fuel Cycle through large scale production and sustained supply of key input materials including heavy water, solvents for nuclear hydrometallurgy, 10 B enriched boron etc

  17. Estimation of the radionuclide inventory in LWR spent fuel assembly structural materials for long-term safety analysis

    Directory of Open Access Journals (Sweden)

    Caruso Stefano

    2016-01-01

    Full Text Available The radionuclide inventory of materials irradiated in a reactor depends on the initial material composition, irradiation history and on the magnitude and spectrum of the neutron flux. The material composition of a fuel assembly structure includes various alloys of Zircaloy, Inconel and stainless steel. The existing impurities in these materials are very important for accurate determination of the activation of all nuclides with a view to assessing the radiological consequences of their geological disposal. In fact, the safety assessments of geological repositories require the average and maximum (in the sense of very conservative inventories of the very long-lived nuclides as input. The purpose of the present work is to describe the methodology applied for determining the activation of these nuclides in fuel assembly structural materials by means of coupled depletion/activation calculations and also to crosscheck the results obtained from two approaches. UO2 and MOX PWR fuels have been simulated using SCALE/TRITON, simultaneously irradiating the fuel region in POWER mode and the cladding region in FLUX mode and aiming to produce binary macro cross-section libraries by applying accurate local neutron spectra in the cladding region as a function of irradiation history that are suitable for activation calculations. The developed activation libraries have been re-employed in a second run using the ORIGEN-S program for a dedicated activation calculation. The axial variation of the neutron flux along the fuel assembly length has also been considered. The SCALE calculations were performed using a 238-group cross-section library, according to the ENDF/B-VII. The results obtained with the ORIGEN-S activation calculations are compared with the results obtained from TRITON via direct irradiation of the cladding, as allowed by the FLUX mode. It is shown that an agreement on the total calculated activities can be found within 55% for MOX and within 22% for

  18. Three-dimensional graphene sheets with NiO nanobelt outgrowths for enhanced capacity and long term high rate cycling Li-ion battery anode material

    Science.gov (United States)

    Shi, Waipeng; Zhang, Yingmeng; Key, Julian; Shen, Pei Kang

    2018-03-01

    An efficient synthesis method to grow well attached NiO nanobelts from 3D graphene sheets (3DGS) is reported herein. Ni-ion exchanged resin provides the initial Ni reactant portion, which serves both as a catalyst to form 3DGS and then as a seeding agent to grow the NiO nanobelts. The macroporous structure of 3DGS provides NiO containment to achieve a high cycling stability of up to 445 mAh g-1 after 360 cycles (and >112% capacity retention after 515 cycles) at a high current density of 2 A g-1. With a 26.8 wt.% content of NiO on 3DGS, increases in specific and volumetric capacity were 41.6 and 75.7% respectively over that of 3DGS at matching current densities. Therefore, the seeded growth of NiO nanobelts from 3DGS significantly boosts volumetric capacity, while 3DGS enables high rate long term cycling of the NiO. The high rate cycling stability of NiO on 3DGS can be attributed to (i) good attachment and contact to the large surface of 3DGS, (ii) high electron conductivity and rapid Li-ion transfer (via the interconnected, highly conductive graphitized walls of 3DGS) and (iii) buffering void space in 3DGS to contain volume expansion of NiO during charge/discharge.

  19. Multilayer graphene for long-term corrosion protection of stainless steel bipolar plates for polymer electrolyte membrane fuel cell

    DEFF Research Database (Denmark)

    Stoot, Adam Carsten; Camilli, Luca; Spiegelhauer, Susie Ann

    2015-01-01

    Abstract Motivated by similar investigations recently published (Pu et al., 2015), we report a comparative corrosion study of three sets of samples relevant as bipolar plates for polymer electrolyte fuel cells: stainless steel, stainless steel with a nickel seed layer (Ni/SS) and stainless steel...... with Ni seed layer coated by a multi-layered graphene thin film (G/Ni/SS). The graphene film, synthesized by chemical vapour deposition (CVD), has a moderate amount of defects according to Raman spectroscopy. Short/medium-term corrosion test shows no significant advantage of using G/Ni/SS rather than Ni...

  20. An assessment of the long-term impact of chemically toxic contaminants from the disposal of nuclear fuel waste

    International Nuclear Information System (INIS)

    Goodwin, B.W.; Garisto, N.C.; Barnard, J.W.

    1987-01-01

    This paper presents a study on the potential for impact on man of chemically toxic contaminants associated with the Canadian concept for the disposal of nuclear fuel waste. The elements of concern are determined through a series of screening criteria such as elemental abundances and solubilities. A systems variability analysis approach is then used to predict the possible concentrations of these elements that may arise in the biosphere. These concentrations are compared with environmental guidelines such as permissible levels in drinking water. Conclusions are made regarding the potential for the chemically toxic contaminants to have an impact on man. 54 refs

  1. The DUPIC alternative for backend fuel cycle

    International Nuclear Information System (INIS)

    Lee, J.S.; Yang, M.S.; Park, H.S.; Boczar, P.; Sullivan, J.; Gadsby, R.D.

    1997-01-01

    The DUPIC fuel cycle was conceived as an alternative to the conventional fuel cycle backed options, with a view to multiple benefits expectable from burning spent PWR fuel again in CANDU reactors. It is based on the basic idea that the bulk of spent PWR fuel can be directly refabricated into a reusable fuel for CANDU of which high efficiency in neutron utilization would exhaustively burn the fissile remnants in the spent PWR fuel to a level below that of natural uranium. Such ''burn again'' strategy of the DUPIC fuel cycle implies that the spent PWR fuel will become CANDU fuel of higher burnup with relevant benefits such as spent PWR fuel disposition, saving of natural uranium fuel, etc. A salient feature of the DUPIC fuel cycle is neither the fissile content nor the bulk radioactivity is separated from the DUPIC mass flow which must be contained and shielded all along the cycle. This feature can be considered as a factor of proliferation resistance by deterrence against access to sensitive materials. It means also the requirement for remote systems technologies for DUPIC fuel operation. The conflicting aspects between better safeguardability and harder engineering problems of the radioactive fuel operation may be the important reason why the decades' old concept, since INFCE, of ''hot'' fuel cycle has not been pursued with much progress. In this context, the DUPIC fuel cycle could be a live example for development of proliferation resistant fuel cycle. As the DUPIC fuel cycle looks for synergism of fuel linkage from PWR to CANDU (or in broader sense LWR to HWR), Korea occupies a best position for DUPIC exercise with her unique strategy of reactor mix of both reactor types. But the DUPIC benefits can be extended to global bonus, expectable from successful development of the technology. (author)

  2. Fuel cycle cost study with HEU and LEU fuels

    International Nuclear Information System (INIS)

    Matos, J.E.; Freese, K.E.

    1984-01-01

    Fuel cycle costs are compared for a range of 235 U loadings with HEU and LEU fuels using the IAEA generic 10 MW reactor as an example. If LEU silicide fuels are successfully demonstrated and licensed, the results indicate that total fuel cycle costs can be about the same or lower than those with the HEU fuels that are currently used in most research reactors

  3. Long-term effects of antibiotics, norfloxacin, and sulfamethoxazole, in a partial life-cycle study with zebrafish (Danio rerio): effects on growth, development, and reproduction.

    Science.gov (United States)

    Yan, Zhenhua; Lu, Guanghua; Ye, Qiuxia; Liu, Jianchao

    2016-09-01

    A partial life-cycle study with zebrafish (Danio rerio) was conducted to evaluate the long-term effects of antibiotics, norfloxacin (NOR) and sulfamethoxazole (SMX). A series of bio-endpoints correlated to the growth, development, and reproduction was assessed. The results showed that the body weight and the condition factor were depressed by SMX at 200 μg/L during the growth period. Meanwhile, the activities of metabolic enzyme (ethoxyresorufin O-deethylase, EROD) and antioxidant enzymes (superoxide dismutase, SOD and catalase, CAT) were stimulated in all cases. The consequences of parental exposure to antibiotics for the next generation were also examined. The egg production of parents were depressed by the 200 μg/L NOR and SMX alone or in combination. Similarly, decreased hatching, survival, and enhanced development abnormality of the next generation also occurred after parental exposure to SMX at the highest concentration. The heartbeat however was not altered in all cases. Furthermore, there was no significant difference in the bio-endpoints between the combined and individual treatment in most cases, with the exception of lower EROD activity and egg production in the co-treatment. The results suggest that long-term exposure to NOR and SMX at environmentally relevant concentrations, individually and in a mixture, may not significantly pose a threat to the growth, development, and reproduction of zebrafish, and an adverse effect may be expected at high concentration.

  4. Provision or Good Genes? Menstrual Cycle Shifts in Women's Preferences for Short-Term and Long-Term Mates' Altruistic Behavior

    Directory of Open Access Journals (Sweden)

    Ryo Oda

    2014-04-01

    Full Text Available Men's altruism may have evolved, via female choice, as a signal of either their genetic quality or their willingness to allocate resources to offspring. The possibility that men display altruism to signal their genetic quality may be tested by examining women's preference for men's altruism across the stages of the menstrual cycle. Because women can maximize reproductive benefits by mating with men who have “good genes” on high-fertility versus low-fertility days, women should show a heightened preference for male altruism on high-fertility days compared to low-fertility days, and this heightened preference should be more apparent when women evaluate men for short-term sexual relationships than for long-term committed relationships. The possibility that men display altruism to signal their willingness to provision, as opposed to their genetic quality, may be tested by examining women's preference for men's altruism toward different recipients. More specifically, altruistic behavior toward family members may reflect a willingness to provide resources for kin and, hence, willingness to provision, whereas altruistic behavior toward strangers may function as an honest signal of genetic quality. In two samples of young women (TVs = 131 and 481, we found no differences between high- and low-fertility participants in preference for men's altruism, and women preferred men's altruism more in long-term than short-term relationships. The findings suggest that men's altruistic behavior functions as a signal of willingness to provide resources rather than genetic quality.

  5. Geodetic constraints on slip partitioning at a convergent plate boundary: Reconciling long-term structural deformation with earthquake cycle observations in West Java

    Science.gov (United States)

    Koulali, A.; McClusky, S.; Susilo, S.; Leonard, Y.; Cummins, P. R.; Tregoning, P.; Meilano, I.; Efendi, J.; Wijanarto, A. B.

    2016-12-01

    Slip partitioning models have been used extensively to describe the broad zones of deformation in oblique convergence zones. Traditionally these models have exploited course spatial and temporal constraints from geomorphology, seismology and geodesy. However, the development of high resolution geodetic measurements in the recent years have allowed the imaging of multiple transient processes occurring during the seismic cycle ranging from post-seismic relaxation to slow slip events, which raise questions about our ability to understand the long-term patterns of relative motion in actively convergent deforming regions. Here we present the example of West Java, where continuous GPS observations show a time-dependent change in the linear rate of surface motion, which we interpret as an ongoing long-term post-seismic deformation following the 2006 Mw 7.8 Java earthquake. We use a combination of a regional tectonic block model and a viscoelastic relaxation model to consider the post-seismic transient and we propose a kinematic model of convergence of the Australian Plate and the Sunda Block, involving a slip partitioning between the Java Trench and a left-lateral structure extending E-W along Java, with most of the normal component is occurring onto the subduction Thrust and a much smaller parallel motion accommodated along the Barabis ( 5± 0.2 mm/yr) and Kendeng (˜ 0.8 ± 0.3 mm/yr) Thrusts. Our findings correlate with observations from historical seismicity and highlight a new potential seismic hazard in Java Island.

  6. Long-term fuel retention and release in JET ITER-Like Wall at ITER-relevant baking temperatures

    Science.gov (United States)

    Heinola, K.; Likonen, J.; Ahlgren, T.; Brezinsek, S.; De Temmerman, G.; Jepu, I.; Matthews, G. F.; Pitts, R. A.; Widdowson, A.; Contributors, JET

    2017-08-01

    The fuel outgassing efficiency from plasma-facing components exposed in JET-ILW has been studied at ITER-relevant baking temperatures. Samples retrieved from the W divertor and Be main chamber were annealed at 350 and 240 °C, respectively. Annealing was performed with thermal desoprtion spectrometry (TDS) for 0, 5 and 15 h to study the deuterium removal effectiveness at the nominal baking temperatures. The remained fraction was determined by emptying the samples fully of deuterium by heating W and Be samples up to 1000 and 775 °C,respectively. Results showed the deposits in the divertor having an increasing effect to the remaining retention at temperatures above baking. Highest remaining fractions 54 and 87 % were observed with deposit thicknesses of 10 and 40 μm, respectively. Substantially high fractions were obtained in the main chamber samples from the deposit-free erosion zone of the limiter midplane, in which the dominant fuel retention mechanism is via implantation: 15 h annealing resulted in retained deuterium higher than 90 % . TDS results from the divertor were simulated with TMAP7 calculations. The spectra were modelled with three deuterium activation energies resulting in good agreement with the experiments.

  7. OPTIMIZATION OF THE CATHODE LONG-TERM STABILITY IN MOLTEN CARBONATE FUEL CELLS: EXPERIMENTAL STUDY AND MATHEMATICAL MODELING

    Energy Technology Data Exchange (ETDEWEB)

    Hector Colonmer; Prabhu Ganesan; Nalini Subramanian; Dr. Bala Haran; Dr. Ralph E. White; Dr. Branko N. Popov

    2002-09-01

    This project focused on addressing the two main problems associated with state of art Molten Carbonate Fuel Cells, namely loss of cathode active material and stainless steel current collector deterioration due to corrosion. We followed a dual approach where in the first case we developed novel materials to replace the cathode and current collector currently used in molten carbonate fuel cells. In the second case we improved the performance of conventional cathode and current collectors through surface modification. States of art NiO cathode in MCFC undergo dissolution in the cathode melt thereby limiting the lifetime of the cell. To prevent this we deposited cobalt using an electroless deposition process. We also coated perovskite (La{sub 0.8}Sr{sub 0.2}CoO{sub 3}) in NiO thorough a sol-gel process. The electrochemical oxidation behavior of Co and perovskites coated electrodes is similar to that of the bare NiO cathode. Co and perovskite coatings on the surface decrease the dissolution of Ni into the melt and thereby stabilize the cathode. Both, cobalt and provskites coated nickel oxide, show a higher polarization compared to that of nickel oxide, which could be due to the reduced surface area. Cobalt substituted lithium nickel oxide (LiNi{sub 0.8}Co{sub 0.2}O{sub 2}) and lithium cobalt oxide were also studied. LiNi{sub x}Co{sub 1-x}O{sub 2} was synthesized by solid-state reaction procedure using lithium nitrate, nickel hydroxide and cobalt oxalate precursor. LiNi{sub x}Co{sub 1-x}O{sub 2} showed smaller dissolution of nickel than state of art nickel oxide cathode. The performance was comparable to that of nickel oxide. The corrosion of the current collector in the cathode side was also studied. The corrosion characteristics of both SS304 and SS304 coated with Co-Ni alloy were studied. This study confirms that surface modification of SS304 leads to the formation of complex scales with better barrier properties and better electronic conductivity at 650 C. A three

  8. Working and reference memory across the estrous cycle of rat: a long-term study in gonadally intact females.

    Science.gov (United States)

    Pompili, Assunta; Tomaz, Carlos; Arnone, Benedetto; Tavares, Maria Clotilde; Gasbarri, Antonella

    2010-11-12

    The results of many studies conducted over the past two decades suggested a role of estrogen on mammal's ability to learn and remember. In the present paper, we analyzed the influence that the endogenous fluctuation of estrogen, naturally present across the different phases of estrous cycle of female rats, can exert over the performance of tasks utilized to assess memory. In particular, we analyzed the performances in an eight arms radial maze task, dependent upon working memory, and in a water maze (WM) task, dependent upon spatial reference memory. The water maze is aversively motivated by the desire to escape onto a safe platform, whereas the radial arm maze (RAM) is motivated by food reward. The difference in reinforcement may affect the speed of learning, the strategy adopted and the necessity for accurate navigation. Therefore, coherent results obtained through the two different tasks can be due to mnemonic factors. The study was conducted during a long period of time, 14 months, utilizing gonadally intact females, without pharmacological and surgical treatments. In order to evaluate the post-acquisition phase we first trained the animals to reach the criterion in performing tasks, and then we submitted them to experimental phase. Our results show that estrogen can have an effect on memory processes, and that this effect may be different in relation to different kinds of memory. In fact, in our study, estrogen selectively improved working memory, but not reference memory, during post-acquisition performance of a RAM task with four baited and four un-baited arms. Moreover, WM performances showed that estrogen have a negative effect on spatial reference memory. (c) 2010 Elsevier B.V. All rights reserved.

  9. Fuel-cycle cost comparisons with oxide and silicide fuels

    International Nuclear Information System (INIS)

    Matos, J.E.; Freese, K.E.

    1982-01-01

    This paper addresses fuel cycle cost comparisons for a generic 10 MW reactor with HEU aluminide fuel and with LEU oxide and silicide fuels in several fuel element geometries. The intention of this study is to provide a consistent assessment of various design options from a cost point of view. Fuel cycle cost benefits could result if a number of reactors were to utilize fuel elements with the same number or different numbers of the same standard fuel plate. Data are presented to quantify these potential cost benefits. This analysis shows that there are a number of fuel element designs using LEU oxide or silicide fuels that have either the same or lower total fuel cycle costs than the HEU design. Use of these fuels with the uranium densities considered requires that they are successfully demonstrated and licensed

  10. Economic aspects of Dukovany NPP fuel cycle

    International Nuclear Information System (INIS)

    Vesely, P.; Borovicka, M.

    2001-01-01

    The paper discusses some aspects of high burnup program implementation at Dukovany NPP and its influence on the fuel cycle costs. Dukovany internal fuel cycle is originally designed as a three years cycle of the Out-In-In fuel reloading patterns. These reloads are not only uneconomical but they additionally increased the radiation load of the reactor pressure vessel due to high neutron leakage typical for Out-In-In loading pattern. To avoid the high neutron leakage from the core a transition to 4-year fuel cycle is started in 1987. The neutron leakage from the core is sequentially decreased by insertion of older fuel assemblies at the core periphery. Other developments in fuel cycle are: 1) increasing of enrichment in control assemblies (3.6% of U-235); 2) improvement in fuel assembly design (reduce the assembly shroud thickness from 2.1 to 1.6 mm); 3) introduction of Zr spacer grid instead of stainless steel; 4) introduction of new type of assembly with profiled enrichment with average value of 3.82%. Due to increased reactivity of the new assemblies the transition to the partial 5-year fuel cycle is required. Typical fuel loading pattern for 3, 3.5, 4 and 5-year cycles are shown in the presented paper. An evaluation of fuel cost is also discussed by using comparative analysis of different fuel cycle options. The analysis shows that introduction of the high burnup program has decrease relative fuel cycle costs

  11. HLW Long-term Management Technology Development

    International Nuclear Information System (INIS)

    Choi, Jong Won; Kang, C. H.; Ko, Y. K.

    2010-02-01

    Permanent disposal of spent nuclear fuels from the power generation is considered to be the unique method for the conservation of human being and nature in the present and future. In spite of spent nuclear fuels produced from power generation, based on the recent trends on the gap between supply and demand of energy, the advance on energy price and reduction of carbon dioxide, nuclear energy is expected to play a role continuously in Korea. It means that a new concept of nuclear fuel cycle is needed to solve problems on spent nuclear fuels. The concept of the advanced nuclear fuel cycle including PYRO processing and SFR was presented at the 255th meeting of the Atomic Energy Commission. According to the concept of the advanced nuclear fuel cycle, actinides and long-term fissile nuclides may go out of existence in SFR. And then it is possible to dispose of short term decay wastes without a great risk bearing. Many efforts had been made to develop the KRS for the direct disposal of spent nuclear fuels in the representative geology of Korea. But in the case of the adoption of Advanced nuclear fuel cycle, the disposal of PYRO wastes should be considered. For this, we carried out the Safety Analysis on HLW Disposal Project with 5 sub-projects such as Development of HLW Disposal System, Radwaste Disposal Safety Analysis, Feasibility study on the deep repository condition, A study on the Nuclide Migration and Retardation Using Natural Barrier, and In-situ Study on the Performance of Engineered Barriers

  12. Radioecology of nuclear fuel cycles

    International Nuclear Information System (INIS)

    Schreckhise, R.G.; Cadwell, L.L.; Emery, R.M.

    1981-01-01

    This study provides information to help assess the environmental impacts and certain potential human hazards associated with nuclear fuel cycles. A data base is being developed to define and quantify biological transport routes which will permit credible predictions and assessment of routine and potential large-scale releases of radionuclides and other toxic materials. Information obtained from existing storage and disposal sites will provide a meaningful radioecological perspective with which to improve the effectiveness of waste management practices. This paper focuses on terrestrial and aquatic radioecology of waste management areas and biotic transport parameters

  13. Separating long-term deformation cycles and atmospheric signals at Mount St. Helens using PS-InSAR

    Science.gov (United States)

    Welch, M.

    2015-12-01

    Since its eruption in 1980, Mount St. Helens has experienced multiple inflation-deflation cycles associated with dome building eruptions. During the most recent dome-building episode, which spanned 2004 to 2008, GPS recorded the transition from pre-eruptive inflation to co-eruptive deflation and a final transition back to inflation. Such observations provide important constraints on the timing and mechanics of cyclic magma recharge and extrusion. Currently, the subtle surface deformation signal at St Helens is monitored primarily by ground based geodetic techniques like GPS. Satellite-based InSAR has the potential to substantially augment these techniques by providing spatially continuous, precise measurements of surface displacements, and may also reveal other volcanic or surficial processes too localized to be detected by ground based methods. Traditional interferometry is challenging to apply to volcanoes in the Cascades. Widespread phase decorrelation caused by persistent snow cover and dense vegetation, combined with large, elevation dependent atmospheric phase delays, mask or make deformation signals difficult to detect. By applying StaMPS, a Persistent Scatterers (PS) technique, phase decorrelation is mitigated by utilizing only the pixels with the highest, statistically derived, signal to noise ratio. However, atmospheric water vapor, which delays the radar signal, remains problematic, particularly on the volcano edifice. To assess the bias imposed by the atmosphere, we perform a series of sensitivity tests using a suite of methods including several that rely on the linear or power-law correlation of phase delay to topography and knowledge of the spatial scale of the signal. We also apply methods that calculate wet and dry phase delay from atmospheric reanalysis datasets such as ERA-Interim provided by the ECMWF. SAR data from the ERS, Envisat, and ALOS satellites, along with newer datasets, are processed with these tools to create a time series spanning

  14. National Policy on Nuclear Fuel Cycle

    International Nuclear Information System (INIS)

    Soedyartomo, S.

    1996-01-01

    National policy on nuclear fuel cycle is aimed at attaining the expected condition, i.e. being able to support optimality the national energy policy and other related Government policies taking into account current domestic nuclear fuel cycle condition and the trend of international nuclear fuel cycle development, the national strength, weakness, thread and opportunity in the field of energy. This policy has to be followed by the strategy to accomplish covering the optimization of domestic efforts, cooperation with other countries, and or purchasing licences. These policy and strategy have to be broken down into various nuclear fuel cycle programmes covering basically assesment of the whole cycle, performing research and development of the whole cycle without enrichment and reprocessing being able for weapon, as well as programmes for industrialization of the fuel cycle stepwisery commencing with the middle part of the cycle and ending with the edge of the back-end of the cycle

  15. Spent fuel as a waste form: Data needs to allow long term performance assessment under repository disposal conditions

    International Nuclear Information System (INIS)

    Oversby, V.M.

    1986-12-01

    Performance assessment calculations are required for high level waste repositories for a period of 10,000 years. The Siting Guidelines require a comparison of sites following site characterization and prior to final site selection to be made over a 100,000 year period. To perform the required calculations, a detailed knowledge of the physical and chemical processes that affect waste form performance will be needed for each site. This paper will review the factors that affect the release of radionuclides from spent fuel under repository conditions, summarize our present state of knowledge, and suggest areas where more work is needed to support the performance assessment calculations. 17 refs., 5 figs., 3 tabs

  16. OPTIMIZATION OF THE CATHODE LONG-TERM STABILITY IN MOLTEN CARBONATE FUEL CELLS: EXPERIMENTAL STUDY AND MATHEMATICAL MODELING

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Ralph E. White; Dr. Branko N. Popov

    2002-04-01

    The dissolution of NiO cathodes during cell operation is a limiting factor to the successful commercialization of molten carbonate fuel cells (MCFCs). Lithium cobalt oxide coating onto the porous nickel electrode has been adopted to modify the conventional MCFC cathode which is believed to increase the stability of the cathodes in the carbonate melt. The material used for surface modification should possess thermodynamic stability in the molten carbonate and also should be electro catalytically active for MCFC reactions. Two approaches have been adopted to get a stable cathode material. First approach is the use of LiNi{sub 0.8}Co{sub 0.2}O{sub 2}, a commercially available lithium battery cathode material and the second is the use of tape cast electrodes prepared from cobalt coated nickel powders. The morphology and the structure of LiNi{sub 0.8}Co{sub 0.2}O{sub 2} and tape cast Co coated nickel powder electrodes were studied using scanning electron microscopy and X-Ray diffraction studies respectively. The electrochemical performance of the two materials was investigated by electrochemical impedance spectroscopy and polarization studies. A three phase homogeneous model was developed to simulate the performance of the molten carbonate fuel cell cathode. The homogeneous model is based on volume averaging of different variables in the three phases over a small volume element. The model gives a good fit to the experimental data. The model has been used to analyze MCFC cathode performance under a wide range of operating conditions.

  17. Large-scale fuel cycle centres

    International Nuclear Information System (INIS)

    Smiley, S.H.; Black, K.M.

    1977-01-01

    The US Nuclear Regulatory Commission (NRC) has considered the nuclear energy centre concept for fuel cycle plants in the Nuclear Energy Centre Site Survey 1975 (NECSS-75) Rep. No. NUREG-0001, an important study mandated by the US Congress in the Energy Reorganization Act of 1974 which created the NRC. For this study, the NRC defined fuel cycle centres as consisting of fuel reprocessing and mixed-oxide fuel fabrication plants, and optional high-level waste and transuranic waste management facilities. A range of fuel cycle centre sizes corresponded to the fuel throughput of power plants with a total capacity of 50,000-300,000MW(e). The types of fuel cycle facilities located at the fuel cycle centre permit the assessment of the role of fuel cycle centres in enhancing the safeguard of strategic special nuclear materials - plutonium and mixed oxides. Siting fuel cycle centres presents a smaller problem than siting reactors. A single reprocessing plant of the scale projected for use in the USA (1500-2000t/a) can reprocess fuel from reactors producing 50,000-65,000MW(e). Only two or three fuel cycle centres of the upper limit size considered in the NECSS-75 would be required in the USA by the year 2000. The NECSS-75 fuel cycle centre evaluation showed that large-scale fuel cycle centres present no real technical siting difficulties from a radiological effluent and safety standpoint. Some construction economies may be achievable with fuel cycle centres, which offer opportunities to improve waste-management systems. Combined centres consisting of reactors and fuel reprocessing and mixed-oxide fuel fabrication plants were also studied in the NECSS. Such centres can eliminate shipment not only of Pu but also mixed-oxide fuel. Increased fuel cycle costs result from implementation of combined centres unless the fuel reprocessing plants are commercial-sized. Development of Pu-burning reactors could reduce any economic penalties of combined centres. The need for effective fissile

  18. Exploratory Design of a Reactor/Fuel Cycle Using Spent Nuclear Fuel Without Conventional Reprocessing - 13579

    Energy Technology Data Exchange (ETDEWEB)

    Bertch, Timothy C.; Schleicher, Robert W.; Rawls, John D. [General Atomics 3550 General Atomics Court San Diego, CA 92130 (United States)

    2013-07-01

    General Atomics has started design of a waste to energy nuclear reactor (EM2) that can use light water reactor (LWR) spent nuclear fuel (SNF). This effort addresses two problems: using an advanced small reactor with long core life to reduce nuclear energy overnight cost and providing a disposal path for LWR SNF. LWR SNF is re-fabricated into new EM2 fuel using a dry voloxidation process modeled on AIROX/ OREOX processes which remove some of the fission products but no heavy metals. By not removing all of the fission products the fuel remains self-protecting. By not separating heavy metals, the process remains proliferation resistant. Implementation of Energy Multiplier Module (EM2) fuel cycle will provide low cost nuclear energy while providing a long term LWR SNF disposition path which is important for LWR waste confidence. With LWR waste confidence recent impacts on reactor licensing, an alternate disposition path is highly relevant. Centered on a reactor operating at 250 MWe, the compact electricity generating system design maximizes site flexibility with truck transport of all system components and available dry cooling features that removes the need to be located near a body of water. A high temperature system using helium coolant, electricity is efficiently produced using an asynchronous high-speed gas turbine while the LWR SNF is converted to fission products. Reactor design features such as vented fuel and silicon carbide cladding support reactor operation for decades between refueling, with improved fuel utilization. Beyond the reactor, the fuel cycle is designed so that subsequent generations of EM2 reactor fuel will use the previous EM2 discharge, providing its own waste confidence plus eliminating the need for enrichment after the first generation. Additional LWR SNF is added at each re-fabrication to replace the removed fission products. The fuel cycle uses a dry voloxidation process for both the initial LWR SNF re-fabrication and later for EM2

  19. Exploratory Design of a Reactor/Fuel Cycle Using Spent Nuclear Fuel Without Conventional Reprocessing - 13579

    International Nuclear Information System (INIS)

    Bertch, Timothy C.; Schleicher, Robert W.; Rawls, John D.

    2013-01-01

    General Atomics has started design of a waste to energy nuclear reactor (EM2) that can use light water reactor (LWR) spent nuclear fuel (SNF). This effort addresses two problems: using an advanced small reactor with long core life to reduce nuclear energy overnight cost and providing a disposal path for LWR SNF. LWR SNF is re-fabricated into new EM2 fuel using a dry voloxidation process modeled on AIROX/ OREOX processes which remove some of the fission products but no heavy metals. By not removing all of the fission products the fuel remains self-protecting. By not separating heavy metals, the process remains proliferation resistant. Implementation of Energy Multiplier Module (EM2) fuel cycle will provide low cost nuclear energy while providing a long term LWR SNF disposition path which is important for LWR waste confidence. With LWR waste confidence recent impacts on reactor licensing, an alternate disposition path is highly relevant. Centered on a reactor operating at 250 MWe, the compact electricity generating system design maximizes site flexibility with truck transport of all system components and available dry cooling features that removes the need to be located near a body of water. A high temperature system using helium coolant, electricity is efficiently produced using an asynchronous high-speed gas turbine while the LWR SNF is converted to fission products. Reactor design features such as vented fuel and silicon carbide cladding support reactor operation for decades between refueling, with improved fuel utilization. Beyond the reactor, the fuel cycle is designed so that subsequent generations of EM2 reactor fuel will use the previous EM2 discharge, providing its own waste confidence plus eliminating the need for enrichment after the first generation. Additional LWR SNF is added at each re-fabrication to replace the removed fission products. The fuel cycle uses a dry voloxidation process for both the initial LWR SNF re-fabrication and later for EM2

  20. Fuel cycle cost projections. [PWR; BWR

    Energy Technology Data Exchange (ETDEWEB)

    Clark, L.L.; Chockie, A.D.

    1979-12-01

    This report estimates current and future costs associated with the light water reactor nuclear fuel cycle for both once-through and thermal recycle cases. Using a range of future nuclear power generating scenarios, process flows are developed for each segment of the nuclear fuel cycle. Capital and operating costs are estimated and are combined with the process flows to generate unit cost projections for each fuel cycle segment. The unit costs and process flows are combined in the NUCOST program to estimate fuel cycle power costs through the year 2020. The unit costs are also used to estimate the fuel costs of an individual model PWR and BWR.

  1. Long-Term cosmic ray experiment in the atmosphere: Energetic electron precipitation events during the 20-23 solar activity cycles.

    Science.gov (United States)

    Makhmutov, V. S.; Bazilevskaya, G. A.; Krainev, M. B.; Storini, M.

    2001-08-01

    More than 400 energetic electron precipitation events (EPEs) were observed in the Earth's Northern polar atmosphere (Murmansk region, 68°57'N, 33°03'E) during a long-term cosmic ray balloon experiment (from 1957 up to now). It is shown that the significant X-ray fluxes, caused by precipitating electrons at the top of the atmosphere, sometimes penetrated down to the atmospheric depth of ~60 g· cm-2 (about 20 km). It means that primary energy of precipitating electrons was more than ~ 6 10 MeV. Here we summarize only the characteristics of the energetic electron precipitation events recorded during solar activity cycles 20 to 23. We dis cuss results from the analyses of the interplanetary and geomagnetic conditions related to these events in the atmosphere.

  2. Survey of the nuclear fuel cycle

    International Nuclear Information System (INIS)

    Zech, H.J.; Pickert, F.K.

    1975-01-01

    A brief outline of the technical aspects of the fuel cycle, starting from the mining of uranium up to fuel element fabrication, is followed by a more detailed description of the management of the outer fuel cycle. This includes the system of contracts and their reciprocal technical and chronological interdepence, as well as financial aspects, market conditions and trends. (RB) [de

  3. OPTIMIZATION OF THE CATHODE LONG-TERM STABILITY IN MOLTEN CARBONATE FUEL CELLS: EXPERIMENTAL STUDY AND MATHEMATICAL MODELING

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Ralph E. White; Dr. Branko N. Popov

    2001-10-01

    The dissolution of NiO cathodes during cell operation is a limiting factor to the successful commercialization of molten carbonate fuel cells (MCFCs). Lithium cobalt oxide coating onto the porous nickel electrode has been adopted to modify the conventional MCFC cathode which is believed to increase the stability of the cathodes in the carbonate melt. The material used for surface modification should possess thermodynamic stability in the molten carbonate and also should be electro catalytically active for MCFC reactions. Lithium Cobalt oxide was coated on Ni cathode by a sol-gel coating. The morphology and the LiCoO{sub 2} formation of LiCoO{sub 2} coated NiO was studied using scanning electron microscopy and X-Ray diffraction studies respectively. The electrochemical performance lithium cobalt oxide coated NiO cathodes were investigated with open circuit potential measurement and current-potential polarization studies. These results were compared to that of bare NiO. Dissolution of nickel into the molten carbonate melt was less in case of lithium cobalt oxide coated nickel cathodes. LiCoO{sub 2} coated on the surface prevents the dissolution of Ni in the melt and thereby stabilizes the cathode. Finally, lithium cobalt oxide coated nickel shows similar polarization characteristics as nickel oxide. Conventional theoretical models for the molten carbonate fuel cell cathode are based on the thin film agglomerate model. The principal deficiency of the agglomerate model, apart from the simplified pore structure assumed, is the lack of measured values for film thickness and agglomerate radius. Both these parameters cannot be estimated appropriately. Attempts to estimate the thickness of the film vary by two orders of magnitude. To avoid these problems a new three phase homogeneous model has been developed using the volume averaging technique. The model considers the potential and current variation in both liquid and solid phases. Using this approach, volume averaged

  4. Assessing the potential long-term increase of oceanic fossil fuel CO2 uptake due to CO2-calcification feedback

    Directory of Open Access Journals (Sweden)

    T. M. Lenton

    2007-07-01

    Full Text Available Plankton manipulation experiments exhibit a wide range of sensitivities of biogenic calcification to simulated anthropogenic acidification of the ocean, with the "lab rat" of planktic calcifiers, Emiliania huxleyi apparently not representative of calcification generally. We assess the implications of this observational uncertainty by creating an ensemble of realizations of an Earth system model that encapsulates a comparable range of uncertainty in calcification response to ocean acidification. We predict that a substantial reduction in marine carbonate production is possible in the future, with enhanced ocean CO2 sequestration across the model ensemble driving a 4–13% reduction in the year 3000 atmospheric fossil fuel CO2 burden. Concurrent changes in ocean circulation and surface temperatures in the model contribute about one third to the increase in CO2 uptake. We find that uncertainty in the predicted strength of CO2-calcification feedback seems to be dominated by the assumption as to which species of calcifier contribute most to carbonate production in the open ocean.

  5. Fuel Cycle System Analysis Handbook

    Energy Technology Data Exchange (ETDEWEB)

    Steven J. Piet; Brent W. Dixon; Dirk Gombert; Edward A. Hoffman; Gretchen E. Matthern; Kent A. Williams

    2009-06-01

    This Handbook aims to improve understanding and communication regarding nuclear fuel cycle options. It is intended to assist DOE, Campaign Managers, and other presenters prepare presentations and reports. When looking for information, check here. The Handbook generally includes few details of how calculations were performed, which can be found by consulting references provided to the reader. The Handbook emphasizes results in the form of graphics and diagrams, with only enough text to explain the graphic, to ensure that the messages associated with the graphic is clear, and to explain key assumptions and methods that cause the graphed results. Some of the material is new and is not found in previous reports, for example: (1) Section 3 has system-level mass flow diagrams for 0-tier (once-through), 1-tier (UOX to CR=0.50 fast reactor), and 2-tier (UOX to MOX-Pu to CR=0.50 fast reactor) scenarios - at both static and dynamic equilibrium. (2) To help inform fast reactor transuranic (TRU) conversion ratio and uranium supply behavior, section 5 provides the sustainable fast reactor growth rate as a function of TRU conversion ratio. (3) To help clarify the difference in recycling Pu, NpPu, NpPuAm, and all-TRU, section 5 provides mass fraction, gamma, and neutron emission for those four cases for MOX, heterogeneous LWR IMF (assemblies mixing IMF and UOX pins), and a CR=0.50 fast reactor. There are data for the first 10 LWR recycle passes and equilibrium. (4) Section 6 provides information on the cycle length, planned and unplanned outages, and TRU enrichment as a function of fast reactor TRU conversion ratio, as well as the dilution of TRU feedstock by uranium in making fast reactor fuel. (The recovered uranium is considered to be more pure than recovered TRU.) The latter parameter impacts the required TRU impurity limits specified by the Fuels Campaign. (5) Section 7 provides flows for an 800-tonne UOX separation plant. (6) To complement 'tornado' economic

  6. Loads imposed on dual purpose casks in German on-site-storage facilities for long term intermediate storage of spent nuclear fuel

    Energy Technology Data Exchange (ETDEWEB)

    Wetzel, N.; Rabe, O. [TUeV NORD EnSys Hannover GmbH und Co. KG, Hanover (Germany)

    2004-07-01

    In accordance with recent changes of the atomic energy act and in order to secure reliable removal of spent fuel from the nuclear power plants' fuel storage ponds the German utilities filed license applications for a total of 12 onsite- storage facilities for spent fuel assemblies. By the end of 2003 the last of these storage facilities were licensed and are currently under construction. The first on-site-storage facility of that line became operational in late 2002. There are several design lines of storage facilities with different handling procedures or possible accident conditions. Short term interim storage facilities for a few casks are characterized by individual concrete hoods shielding the casks in horizontal position whereas long term intermediate storage facilities currently erected for large numbers of casks typically feature a condensed pattern of casks stored in upright position and massive structures of reinforced concrete. TUeV Hannover/Sachsen-Anhalt e. V. (now TUeV NORD EnSys Hannover GmbH and Co. KG) has been contracted as a body of independent experts for the assessment of all related safety requirements on behalf of the national licensing authority, the federal office for radiation protection (BfS).

  7. Strategy development of nuclear fuel cycle technologies for nuclear energy program in Yugoslavia

    International Nuclear Information System (INIS)

    Afgan, N.

    1987-01-01

    Strategy of technology development includes also development of nuclear fuel cycle technologies required for nuclear energy programme in Yugoslavia. For this reason, it is of interest to take into consideration possible options which would be the basis for long-term strategy of the nuclear fuel technology development in our country. In the paper criteria which could be used in the technology selection and its valorisation are given. Based on postulated criteria priority selection is made which has shown that the highest importance in the selection of nuclear fuel cycle should be given to the uranium enrichment technology and irradiated fuel reprocessing. (author)

  8. MoS2/Ni3S4 composite nanosheets on interconnected carbon shells as an excellent supercapacitor electrode architecture for long term cycling at high current densities

    Science.gov (United States)

    Qin, Shengchun; Yao, Tinghui; Guo, Xin; Chen, Qiang; Liu, Dequan; Liu, Qiming; Li, Yali; Li, Junshuai; He, Deyan

    2018-05-01

    In this paper, we report an electrode architecture of molybdenum disulfide (MoS2)/nickel sulfide (Ni3S4) composite nanosheets anchored on interconnected carbon (C) shells (C@MoS2/Ni3S4). Electrochemical measurements indicate that the C@MoS2/Ni3S4 structure possesses excellent supercapacitive properties especially for long term cycling at high current densities. A specific capacitance as high as ∼640.7 F g-1 can still be delivered even after 10,000 cycles at a high current density of 20 A g-1. From comparison of microstructures and electrochemical properties of the related materials/structures, the improved performance of C@MoS2/Ni3S4 can be attributed to the relatively dispersedly distributed nanosheet-shaped MoS2/Ni3S4 that provides efficient contact with electrolyte and effectively buffers the volume change during charge/discharge processes, enhanced cycling stability by MoS2, and reduced equivalent series resistance by the interconnected C shells.

  9. Thorium fuel cycle: a nuclear strategy and fuel recycle technology

    Energy Technology Data Exchange (ETDEWEB)

    Kasten, P.R.; Dahlberg, R.C.; Wymer, R.G.

    1978-01-01

    Use of thorium fuel cycles in thermal reactors appears to permit a moderate rate of introduction of fast breeder reactors into the nuclear economy and helps maintain a relatively low ratio of FBRs to thermal reactors in the future. To implement the benefits of thorium fuel cycles, however, will require fuel recycle research and development. Fuel recycle technology developed for uranium and plutonium cycles will be beneficial to thorium fuel cycle development; however, significant additional R and D is required to implement either the HEUTH or the DUTH cycles. The metal-clad reactors in general have relatively common generic technology development requirements, although there are significant differences between fast and thermal reactor fuel recycle needs. The thorium fuel recycle R and D requirements of HTGRs are more reactor-specific than of the other reactor types; however, some specific efforts will be required for all the different reactor types.

  10. Plutonium in an enduring fuel cycle

    International Nuclear Information System (INIS)

    Pillay, K.K.S.

    1998-05-01

    Nuclear fuel cycles evolved over the past five decades have allowed many nations of the world to enjoy the benefits of nuclear energy, while contributing to the sustainable consumption of the world's energy resources. The nuclear fuel cycle for energy production suffered many traumas since the 1970s because of perceived risks of proliferation of nuclear weapons. However, the experience of the past five decades has shown that the world community is committed to safeguarding all fissile materials and continuing the use of nuclear energy resources. Decisions of a few nations to discard spent nuclear fuels in geologic formations are contrary to the goals of an enduring nuclear fuel cycle and sustainable development being pursued by the world community. The maintenance of an enduring nuclear fuel cycle is dependent on sensible management of all the resources of the fuel cycle, including spent fuels

  11. Thorium fuel cycle - Potential benefits and challenges

    International Nuclear Information System (INIS)

    2005-05-01

    There has been significant interest among Member States in developing advanced and innovative technologies for safe, proliferation resistant and economically efficient nuclear fuel cycles, while minimizing waste and environmental impacts. This publication provides an insight into the reasons for renewed interest in the thorium fuel cycle, different implementation scenarios and options for the thorium cycle and an update of the information base on thorium fuels and fuel cycles. The present TECDOC focuses on the upcoming thorium based reactors, current information base, front and back end issues, including manufacturing and reprocessing of thorium fuels and waste management, proliferation-resistance and economic issues. The concluding chapter summarizes future prospects and recommendations pertaining to thorium fuels and fuel cycles

  12. World nuclear fuel cycle requirements 1991

    International Nuclear Information System (INIS)

    1991-01-01

    The nuclear fuel cycle consists of mining and milling uranium ore, processing the uranium into a form suitable for generating electricity, ''burning'' the fuel in nuclear reactors, and managing the resulting spent nuclear fuel. This report presents projections of domestic and foreign requirements for natural uranium and enrichment services as well as projections of discharges of spent nuclear fuel. These fuel cycle requirements are based on the forecasts of future commercial nuclear power capacity and generation published in a recent Energy Information Administration (EIA) report. Also included in this report are projections of the amount of spent fuel discharged at the end of each fuel cycle for each nuclear generating unit in the United States. The International Nuclear Model is used for calculating the projected nuclear fuel cycle requirements. 14 figs., 38 tabs

  13. World nuclear fuel cycle requirements 1991

    Energy Technology Data Exchange (ETDEWEB)

    1991-10-10

    The nuclear fuel cycle consists of mining and milling uranium ore, processing the uranium into a form suitable for generating electricity, burning'' the fuel in nuclear reactors, and managing the resulting spent nuclear fuel. This report presents projections of domestic and foreign requirements for natural uranium and enrichment services as well as projections of discharges of spent nuclear fuel. These fuel cycle requirements are based on the forecasts of future commercial nuclear power capacity and generation published in a recent Energy Information Administration (EIA) report. Also included in this report are projections of the amount of spent fuel discharged at the end of each fuel cycle for each nuclear generating unit in the United States. The International Nuclear Model is used for calculating the projected nuclear fuel cycle requirements. 14 figs., 38 tabs.

  14. Logistics of the research reactor fuel cycle: AREVA solutions

    International Nuclear Information System (INIS)

    Ohayon, David; Halle, Laurent; Naigeon, Philippe; Falgoux, Jean-Louis; Obadia, Franck; Auziere, Philippe

    2004-01-01

    Full text: The AREVA Group Companies offer comprehensive solutions for the entire fuel cycle of Research Reactors comply with IAEA standards. CERCA and COGEMA LOGISTICS have developed a full partnership in the front end cycle In the field of uranium CERCA and COGEMA LOGISTICS have the long term experience of the shipment from Russia, USA to the CERCA plant. Since 1960, CERCA has manufactured over 300,000 fuel plates and 15,000 fuel elements of more than 70 designs. These fuel elements have been delivered to 40 research reactors in 20 countries. For the Back-End stage, COGEMA and COGEMA LOGISTICS propose customised solutions and services for international shipments. COGEMA LOGISTICS has developed a new generation of packaging to meet the various needs and requirements of the Laboratories and Research Reactors all over the world, and complex regulatory framework.Comprehensive assistance dedicated, services, technical studies, packaging and transport systems are provided by AREVA for every step of research reactor fuel cycle. (author)

  15. Overview of the nuclear fuel cycle

    International Nuclear Information System (INIS)

    Knief, R.A.

    1978-01-01

    The nuclear fuel cycle is substantially more complicated than the energy production cycles of conventional fuels because of the very low abundance of uranium 235, the presence of radioactivity, the potential for producing fissile nuclides from irradiation, and the risk that fissile materials will be used for nuclear weapons. These factors add enrichment, recycling, spent fuel storage, and safeguards to the cycle, besides making the conventional steps of exploration, mining, processing, use, waste disposal, and transportation more difficult

  16. NUFCOS - nuclear fuel cycle optimization system

    International Nuclear Information System (INIS)

    Kaikkonen, H.; Salo, J.-P.; Vieno, T.; Vira, J.

    1979-05-01

    NUFCOS is a multigoal nuclear fuel cycle optimization code with an arbitrary number of decision objectives. The multigoal decision-making is based on the evolving techniques of fuzzy optimization. After a short description of the fuel cycle model and the calculation methods this report gives the input instructions in the case of three optimization criteria: minimization of fuel cycle costs, economical risk and nuclear weapons proliferation risk. (author)

  17. Nonproliferation characteristics of advanced fuel cycle concepts

    International Nuclear Information System (INIS)

    Persiani, P.J.

    1998-01-01

    The purpose of this study is to comment on the proliferation characteristic profiles of some of the proposed fuel cycle alternatives to help ensure that nonproliferation concerns are introduced into the early stages of a fuel cycle concept development program, and to perhaps aid in the more effective implementation of the international nonproliferation regime initiatives and safeguards methods and systems. Alternative cycle concepts proposed by several countries involve the recycle of spent fuel without the separation of plutonium from uranium and fission products

  18. Sustainable multilateral nuclear fuel cycle framework. (2) Models for multilateral nuclear fuel cycle approach

    International Nuclear Information System (INIS)

    Adachi, T; Tanaka, S; Tazaki, M; Akiba, M; Takashima, R; Kuno, Y

    2011-01-01

    To construct suitable models for a reliable and sustainable international/regional framework in the fields of nuclear fuel cycle, it is essential to reflect recent political situations including such that 1) a certain number of emerging countries especially in south-east Asia want to introduce and develop nuclear power in the long-terms despite the accident of the Fukushima Daiichi NPP, and 2) exposition of nuclear proliferation threats provided by North Korea and Iran. It is also to be considered that Japan is an unique country having enrichment and reprocessing facilities on commercial base among non-nuclear weapon countries. Although many models presented for the internationalization have not been realized yet, studies at the University of Tokyo aim at multilateral nuclear approach (MNA) in Asian-Pacific countries balancing between nuclear non-proliferation and nuclear fuel supply/service and presenting specific examples such as prerequisites for participating countries, scope of cooperative activities, ownership of facilities and type of agreements/frameworks. We will present a model basic agreement and several bilateral and multi-lateral agreements for the combinations of industry or government led consortia including Japan and its neighboring countries and made a preliminary evaluation for the combination of processes/facilities based on the INFCIRC/640 report for MNA. (author)

  19. The Nuclear Fuel Cycle Information System

    International Nuclear Information System (INIS)

    1987-02-01

    The Nuclear Fuel Cycle Information System (NFCIS) is an international directory of civilian nuclear fuel cycle facilities. Its purpose is to identify existing and planned nuclear fuel cycle facilities throughout the world and to indicate their main parameters. It includes information on facilities for uranium ore processing, refining, conversion and enrichment, for fuel fabrication, away-from-reactor storage of spent fuel and reprocessing, and for the production of zirconium metal and Zircaloy tubing. NFCIS currently covers 271 facilities in 32 countries and includes 171 references

  20. APEX nuclear fuel cycle for production of LWR fuel and elimination of radioactive waste

    International Nuclear Information System (INIS)

    Steinberg, M.; Powell, J.R.

    1981-08-01

    The development of a nuclear fission fuel cycle is proposed which eliminates all the radioactive fission product waste effluent and the need for geological-age high level waste storage and provides a long term supply of fissile fuel for an LWR power reactor economy. The fuel cycle consists of reprocessing LWR spent fuel (1 to 2 years old) to remove the stable nonradioactive (NRFP, e.g. lanthanides, etc.) and short-lived fission products SLFP e.g. half-lives of (1 to 2 years) and returning, in dilute form, the long-lived fission products, ((LLFPs, e.g. 30 y half-life Cs, Sr, and 10 y Kr, and 16 x 10 6 y I) and the transuranics (TUs, e.g. Pu, Am, Cm, and Np) to be refabricated into fresh fuel elements. Makeup fertile and fissile fuel are to be supplied through the use of a Spallator (linear accelerator spallation-target fuel-producer). The reprocessing of LWR fuel elements is to be performed by means of the Chelox process which consists of Airox treatment (air oxidation and hydrogen reduction) followed by chelation with an organic reagent (β-diketonate) and vapor distillation of the organometallic compounds for separation and partitioning of the fission products

  1. Sustainability of Advanced Fuel Cycles

    International Nuclear Information System (INIS)

    Kuznetsov, Vladimir

    2013-01-01

    ⇒ The IAEA’s International Project on Innovative Nuclear Reactors and Fuel Cycles (INPRO) was established in 2000. ⇒ INPRO cooperates with Member States to ensure that sustainable nuclear energy is available to help meet the energy needs of the 21st century. ⇒ INPRO is part of the integrated services of the IAEA provided to Member States considering initial development or expansion of nuclear energy programmes. ⇒ INPRO Methodology for nuclear energy system assessment - a comprehensive set of internationally agreed basic principles, requirements and criteria in the important areas of economics, safety, waste management, proliferation resistance, physical protection, environment and infrastructure. ⇒ Meeting the INPRO criteria in all of the areas ensures sustainability of nuclear energy system and its high potential to meet growing energy demand throughout the present century

  2. Reprocessing in breeder fuel cycles

    International Nuclear Information System (INIS)

    Burch, W.D.; Groenier, W.S.

    1982-01-01

    Over the past decade, the United States has developed plans and carried out programs directed toward the demonstration of breeder fuel reprocessing in connection with the first breeder demonstration reactor. A renewed commitment to moving forward with the construction of the Clinch River Breeder Reactor (CRBR) has been made, with startup anticipated near the end of this decade. While plans for the CRBR and its associated fuel cycle are still being firmed up, the basic research and development programs required to carry out the demonstrations have continued. This paper updates the status of the reprocessing plans and programs. Policies call for breeder recycle to begin in the early to mid-1990's. Contents of this paper are: (1) evolving plans for breeder reprocessing (demonstration reprocessing plant, reprocessing head-end colocated at an existing facility); (2) relationship to LWR reprocessing; (3) integrated equipment test (IET) facility and related hardware development activities (mechanical considerations in shearing and dissolving, remote operations and maintenance demonstration phase of IET, integrated process demonstration phase of IET, separate component development activities); and (4) supporting process R and D

  3. DUPIC fuel cycle economics assessment (1)

    International Nuclear Information System (INIS)

    Choi, H. B.; Roh, G. H.; Kim, D. H.

    1999-04-01

    This is a state-of-art report that describes the current status of the DUPIC fuel cycle economics analysis conducted by the DUPIC fuel compatibility assessment group of the DUPIC fuel development project. For the DUPIC fuel cycle economics analysis, the DUPIC fuel compatibility assessment group has organized the 1st technical meeting composed of 8 domestic specialists from government, academy, industry, etc. and a foreign specialist of hot-cell design from TRI on July 16, 1998. This report contains the presentation material of the 1st technical meeting, published date used for the economics analysis and opinions of participants, which could be utilized for further DUPIC fuel cycle and back-end fuel cycle economics analyses. (author). 11 refs., 7 charts

  4. DOCUMENTATION OF NATIONAL WEATHER CONDITIONS AFFECTING LONG-TERM DEGRADATION OF COMMERCIAL SPENT NUCLEAR FUEL AND DOE SPENT NUCLEAR FUEL AND HIGH-LEVEL WASTE

    Energy Technology Data Exchange (ETDEWEB)

    W. L. Poe, Jr.; P.F. Wise

    1998-11-01

    The U.S. Department of Energy (DOE) is preparing a proposal to construct, operate 2nd monitor, and eventually close a repository at Yucca Mountain in Nye County, Nevada, for the geologic disposal of spent nuclear fuel (SNF) and high-level radioactive waste (HLW). As part of this effort, DOE has prepared a viability assessment and an assessment of potential consequences that may exist if the repository is not constructed. The assessment of potential consequences if the repository is not constructed assumes that all SNF and HLW would be left at the generator sites. These include 72 commercial generator sites (three commercial facility pairs--Salem and Hope Creek, Fitzpatrick and Nine Mile Point, and Dresden and Morris--would share common storage due to their close proximity to each other) and five DOE sites across the country. DOE analyzed the environmental consequences of the effects of the continued storage of these materials at these sites in a report titled Continued Storage Analysis Report (CSAR; Reference 1 ) . The CSAR analysis includes a discussion of the degradation of these materials when exposed to the environment. This document describes the environmental parameters that influence the degradation analyzed in the CSAR. These include temperature, relative humidity, precipitation chemistry (pH and chemical composition), annual precipitation rates, annual number of rain-days, and annual freeze/thaw cycles. The document also tabulates weather conditions for each storage site, evaluates the degradation of concrete storage modules and vaults in different regions of the country, and provides a thermal analysis of commercial SNF in storage.

  5. Long-term collections

    CERN Multimedia

    Collectes à long terme

    2007-01-01

    The Committee of the Long Term Collections (CLT) asks for your attention for the following message from a young Peruvian scientist, following the earthquake which devastated part of her country a month ago.

  6. Introducing advanced nuclear fuel cycles in Canada

    International Nuclear Information System (INIS)

    Duret, M.F.

    1978-05-01

    The ability of several different advanced fuel cycles to provide energy for a range of energy growth scenarios has been examined for a few special situations of interest in Canada. Plutonium generated from the CANDU-PHW operating on natural uranium is used to initiate advanced fuel cycles in the year 2000. The four fuel cycles compared are: 1) natural uranium in the CANDU-PHW; 2) high burnup thorium cycle in the CANDU-PHW; 3) self-sufficient thorium cycle in the CANDU-PHW; 4) plutonium-uranium cycle in a fast breeder reactor. The general features of the results are quite clear. While any plutonium generated prior to the introduction of the advanced fuel cycle remains, system requirements for natural uranium for each of the advanced fuel cycles are the same and are governed by the rate at which plants operating on natural uranium can be retired. When the accumulated plutonium inventory has been entirely used, natural uranium is again required to provide inventory for the advanced fuel cycle reactors. The time interval during which no uranium is required varies only from about 25 to 40 years for both thorium cycles, depending primarily on the energy growth rate. The breeder does not require the entire plutonium inventory produced and so would call for less processing of fuel from the PHW reactors. (author)

  7. Managing aging effects on dry cask storage systems for extended long-term storage and transportation of used fuel - rev. 0

    International Nuclear Information System (INIS)

    Chopra, O.K.; Diercks, D.; Fabian, R.; Ma, D.; Shah, V.; Tam, S.W.; Liu, Y.

    2012-01-01

    The cancellation of the Yucca Mountain repository program in the United States raises the prospect of extended long-term storage (i.e., >120 years) and deferred transportation of used fuel at operating and decommissioned nuclear power plant sites. Under U.S. federal regulations contained in Title 10 of the Code of Federal Regulations (CFR) 72.42, the initial license term for an Independent Spent Fuel Storage Installation (ISFSI) must not exceed 40 years from the date of issuance. Licenses may be renewed by the U.S. Nuclear Regulatory Commission (NRC) at the expiration of the license term upon application by the licensee for a period not to exceed 40 years. Application for ISFSI license renewals must include the following: (1) Time-limited aging analyses (TLAAs) that demonstrate that structures, systems, and components (SSCs) important to safety will continue to perform their intended function for the requested period of extended operation; and (2) a description of the aging management program (AMP) for management of issues associated with aging that could adversely affect SSCs important to safety. In addition, the application must also include design bases information as documented in the most recent updated final safety analysis report as required by 10 CFR 72.70. Information contained in previous applications, statements, or reports filed with the Commission under the license may be incorporated by reference provided that those references are clear and specific. The NRC has recently issued the Standard Review Plan (SRP) for renewal of used-fuel dry cask storage system (DCSS) licenses and Certificates of Compliance (CoCs), NUREG-1927, under which NRC may renew a specific license or a CoC for a term not to exceed 40 years. Both the license and the CoC renewal applications must contain revised technical requirements and operating conditions (fuel storage, surveillance and maintenance, and other requirements) for the ISFSI and DCSS that address aging effects that

  8. Managing aging effects on dry cask storage systems for extended long-term storage and transportation of used fuel - rev. 0

    Energy Technology Data Exchange (ETDEWEB)

    Chopra, O.K.; Diercks, D.; Fabian, R.; Ma, D.; Shah, V.; Tam, S.W.; Liu, Y. (Decision and Information Sciences); ( EVS); ( NE)

    2012-07-06

    The cancellation of the Yucca Mountain repository program in the United States raises the prospect of extended long-term storage (i.e., >120 years) and deferred transportation of used fuel at operating and decommissioned nuclear power plant sites. Under U.S. federal regulations contained in Title 10 of the Code of Federal Regulations (CFR) 72.42, the initial license term for an Independent Spent Fuel Storage Installation (ISFSI) must not exceed 40 years from the date of issuance. Licenses may be renewed by the U.S. Nuclear Regulatory Commission (NRC) at the expiration of the license term upon application by the licensee for a period not to exceed 40 years. Application for ISFSI license renewals must include the following: (1) Time-limited aging analyses (TLAAs) that demonstrate that structures, systems, and components (SSCs) important to safety will continue to perform their intended function for the requested period of extended operation; and (2) a description of the aging management program (AMP) for management of issues associated with aging that could adversely affect SSCs important to safety. In addition, the application must also include design bases information as documented in the most recent updated final safety analysis report as required by 10 CFR 72.70. Information contained in previous applications, statements, or reports filed with the Commission under the license may be incorporated by reference provided that those references are clear and specific. The NRC has recently issued the Standard Review Plan (SRP) for renewal of used-fuel dry cask storage system (DCSS) licenses and Certificates of Compliance (CoCs), NUREG-1927, under which NRC may renew a specific license or a CoC for a term not to exceed 40 years. Both the license and the CoC renewal applications must contain revised technical requirements and operating conditions (fuel storage, surveillance and maintenance, and other requirements) for the ISFSI and DCSS that address aging effects that

  9. Soil Conditions Rather Than Long-Term Exposure to Elevated CO2 Affect Soil Microbial Communities Associated with N-Cycling

    Directory of Open Access Journals (Sweden)

    Kristof Brenzinger

    2017-10-01

    Full Text Available Continuously rising atmospheric CO2 concentrations may lead to an increased transfer of organic C from plants to the soil through rhizodeposition and may affect the interaction between the C- and N-cycle. For instance, fumigation of soils with elevated CO2 (eCO2 concentrations (20% higher compared to current atmospheric concentrations at the Giessen Free-Air Carbon Dioxide Enrichment (GiFACE sites resulted in a more than 2-fold increase of long-term N2O emissions and an increase in dissimilatory reduction of nitrate compared to ambient CO2 (aCO2. We hypothesized that the observed differences in soil functioning were based on differences in the abundance and composition of microbial communities in general and especially of those which are responsible for N-transformations in soil. We also expected eCO2 effects on soil parameters, such as on nitrate as previously reported. To explore the impact of long-term eCO2 on soil microbial communities, we applied a molecular approach (qPCR, T-RFLP, and 454 pyrosequencing. Microbial groups were analyzed in soil of three sets of two FACE plots (three replicate samples from each plot, which were fumigated with eCO2 and aCO2, respectively. N-fixers, denitrifiers, archaeal and bacterial ammonia oxidizers, and dissimilatory nitrate reducers producing ammonia were targeted by analysis of functional marker genes, and the overall archaeal community by 16S rRNA genes. Remarkably, soil parameters as well as the abundance and composition of microbial communities in the top soil under eCO2 differed only slightly from soil under aCO2. Wherever differences in microbial community abundance and composition were detected, they were not linked to CO2 level but rather determined by differences in soil parameters (e.g., soil moisture content due to the localization of the GiFACE sets in the experimental field. We concluded that +20% eCO2 had little to no effect on the overall microbial community involved in N-cycling in the

  10. Fast Reactor Fuel Cycle Cost Estimates for Advanced Fuel Cycle Studies

    International Nuclear Information System (INIS)

    Harrison, Thomas

    2013-01-01

    Presentation Outline: • Why Do I Need a Cost Basis?; • History of the Advanced Fuel Cycle Cost Basis; • Description of the Cost Basis; • Current Work; • Fast Reactor Fuel Cycle Applications; • Sample Fuel Cycle Cost Estimate Analysis; • Future Work

  11. Advanced fuel cycles for WWER-1000 reactors

    International Nuclear Information System (INIS)

    Semchenkov, Y. M.; Pavlovichev, A. M.; Pavlov, V. I.; Spirkin, E. I.; Styrin, Y. A.; Kosourov, E. K.

    2007-01-01

    Main stages of Russian uranium fuel development regarding improvement of safety and economics of fuel load operation are presented. Intervals of possible changes in fuel cycle duration have been demonstrated for the use of current and perspective fuel. Examples of equilibrium fuel load patterns have been demonstrated and main core neutronics parameters have been presented. Problems on the use of axial blankets with reduced enrichment in WWER-1000 fuel assemblies are considered. Some results are presented regarding core neutronic characteristics of WWER-1000 at the use of regenerated uranium and uranium-plutonium fuel. Examples of equilibrium fuel cycles for the core partially loaded with MOX fuel from weapon-grade plutonium are also considered (Authors)

  12. Uncertainty Analyses of Advanced Fuel Cycles

    Energy Technology Data Exchange (ETDEWEB)

    Laurence F. Miller; J. Preston; G. Sweder; T. Anderson; S. Janson; M. Humberstone; J. MConn; J. Clark

    2008-12-12

    The Department of Energy is developing technology, experimental protocols, computational methods, systems analysis software, and many other capabilities in order to advance the nuclear power infrastructure through the Advanced Fuel Cycle Initiative (AFDI). Our project, is intended to facilitate will-informed decision making for the selection of fuel cycle options and facilities for development.

  13. Uncertainty Analyses of Advanced Fuel Cycles

    International Nuclear Information System (INIS)

    Miller, Laurence F.; Preston, J.; Sweder, G.; Anderson, T.; Janson, S.; Humberstone, M.; MConn, J.; Clark, J.

    2008-01-01

    The Department of Energy is developing technology, experimental protocols, computational methods, systems analysis software, and many other capabilities in order to advance the nuclear power infrastructure through the Advanced Fuel Cycle Initiative (AFDI). Our project, is intended to facilitate will-informed decision making for the selection of fuel cycle options and facilities for development

  14. The IFR modern nuclear fuel cycle

    International Nuclear Information System (INIS)

    Hannum, W.H.

    1991-01-01

    Nuclear power is an essential component of the world's energy supply. The IFR program, by returning to fundamentals, offers a fresh approach to closing the nuclear fuel cycle. This closed fuel cycle represents the ultimate in efficient resource utilization and environmental accountability. 35 refs., 2 tabs

  15. The IFR modern nuclear fuel cycle

    Energy Technology Data Exchange (ETDEWEB)

    Hannum, W.H.

    1991-01-01

    Nuclear power is an essential component of the world's energy supply. The IFR program, by returning to fundamentals, offers a fresh approach to closing the nuclear fuel cycle. This closed fuel cycle represents the ultimate in efficient resource utilization and environmental accountability. 35 refs., 2 tabs.

  16. Status of IFR fuel cycle demonstration

    International Nuclear Information System (INIS)

    Lineberry, M.J.; Phipps, R.D.; McFarlane, H.F.

    1993-01-01

    The next major step in Argonne's Integral Fast Reactor (IFR) Program is demonstration of the pyroprocess fuel cycle, in conjunction with continued operation of EBR-II. The Fuel Cycle Facility (FCF) is being readied for this mission. This paper will address the status of facility systems and process equipment, the initial startup experience, and plans for the demonstration program

  17. Long-term experiences in the use of rapeseed oil fuel in tractors of the emissions levels I and II; Langzeiterfahrungen zum Einsatz von Rapsoelkraftstoff in Traktoren der Abgasstufe I und II

    Energy Technology Data Exchange (ETDEWEB)

    Emberger, Peter; Thuneke, Klaus; Remmele, Edgar

    2013-06-01

    The operational behavior as well as the emission behavior should be clarified in long-term use by means of tractors which are powered by rapeseed oil fuel. This is based on the following measures: review of the quality of rapeseed oil fuel used; testing of the quality of the engine oil on a random basis; documentation of failures, maintenance and repair work; measurement of performance and fuel economy; measurement of exhaust emissions; diagnosis of engines.

  18. The safety of the nuclear fuel cycle

    International Nuclear Information System (INIS)

    1993-01-01

    The nuclear fuel cycle covers the procurement and preparation of fuel for nuclear power reactors, its recovery and recycling after use and the safe storage of all wastes generated through these operations. The facilities associated with these activities have an extensive and well documented safety record accumulated over the past 40 years by technical experts and safety authorities. This report constitutes an up-to-date analysis of the safety of the nuclear fuel cycle, based on the available experience in OECD countries. It addresses the technical aspects of fuel cycle operations, provides information on operating practices and looks ahead to future activities

  19. Fuel cycle strategies and plutonium management in Europe

    International Nuclear Information System (INIS)

    Haas, D.

    2006-01-01

    Full text of publication follows: An overview will first be drawn on the present nuclear power production in Europe, and on the fuel cycle strategies followed in various countries. Indeed, for most countries in Europe, spent fuel is presently stored at reactor site, either for further conditioning and final deep geological storage, or in the expectation on a further decision on one of these options. Other countries have opted for spent fuel reprocessing as basic fuel cycle strategy. This option presents amongst other the merit of leading to a reduction of the final high level waste volume that will need in any case a geological disposal. It also allows the recovery from the spent fuel of energetic elements, principally the plutonium (Pu). The intention at the origin was to use this Pu in a fleet of fast breeder reactors, with the aim to make the best use of the uranium ore. However, fore reasons mainly linked to the low price of uranium (but also due to technical difficulties and political opposition), the project failed to develop. Now, the countries having followed the reprocessing option have to cope with an increasing amount of separated Pu. One industrial path, namely Pu recycling as MOX is presently operational in several European countries. It allows to reduce the increase in Pu stocks, but not to reduce it. Moreover, the quality of recycled Pu (in terms of its energetic value and of its radiotoxicity) decreases at each potential step of re-irradiation. Therefore, optimised or new ways of managing the Pu stocks in the medium and long term are required. The paper will present a status of the options considered today: - optimised Pu recycling as MOX in advanced LWR reactors (100 % MOX), as well as related optimised core designs; - utilisation of non-uranium matrices instead of uranium to prevent further Pu and minor actinides creation; - once-through Pu burning (up to high rates of destruction) in HTR fuel kernels; - multi-recycling of Pu in fast reactors of

  20. Fuel cycle technologies - The next 50 years

    International Nuclear Information System (INIS)

    Chamberlain, L.N.; Ion, S.E.; Patterson, J.

    1997-01-01

    World energy demands are set to increase through the next Millennium. As fossil fuel reserves fall and environmental concerns increase there is likely to be a growing dependence on nuclear and renewable sources for electricity generation. This paper considers some of the desirable attributes of the nuclear fuel cycle in the year 2050 and emphasises the importance of considering the whole of the fuel cycle in an integrated way - the concept of the 'holistic' fuel cycle. We then consider how some sectors of the fuel cycle will develop, through a number of multi- national contributions covering: enrichment, fuel, aqueous reprocessing, non-aqueous reprocessing, P and T, MOX, direct disposal, waste. Finally, we summarize some of the key technical and institutional challenges that lie ahead if nuclear power is going to play its part in ensuring that planet Earth is a safe and hospitable place to live. (author)

  1. Systemic Virus Infections Differentially Modulate Cell Cycle State and Functionality of Long-Term Hematopoietic Stem Cells In Vivo

    Directory of Open Access Journals (Sweden)

    Christoph Hirche

    2017-06-01

    Full Text Available Quiescent long-term hematopoietic stem cells (LT-HSCs are efficiently activated by type I interferon (IFN-I. However, this effect remains poorly investigated in the context of IFN-I-inducing virus infections. Here we report that both vesicular stomatitis virus (VSV and murine cytomegalovirus (MCMV infection induce LT-HSC activation that substantially differs from the effects triggered upon injection of synthetic IFN-I-inducing agents. In both infections, inflammatory responses had to exceed local thresholds within the bone marrow to confer LT-HSC cell cycle entry, and IFN-I receptor triggering was not critical for this activation. After resolution of acute MCMV infection, LT-HSCs returned to phenotypic quiescence. However, non-acute MCMV infection induced a sustained inflammatory milieu within the bone marrow that was associated with long-lasting impairment of LT-HSC function. In conclusion, our results show that systemic virus infections fundamentally affect LT-HSCs and that also non-acute inflammatory stimuli in bone marrow donors can affect the reconstitution potential of bone marrow transplants.

  2. Systemic Virus Infections Differentially Modulate Cell Cycle State and Functionality of Long-Term Hematopoietic Stem Cells In Vivo.

    Science.gov (United States)

    Hirche, Christoph; Frenz, Theresa; Haas, Simon F; Döring, Marius; Borst, Katharina; Tegtmeyer, Pia-K; Brizic, Ilija; Jordan, Stefan; Keyser, Kirsten; Chhatbar, Chintan; Pronk, Eline; Lin, Shuiping; Messerle, Martin; Jonjic, Stipan; Falk, Christine S; Trumpp, Andreas; Essers, Marieke A G; Kalinke, Ulrich

    2017-06-13

    Quiescent long-term hematopoietic stem cells (LT-HSCs) are efficiently activated by type I interferon (IFN-I). However, this effect remains poorly investigated in the context of IFN-I-inducing virus infections. Here we report that both vesicular stomatitis virus (VSV) and murine cytomegalovirus (MCMV) infection induce LT-HSC activation that substantially differs from the effects triggered upon injection of synthetic IFN-I-inducing agents. In both infections, inflammatory responses had to exceed local thresholds within the bone marrow to confer LT-HSC cell cycle entry, and IFN-I receptor triggering was not critical for this activation. After resolution of acute MCMV infection, LT-HSCs returned to phenotypic quiescence. However, non-acute MCMV infection induced a sustained inflammatory milieu within the bone marrow that was associated with long-lasting impairment of LT-HSC function. In conclusion, our results show that systemic virus infections fundamentally affect LT-HSCs and that also non-acute inflammatory stimuli in bone marrow donors can affect the reconstitution potential of bone marrow transplants. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  3. Packaging Reliability Effect of ENIG and ENEPIG Surface Finishes in Board Level Thermal Test under Long-Term Aging and Cycling.

    Science.gov (United States)

    Shen, Chaobo; Hai, Zhou; Zhao, Cong; Zhang, Jiawei; Evans, John L; Bozack, Michael J; Suhling, Jeffrey C

    2017-04-26

    This study illustrates test results and comparative literature data on the influence of isothermal aging and thermal cycling associated with Sn-1.0Ag-0.5Cu (SAC105) and Sn-3.0Ag-0.5Cu (SAC305) ball grid array (BGA) solder joints finished with ENIG and ENEPIG on the board side and ENIG on the package side compared with ImAg plating on both sides. The resulting degradation data suggests that the main concern for 0.4 mm pitch 10 mm package size BGA is package side surface finish, not board side. That is, ENIG performs better than immersion Ag for applications involving long-term isothermal aging. SAC305, with a higher relative fraction of Ag₃Sn IMC within the solder, performs better than SAC105. SEM and polarized light microscope analysis show cracks propagated from the corners to the center or even to solder bulk, which eventually causes fatigue failure. Three factors are discussed: IMC, grain structure, and Ag₃Sn particle. The continuous growth of Cu-Sn intermetallic compounds (IMC) and grains increase the risk of failure, while Ag₃Sn particles seem helpful in blocking the crack propagation.

  4. BWROPT: A multi-cycle BWR fuel cycle optimization code

    Energy Technology Data Exchange (ETDEWEB)

    Ottinger, Keith E.; Maldonado, G. Ivan, E-mail: Ivan.Maldonado@utk.edu

    2015-09-15

    Highlights: • A multi-cycle BWR fuel cycle optimization algorithm is presented. • New fuel inventory and core loading pattern determination. • The parallel simulated annealing algorithm was used for the optimization. • Variable sampling probabilities were compared to constant sampling probabilities. - Abstract: A new computer code for performing BWR in-core and out-of-core fuel cycle optimization for multiple cycles simultaneously has been developed. Parallel simulated annealing (PSA) is used to optimize the new fuel inventory and placement of new and reload fuel for each cycle considered. Several algorithm improvements were implemented and evaluated. The most significant of these are variable sampling probabilities and sampling new fuel types from an ordered array. A heuristic control rod pattern (CRP) search algorithm was also implemented, which is useful for single CRP determinations, however, this feature requires significant computational resources and is currently not practical for use in a full multi-cycle optimization. The PSA algorithm was demonstrated to be capable of significant objective function reduction and finding candidate loading patterns without constraint violations. The use of variable sampling probabilities was shown to reduce runtime while producing better results compared to using constant sampling probabilities. Sampling new fuel types from an ordered array was shown to have a mixed effect compared to random new fuel type sampling, whereby using both random and ordered sampling produced better results but required longer runtimes.

  5. Nuclear Fuel Cycle Information System. A directory of nuclear fuel cycle facilities. 2009 ed

    International Nuclear Information System (INIS)

    2009-04-01

    The Nuclear Fuel Cycle Information System (NFCIS) is an international directory of civilian nuclear fuel cycle facilities, published online as part of the Integrated Nuclear Fuel Cycle Information System (iNFCIS: http://www-nfcis.iaea.org/). This is the fourth hardcopy publication in almost 30 years and it represents a snapshot of the NFCIS database as of the end of 2008. Together with the attached CD-ROM, it provides information on 650 civilian nuclear fuel cycle facilities in 53 countries, thus helping to improve the transparency of global nuclear fuel cycle activities

  6. External cost assessment for nuclear fuel cycle

    International Nuclear Information System (INIS)

    Park, Byung Heung; Ko, Won Il

    2015-01-01

    Nuclear power is currently the second largest power supply method in Korea and the number of nuclear power plants are planned to be increased as well. However, clear management policy for spent fuels generated from nuclear power plants has not yet been established. The back-end fuel cycle, associated with nuclear material flow after nuclear reactors is a collection of technologies designed for the spent fuel management and the spent fuel management policy is closely related with the selection of a nuclear fuel cycle. Cost is an important consideration in selection of a nuclear fuel cycle and should be determined by adding external cost to private cost. Unlike the private cost, which is a direct cost, studies on the external cost are focused on nuclear reactors and not at the nuclear fuel cycle. In this research, external cost indicators applicable to nuclear fuel cycle were derived and quantified. OT (once through), DUPIC (Direct Use of PWR SF in CANDU), PWR-MOX (PWR PUREX reprocessing), and Pyro-SFR (SFR recycling with pyroprocessing) were selected as nuclear fuel cycles which could be considered for estimating external cost in Korea. Energy supply security cost, accident risk cost, and acceptance cost were defined as external cost according to precedent and estimated after analyzing approaches which have been adopted for estimating external costs on nuclear power generation

  7. Safeguarding the fuel cycle: Methodologies

    International Nuclear Information System (INIS)

    Gruemm, H.

    1984-01-01

    The effectiveness of IAEA safeguards is characterized by the extent to which they achieve their basic purpose - credible verification that no nuclear material is diverted from peaceful uses. This effectiveness depends inter alia but significantly on manpower in terms of the number and qualifications of inspectors. Staff increases will be required to improve effectiveness further, if this is requested by Member States, as well as to take into account new facilities expected to come under safeguards in the future. However, they are difficult to achieve due to financial constraints set by the IAEA budget. As a consequence, much has been done and is being undertaken to improve utilization of available manpower, including standardization of inspection procedures; improvement of management practices and training; rationalization of planning, reporting, and evaluation of inspection activities; and development of new equipment. This article focuses on certain aspects of the verification methodology presently used and asks: are any modifications of this methodology conceivable that would lead to economies of manpower, without loss of effectiveness. It has been stated in this context that present safeguards approaches are ''facility-oriented'' and that the adoption of a ''fuel cycle-oriented approach'' might bring about the desired savings. Many studies have been devoted to this very interesting suggestion. Up to this moment, no definite answer is available and further studies will be necessary to come to a conclusion. In what follows, the essentials of the problem are explained and some possible paths to a solution are discussed

  8. Radioecology of nuclear fuel cycles

    International Nuclear Information System (INIS)

    Schreckhise, R.G.; Cadwell, L.L.; Emery, R.M.

    1980-01-01

    Sites where radioactive wastes are found are solid waste burial grounds, soils below liquid stoage areas, surface ditches and ponds, and the terrestrial environment around chemical processing facilities that discharge airborne radioactive debris from stacks. This study provides information to help assess the environmental impacts and certain potentiall human hazards associated with nuclear fuel cycles. A data base is being developed to define and quantify biological transport routes which will permit credible predictions and assessment of routine and potential large-scale releases of radionuclides and other toxic materials. These data, used in assessment models, will increase the accuracy of estimating radiation doses to man and other life forms. Information obtained from existing storage and disposal sites will provide a meaningful radioecological perspective with which to improve the effectiveness of waste management practices. Results will provide information to determine if waste management procedures on the Hanford Site have caused ecological perturbations, and if so, to determine the source, nature, and magnitude of such disturbances

  9. The influence of the biological pump on ocean chemistry: implications for long-term trends in marine redox chemistry, the global carbon cycle, and marine animal ecosystems.

    Science.gov (United States)

    Meyer, K M; Ridgwell, A; Payne, J L

    2016-05-01

    The net export of organic matter from the surface ocean and its respiration at depth create vertical gradients in nutrient and oxygen availability that play a primary role in structuring marine ecosystems. Changes in the properties of this 'biological pump' have been hypothesized to account for important shifts in marine ecosystem structure, including the Cambrian explosion. However, the influence of variation in the behavior of the biological pump on ocean biogeochemistry remains poorly quantified, preventing any detailed exploration of how changes in the biological pump over geological time may have shaped long-term shifts in ocean chemistry, biogeochemical cycling, and ecosystem structure. Here, we use a 3-dimensional Earth system model of intermediate complexity to quantitatively explore the effects of the biological pump on marine chemistry. We find that when respiration of sinking organic matter is efficient, due to slower sinking or higher respiration rates, anoxia tends to be more prevalent and to occur in shallower waters. Consequently, the Phanerozoic trend toward less bottom-water anoxia in continental shelf settings can potentially be explained by a change in the spatial dynamics of nutrient cycling rather than by any change in the ocean phosphate inventory. The model results further suggest that the Phanerozoic decline in the prevalence ocean anoxia is, in part, a consequence of the evolution of larger phytoplankton, many of which produce mineralized tests. We hypothesize that the Phanerozoic trend toward greater animal abundance and metabolic demand was driven more by increased oxygen concentrations in shelf environments than by greater food (nutrient) availability. In fact, a lower-than-modern ocean phosphate inventory in our closed system model is unable to account for the Paleozoic prevalence of bottom-water anoxia. Overall, these model simulations suggest that the changing spatial distribution of photosynthesis and respiration in the oceans has

  10. Working Fluid Stability in Large-Scale Organic Rankine Cycle-Units Using Siloxanes—Long-Term Experiences and Fluid Recycling

    Directory of Open Access Journals (Sweden)

    Tobias G. Erhart

    2016-05-01

    Full Text Available The results in this work show the influence of long-term operation on the decomposition of working fluids in eight different organic rankine cycle (ORC power plants (both heat-led and electricity-led in a range of 900 kW el to 2 MW el . All case study plants are using octamethyltrisiloxane (MDM as a working fluid; the facilities are between six to 12 years old. Detailed analyses, including the fluid distribution throughout the cycle, are conducted on one system. All presented fluid samples are analyzed via head space gas chromatography mass spectrometry (HS-GC-MS. Besides the siloxane composition, the influence of contaminants, such as mineral oil-based lubricants (and their components, is examined. In most cases, the original working fluid degrades to fractions of siloxanes with a lower boiling point (low boilers and fractions with a higher boiling point (high boilers. As a consequence of the analyses, a new fluid recycling and management system was designed and tested in one case study plant (Case Study #8. Pre-post comparisons of fluid samples prove the effectiveness of the applied methods. The results show that the recovery of used working fluid offers an alternative to the purchase of fresh fluid, since operating costs can be significantly reduced. For large facilities, the prices for new fluid range from € 15 per liter (in 2006 to € 22 per liter (in 2013, which is a large reinvestment, especially in light of filling volumes of 4000 liters to 7000 liters per unit. Using the aforementioned method, a price of € 8 per liter of recovered MDM can be achieved.

  11. Advanced fuel cycles and burnup increase of WWER-440 fuel

    International Nuclear Information System (INIS)

    Proselkov, V.; Saprykin, V.; Scheglov, A.

    2003-01-01

    Analyses of operational experience of 4.4% enriched fuel in the 5-year fuel cycle at Kola NPP Unit 3 and fuel assemblies with Uranium-Gadolinium fuel at Kola NPP Unit 4 are made. The operability of WWER-440 fuel under high burnup is studied. The obtained results indicate that the fuel rods of WWER-440 assemblies intended for operation within six years of the reviewed fuel cycle totally preserve their operability. Performed analyses have demonstrated the possibility of the fuel rod operability during the fuel cycle. 12 assemblies were loaded into the reactor unit of Kola 3 in 2001. The predicted burnup in six assemblies was 59.2 MWd/kgU. Calculated values of the burnup after operation for working fuel assemblies were ∼57 MWd/kgU, for fuel rods - up to ∼61 MWd/kgU. Data on the coolant activity, specific activity of the benchmark iodine radionuclides of the reactor primary circuit, control of the integrity of fuel rods of the assemblies that were operated for six years indicate that not a single assembly has reached the criterion for the early discharge

  12. Nuclear-fuel-cycle costs. Consolidated Fuel-Reprocessing Program

    International Nuclear Information System (INIS)

    Burch, W.D.; Haire, M.J.; Rainey, R.H.

    1981-01-01

    The costs for the back-end of the nuclear fuel cycle, which were developed as part of the Nonproliferation Alternative Systems Assessment Program (NASAP), are presented. Total fuel-cycle costs are given for the pressurized-water reactor once-through and fuel-recycle systems, and for the liquid-metal fast-breeder-reactor system. These calculations show that fuel-cycle costs are a small part of the total power costs. For breeder reactors, fuel-cycle costs are about half that of the present once-through system. The total power cost of the breeder-reactor system is greater than that of light-water reactor at today's prices for uranium and enrichment

  13. Serving the fuel cycle: preparing tomorrow's packagings

    International Nuclear Information System (INIS)

    Roland, V.

    2001-01-01

    The main fleet of transport packagings serving today the fuel cycle was born more than 20 years ago. Or was it they? The present paper will show that serving the fuel cycle by preparing tomorrow's logistics is actually an on-going process, rather than a rupture. We shall review the great packagings of the fuel cycle: In the front end, the major actors are the UF 4 , UF 6 , enriched UF 6 , UO 2 powders, fresh fuel packagings. In the back end of the fuel cycle, we find the dry transport casks of the TN-12, TN-17, TN-13, family and also the Excellox wet flasks. In the waste management, a whole fleet of containers, culminating in the TN Gemini, are available or being created. (author)

  14. Politics of nuclear power and fuel cycle

    International Nuclear Information System (INIS)

    Uddin, R.

    2007-01-01

    -is likely to remain evolving depending on regional and global affairs. Opposition or support for nuclear technology is also likely to be a function of regional and global politics. In response to such pressures, IAEA is organizing a workshop of 140 countries to discuss proposals to guarantee countries' supply of nuclear fuel (September 19-21-, 2006; Vienna). Premise and Question: A single nuclear power plant in a country may be good for the prestige of the country, but such units are unlikely to make a major impact on the energy scene. Hence, in order for nuclear power to play a significant role, countries that decide to 'go nuclear,' would most likely want to diversify a significant fraction of their electricity generating capacity (and possibly heating and, in the future, hydrogen production) to nuclear, possibly requiring at least few and possibly many nuclear power plants. In order to proceed with the nuclear option, these countries would expect a certain level of long term assurance on the fuel supply. What is the kind of options that would satisfy the needs of these countries and at the same time addressing the non-proliferation concerns? Options: The options available to countries for their nuclear program can be categorized as follows. A. Fully indigenous program with complete development of power plants and fuel cycle. B. Fully or partly indigenous program for power plant development; while depending on international consortium for fuel supply and waste treatment. C. Rely on international consortia to build and operate all aspects of nuclear power plants (with local manpower). Others: A total of around fifty to seventy five countries are likely to be interested in nuclear power in the next fifty years. These can be divided in to the three groups (A-C) given above. It is likely that, with time, there will be some expectation to move to higher levels (C to B and B to A). Countries already in group A and those willing to start in group C do not pose an issue. It is

  15. Nuclear Fusion Fuel Cycle Research Perspectives

    International Nuclear Information System (INIS)

    Chung, Hongsuk; Koo, Daeseo; Park, Jongcheol; Kim, Yeanjin; Yun, Sei-Hun

    2015-01-01

    As a part of the International Thermonuclear Experimental Reactor (ITER) Project, we at the Korea Atomic Energy Research Institute (KAERI) and our National Fusion Research Institute (NFRI) colleagues are investigating nuclear fusion fuel cycle hardware including a nuclear fusion fuel Storage and Delivery System (SDS). To have a better knowledge of the nuclear fusion fuel cycle, we present our research efforts not only on SDS but also on the Fuel Supply System (FS), Tokamak Exhaust Processing System (TEP), Isotope Separation System (ISS), and Detritiation System (DS). To have better knowledge of the nuclear fusion fuel cycle, we presented our research efforts not only on SDS but also on the Fuel Supply System (FS), Tokamak Exhaust Processing System (TEP), Isotope Separation System (ISS), and Detritiation System (DS). Our efforts to enhance the tritium confinement will be continued for the development of cleaner nuclear fusion power plants

  16. French development program on fuel cycle

    International Nuclear Information System (INIS)

    Viala, M.; Bourgeois, M.

    1991-01-01

    The need to close the fuel cycle of fast reactors makes the development of the cycle installations (fuel fabrication, irradiated assembly conditioning before reprocessing, reprocessing and waste management) especially independent with the development of the reactor. French experience with the integrated cycle over a period of about 25 years, the tonnage of fuels fabricated (more than 100 t of mixed oxides) for the Rapsodie, Phoenix and SuperPhoenix reactors, and the tonnage of reprocessed fuel (nearly 30 t of plutonium fuel) demonstrate the control of the cycle operations. The capacities of the cycle installations in existence and under construction are largely adequate for presents needs, even including a new European EFR reactor. They include the Cadarache fuel fabrication complex, the La Hague UP2-800 reprocessing plant, and the Marcoule pilot facility. Short- and medium-term R and D programs are connected with fuel developments, with the primary objective of very high burnups. For the longer term and for a specific plant to reprocess fast reactor fuels, the programs could concern new fabrication and reprocessing systems and the study of the consequences of the reduction in fuel out-of-core time

  17. Back end of an enduring fuel cycle

    International Nuclear Information System (INIS)

    Pillay, K.K.S.

    1998-03-01

    An enduring nuclear fuel cycle is an essential part of sustainable consumption, the process whereby world's riches are consumed in a responsible manner so that future generations can continue to enjoy at least some of them. In many countries, the goal of sustainable development has focused attention on the benefits of nuclear technologies. However, sustenance of the nuclear fuel cycle is dependent on sensible management of all the resources of the fuel cycle, including energy, spent fuels, and all of its side streams. The nuclear fuel cycle for energy production has suffered many traumas since the mid seventies. The common basis of technologies producing nuclear explosives and consumable nuclear energy has been a preoccupation for some, predicament for others, and a perception problem for many. It is essential to reestablish a reliable back end of the nuclear fuel cycle that can sustain the resource requirements of an enduring full cycle. This paper identifies some pragmatic steps necessary to reverse the trend and to maintain a necessary fuel cycle option for the future

  18. MHR fuel cycle options for future sustainability of nuclear power

    International Nuclear Information System (INIS)

    Baxter, Alan; Venneri, Francesco; Rodriguez, Carmelo; Fikani, Michael

    2005-01-01

    The future sustainability of the nuclear option is not significantly tied to the level of resources. For example, current high quality uranium reserves (∼3.34x10 6 tons) are enough for more than 55 years at present consumption rates (IAEA estimate). Doubling of the present uranium ore price (∼$26/kg) could create about a tenfold increase in resources, providing more than 550 years of supply at present rates (World Nuclear Association estimate). There are also thorium reserves which are estimated to be about three times those of uranium, and would allow for a significant increase in annual consumption levels. The key to a sustainable nuclear future is really tied to the political and technical problems of long term waste disposal, and the perceived risks of nuclear weapons proliferation. Thus fuel cycle options for a sustainable nuclear future must address and solve these issues. High temperature, Gas-Cooled, Graphite Moderated, reactors (MHRs) have nuclear and operational characteristics to provide multiple fuel cycle options to solve these issues. Three fuel cycles for the MHD are described in this paper, and their capabilities for meeting a sustainable nuclear future in terms of nuclear waste minimization and destruction, and reduction of proliferation risk, are discussed. (author)

  19. The DUPIC alternative for backend fuel cycle

    International Nuclear Information System (INIS)

    Lee, J.S.; Choi, J.W.; Park, H.S.; Boczar, P.; Sullivan, J.; Gadsby, R.D.

    1997-01-01

    From the early nineties, a research programme, called DUPIC (Direct Use of Spent PWR Fuel in CANDU) has been undertaken in an international exercise involving Korea, Canada, the U.S. and later the IAEA. The basic idea of this fuel cycle alternative is that the spent fuel from LWR contains enough fissile remnant to be burnt again in CANDUs thanks to its excellent neutron economy. A systematic R and D plan has now gained a full momentum to verify experimentally the DUPIC fuel cycle concept. 4 refs

  20. Long-Term Collections

    CERN Multimedia

    Comité des collectes à long terme

    2011-01-01

    It is the time of the year when our fireman colleagues go around the laboratory for their traditional calendars sale. A part of the money of the sales will be donated in favour of the long-term collections. We hope that you will welcome them warmly.

  1. International Nuclear Fuel Cycle Fact Book

    Energy Technology Data Exchange (ETDEWEB)

    Leigh, I.W.; Patridge, M.D.

    1991-05-01

    As the US Department of Energy (DOE) and DOE contractors have become increasingly involved with other nations in nuclear fuel cycle and waste management cooperative activities, a need has developed for a ready source of information concerning foreign fuel cycle programs, facilities, and personnel. This Fact Book was compiled to meet that need. The information contained in the International Nuclear Fuel Cycle Fact Book has been obtained from many unclassified sources: nuclear trade journals and newsletters; reports of foreign visits and visitors; CEC, IAEA, and OECN/NEA activities reports; not reflect any one single source but frequently represent a consolidation/combination of information.

  2. Globalisation of the nuclear fuel cycle

    International Nuclear Information System (INIS)

    Rougeau, J.-P.; Durret, L.-F.

    1995-01-01

    Three main features of the globalisation of the nuclear fuel cycle are identified and discussed. The first is an increase in the scale of the nuclear fuel cycle materials and services markets in the past 20 years. This has been accompanied by a growth in the sophistication of the fuel cycle. Secondly, the nuclear industry is now more vulnerable to outside pressures; it is no longer possible to make strategic decisions on the industry within a country solely on national considerations. Thirdly, there are changes in the decision-making process at the political, regulatory, operational and industrial level which are the consequence of global factors. (UK)

  3. Globalisation of the nuclear fuel cycle

    Energy Technology Data Exchange (ETDEWEB)

    Rougeau, J.-P.; Durret, L.-F.

    1995-12-31

    Three main features of the globalisation of the nuclear fuel cycle are identified and discussed. The first is an increase in the scale of the nuclear fuel cycle materials and services markets in the past 20 years. This has been accompanied by a growth in the sophistication of the fuel cycle. Secondly, the nuclear industry is now more vulnerable to outside pressures; it is no longer possible to make strategic decisions on the industry within a country solely on national considerations. Thirdly, there are changes in the decision-making process at the political, regulatory, operational and industrial level which are the consequence of global factors. (UK).

  4. Fuel cycle financing, capital requirements and sources of funds

    International Nuclear Information System (INIS)

    Manderbach, R.W.

    1977-01-01

    An issue of global importance today is the economic case for nuclear power and the conservation of precious fossil resources. A question important to all of us is can sufficient financial resources be attracted to the nuclear industry in order to develop a complete fuel cycle industry capable of meeting the requirements of a global nuclear power industry. Future growth of the nuclear power industry will depend to a large extent on the timely development of a private competitive industry covering the total fuel cycle. The report of the Edison Electric Institute on Nuclear Fuels Supply estimates that by 1985 initial capital investment in the nuclear fuel cycle will total $15 billion and by the year 2000, $60 billion will be required. Although undoubtedly the amount of funding projected is manageable from a global availability standpoint, there is a hesitancy to commit financial resources to certain segments of the fuel cycle. This is because of the many unresolved problems in connection with the nuclear industry such as uncertainty regarding local and international governmental regulations and legislation, environmental and alternative technological considerations coupled, of course, with the substantial capital long term commitments needed in each of the several segments of the processes. Activities associated with the nuclear fuel cycle have unique investment requirements. Investments are needed in many diverse unrelated fields such as resource development and high technology process some of which are not yet fully commercialized. Sources of capital will be examined on a national scale, such as net earnings, depreciation, capital market and public subsidies. The paper also examines, in the broader context, capital investments in highly industrialized and developing countries as well as discussing the possible areas of Government guarantees and financing. The intensive capital required in certain segments of the cycle, which are to be developed by private

  5. Nuclear Fuel Cycle Evaluation and Real Options

    Directory of Open Access Journals (Sweden)

    L. Havlíček

    2008-01-01

    Full Text Available The first part of this paper describes the nuclear fuel cycle. It is divided into three parts. The first part, called Front-End, covers all activities connected with fuel procurement and fabrication. The middle part of the cycle includes fuel reload design activities and the operation of the fuel in the reactor. Back-End comprises all activities ensuring safe separation of spent fuel and radioactive waste from the environment. The individual stages of the fuel cycle are strongly interrelated. Overall economic optimization is very difficult. Generally, NPV is used for an economic evaluation in the nuclear fuel cycle. However the high volatility of uranium prices in the Front-End, and the large uncertainty of both economic and technical parameters in the Back-End, make the use of NPV difficult. The real option method is able to evaluate the value added by flexibility of decision making by a company under conditions of uncertainty. The possibility of applying this method to the nuclear fuel cycle evaluation is studied. 

  6. Several remarks on the fuel cycle economy

    International Nuclear Information System (INIS)

    Roman Kubin; Rudolf Vespalec

    2007-01-01

    Present paper deals with some aspects influencing significantly cost of nuclear fuel and possibilities of its usage in optimal fuel cycle technology. Our discussion is focused on the phase of fuel procurement that means financial parts of the contract as well as its technical Appendices. Typically the fuel fabrication price is taken as the main economy indicator; nevertheless also many other financial and technical features of the contract must be taken into account in order to reach the best price of electricity sold into public energy grid. Our experience from several international tenders shows that the consistent complex of commercial and technical parameters of the contract is necessary to achieve optimal economic results and prepare proper conditions for advanced fuel cycle technology. Among those essential characteristics are payment conditions and schedule and extent of vendor's services and assistance to the operator. Very important role play also technical parameters, as safety and operational limits, influencing loading pattern quality and operating flexibility. Obviously also a level of operator's fuel cycle technology is a crucial point that is necessary for usage of technical quality of the fuel at the power plant. The final electricity price, produced by the plant, and uranium consumption are the only objective criteria to evaluate economic level of the fuel contract and the fuel cycle at all (Authors)

  7. Globalisation of the nuclear fuel cycle - impact of developments on fuel management

    Energy Technology Data Exchange (ETDEWEB)

    Durpel, L. van den; Bertel, E. [OECD Nuclear Energy Agency, 92 - Issy-les-Moulineaux (France)

    2000-02-01

    Nuclear energy will have to cope more and more with a rapid changing environment due to economic competitive pressure and the deregulatory progress. In current economic environment, utilities will have to focus strongly on the reduction of their total generation costs, covering the fuel cycle costs, which are only partly under their control. Developments in the fuel cycle will be in the short-term rather evolutionary addressing the current needs of utilities. However, within the context of sustainable development and more and more inclusion of externalities in energy generation costs, more performing developments in the fuel cycle could become important and feasible. A life-cycle design approach of the fuel cycle will be requested in order to cover all factors in order to decrease significantly the nuclear energy generation cost to complete with other alternative fuels in the long-term. This paper will report on some of the trends one could distinguish in the fuel cycle with emphasis on cost reduction. OECD/NEA is currently conducting a study on the fuel cycle aiming to assess current and future nuclear fuel cycles according to the potential for further improvement of the full added-value chain of these cycles from a mainly technological and economic perspective including environmental and social considerations. (orig.) [German] Die Kernenergie wird sich mehr und mehr in einem Umfeld behaupten muessen, das durch schnelle Veraenderungen auf Grund des Wettbewerbsdrucks in der Wirtschaft und des Liberalisierungsprozesses gekennzeichnet ist. Im heutigen Wirtschaftsumfeld muessen sich die Energieversorgungsunternehmen hauptsaechlich auf die Senkung ihrer Stromerzeugungs-Gesamtkosten konzentrieren. Darunter fallen auch die Brennstoffkreislaufkosten, die sie nur zum Teil beeinflussen koennen. Kurzfristig gesehen, duerften die Entwicklungen im Brennstoffkreislauf eher evolutionaer verlaufen und den jeweiligen Beduerfnissen der EVUs entsprechen. Im Zusammenhang mit einer

  8. Back-end nuclear fuel cycle strategy: The approaches in Ukraine

    International Nuclear Information System (INIS)

    Afnasyev, A.; Medun, V.; Trehub, Yu.

    2002-01-01

    Ukraine has 14 nuclear units in operation and 4 units more under construction. Now in Ukraine a share of installed nuclear capacity in total installed capacity is essential and it is planned to increase it further. In this connection a spent nuclear fuel management in Ukraine for the current period and future is becoming important in a nuclear fuel cycle. A current situation in relation to the spent nuclear fuel management in Ukraine is described in the paper. It is reviewed: legislative basis for a spent nuclear fuel management strategy; an assessment for a spent fuel growth; the national possibilities for the spent fuel management; an organization chart for a spent nuclear fuel management, etc. Some factors that can determine a long-term spent fuel management strategy in Ukraine are in the conclusion. (author)

  9. Fast reactors fuel Cycle: State in Europe

    International Nuclear Information System (INIS)

    1991-01-01

    In this SFEN day we treat all aspects (economics-reactor cores, reprocessing, experience return) of the LMFBR fuel cycle in Europe and we discuss about the development of this type of reactor (EFR project) [fr

  10. Ecological effects of fuel cycle activities

    International Nuclear Information System (INIS)

    Barnthouse, L.; Cada, G.; Kroodsma, R.; Shriner, D.; Tolbert, V.; Turner, R.

    1994-01-01

    The purpose of this paper is to summarize the approach used to characterize ecological impacts of the coal fuel cycle. The same approach is used for many of the impacts in other fuel cycles as well. The principal analytical approach being used in the study is an accounting framework - that is, a series of matrices that map each phase of the fuel cycle to a suite of possible. emissions, each emission to a suite of impact categories, and each impact category to an external cost. This paper summarizes the ecological impacts of all phases of the coal fuel cycle, defines the ecological impact categories used in the study's 'accounting framework', and discusses alternative approaches to quantification. Externalities associated with CO 2 -induced global climate change are beyond the scope of this paper and are not discussed

  11. Assessment of the long-term risks of inadvertent human intrusion into a proposed Canadian nuclear fuel waste disposal vault in deep plutonic rock -revision 1

    International Nuclear Information System (INIS)

    Wuschke, D.M.

    1996-04-01

    Canada has conducted an extensive research program on a concept of safe disposal of nuclear fuel wastes deep In plutonic rock of the Canadian Shield. An essential goal of this program has been to develop and demonstrate a methodology to evaluate the performance of the facility against safety criteria established by Canada's regulatory agency, the Atomic Energy Control Board. These criteria are expressed in terms of risk, where risk is defined as the sum, over all significant scenarios, of the product of the probability of the scenario, the magnitude of the resultant dose, and the probability of a health effect per unit dose. This report describes the methodology developed to assess the long-term risk from inadvertent human intrusion into such a facility, and the results of its application to the proposed facility. Four intrusion scenarios were analysed, all initiated by a drilling operation. These scenarios are exposure of a member of the drilling crew, of a technologist conducting a core examination, of a construction worker and of a resident. The consequence of each scenario was estimated using standard computer codes for environmental pathways analysis and radiation dosimetry. For comparison with the risk criterion, an estimate of the probability of each scenario is also required. An event-tree methodology was used to estimate these probabilities. The estimated risks from these intrusion scenarios are several orders of magnitude below the established risk criterion. The event-tree methodology has the advantages of explicity displaying the assumptions made, of permitting easy testing of the sensitivity of the risk estimates to assumptions, and of combining technical and sociological information. (author). 53 refs., 8 tabs., 2 figs

  12. Regional nuclear fuel cycle centers study project

    International Nuclear Information System (INIS)

    Bennett, L.; Catlin, R.G.; Meckoni, V.

    1977-01-01

    The concept of regional fuel cycle centers (RFCC) has attracted wide interest. The concept was endorsed by many countries in discussions at the General Conference of the International Atomic Energy Agency and at the General Assembly of the United Nations. Accordingly, in 1975, the IAEA initiated a detailed study of the RFCC concept. The Agency study has concentrated on what is referred to as the ''back-end'' of the fuel cycle because that is the portion which is currently problematic. The study covers transport, storage, processing and recycle activities starting from the time the spent fuel leaves the reactor storage pools and through all steps until the recycled fuel is in finished fuel elements and shipped to the reactor. A detailed evaluation of the specific features of large regional fuel cycle centers established on a multinational basis vis-a-vis smaller dispersed fuel cycle facilities set up on a national basis has been carried out. The methodology for assessment of alternative strategies for fuel storage, reprocessing, and recycling of plutonium has been developed, characteristic data on material flows and cost factors have been generated, and an analytic system has been developed to carry out such evaluations including appropriate sensitivity analysis. Studies in related areas on institutional and legal, organizational, environmental, materials control and other essential aspects have also been made. The material developed during the course of this Study would enable any group of interested Member States to examine and work out alternative strategies pertinent to their present and projected nuclear fuel cycle needs, as well as evolve institutional, legal and other appropriate frameworks or agreements for the establishment of fuel cycle centers on a multinational cooperative basis

  13. An Integrated Fuel Depletion Calculator for Fuel Cycle Options Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, Erich [Univ. of Texas, Austin, TX (United States); Scopatz, Anthony [Univ. of Wisconsin, Madison, WI (United States)

    2016-04-25

    Bright-lite is a reactor modeling software developed at the University of Texas Austin to expand upon the work done with the Bright [1] reactor modeling software. Originally, bright-lite was designed to function as a standalone reactor modeling software. However, this aim was refocused t couple bright-lite with the Cyclus fuel cycle simulator [2] to make it a module for the fuel cycle simulator.

  14. Energy security externalities and fuel cycle comparisons

    International Nuclear Information System (INIS)

    Bohi, D.; Toman, M.

    1994-01-01

    Externalities related to 'energy security' may be one way in which the full social costs of energy use diverge from the market prices of energy commodities. Such divergences need to be included in reckoning the full costs of different fuel cycles. In this paper we critically examine potential externalities related to energy security and issues related to the measurement of 2 these externalities, in the context of fuel cycle comparisons

  15. An introduction to the nuclear fuel cycle

    International Nuclear Information System (INIS)

    Leuze, R.E.

    1986-01-01

    This overview of the nuclear fuel cycle is divided into three parts. First, is a brief discussion of the basic principles of how nuclear reactors work;second, is a look at the major types of nuclear reactors being used and world-wide nuclear capacity;and third, is an overview of the nuclear fuel cycle and the present industrial capability in the US. 34 figs., 10 tabs

  16. Fuel cycle and waste newsletter. Vol. 2, No. 2, August 2006

    International Nuclear Information System (INIS)

    2006-08-01

    Over the last few years there has been a contiguously increasing interest in the issues connected to the nuclear fuel cycle. After more than 10 years of low and stable uranium prices, the prices on the spot market have rapidly increased. The latest published spot market price (∼ 47 US$/lb U3O8) is about 7 times the historic low registered at the beginning of 2001, reflecting the inbalance between primary supply and demand and the expected reduction in stockpiles and other secondary supplies. This has lead to increased activities on exploration and mining developments. In many countries we see signs of rising expectations for the use of nuclear energy. This puts focus on the long term uranium supply and the long term sustainability of nuclear power. The interest for closed fuel cycle activities has therefore increased substantially also in countries that until recently did not consider recycling. Within the Generation IV International Forum four of the six concepts studied are fast or epithermal reactors with a closed fuel cycle. Recent initiatives like the Russian proposal for an International Fuel Cycle Centre and the US proposal for a Global Nuclear Energy Partnership also involves development work on treatment and recycling of fuel. But recycling also raises issues of proliferation and the recent initiatives also have components addressing this. This issue of the Fuel Cycle and Waste Newsletter is entirely devoted to the work performed within the Nuclear Fuel Cycle and Materials Section of our Division. It reviews the International Conference on Management of Spent Fuel from Nuclear Power reactors and it covers a very broad spectrum of activities from uranium and thorium exploration, through the use of nuclear fuel in reactors to the management of the spent fuel and its subsequent recycling. Furthermore it lists coordinated research projects, recent publications, forthcoming meetings, conference announcements and web links

  17. Critical review of nuclear fuel cycle

    International Nuclear Information System (INIS)

    Kuster, N.

    1996-01-01

    Transmutation of long-lived radionuclides is considered as an alternative to the in-depth disposal of spent nuclear fuel, in particular, on the final stage of the nuclear fuel cycle. The majority of conclusions is the result of the common work of the Karlsruhe FZK and the Commissariat on nuclear energy of France (CEA)

  18. Description Fuel Cycle Spanish. Technical Visits

    International Nuclear Information System (INIS)

    Ochoa Valero, R.; Vinuesa Carretero, A.

    2014-01-01

    The nuclear fuel cycle includes all processes and operations from the mining of uranium to the management of radioactive waste generated. These processes include the manufacture of nuclear fuel, the operation of the plants and the storage of radioactive waste in the corresponding temporary stores. (Author)

  19. Overview of light water reactor fuel cycles

    Energy Technology Data Exchange (ETDEWEB)

    Leuze, R.E.

    1976-01-01

    A brief overview of the LWR fuel cycle is given, and the status of the LWR fuel cycle in the U.S. is briefly summarized. A broad base including a variety of industrial facilities is necessary to provide fuel for LWR's. However, capital investments for all the facilities combined are only about 15 percent of the capital needed for the reactors themselves. Capability for the front end of the fuel cycle, mining through fuel fabrication, is adequate for the present, but the expanded capacity will be required in 15 to 20 years, and this calls for immediate action because of long lead times. There are no operating facilities for the back-end of the fuel cycle, which includes spent fuel reprocessing, permanent waste storage, and mixed-oxide fuel fabrication. Decisions must be made concerning permanent waste storage concepts and regulations relating to the use and handling of plutonium before such facilities can be provided and put into operation. (LK)

  20. Out-of-core fuel cycle optimization for nonequilibrium cycles

    International Nuclear Information System (INIS)

    Comes, S.A.; Turinsky, P.J.

    1988-01-01

    A methodology has been developed for determining the family of near-optimum fuel management schemes that minimize the levelized fuel cycle costs of a light water reactor over a multicycle planning horizon. Feed batch enrichments and sizes, burned batches to reinsert, and burnable poison loadings are determined for each cycle in the planning horizon. Flexibility in the methodology includes the capability to assess the economic benefits of various partially burned bath reload strategies as well as the effects of using split feed enrichments and enrichment palettes. Constraint limitations are imposed on feed enrichments, discharge burnups, moderator temperature coefficient, and cycle energy requirements

  1. Supply assurance in the nuclear fuel cycle

    International Nuclear Information System (INIS)

    Neff, T.L.; Jacoby, H.D.

    1979-01-01

    Nuclear fuel assurance, in the face of world and political uncertainties, is interrelated with nuclear technology development plans and international safeguards considerations. This has led some countries to accelerate their commitments to nuclear commercialization faster than necessary and has made non-proliferation policies harder to enforce. Fuel assurance is described on a national basis in three time scales: short-term, or resilience to supply interruptions; mid-term, or contract conditions in which governments make commitments to purchase or deliver; and long-term, or resource adequacy. A review of former assurance problems and current trends in the enrichment and uranium markets indicates that supplier concentration is no longer the major problem so much as non-proliferation actions. The present state of unstable equilibrium is expected to move in the direction of less fuel-supply assurance for countries having a small market or not subscribing to non-proliferation criteria. The authors, while generally optimistic that the fuel-supply system will function, express concern that policies for fuel stockpiles and the condition of uranium markets need improvement. 21 references

  2. BWR fuel cycle optimization using neural networks

    International Nuclear Information System (INIS)

    Ortiz-Servin, Juan Jose; Castillo, Jose Alejandro; Pelta, David Alejandro

    2011-01-01

    Highlights: → OCONN a new system to optimize all nuclear fuel management steps in a coupled way. → OCON is based on an artificial recurrent neural network to find the best combination of partial solutions to each fuel management step. → OCONN works with a fuel lattices' stock, a fuel reloads' stock and a control rod patterns' stock, previously obtained with different heuristic techniques. → Results show OCONN is able to find good combinations according the global objective function. - Abstract: In nuclear fuel management activities for BWRs, four combinatorial optimization problems are solved: fuel lattice design, axial fuel bundle design, fuel reload design and control rod patterns design. Traditionally, these problems have been solved in separated ways due to their complexity and the required computational resources. In the specialized literature there are some attempts to solve fuel reloads and control rod patterns design or fuel lattice and axial fuel bundle design in a coupled way. In this paper, the system OCONN to solve all of these problems in a coupled way is shown. This system is based on an artificial recurrent neural network to find the best combination of partial solutions to each problem, in order to maximize a global objective function. The new system works with a fuel lattices' stock, a fuel reloads' stock and a control rod patterns' stock, previously obtained with different heuristic techniques. The system was tested to design an equilibrium cycle with a cycle length of 18 months. Results show that the new system is able to find good combinations. Cycle length is reached and safety parameters are fulfilled.

  3. IFR fuel cycle--pyroprocess development

    International Nuclear Information System (INIS)

    Laidler, J.J.; Miller, W.E.; Johnson, T.R.; Ackerman, J.P.; Battles, J.E.

    1992-01-01

    The Integral Fast Reactor (IFR) fuel cycle is based on the use of a metallic fuel alloy, with nominal composition U-2OPu-lOZr. In its present state of development, this fuel system offers excellent high-burnup capabilities. Test fuel has been carried to burnups in excess of 20 atom % in EBR-II irradiations, and to peak burnups over 15 atom % in FFTF. The metallic fuel possesses physical characteristics, in particular very high thermal conductivity, that facilitate a high degree of passive inherent safety in the IFR design. The fuel has been shown to provide very large margins to failure in overpower transient events. Rapid overpower transient tests carried out in the TREAT reactor have shown the capability to withstand up to 400% overpower conditions before failing. An operational transient test conducted in EBR-II at a power ramp rate of 0.1% per second reached its termination point of 130% of normal power without any fuel failures. The IFR metallic fuel also exhibits superior compatibility with the liquid sodium coolant. Equally as important as the performance advantages offered by the use of metallic fuel is the fact that this fuel system permits the use of an innovative reprocessing method, known as ''pyroprocessing,'' featuring fused-salt electrorefining of the spent fuel. Development of the IFR pyroprocess has been underway at the Argonne National Laboratory for over five years, and great progress has been made toward establishing a commercially-viable process. Pyroprocessing offers a simple, compact means for closure of the fuel cycle, with anticipated significant savings in fuel cycle costs

  4. A strategy analysis of the fast breeder reactor introduction and nuclear fuel cycle systems deployment

    International Nuclear Information System (INIS)

    Wajima, Tsunetaka; Kawashima, Katsuyuki; Yamashita, Takashi

    1996-01-01

    A study is made on a strategy analysis of the long term nuclear fuel cycle systems deployment in accordance with the nuclear power growth projection and fast breeder reactor (FBR) introduction. In the analysis, the reprocessed plutonium (Pu) is charged into the reactor in such a way that the reprocessed Pu is not stored outside the reactor, i.e., there is no excess Pu outside the reactor. The analysis characterized the fuel cycle systems, and showed the usefulness of the present method to determine future directions for the FBR introduction and nuclear fuel cycle systems deployment. Concerning an intermediate-term strategy, the time of introduction and required capacities of a second commercial LWR reprocessing plant, Pu-thermal, and the first FBR reprocessing plant deployment are evaluated. A long term strategy analysis shows that the two or three large plants are run in parallel for each fuel cycle facility and that FBR related facilities deal with a markedly large amount of Pu. It is concluded that the early stage introduction of FBRs of significant capacities seems necessary to materialize a consistent total FBR/fuel cycle system where Pu balance becomes feasible through its flexible operation of, for instance, adjusting breeding ratio, in order to keep the transparency of the Pu utilization. (author)

  5. Advance reactor and fuel-cycle systems--potentials and limitations for United States utilities

    International Nuclear Information System (INIS)

    Zebroski, E.L.; Williams, R.F.

    1979-01-01

    This paper reviews the potential benefits and limitations of advance reactor and fuel-cycle systems for United States utilities. The results of the review of advanced technologies show that for the near and midterm, the only advance reactor and fuel-cycle system with significant potential for United States utilities is the current LWR, and evolutionary, not revolutionary, enhancements. For the long term, the liquid-metal breeder reactor continues to be the most promising advance nuclear option. The major factors leading to this conclusion are summarized

  6. Synergistic fuel cycles of the future

    International Nuclear Information System (INIS)

    Meneley, D.A.; Dastur, A.R.

    1997-01-01

    Good neutron economy is the basis of the fuel cycle flexibility in the CANDU reactor. This paper describes the fuel cycle options available to the CANDU owner with special emphasis on resource conservation and waste management. CANDU fuel cycles with low initial fissile content operate with relatively high conversion ratio. The natural uranium cycle provides over 55 % of energy from the plutonium that is created during fuel life. Resource utilization is over 7 MWd/kg NU. This can be improved by slight enrichment (between 0.9 and 1.2 wt % U235) of the fuel. Resource utilization increases to 11 MWd/kg NU with the Slightly Enriched Uranium cycle. Thorium based cycles in CANDU operate at near-breeder efficiency. Obey provide attractive options when used with natural uranium or separated (reactor grade and weapons grade) plutonium as driver fuels. In the latter case, the energy from the U233 plus the initial plutonium content amounts to 3.4 GW(th).d/kg Pu-fissile. The same utilization is expected from the use of FBR plutonium in a CANDU thorium cycle. Extension of natural resource is achieved by the use of spent fuels in CANDU. The LWR/CANDU Tandem cycle leads to an additional 77 % of energy through the use of reprocessed LWR fuel (which has a fissile content of 1.6 wt %) in CANDU. Dry reprocessing of LWR fuel with the OREOX process (a more safeguardable alternative to the PUREX process) provides an additional 50 % energy. Uranium recovered (RU) from separation of plutonium contained in spent LWR fuel provides an additional 15 MWd/kg RU. CANDU's low fissile requirement provides the possibility, through the use of non-fertile targets, of extracting energy from the minor actinides contained in spent fuel. In addition to the resource utilization advantage described above, there is a corresponding reduction in waste arisings with such cycles. This is especially significant when separated plutonium is available as a fissile resource. (author)

  7. Current status and prospects on Rokkasho nuclear fuel cycle project

    International Nuclear Information System (INIS)

    Suzuki, Mitsuo

    2003-01-01

    JNFL has been established aiming at fulfillment of Nuclear Fuel Cycle, as well as to contribute to the long-term and stable supply of nuclear power in Japan. 'Uranium Enrichment Plant' with its production of 1,050 SWU/y and planned to be expand to 1,500 SWU/y, 'Low Level Radioactive Waste Disposal Center' with 150,000/200 l drums stored, out of its 400,000 drums capacity, and 'Vitrified Waste Storage Center' with 760 canisters stored, out of its 1440 canisters capacity, are already in its operation. It is now preparing for the operation of '800 t/y Reprocessing Plant' and construction of '130t HM/y MOX Fuel Fabrication Plant'. As for the Reprocessing Plant, 780t of spent fuels has been already received and stored in the storage pools. Main plant is now in the course of test operation and planned to start the commercial operation by July 2006. Due to some defects found during the course of its construction, JNFL is now reviewing the Total Quality Assurance Structure to improve and reinforce its system. And for the MOX Fuel Fabrication Plant, activities towards obtaining the local autonomy's agreement for the construction are being made energetically. It is essential to obtain the good understanding of the public community to promote these projects successfully; JNFL is putting its best efforts to dispatch all the necessary information to the public in a timely manner. (author)

  8. Development of System Engineering Technology for Nuclear Fuel Cycle

    International Nuclear Information System (INIS)

    Kim, Ho Dong; Kim, Sung Ki; Song, Kee Chan

    2010-04-01

    This report is aims to establish design requirements for constructing mock-up system of pyroprocess by 2011 to realize long-term goal of nuclear energy promotion comprehensive plan, which is construction of engineering scale pyroprocess integrated process demonstration facility. The development of efficient process for spent fuel and establishment of system engineering technology to demonstrate the process are required to develop nuclear energy continuously. The detailed contents of research for these are as follows; - Design of Mock-up facility for demonstrate pyroprocess, Construction, Approval, Trial run, Performance test - Development of nuclear material accountancy technology for unit processes of pyroprocess and design of safeguards system - Remote operation of demonstrating pyroprocess / Development of maintenance technology and equipment - Establishment of transportation system and evaluation of pre-safety for interim storage system - Deriving and implementation of a method to improve nuclear transparency for commercialization proliferation resistance nuclear fuel cycle Spent fuel which is the most important pending problem of nuclear power development would be reduced and recycled by developing the system engineering technology of pyroprocess facility by 2010. This technology would contribute to obtain JD for the use of spent fuel between the ROK-US and to amend the ROK-US Atomic Energy Agreement scheduled in 2014

  9. CANDU advanced fuel cycles: key to energy sustainability

    International Nuclear Information System (INIS)

    Boczar, P.G.; Fehrenbach, P.J.

    1996-06-01

    In the fast-growing economies of the Pacific Basin region, sustainability is an important requisite for new energy development. Many countries in this region have seen, and continue to see, very large increases in energy and electricity demand. The investment in any nuclear technology is large. Countries making that investment want to ensure that the technology can be sustained and that it can evolve in an ever-changing environment. Three key aspects in ensuring a sustainable energy future are: technological sustainability; economic sustainability; and environmental sustainability (including resource utilization). The fuel-cycle flexibility of the CANDU reactor provides a ready path to sustainable energy development in both the short and the long term. (author). 23 refs

  10. CANDU advanced fuel cycles: key to energy sustainability

    International Nuclear Information System (INIS)

    Boczar, P.G.; Fehrenbach, P.J.; Meneley, D.A.

    1996-01-01

    In the fast-growing economies of the Pacific Basin region, sustainability is an important requisite for new energy development. Many countries in this region have seen, and continue to see, very large increases in energy and electricity demand. The investment in any nuclear technology is large. Countries making that investment want to ensure that the technology can be sustained and that it can evolve in an ever-changing environment. Three key aspects in ensuring a sustainable energy future, are technological sustainability, economic sustainability, and environmental sustainability (including resource utilization). The fuel-cycle flexibility of the CANDU reactor provides a ready path to sustainable energy development in both the short and long term. (author)

  11. Fuel cycle optimization in PWR'S

    International Nuclear Information System (INIS)

    Castro Lobo, P.D. de; Amorim, E.S. do.

    1979-08-01

    Neutronics aspects of a reactor core throughout its cycle were investigated in a search for increasing in-core utilization of the residual fissile isotopes content in the cycle discharged disposal. The effects due to design modifications introduced at burnup levels near the end-of-cycle, in an equilibrium cycle condition, have indicated the possibility of a better in-core utilization of the residual fissile isotopes existing in the cycle discharged disposal. The potential benefits are significant to warranty an examination of the mechanical and thermal hydraulic involved. At convenient burnup levels, change in H 2 O/UO 2 volume ratio were introduced allowing an intense depletion of the residual fissile isotopes existing in assemblies with high exposures levels. (Author) [pt

  12. Life cycle models of conventional and alternative-fueled automobiles

    Science.gov (United States)

    Maclean, Heather Louise

    development for the combinations. Overall, none of the alternatives emerges as a clear winner, lowering the externalities and improving sustainability, while considering technology issues and vehicle attributes. The majority of the alternatives are not likely to displace the baseline automobile. However, the attractiveness of the alternatives depends on the focus of future regulations, government priorities, and technology development. If long-term global sustainability is the principal concern, then improvements in fuel economy alone will not provide the level of reduction in impact required. A switch to renewable fuels (e.g., alcohols or diesel produced from biomass) to power the vehicles will likely be necessary. (Abstract shortened by UMI.)

  13. The nuclear fuel cycle, an overview

    International Nuclear Information System (INIS)

    Ballery, J.L.; Cazalet, J.; Hagemann, R.

    1995-01-01

    Because uranium is widely distributed on the face of the Earth, nuclear energy has a very large potential as an energy source in view of future depletion of fossil fuel reserves. Also future energy requirements will be very sizeable as populations of developing countries are often growing and make the energy question one of the major challenges for the coming decades. Today, nuclear contributes some 340 GWe to the energy requirements of the world. Present and future nuclear programs require an adequate fuel cycle industry, from mining, refining, conversion, enrichment, fuel fabrication, fuel reprocessing and the storage of the resulting wastes. The commercial fuel cycle activities amount to an annual business in the 7-8 billions of US Dollars in the hands of a large number of industrial operators. This paper gives details about companies and countries involved in each step of the fuel cycle and about the national strategies and options chosen regarding the back end of the fuel cycle (waste storage and reprocessing). These options are illustrated by considering the policy adopted in three countries (France, United Kingdom, Japan) versed in reprocessing. (J.S.). 13 figs., 2 tabs

  14. Pressurized water reactor thorium fuel cycle studies

    International Nuclear Information System (INIS)

    Aktogu, Ali.

    1981-06-01

    The use of a thorium fuel cycle in a PWR is studied. The thorium has no fissile isotope and a fissile nuclide must be added to the thorium fuel. This nuclide can be uranium 235, plutonium 239 or uranium 233. In this work we have kept the fuel assembly geometry and the control rod system of an usual PWR. Cell calculations showed that the moderation ratio of an usual PWR can be used with uranium 235 and plutonium 239 fuels. But this moderation ratio must be decreased and accordingly the pumping power must be increased in the case of a uranium 233 fuel. The three fuels can be controlled with soluble boron. The power distribution inside an assembly agrees with the safety rules and the worth of the control rods is sufficient. To be interesting the thorium fuels must be recycled. Because the activity and the residual power are higher for a thorium fuel than for a uranium fuel the shielding of the shipping casks and storage pools must be increased. The Uranium 235-Thorium fuel is the best even if it needs expensive enrichment work. With this type of fuel more natural uranium is saved. The thorium fuel would become very interesting if we observe again in the future an increase of the uranium cost [fr

  15. The front end of the fuel cycle

    International Nuclear Information System (INIS)

    Cohen, K.P.

    1985-01-01

    The purpose of this paper is to examine the front end of the fuel cycle as it relates to nuclear power and proliferation, with the ultimate purpose of recommending policies that foster widespread use of nuclear power without contributing to the risk of proliferation of nuclear weapons. Reactor design and construction, the production of reactor materials such as D/sub 2/O and zirconium, uranium mining, and uranium enrichment--all are characteristic front end activities. To keep the scope manageable, the first and fourth topics are the focus. There is, of course, no clear distinction between the front end and the back end of the fuel cycle, since the back of one fuel cycle can well be the front end of another. Even when fuel is not recycled, the choice of the front end often depends on the products one desires from the back end

  16. Overview of the LIFE fuel cycle

    Directory of Open Access Journals (Sweden)

    Reyes S.

    2013-11-01

    Full Text Available The Laser Inertial Fusion Energy (LIFE engine is a laser-driven inertial fusion energy system being developed with the goal to deliver fusion power in the next decade. A pre-conceptual design is being developed for the LIFE fuel cycle, with the purpose of maximizing the potential safety advantages of fusion energy. Some key features of the LIFE fuel cycle include a high tritium fuel burn-up fraction, a relatively high tritium breeding ratio, low tritium permeation from the coolant/breeder, and limited tritium inventories throughout the facility. The present paper offers an overview the pre-conceptual design of the LIFE fuel cycle, including a summary of the development plan for the delivery of the related tritium processing equipment.

  17. CANDU fuel cycles - present and future

    International Nuclear Information System (INIS)

    Mooradian, A.J.

    1976-05-01

    The present commercially proven Canadian nuclear power system is based on a once-through natural uranium fuel cycle characterized by high uranium utilization and a high conversion efficiency. The cycle closes with secure retrievable storage of spent fuel. This cycle is based on a CANDU reactor concept which is now well understood. Both active and passive fuel storage options have been investigated and will be described in this paper. Future development of the CANDU system is focussed on conservation of uranium by plutonium and thorium recycle. The full exploitation of these options requires continued emphasis on neutron conservation, efficiency of extraction and fuel refabrication processes. The results of recent studies are discussed in this paper. (author)

  18. Fuel cycle related parametric study considering long lived actinide production, decay heat and fuel cycle performances

    International Nuclear Information System (INIS)

    Raepsaet, X.; Damian, F.; Lenain, R.; Lecomte, M.

    2001-01-01

    One of the very attractive HTGR reactor characteristics is its highly versatile and flexible core that can fulfil a wide range of diverse fuel cycles. Based on a GTMHR-600 MWth reactor, analyses of several fuel cycles were carried out without taking into account common fuel particle performance limits (burnup, fast fluence, temperature). These values are, however, indicated in each case. Fuel derived from uranium, thorium and a wide variety of plutonium grades has been considered. Long-lived actinide production and total residual decay heat were evaluated for the various types of fuel. The results presented in this papers provide a comparison of the potential and limits of each fuel cycle and allow to define specific cycles offering lowest actinide production and residual heat associated with a long life cycle. (author)

  19. International issue: the nuclear fuel cycle

    International Nuclear Information System (INIS)

    Anon.

    1982-01-01

    In this special issue a serie of short articles of informations are presented on the following topics: the EEC's medium term policy regarding the reprocessing and storage of spent fuel, France's natural uranium supply, the Pechiney Group in the nuclear field, zircaloy cladding for nuclear fuel elements, USSI: a major French nuclear engineering firm, gaseous diffusion: the only commercial enrichment process, the transport of nuclear materials in the fuel cycle, Cogema and spent fuel reprocessing, SGN: a leader in the fuel cycle, quality control of mechanical, thermal and termodynamic design in nuclear engineering, Sulzer's new pump testing station in Mantes, the new look of the Ateliers et Chantiers de Bretagne, tubes and piping in nuclear power plants, piping in pressurized water reactor. All these articles are written in English and in French [fr

  20. Nuclear fuel cycle facility accident analysis handbook

    Energy Technology Data Exchange (ETDEWEB)

    Ayer, J E; Clark, A T; Loysen, P; Ballinger, M Y; Mishima, J; Owczarski, P C; Gregory, W S; Nichols, B D

    1988-05-01

    The Accident Analysis Handbook (AAH) covers four generic facilities: fuel manufacturing, fuel reprocessing, waste storage/solidification, and spent fuel storage; and six accident types: fire, explosion, tornado, criticality, spill, and equipment failure. These are the accident types considered to make major contributions to the radiological risk from accidents in nuclear fuel cycle facility operations. The AAH will enable the user to calculate source term releases from accident scenarios manually or by computer. A major feature of the AAH is development of accident sample problems to provide input to source term analysis methods and transport computer codes. Sample problems and illustrative examples for different accident types are included in the AAH.

  1. Nuclear fuel cycle facility accident analysis handbook

    International Nuclear Information System (INIS)

    Ayer, J.E.; Clark, A.T.; Loysen, P.; Ballinger, M.Y.; Mishima, J.; Owczarski, P.C.; Gregory, W.S.; Nichols, B.D.

    1988-05-01

    The Accident Analysis Handbook (AAH) covers four generic facilities: fuel manufacturing, fuel reprocessing, waste storage/solidification, and spent fuel storage; and six accident types: fire, explosion, tornado, criticality, spill, and equipment failure. These are the accident types considered to make major contributions to the radiological risk from accidents in nuclear fuel cycle facility operations. The AAH will enable the user to calculate source term releases from accident scenarios manually or by computer. A major feature of the AAH is development of accident sample problems to provide input to source term analysis methods and transport computer codes. Sample problems and illustrative examples for different accident types are included in the AAH

  2. Fuel cell hybrid taxi life cycle analysis

    Energy Technology Data Exchange (ETDEWEB)

    Baptista, Patricia, E-mail: patricia.baptista@ist.utl.pt [IDMEC-Instituto Superior Tecnico, Universidade Tecnica de Lisboa, Av. Rovisco Pais, 1, 1049-001 Lisboa (Portugal); Ribau, Joao; Bravo, Joao; Silva, Carla [IDMEC-Instituto Superior Tecnico, Universidade Tecnica de Lisboa, Av. Rovisco Pais, 1, 1049-001 Lisboa (Portugal); Adcock, Paul; Kells, Ashley [Intelligent Energy, Charnwood Building, HolywellPark, Ashby Road, Loughborough, LE11 3GR (United Kingdom)

    2011-09-15

    A small fleet of classic London Taxis (Black cabs) equipped with hydrogen fuel cell power systems is being prepared for demonstration during the 2012 London Olympics. This paper presents a Life Cycle Analysis for these vehicles in terms of energy consumption and CO{sub 2} emissions, focusing on the impacts of alternative vehicle technologies for the Taxi, combining the fuel life cycle (Tank-to-Wheel and Well-to-Tank) and vehicle materials Cradle-to-Grave. An internal combustion engine diesel taxi was used as the reference vehicle for the currently available technology. This is compared to battery and fuel cell vehicle configurations. Accordingly, the following energy pathways are compared: diesel, electricity and hydrogen (derived from natural gas steam reforming). Full Life Cycle Analysis, using the PCO-CENEX drive cycle, (derived from actual London Taxi drive cycles) shows that the fuel cell powered vehicle configurations have lower energy consumption (4.34 MJ/km) and CO{sub 2} emissions (235 g/km) than both the ICE Diesel (9.54 MJ/km and 738 g/km) and the battery electric vehicle (5.81 MJ/km and 269 g/km). - Highlights: > A Life Cycle Analysis of alternative vehicle technologies for the London Taxi was performed. > The hydrogen powered vehicles have the lowest energy consumption and CO{sub 2} emissions results. > A hydrogen powered solution can be a sustainable alternative in a full life cycle framework.

  3. Fuel cell hybrid taxi life cycle analysis

    International Nuclear Information System (INIS)

    Baptista, Patricia; Ribau, Joao; Bravo, Joao; Silva, Carla; Adcock, Paul; Kells, Ashley

    2011-01-01

    A small fleet of classic London Taxis (Black cabs) equipped with hydrogen fuel cell power systems is being prepared for demonstration during the 2012 London Olympics. This paper presents a Life Cycle Analysis for these vehicles in terms of energy consumption and CO 2 emissions, focusing on the impacts of alternative vehicle technologies for the Taxi, combining the fuel life cycle (Tank-to-Wheel and Well-to-Tank) and vehicle materials Cradle-to-Grave. An internal combustion engine diesel taxi was used as the reference vehicle for the currently available technology. This is compared to battery and fuel cell vehicle configurations. Accordingly, the following energy pathways are compared: diesel, electricity and hydrogen (derived from natural gas steam reforming). Full Life Cycle Analysis, using the PCO-CENEX drive cycle, (derived from actual London Taxi drive cycles) shows that the fuel cell powered vehicle configurations have lower energy consumption (4.34 MJ/km) and CO 2 emissions (235 g/km) than both the ICE Diesel (9.54 MJ/km and 738 g/km) and the battery electric vehicle (5.81 MJ/km and 269 g/km). - Highlights: → A Life Cycle Analysis of alternative vehicle technologies for the London Taxi was performed. → The hydrogen powered vehicles have the lowest energy consumption and CO 2 emissions results. → A hydrogen powered solution can be a sustainable alternative in a full life cycle framework.

  4. 77 FR 19278 - Informational Meeting on Nuclear Fuel Cycle Options

    Science.gov (United States)

    2012-03-30

    ... criteria or the pros and cons of any particular fuel cycle option. Opportunity for providing input on the... Informational Meeting on Nuclear Fuel Cycle Options AGENCY: Office of Fuel Cycle Technologies, Office of Nuclear Energy, Department of Energy. ACTION: Notice of meeting. SUMMARY: The Office of Fuel Cycle Technologies...

  5. Measurements of Fission Cross Sections for the Isotopes relevant to the Thorium Fuel Cycle

    CERN Multimedia

    2002-01-01

    The present concern about a sustainable energy supply is characterised by a considerable uncertainty: the green house effect and foreseeable limits in fossil fuel resources on the one hand, the concern about the environmental impact of nuclear fission energy and the long term fusion research on the other hand, have led to the consideration of a variety of advanced strategies for the nuclear fuel cycle and related nuclear energy systems. The present research directories concern such strategies as the extension of the life span of presently operating reactors, the increase of the fuel burn-up, the plutonium recycling, and in particular the incineration of actinides and long-Lived fission products, the accelerator driven systems (ADS), like the "Energy Amplifier" (EA) concept of C. Rubbia, and the possible use of the Thorium fuel cycle. The detailed feasibility study and safety assessment of these strategies requires the accurate knowledge of neutron nuclear reaction data. Both, higher fuel burn-up and especiall...

  6. Long-Term Collection

    CERN Multimedia

    Staff Association

    2016-01-01

    Dear Colleagues, As previously announced in Echo (No. 254), your delegates took action to draw attention to the projects of the Long-Term Collections (LTC), the humanitarian body of the CERN Staff Association. On Tuesday, 11 October, at noon, small Z-Cards were widely distributed at the entrances of CERN restaurants and we thank you all for your interest. We hope to have achieved an important part of our goal, which was to inform you, convince you and find new supporters among you. We will find out in the next few days! An exhibition of the LTC was also set up in the Main Building for the entire week. The Staff Association wants to celebrate the occasion of the Long-Term Collection’s 45th anniversary at CERN because, ever since 1971, CERN personnel have showed great support in helping the least fortunate people on the planet in a variety of ways according to their needs. On a regular basis, joint fundraising appeals are made with the Directorate to help the victims of natural disasters around th...

  7. Collectes à long terme

    CERN Multimedia

    Collectes à long terme

    2014-01-01

    En cette fin d’année 2014 qui approche à grands pas, le Comité des Collectes à Long Terme remercie chaleureusement ses fidèles donatrices et donateurs réguliers pour leurs contributions à nos actions en faveur des plus démunis de notre planète. C’est très important, pour notre Comité, de pouvoir compter sur l’appui assidu que vous nous apportez. Depuis plus de 40 ans maintenant, le modèle des CLT est basé principalement sur des actions à long terme (soit une aide pendant 4-5 ans par projet, mais plus parfois selon les circonstances), et sa planification demande une grande régularité de ses soutiens financiers. Grand MERCI à vous ! D’autres dons nous parviennent au cours de l’année, et ils sont aussi les bienvenus. En particulier, nous tenons à remercier...

  8. Long-Term Collections

    CERN Multimedia

    Staff Association

    2016-01-01

    45 years helping in developing countries! CERN personnel have been helping the least fortunate people on the planet since 1971. How? With the Long-Term Collections! Dear Colleagues, The Staff Association’s Long-Term Collections (LTC) Committee is delighted to share this important milestone in the life of our Laboratory with you. Indeed, whilst the name of CERN is known worldwide for scientific discoveries, it also shines in the many humanitarian projects which have been supported by the LTC since 1971. Several schools and clinics, far and wide, carry its logo... Over the past 45 years, 74 projects have been supported (9 of which are still ongoing). This all came from a group of colleagues who wanted to share a little of what life offered them here at CERN, in this haven of mutual understanding, peace and security, with those who were less fortunate elsewhere. Thus, the LTC were born... Since then, we have worked as a team to maintain the dream of these visionaries, with the help of regular donat...

  9. Multi-cycle boiling water reactor fuel cycle optimization

    Energy Technology Data Exchange (ETDEWEB)

    Ottinger, K.; Maldonado, G.I. [University of Tennessee, 311 Pasqua Engineering Building, Knoxville, TN 37996-2300 (United States)

    2013-07-01

    In this work a new computer code, BWROPT (Boiling Water Reactor Optimization), is presented. BWROPT uses the Parallel Simulated Annealing (PSA) algorithm to solve the out-of-core optimization problem coupled with an in-core optimization that determines the optimum fuel loading pattern. However it uses a Haling power profile for the depletion instead of optimizing the operating strategy. The result of this optimization is the optimum new fuel inventory and the core loading pattern for the first cycle considered in the optimization. Several changes were made to the optimization algorithm with respect to other nuclear fuel cycle optimization codes that use PSA. Instead of using constant sampling probabilities for the solution perturbation types throughout the optimization as is usually done in PSA optimizations the sampling probabilities are varied to get a better solution and/or decrease runtime. The new fuel types available for use can be sorted into an array based on any number of parameters so that each parameter can be incremented or decremented, which allows for more precise fuel type selection compared to random sampling. Also, the results are sorted by the new fuel inventory of the first cycle for ease of comparing alternative solutions. (authors)

  10. Dynamic Analysis of Fuel Cycle Transitioning

    International Nuclear Information System (INIS)

    Dixon, Brent; Piet, Steve; Shropshire, David; Matthern, Gretchen

    2009-01-01

    This paper examines the time-dependent dynamics of transitioning from a once-through fuel cycle to a closed fuel cycle. The once-through system involves only Light Water Reactors (LWRs) operating on uranium oxide fuel (UOX), while the closed cycle includes both LWRs and fast spectrum reactors (FRs) in either a single-tier system or two-tier fuel system. The single-tier system includes full transuranic recycle in FRs while the two-tier system adds one pass of mixed oxide uranium-plutonium (MOX U-Pu) fuel in the LWR. While the analysis primarily focuses on burner fast reactors, transuranic conversion ratios up to 1.0 are assessed and many of the findings apply to any fuel cycle transitioning from a thermal once-through system to a synergistic thermal-fast recycle system. These findings include uranium requirements for a range of nuclear electricity growth rates, the importance of back end fuel cycle facility timing and magnitude, the impact of employing a range of fast reactor conversion ratios, system sensitivity to used fuel cooling time prior to recycle, impacts on a range of waste management indicators, and projected electricity cost ranges for once-through, single-tier and two-tier systems. The study confirmed that significant waste management benefits can be realized as soon as recycling is initiated, but natural uranium savings are minimal in this century. The use of MOX in LWRs decouples the development of recycle facilities from fast reactor fielding, but also significantly delays and limits fast reactor deployment. In all cases, fast reactor deployment was significantly below than predicted by static equilibrium analyses.

  11. Report on the long-term interim storage of spent fuels and vitrified wastes; Gutachten zur Langzeitzwischenlagerung abgebrannter Brennelemente und verglaster Abfaelle

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2015-12-03

    Long-term interim storage for several hundred years is an option on the management of high-level radioactive wastes. The decision on final disposal is postponed. Worldwide the long-term interim storage is not part of the disposal concept - a geologic final repository is the ultimate aim. Using today's technology the interim storage over several hundred years is supposed to be uncritical. Aging management is the most important challenge - the renewal of the facilities would have to be expected. Possible social change and their impact on the interim storage problem has not been considered.

  12. Commercialization of nuclear fuel cycle business

    International Nuclear Information System (INIS)

    Yakabe, Hideo

    1998-01-01

    Japan depends on foreign countries almost for establishing nuclear fuel cycle. Accordingly, uranium enrichment, spent fuel reprocessing and the safe treatment and disposal of radioactive waste in Japan is important for securing energy. By these means, the stable supply of enriched uranium, the rise of utilization efficiency of uranium and making nuclear power into home-produced energy can be realized. Also this contributes to the protection of earth resources and the preservation of environment. Japan Nuclear Fuel Co., Ltd. operates four business commercially in Rokkasho, Aomori Prefecture, aiming at the completion of nuclear fuel cycle by the technologies developed by Power Reactor and Nuclear Fuel Development Corporation and the introduction of technologies from foreign countries. The conditions of location of nuclear fuel cycle facilities and the course of the location in Rokkasho are described. In the site of about 740 hectares area, uranium enrichment, burying of low level radioactive waste, fuel reprocessing and high level waste control have been carried out, and three businesses except reprocessing already began the operation. The state of operation of these businesses is reported. Hereafter, efforts will be exerted to the securing of safety through trouble-free operation and cost reduction. (K.I.)

  13. Integrated scheme of long-term for spent fuel management of power nuclear reactors; Esquema integrado de largo plazo para la administracion de combustible gastado de reactores nucleares de potencia

    Energy Technology Data Exchange (ETDEWEB)

    Ramirez S, J. R.; Palacios H, J. C.; Martinez C, E., E-mail: ramon-ramirez@inin.gob.mx [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

    2015-09-15

    After of irradiation of the nuclear fuel in the reactor core, is necessary to store it for their cooling in the fuel pools of the reactor. This is the first step in a processes series before the fuel can reach its final destination. Until now there are two options that are most commonly accepted for the end of the nuclear fuel cycle, one is the open nuclear fuel cycle, requiring a deep geological repository for the fuel final disposal. The other option is the fuel reprocessing to extract the plutonium and uranium as valuable materials that remaining in the spent fuel. In this study the alternatives for the final part of the fuel cycle, which involves the recycling of plutonium and the minor actinides in the same reactor that generated them are shown. The results shown that this is possible in a thermal reactor and that there are significant reductions in actinides if they are recycled into reactor fuel. (Author)

  14. Advanced Fuel Cycle Initiative (AFCI) Repository Impact Evaluation FY-05 Progress Report

    International Nuclear Information System (INIS)

    Halsey, W G

    2005-01-01

    An important long-term objective of advanced nuclear fuel cycle (AFC) technologies is to provide improvement in the long-term management of radioactive waste. Compared to a once-thru fuel cycle, it is possible to generate far less waste, and potentially easier waste to manage, with advanced fuel cycles. However, the precise extent and value of these benefits are complex and difficult to quantify. This document presents a status report of efforts within AFCI Systems Analysis to define and quantify the AFC benefits to geologic disposal, development of cooperative efforts with the US repository program, and participation with international evaluations of AFC impacts on waste management. The primary analysis of repository benefits is conducted by ANL. This year repository impact evaluations have included: (1) Continued evaluation of LWR recycle benefits in support of scenario analysis. (2) Extension of repository analyses to consider long-term dose reductions. (3) Developing the opportunity for cooperation with the U.S. repository program. (4) International cooperation with OECD-NEA

  15. The nuclear fuel cycle light and shadow

    International Nuclear Information System (INIS)

    Giraud, A.

    1977-01-01

    The nuclear fuel cycle industry has a far reaching effect on future world energy developments. The growth in turnover of this industry follows a known patterm; by 1985 this turnover will have reached a figure of 2 billion dollars. Furthermore, the fuel cycle plays a determining role in ensuring the physical continuity of energy supplies for countries already engaged in the nuclear domain. Finally, the development of this industry is subject to economic and political constraints which imply the availability of raw materials, technological know-how, and production facilities. Various factors which could have an adverse influence on the cycle: technical, economic, or financial difficulties, environmental impact, nuclear safety, theft or diversion of nuclear materials, nuclear weapon, proliferation risks, are described, and the interaction between the development of the cycle, energy independance, and the fulfillment of nuclear energy programs is emphasized. It is concluded that the nuclear fuel cycle industry is confronted with difficulties due to its extremely rapid growth rate (doubling every 5 years); it is a long time since such a growth rate has been experienced by any heavy industry. The task which lays before us is difficult, but the fruit is worth the toil, as it is the fuel cycle which will govern the growth of the nuclear industry [fr

  16. The integral fast reactor fuel cycle

    International Nuclear Information System (INIS)

    Chang, Y.I.

    1990-01-01

    The liquid-metal reactor (LMR) has the potential to extend the uranium resource by a factor of 50 to 100 over current commercial light water reactors (LWRs). In the integral fast reactor (IFR) development program, the entire reactor system - reactor, fuel cycle, and waste process - is being developed and optimized at the same time as a single integral entity. A key feature of the IFR concept is the metallic fuel. The lead irradiation tests on the new U-Pu-Zr metallic fuel in the Experimental Breeder Reactor II have surpassed 185000 MWd/t burnup, and its high burnup capability has now been fully demonstrated. The metallic fuel also allows a radically improved fuel cycle technology. Pyroprocessing, which utilizes high temperatures and molten salt and molten metal solvents, can be advantageously utilized for processing metal fuels because the product is metal suitable for fabrication into new fuel elements. Direct production of a metal product avoids expensive and cumbersome chemical conversion steps that would result from use of the conventional Purex solvent extraction process. The key step in the IFR process is electrorefining, which provides for recovery of the valuable fuel constituents, uranium and plutonium, and for removal of fission products. A notable feature of the IFR process is that the actinide elements accompany plutonium through the process. This results in a major advantage in the high-level waste management

  17. Long-term uranium supply-demand analyses

    International Nuclear Information System (INIS)

    1986-12-01

    It is the intention of this study to investigate the long-term uranium supply demand situation using a number of supply and demand related assumptions. For supply, these assumptions as used in the Resources and Production Projection (RAPP) model include country economic development status, and consequent lead times for exploration and development, uranium development status, country infrastructure, and uranium resources including the Reasonably Assured (RAR), Estimated Additional, Categories I and II, (EAR-I and II) and Speculative Resource categories. The demand assumptions were based on the ''pure'' reactor strategies developed by the NEA Working Party on Nuclear Fuel Cycle Requirements for the 1986 OECD (NEA)/IAEA reports ''Nuclear Energy and its Fuel Cycle: Prospects to 2025''. In addition for this study, a mixed strategy case was computed using the averages of the Plutonium (Pu) burning LWR high, and the improved LWR low cases. It is understandable that such a long-term analysis cannot present hard facts, but it can show which variables may in fact influence the long-term supply-demand situation. It is hoped that results of this study will provide valuable information for planners in the uranium supply and demand fields. Periodical re-analyses with updated data bases will be needed from time to time

  18. Transparency associated with the nuclear fuel cycle

    International Nuclear Information System (INIS)

    2009-01-01

    The author first recalls that the French nuclear industry works within the frame defined by international treaties and laws which ensure rigor and transparency. He gives some explanations for the resorting to Russian installations and for reprocessed uranium recycling (among them: supply security for the French nuclear industry, strategy of complete use of uranium energetic potential). Then, he outlines how the French State must further improve transparency and pedagogy about radioactive waste and material management. A technical appendix is provided, describing the fuel cycle (natural uranium extraction, conversion and enrichment, fuel fabrication, irradiation, used fuel processing, reprocessed uranium recycling, plutonium recycling in MOX, waste storage), giving an overview of the international supply context (concurrence and security needs), discussing valorization perspectives for materials which are not used in the current fuel cycle, describing the various aspects of radioactive waste management for the various types of wastes (long life, low or high activity for example), describing the control performed by public authorities and organisations

  19. Safety of Long-term Interim Storage Facilities - Workshop Proceedings

    International Nuclear Information System (INIS)

    2014-01-01

    The objective of this workshop was to discuss and review current national activities, plans and regulatory approaches for the safety of long term interim storage facilities dedicated to spent nuclear fuel (SF), high level waste (HLW) and other radioactive materials with prolonged storage regimes. It was also intended to discuss results of experiments and to identify necessary R and D to confirm safety of fuel and cask during the long-term storage. Safety authorities and their Technical Support Organisation (TSO), Fuel Cycle Facilities (FCF) operating organisations and international organisations were invited to share information on their approaches, practices and current developments. The workshop was organised in an opening session, three technical sessions, and a conclusion session. The technical sessions were focused on: - National approaches for long term interim storage facilities; - Safety requirements, regulatory framework and implementation issues; - Technical issues and operational experience, needs for R and D. Each session consisted of a number of presentations followed by a panel discussion moderated by the session Chairs. A summary of each session and subsequent discussion that ensued are provided as well as a summary of the results of the workshop with the text of the papers given and presentations made

  20. International Nuclear Fuel Cycle Fact Book

    International Nuclear Information System (INIS)

    Leigh, I.W.; Mitchell, S.J.

    1990-01-01

    As the US Department of Energy (DOE) and DOE contractors have become increasingly involved with other nations in nuclear fuel cycle and waste management cooperative activities, a need has developed for a ready source of information concerning foreign fuel cycle programs, facilities, and personnel. This Fact Book was compiled to meet that need. The information contained in the International Nuclear Fuel Cycle Fact Book has been obtained from many unclassified sources: nuclear trade journals and newsletters; reports of foreign visits and visitors; CEC, IAEA, and OECD/NEA activities reports; proceedings of conferences and workshops, etc. The data listed do not reflect any one single source but frequently represent a consolidation/combination of information

  1. International nuclear fuel cycle fact book

    International Nuclear Information System (INIS)

    1992-09-01

    The International Nuclear Fuel Cycle Fact Book has been compiled in an effort to provide current data concerning fuel cycle and waste management facilities, R ampersand D programs and key personnel on 23 countries, including the US, four multi-national agencies, and 21 nuclear societies. The Fact Book is organized as follows: National summaries-a section for each country which summarizes nuclear policy, describes organizational relationships, and provides addresses and names of key personnel and information on facilities. International agencies-a section for each of the international agencies which has significant fuel cycle involvement and a listing of nuclear societies. Glossary-a list of abbreviations/acronyms of organizations, facilities, technical and other terms. The national summaries, in addition to the data described above, feature a small map for each country as well as some general information. The latter presented from the perspective of the Fact Book user in the United States

  2. Significant incidents in nuclear fuel cycle facilities

    International Nuclear Information System (INIS)

    1996-03-01

    In contrast to nuclear power plants, events in nuclear fuel cycle facilities are not well documented. The INES database covers all the nuclear fuel cycle facilities; however, it was developed in the early 1990s and does not contain information on events prior to that. The purpose of the present report is to collect significant events and analyze them in order to give a safety related overview of nuclear fuel cycle facilities. Significant incidents were selected using the following criteria: release of radioactive material or exposure to radiation; degradation of items important to safety; and deficiencies in design, quality assurance, etc. which include criticality incidents, fire, explosion, radioactive release and contamination. This report includes an explanation, where possible, of root causes, lessons learned and action taken. 4 refs, 4 tabs

  3. International Nuclear Fuel Cycle Fact Book

    Energy Technology Data Exchange (ETDEWEB)

    Leigh, I.W.

    1992-05-01

    As the US Department of Energy (DOE) and DOE contractors have become increasingly involved with other nations in nuclear fuel cycle and waste management cooperative activities, a need exists costs for a ready source of information concerning foreign fuel cycle programs, facilities, and personnel. This Fact Book has been compiled to meet that need. The information contained in the International Nuclear Fuel Cycle Fact Book has been obtained from many unclassified sources: nuclear trade journals and newsletters; reports of foreign visits and visitors; CEC, IAEA, and OECD/NMEA activities reports; and proceedings of conferences and workshops. The data listed typically do not reflect any single source but frequently represent a consolidation/combination of information.

  4. Possible fuel cycle cost reduction for WWERs

    International Nuclear Information System (INIS)

    Pazdera, F.; Kujal, J.

    1991-01-01

    In this paper possible ways for fuel cycle cost reduction in WWER reactors are discussed. One of the most promising items is the burnup extension. The fuel cycle cost reduction was evaluated for both WWER 440 and WWER 1000 reactors. As a part the CSFR/USSR results obtained in the frame of the IAEA WREBUS study are presented. The main conclusions of this evaluation are: optimum batch average burnup is above 60 MWd/kgU; increasing back end cost strongly increases incentives for burnup extension; large political differences in price calculation for the operation in the fuel cycle back end could in some cases support unoptimal decision, to clarify this is very important. The technical and economical aspects of the last item are discussed. (author). 5 refs, 4 figs, 1 tab

  5. International nuclear fuel cycle fact book

    International Nuclear Information System (INIS)

    Leigh, I.W.; Lakey, L.T.; Schneider, K.J.; Silviera, D.J.

    1987-01-01

    As the US Department of Energy (DOE) and DOE contractors have become increasingly involved with other nations in nuclear fuel cycle and waste management cooperative activities, a need has developed for a ready source of information concerning foreign fuel cycle programs, facilities, and personnel. This Fact Book was compiled to meet that need. The information contained has been obtained from nuclear trade journals and newsletters; reports of foreign visits and visitors; CEC, IAEA, and OECD/NEA activities reports; proceedings of conferences and workshops; and so forth. Sources do not agree completely with each other, and the data listed herein does not reflect any one single source but frequently is a consolidation/combination of information. Lack of space as well as the intent and purpose of the Fact Book limit the given information to that pertaining to the Nuclear Fuel Cycle and to data considered of primary interest or most helpful to the majority of users

  6. International nuclear fuel cycle fact book

    International Nuclear Information System (INIS)

    Leigh, I.W.

    1988-01-01

    As the US Department of Energy (DOE) and DOE contractors have become increasingly involved with other nations in nuclear fuel cycle and waste management cooperative activities, a need has developed for a ready source or information concerning foreign fuel cycle programs, facilities, and personnel. This Fact Book was compiled to meet that need. The information contained has been obtained from nuclear trade journals and newsletters; reports of foreign visits and visitors; CEC, IAEA, and OECD/NEA activities reports; proceedings of conferences and workshops; and so forth. Sources do not agree completely with each other, and the data listed herein does not reflect any one single source but frequently is consolidation/combination of information. Lack of space as well as the intent and purpose of the Fact Book limit the given information to that pertaining to the Nuclear Fuel Cycle and to data considered of primary interest or most helpful to the majority of users

  7. International nuclear fuel cycle fact book

    Energy Technology Data Exchange (ETDEWEB)

    Leigh, I.W.

    1988-01-01

    As the US Department of Energy (DOE) and DOE contractors have become increasingly involved with other nations in nuclear fuel cycle and waste management cooperative activities, a need has developed for a ready source or information concerning foreign fuel cycle programs, facilities, and personnel. This Fact Book was compiled to meet that need. The information contained has been obtained from nuclear trade journals and newsletters; reports of foreign visits and visitors; CEC, IAEA, and OECD/NEA activities reports; proceedings of conferences and workshops; and so forth. Sources do not agree completely with each other, and the data listed herein does not reflect any one single source but frequently is consolidation/combination of information. Lack of space as well as the intent and purpose of the Fact Book limit the given information to that pertaining to the Nuclear Fuel Cycle and to data considered of primary interest or most helpful to the majority of users.

  8. International Nuclear Fuel Cycle Fact Book

    Energy Technology Data Exchange (ETDEWEB)

    Leigh, I W; Mitchell, S J

    1990-01-01

    As the US Department of Energy (DOE) and DOE contractors have become increasingly involved with other nations in nuclear fuel cycle and waste management cooperative activities, a need has developed for a ready source of information concerning foreign fuel cycle programs, facilities, and personnel. This Fact Book was compiled to meet that need. The information contained in the International Nuclear Fuel Cycle Fact Book has been obtained from many unclassified sources: nuclear trade journals and newsletters; reports of foreign visits and visitors; CEC, IAEA, and OECD/NEA activities reports; proceedings of conferences and workshops, etc. The data listed do not reflect any one single source but frequently represent a consolidation/combination of information.

  9. International Nuclear Fuel Cycle Fact Book

    International Nuclear Information System (INIS)

    Leigh, I.W.

    1992-05-01

    As the US Department of Energy (DOE) and DOE contractors have become increasingly involved with other nations in nuclear fuel cycle and waste management cooperative activities, a need exists costs for a ready source of information concerning foreign fuel cycle programs, facilities, and personnel. This Fact Book has been compiled to meet that need. The information contained in the International Nuclear Fuel Cycle Fact Book has been obtained from many unclassified sources: nuclear trade journals and newsletters; reports of foreign visits and visitors; CEC, IAEA, and OECD/NMEA activities reports; and proceedings of conferences and workshops. The data listed typically do not reflect any single source but frequently represent a consolidation/combination of information

  10. The Role of Local and Remote Anthropogenic Aerosol Forcing on Long-term Variations in the South Asian Monsoon Annual Cycle

    Science.gov (United States)

    Bollasina, M. A.; Ming, Y.; Ramaswamy, V.

    2013-12-01

    Detection and attribution of long-term variations of the South Asian monsoon is of extreme importance: even small changes in the onset and duration of the monsoon season or in the spatial distribution of the seasonal mean precipitation may severely impact agriculture, health, water availability, ecosystems, and economy for a substantial fraction of the world's population. In the past decades emissions of aerosols have dramatically increased over South Asia due to rapid urbanization and population growth. As a result, the study of the impact of anthropogenic aerosols on the monsoon has recently emerged as one of the topics of highest priority in the scientific community. This study makes use of a state-of-the-art coupled climate model, the GFDL CM3, to investigate two aspects of the aerosol influence on the observed late 20th century changes in the monsoon annual cycle. The model has fully-interactive aerosols and a representation of both direct and indirect aerosol effects. Aerosols are responsible for an earlier shift of the monsoon onset over India, leading, in agreement with observations, to enhanced precipitation in June over most parts of the subcontinent. Our experiments show that the shift is preceded in early spring by strong aerosol forcing over the Bay of Bengal and Indochina, mostly attributable to the direct effect, resulting in increased atmospheric stability that inhibits the monsoon migration in May. The adjusted atmospheric circulation leads to thermodynamical changes over the northwestern continental region, including increased surface heating and near-surface moist static energy, which support a stronger June flow and, facilitated by a relative warming of the Indian Ocean, a vigorous northwestward precipitation shift. These findings underscore the importance of dynamical feedbacks and regional land-surface processes for the aerosol-monsoon link. We also performed historical experiments with time-evolving radiative forcings aimed at isolating the

  11. Effect of long-term inhalation of uranium dust on balance of certain metabolites and enzymes of Krebs cycle on rat kidney tissues

    International Nuclear Information System (INIS)

    Sarsenova, L.K.; Mustafina, R.Kh.

    2010-01-01

    Kidney is the main organ for transportation and cumulation of soluble radioactive nuclides. The changing of bioenergetic processes has the most value for investigation of kidney infringements nature. Purpose of study: exploring the changing dynamics of Krebs cycle dehydrogenases activity and of tricarbonic acid content in rat kidney tissues after long-term inhalation of Uranium ore dust (UOD) for 10 mpc and application of licorice root aqueous solution. The investigation had been performed on winter breeding white out bred male rats which body weight was 120-140 g. UOD inhalation had been conducted in exposure chamber during the 120 days,4 hours per day 5 days per week. Licorice root aqueous solution was injected per os in dose 100 mg/kg 30 days after the inhalation. Isocitric (ICA) and malic acids (MA) were quantified by Hohorost enzymatic method. Activity rate of a-Ketoglutarate, Malat, Succinate and Isocitrate dehydrogenases (AKDG, MDG, SDG, IDG) in the kidney tissue was determined by Kun and Abood method in modification of Oda and Okazaki and Natochin, and assessed by reduction of Neotetrazolium. As control groups intact rats (norm) and intact animals (control) which stood in exposure chamber without UOD 4 hours/day 5 days in week were serving. Each group of 6-10 animals consisted. Data was processed statistically. At UOD inhalation in 10 mpc doze during the first 30 days the ICA content level has decreased more than in 2 times, by 90-th days this indicator has grown in 4 times and has exceeded control on 70 %. By the experiment end for 120 days the level of ICA has decreased, coming nearer to the control. Decrease in concentration of the MA was longer. The decrease maximum - in 2,2 times - has been fixed for 90-s' days of an inhalation. In the subsequent term - to the 120-th day -there was an increase of concentration to the level comparable to the control. Character and depth of radiation influence of the long inhalation of UOD are shown by change of a parity

  12. 1. round table - Spent fuels composition. Back-end of the fuel cycle and reprocessing, plutonium and other nuclear materials management. 2. round table - Separation-transmutation. 3. round table - Scenarios for a long term inventory of nuclear materials and wastes; 1. table ronde - La composition des combustibles uses. L'aval du combustible et le retraitement, la gestion du plutonium et des autres matieres nucleaires. 2. table ronde - Separation-transmutation. 3. table ronde - Scenarii pour un inventaire des matieres et des dechets nucleaires a LT

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2005-07-01

    The law from December 30, 1991, precisely defines 3 axes of researches for the management of high level and long-lived radioactive wastes: separation/transmutation, surface storage and underground disposal. A global evaluation report about these researches is to be supplied in 2006 by the French government to the Parliament. A first synthesis of the knowledge gained after 14 years of research has led the national commission of the public debate (CNDP) to organize a national debate about the general options of management of high-level and long-lived radioactive wastes before the 2006 date line. The debate comprises 4 public hearings (September 2005: Bar-le-Duc, Saint-Dizier, Pont-du-Gard, Cherbourg), 12 round-tables (October and November 2005: Paris, Joinville, Caen, Nancy, Marseille), a synthesis meeting (December 2005, Dunkerque) and a closing meeting (January 2006, Lyon). This document is the synthesis of the round table debates which took place at Paris on the reprocessing of spent fuels. Three aspects are discussed: the risks linked with the recovery of valorizable materials, the economical viability of the separation/transmutation option, and the future of the nuclear option in the French energy policy. Six presentations (transparencies) are attached with these proceedings which treat of: the reprocessing/recycling to the test, perspectives of future wastes, present day wastes/valorizable materials and future scenarios, critical analysis scenarios, why reprocessing spent fuels?, processing of spent fuels and recycling, separation and transmutation of long-lived radioactive wastes, thorium-uranium cycle. (J.S.)

  13. Fuel cycle for a fusion neutron source

    Science.gov (United States)

    Ananyev, S. S.; Spitsyn, A. V.; Kuteev, B. V.

    2015-12-01

    The concept of a tokamak-based stationary fusion neutron source (FNS) for scientific research (neutron diffraction, etc.), tests of structural materials for future fusion reactors, nuclear waste transmutation, fission reactor fuel production, and control of subcritical nuclear systems (fusion-fission hybrid reactor) is being developed in Russia. The fuel cycle system is one of the most important systems of FNS that provides circulation and reprocessing of the deuterium-tritium fuel mixture in all fusion reactor systems: the vacuum chamber, neutral injection system, cryogenic pumps, tritium purification system, separation system, storage system, and tritium-breeding blanket. The existing technologies need to be significantly upgraded since the engineering solutions adopted in the ITER project can be only partially used in the FNS (considering the capacity factor higher than 0.3, tritium flow up to 200 m3Pa/s, and temperature of reactor elements up to 650°C). The deuterium-tritium fuel cycle of the stationary FNS is considered. The TC-FNS computer code developed for estimating the tritium distribution in the systems of FNS is described. The code calculates tritium flows and inventory in tokamak systems (vacuum chamber, cryogenic pumps, neutral injection system, fuel mixture purification system, isotope separation system, tritium storage system) and takes into account tritium loss in the fuel cycle due to thermonuclear burnup and β decay. For the two facility versions considered, FNS-ST and DEMO-FNS, the amount of fuel mixture needed for uninterrupted operation of all fuel cycle systems is 0.9 and 1.4 kg, consequently, and the tritium consumption is 0.3 and 1.8 kg per year, including 35 and 55 g/yr, respectively, due to tritium decay.

  14. Partially closed fuel cycle of WWER-440

    International Nuclear Information System (INIS)

    Darilek, P.; Sebian, V.; Necas, V.

    2002-01-01

    Position of nuclear energy at the energy sources competition is characterised briefly. Multi-tier transmutation system is outlined out as effective back-end solution and consequently as factor that can increase nuclear energy competitiveness. LWR and equivalent WWER are suggested as a first tier reactors. Partially closed fuel cycle with combined fuel assemblies is briefed. Main back-end effects are characterised (Authors)

  15. Microwave processing in MOX fuel cycle

    Energy Technology Data Exchange (ETDEWEB)

    Mallik, G.K. [Advanced Fuel Fabrication Facility, BARC, Tarapur, PO Ghivali, Thane 401 502, Maharasthra (India)]. E-mail: gatiwant@hotmail.com; Malav, R.K.; Panakkal, J.P. [Advanced Fuel Fabrication Facility, BARC, Tarapur, PO Ghivali, Thane 401 502, Maharasthra (India)]. E-mail: panakkal@apsara.barc.ernet.in; Kamath, H.S. [Advanced Fuel Fabrication Facility, BARC, Tarapur, PO Ghivali, Thane 401 502, Maharasthra (India)]. E-mail: hskamath@magnum.barc.ernet.in

    2005-07-01

    The prominent aspect of the microwave heating technique applications in nuclear material processing is its eco-friendly status. It is envisaged that no active liquid waste will be generated from microwave processing. AFFF has fabricated the (U, Pu){sub 2}O mixed oxide fuels for PHWRs, BWRs and PFBR. AFFF is also working for the AHWR fuel cycle. The present paper summarises about the process experiments, instrumental development, results, and future applications of microwave heating technique. (author)

  16. Fueling the Cell Division Cycle.

    Science.gov (United States)

    Salazar-Roa, María; Malumbres, Marcos

    2017-01-01

    Cell division is a complex process with high energy demands. However, how cells regulate the generation of energy required for DNA synthesis and chromosome segregation is not well understood. Recent data suggest that changes in mitochondrial dynamics and metabolic pathways such as oxidative phosphorylation (OXPHOS) and glycolysis crosstalk with, and are tightly regulated by, the cell division machinery. Alterations in energy availability trigger cell-cycle checkpoints, suggesting a bidirectional connection between cell division and general metabolism. Some of these connections are altered in human disease, and their manipulation may help in designing therapeutic strategies for specific diseases including cancer. We review here recent studies describing the control of metabolism by the cell-cycle machinery. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Sodium fast reactors with closed fuel cycle

    CERN Document Server

    Raj, Baldev; Vasudeva Rao, PR 0

    2015-01-01

    Sodium Fast Reactors with Closed Fuel Cycle delivers a detailed discussion of an important technology that is being harnessed for commercial energy production in many parts of the world. Presenting the state of the art of sodium-cooled fast reactors with closed fuel cycles, this book:Offers in-depth coverage of reactor physics, materials, design, safety analysis, validations, engineering, construction, and commissioning aspectsFeatures a special chapter on allied sciences to highlight advanced reactor core materials, specialized manufacturing technologies, chemical sensors, in-service inspecti

  18. Reprocessing in the thorium fuel cycle

    International Nuclear Information System (INIS)

    Merz, E.

    1984-01-01

    An overview of the authors personal view is presented on open questions in regard to still required research and development work for the thorium fuel cycle before its application in a technical-industrial scale may be tackled. For a better understanding, all stations of the back-end of the thorium fuel cycle are briefly illustrated and their special features discussed. They include storage and transportation measures, all steps of reprocessing, as well as the entire radioactive waste treatment. Knowledge gaps are, as far as they are obvious, identified and proposals put forward for additional worthwile investigations. (orig.) [de

  19. Suggestions for future Pu fuel cycle designs

    International Nuclear Information System (INIS)

    Serfontein, Dawid E.; Mulder, Eben J.; Reitsma, Frederik

    2013-01-01

    Recommended follow-up Pu Studies: • Verification of VSOP-A vs. VSOP 99/05, by comparison with MCNP. • DLOFC temperatures with Multi-group Tinte. • Redesign of the reactor: - Replace small concentrated Pu fuel kernels with large (500 μm diameter) diluted kernels to reduce burn-up. - Switch from the direct Brayton cycle to the indirect Rankine steam cycle to reduce fuel temperatures. - Add neutron poisons to the reflectors to suppress power and temperature peaks and to produce negative uniform temperature reactivity coefficients

  20. Nuclear fuel cycles: Adjusting to new realities

    International Nuclear Information System (INIS)

    Semenov, B.A.; Oi, N.

    1993-01-01

    This article presents a brief overview of developments, and describes a number of international activities being undertaken by the IAEA through its programme covering the nuclear fuel cycle. The activities fall into four areas: uranium resources; reactor fuel performance and technology; spent fuel management; and nuclear fuel cycle evaluation. Additionally, important work is being done through sub-programmes related to structural materials used in the nuclear industry. Throughout the nuclear fuel cycle, facilities have been plagued over the years with problems associated with some types of materials subjected to irradiation. Degradation of their mechanical and physical properties have led to the failure of components and costly downtime of reactors. The corrosion of metals and alloys continues to pose serious difficulties. These and other technical matters are being addressed internationally with the Agency's involvement and support. The Agency has been a center of information on uranium geology, exploration, mining, ore processing, and the analysis of supply and demand for many years. Current work further covers the closure of uranium mining and milling projects from the point of view of safety, environmental protection, economics, and licensing. Emphasis also is placed on supporting technical co-operation projects in countries seeking assistance in developing their peaceful nuclear programmes and fuel-cycle capabilities. An International Working Group on Nuclear Fuel Performance and Technology (IWGFPT), which was established in 1977, continues to guide the IAEA's work in the area of fuel design, fabrication, and performance. It now consists of 25 Member States and three international organizations and acts as a forum for contact between developed and developing countries. The IAEA's Regular Advisory Group on Spent Fuel Management was established in 1984. The Group meets every second year to provide technical advice on the Agency's programme and serves as a

  1. Nuclear Fuel Cycle System Analysis (II)

    Energy Technology Data Exchange (ETDEWEB)

    Ko, Won Il; Kwon, Eun Ha; Yoon, Ji Sup; Park, Seong Won

    2007-04-15

    As a nation develops strategies that provide nuclear energy while meeting its various objectives, it must begin with identification of a fuel cycle option that can be best suitable for the country. For such a purpose, this paper takes four different fuel cycle options that are likely adopted by the Korean government, considering the current status of nuclear power generation and the 2nd Comprehensive Nuclear Energy Promotion Plan (CNEPP) - Once-through Cycle, DUPIC Recycle, Thermal Reactor Recycle and GEN-IV Recycle. The paper then evaluates each option in terms of sustainability, environment-friendliness, proliferation-resistance, economics and technologies. Like all the policy decision, however, a nuclear fuel cycle option can not be superior in all aspects of sustainability, environment-friendliness, proliferation-resistance, economics, technologies and so on, which makes the comparison of the options extremely complicated. Taking this into consideration, the paper analyzes all the four fuel cycle options using the Multi-Attribute Utility Theory (MAUT) and the Analytic Hierarchy Process (AHP), methods of Multi-Attribute Decision Making (MADM), that support systematical evaluation of the cases with multi- goals or criteria and that such goals are incompatible with each other. The analysis shows that the GEN-IV Recycle appears to be most competitive.

  2. Variants of Regenerated Fissile Materials Usage in Thermal Reactors as the First Stage of Fuel Cycle Closing

    Science.gov (United States)

    Andrianova, E. A.; Tsibul'skiy, V. F.

    2017-12-01

    At present, 240 000 t of spent nuclear fuel (SF) has been accumulated in the world. Its long-term storage should meet safety conditions and requires noticeable finances, which grow every year. Obviously, this situation cannot exist for a long time; in the end, it will require a final decision. At present, several variants of solution of the problem of SF management are considered. Since most of the operating reactors and those under construction are thermal reactors, it is reasonable to assume that the structure of the nuclear power industry in the near and medium-term future will be unchanged, and it will be necessary to utilize plutonium in thermal reactors. In this study, different strategies of SF management are compared: open fuel cycle with long-term SF storage, closed fuel cycle with MOX fuel usage in thermal reactors and subsequent long-term storage of SF from MOX fuel, and closed fuel cycle in thermal reactors with heterogeneous fuel arrangement. The concept of heterogeneous fuel arrangement is considered in detail. While in the case of traditional fuel it is necessary to reprocess the whole amount of spent fuel, in the case of heterogeneous arrangement, it is possible to separate plutonium and 238U in different fuel rods. In this case, it is possible to achieve nearly complete burning of fissile isotopes of plutonium in fuel rods loaded with plutonium. These fuel rods with burned plutonium can be buried after cooling without reprocessing. They would contain just several percent of initially loaded plutonium, mainly even isotopes. Fuel rods with 238U alone should be reprocessed in the usual way.

  3. Analysis of Korean Nuclear Fuel Cycle System by Using DANESS Code

    International Nuclear Information System (INIS)

    Jeong, Chang Joon

    2009-08-01

    Korean fast reactor scenarios have been analyzed for various kinds of conversion ratio (CR) by the DANESS system dynamic analysis code. The once-through fuel cycle analysis was modeled based on the Korean 'National Energy Basic Plan' up to 2030 and a postulated nuclear demand growth rate until 2150. The fast reactor scenario analysis has been performed for three kinds of conversion ratios such as 0.3, 0.61 and 1.0. Through the calculations, the nuclear reactor deployment scenario, front-end cycle, back-end cycle, and long-term heat load have been investigated. From the once-through results, it is shown that the nuclear power demand would be ∼70 GWe and the total amount of the spent fuel accumulated by 2150 would be ∼168000 t. The fast reactor (FR) scenario analysis results show that the spent fuel inventory and out-pile transuranic element (TRU) can be reduced by increasing the fast reactor conversion ratio. Furthermore, the long-term heat load of spent fuel decreases with increasing the conversion ratio. However, it is known that the deployment of a fast reactor of low conversion ratio does not much reduce the spent fuel and out-pile TRU inventory due to the fast reactor deployment limitation which is related to the availability of TRU

  4. Verifiable Fuel Cycle Simulation Model (VISION): A Tool for Analyzing Nuclear Fuel Cycle Futures

    International Nuclear Information System (INIS)

    Jacobson, Jacob J.; Piet, Steven J.; Matthern, Gretchen E.; Shropshire, David E.; Jeffers, Robert F.; Yacout, A.M.; Schweitzer, Tyler

    2010-01-01

    The nuclear fuel cycle consists of a set of complex components that are intended to work together. To support the nuclear renaissance, it is necessary to understand the impacts of changes and timing of events in any part of the fuel cycle system such as how the system would respond to each technological change, a series of which moves the fuel cycle from where it is to a postulated future state. The system analysis working group of the United States research program on advanced fuel cycles (formerly called the Advanced Fuel Cycle Initiative) is developing a dynamic simulation model, VISION, to capture the relationships, timing, and changes in and among the fuel cycle components to help develop an understanding of how the overall fuel cycle works. This paper is an overview of the philosophy and development strategy behind VISION. The paper includes some descriptions of the model components and some examples of how to use VISION. For example, VISION users can now change yearly the selection of separation or reactor technologies, the performance characteristics of those technologies, and/or the routing of material among separation and reactor types - with the model still operating on a PC in <5 min.

  5. Introduction: Long term prediction

    International Nuclear Information System (INIS)

    Beranger, G.

    2003-01-01

    Making a decision upon the right choice of a material appropriate to a given application should be based on taking into account several parameters as follows: cost, standards, regulations, safety, recycling, chemical properties, supplying, transformation, forming, assembly, mechanical and physical properties as well as the behaviour in practical conditions. Data taken from a private communication (J.H.Davidson) are reproduced presenting the life time range of materials from a couple of minutes to half a million hours corresponding to applications from missile technology up to high-temperature nuclear reactors or steam turbines. In the case of deep storage of nuclear waste the time required is completely different from these values since we have to ensure the integrity of the storage system for several thousand years. The vitrified nuclear wastes should be stored in metallic canisters made of iron and carbon steels, stainless steels, copper and copper alloys, nickel alloys or titanium alloys. Some of these materials are passivating metals, i.e. they develop a thin protective film, 2 or 3 nm thick - the so-called passive films. These films prevent general corrosion of the metal in a large range of chemical condition of the environment. In some specific condition, localized corrosion such as the phenomenon of pitting, occurs. Consequently, it is absolutely necessary to determine these chemical condition and their stability in time to understand the behavior of a given material. In other words the corrosion system is constituted by the complex material/surface/medium. For high level nuclear wastes the main features for resolving problem are concerned with: geological disposal; deep storage in clay; waste metallic canister; backfill mixture (clay-gypsum) or concrete; long term behavior; data needed for modelling and for predicting; choice of appropriate solution among several metallic candidates. The analysis of the complex material/surface/medium is of great importance

  6. Long-Term Symbolic Learning

    National Research Council Canada - National Science Library

    Kennedy, William G; Trafton, J. G

    2007-01-01

    What are the characteristics of long-term learning? We investigated the characteristics of long-term, symbolic learning using the Soar and ACT-R cognitive architectures running cognitive models of two simple tasks...

  7. The industrial nuclear fuel cycle in Argentina

    International Nuclear Information System (INIS)

    Koll, J.H.; Kittl, J.E.; Parera, C.A.; Coppa, R.C.; Aguirre, E.J.

    1977-01-01

    The nuclear power program of Argentina for the period 1976-85 is described, as a basis to indicate fuel requirements and the consequent implementation of a national fuel cycle industry. Fuel cycle activities in Argentina were initiated as soon as 1951-2 in the prospection and mining activities through the country. Following this step, yellow-cake production was initiated in plants of limited capacity. National production of uranium concentrate has met requirements up to the present time, and will continue to do so until the Sierra Pintada Industrial Complex starts operation in 1979. Presently, there is a gap in local production of uranium dioxide and fuel elements for the Atucha power station, which are produced abroad using Argentine uranium concentrate. With its background, the argentine program for the installation of nuclear fuel cycle industries is described, and the techno-economical implications considered. Individual projects are reviewed, as well as the present and planned infrastructure needed to support the industrial effort [es

  8. LONG TERM COLLECTIONS

    CERN Multimedia

    STAFF ASSOCIATION

    2010-01-01

    ACKNOWLEDGMENTS The Long-Term Collections (CLT) committee would like to warmly thank its faithful donors who, year after year, support our actions all over the world. Without you, all this would not be possible. We would like to thank, in particular, the CERN Firemen’s Association who donated 5000 CHF in the spring thanks to the sale of their traditional calendar, and the generosity of the CERN community. A huge thank you to the firemen for their devotion to our cause. And thank you to all those who have opened their door, their heart, and their purses! Similarly, we warmly thank the CERN Yoga Club once again for its wonderful donation of 2000 CHF we recently received. We would also like to tell you that all our projects are running well. Just to remind you, we are currently supporting the activities of the «Réflexe-Partage» Association in Mali; the training centre of «Education et Développement» in Abomey, Benin; and the orphanage and ...

  9. Possibility of regional fuel cycle centres in the context of Bangladesh

    International Nuclear Information System (INIS)

    Innas, A.M.; Ahsan, M.; Husain, S.R.; Chowdhury, R.K.; Rahman, A.

    1977-01-01

    The region consisting of Afghanistan, Pakistan, India, Ceylon, Bangladesh, Burma, Malaysia, Thailand, Singapore and Indonesia is considered for a model study on the possibility of establishing regional fuel cycle centres. Nuclear power generation capacity for this region is estimated and projected through 2000 A.D. and accordingly the demands for various nuclear fuel cycle services are determined. Preliminary calculations show that for the region conversion and fuel fabrication plants may be economically feasible before 1990 whereas reprocessing plants may become feasible only after 1990. The possibility of enrichment plant is even more uncertain. Ore, enrichment and fabrication in future may constitute more than 95-98% of the total fuel cycle cost. For fuel cycle economy, therefore, regional cooperation should be emphasized for these services. Reprocessing has to be considered because of the valuable fissile materials present in the spent fuel. Assuming that regional fuel cycle centre/centres may be established in Bangladesh, the study considered the local advantages and disadvantages of such an effort. Though no major problem could be identified in the case of conversion and fabrication plants, considerable difficulty is anticipated from a large reprocessing plant because of waste management and disposal problems. Bangladesh does not appear to have any suitable waste disposal site in view of the present technology. However, if the long term leaching problemns of solidified wastes are resolved then wastes may be dumped in the sea-canyon in the Bay of Bengal (called the ''Swatch of no ground'') or in the deep underground caverns

  10. Concept for fuel-cycle based safeguards

    International Nuclear Information System (INIS)

    deMontmollin, J.M.; Higinbotham, W.A.; Gupta, D.

    1985-01-01

    Although the guidelines for NPT safeguards specify that the State's fuel cycle and degree of international independence are to be taken into account, the same model approach and absolute-quantity inspection goals are applied to all similar facilities, irrespective of the State's fuel cycle, and the findings are reported in those terms. A concept whereby safeguards might more effectively and efficiently accomplish the purposes of NPT safeguards is explored. The principal features are: (1) division of the fuel cycle into three zones, each containing material having a different degree of significance for safeguards; (2) closing a verified material balance around each zone, supplementing the present MBA balances for more sensitive facilities and replacing them for others; (3) maintenance by the IAEA of a current book inventory for each facility by means of immediate, abbreviated reporting of interfacility transfers; (4) near real-time analysis of material flow patterns through the fuel cycle; and (5) a periodic statement of the findings for the entire State that takes the form that there is assurance that all nuclear materials under safeguards are accounted for to some stated degree of uncertainty

  11. Nuclear fuel cycle cost and cost calculation

    International Nuclear Information System (INIS)

    Schmiedel, P.; Schricker, W.

    1975-01-01

    Four different methods of calculating the cost of the fuel cycle are explained, starting from the individual cost components with their specific input data. The results (for LWRs) are presented in tabular form and in the form of diagrams. (RB) [de

  12. Waste management and the nuclear fuel cycle

    International Nuclear Information System (INIS)

    Molinari, J.

    1982-01-01

    The present lecture deals with energy needs and nuclear power, the importance of waste and its relative place in the fuel cycle, the games of controversies over nuclear waste in the strategies of energy and finally with missions and functions of the IAEA for privileging the rational approach and facilitating the transfer of technology. (RW)

  13. High Conversion Thorium Fuel Cycle for PWRs

    International Nuclear Information System (INIS)

    Shwageraus, Eugene; Volasky, Daphna; Fridman, Emil

    2008-01-01

    This study explores the basic possibility of achieving a self-sustainable Th- 233 U fuel cycle that can be adopted in the current generation of Pressurized Water Reactors. The study outlines possible core design strategies of a typical PWR in order to achieve Breeding Ratio (BR) close to unity. Major design tradeoffs in the core design are discussed. Preliminary neutronic analysis performed on the fuel assembly level with BOXER computer code suggests that net breeding of 233 U is feasible in principle within a typical PWR operating envelope. However, some reduction in the core power density and/or shorter than typical fuel cycle length would most likely be required in order to achieve such performance. (authors)

  14. Long-term safety for the final repository for spent nuclear fuel at Forsmark. Main report of the SR-Site project

    Energy Technology Data Exchange (ETDEWEB)

    2011-03-15

    The central conclusion of the safety assessment SR-Site is that a KBS-3 repository that fulfils long-term safety requirements can be built at the Forsmark site. This conclusion is reached because the favourable properties of the Forsmark site ensure the required long-term durability of the barriers of the KBS-3 repository. In particular, the copper canisters with their cast iron inserts have been demonstrated to provide a sufficient resistance to the mechanical and chemical loads to which they may be subjected in the repository environment. The conclusion is underpinned by: - The reliance of the KBS-3 repository on i) a geological environment that exhibits long-term stability with respect to properties of importance for long-term safety, i.e. mechanical stability, low groundwater flow rates at repository depth and the absence of high concentrations of detrimental components in the groundwater, and ii) the choice of naturally occurring materials (copper and bentonite clay) for the engineered barriers that are sufficiently durable in the repository environment to provide the barrier longevity required for safety. - The understanding, through decades of research at SKB and in international collaboration, of the phenomena that affect long-term safety, resulting in a mature knowledge base for the safety assessment. - The understanding of the characteristics of the site through several years of surface-based investigations of the conditions at depth and of scientific interpretation of the data emerging from the investigations, resulting in a mature model of the site, adequate for use in the safety assessment. - The detailed specifications of the engineered parts of the repository and the demonstration of how components fulfilling the specifications are to be produced in a quality assured manner, thereby providing a quality assured initial state for the safety assessment. The detailed analyses demonstrate that canister failures in a one million year perspective are rare

  15. Long-term safety for the final repository for spent nuclear fuel at Forsmark. Main report of the SR-Site project

    International Nuclear Information System (INIS)

    2011-03-01

    The central conclusion of the safety assessment SR-Site is that a KBS-3 repository that fulfils long-term safety requirements can be built at the Forsmark site. This conclusion is reached because the favourable properties of the Forsmark site ensure the required long-term durability of the barriers of the KBS-3 repository. In particular, the copper canisters with their cast iron inserts have been demonstrated to provide a sufficient resistance to the mechanical and chemical loads to which they may be subjected in the repository environment. The conclusion is underpinned by: - The reliance of the KBS-3 repository on i) a geological environment that exhibits long-term stability with respect to properties of importance for long-term safety, i.e. mechanical stability, low groundwater flow rates at repository depth and the absence of high concentrations of detrimental components in the groundwater, and ii) the choice of naturally occurring materials (copper and bentonite clay) for the engineered barriers that are sufficiently durable in the repository environment to provide the barrier longevity required for safety. - The understanding, through decades of research at SKB and in international collaboration, of the phenomena that affect long-term safety, resulting in a mature knowledge base for the safety assessment. - The understanding of the characteristics of the site through several years of surface-based investigations of the conditions at depth and of scientific interpretation of the data emerging from the investigations, resulting in a mature model of the site, adequate for use in the safety assessment. - The detailed specifications of the engineered parts of the repository and the demonstration of how components fulfilling the specifications are to be produced in a quality assured manner, thereby providing a quality assured initial state for the safety assessment. The detailed analyses demonstrate that canister failures in a one million year perspective are rare

  16. Fuel Cycle and Waste Newsletter, Vol. 8, No. 3, September 2012

    International Nuclear Information System (INIS)

    2012-09-01

    This Newsletter consists of topics on: - The Disposal of Spent Fuel Is in the Foreseeable Future; - Fuelling the Safe and Secure Use of Nuclear Technologies; - Action Plan Status; Mexican TRIGA Mark III Is Now Fuelled with LEU; - Getting a Research Reactor Up and Running; - Decommissioning Research Reactors; - Preserving of Records, Knowledge and Memory across Generations; - Where Do We Stand with EPPUNE?; - Recovering Irradiators in Costa Rica; - Global Uranium Supply Ensured for Long Term, New 'Red Book' Shows; - Recent Publications; - Introduction of Authors; - Upcoming Meetings 2012; - Division of Nuclear Fuel Cycle and Waste Technology - Web Links and Organizational Structure; - Sneak Preview of the Next Newsletter.

  17. The nuclear fuel cycle versus the carbon cycle

    International Nuclear Information System (INIS)

    Ewing, R.C.

    2005-01-01

    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 significant 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 flexibility 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 significant effect on the fission product yield, and the consumption of long-lived actinides, by fission, is best achieved by fast neutrons. Within each cycle, the volume and composition of the high-level nuclear waste and fissile 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 fissile 233 U with minimum production of Pu. In this paper, I will contrast the production of excess carbon in the form of CO 2 from fossil fuels with

  18. Environmental impact of nuclear fuel cycle operations

    International Nuclear Information System (INIS)

    Wilkinson, W.L.

    1989-09-01

    This paper considers the environmental impact of nuclear fuel cycle operations, particularly those operated by British Nuclear Fuels plc, which include uranium conversion, fuel fabrication, uranium enrichment, irradiated fuel transport and storage, reprocessing, uranium recycle and waste treatment and disposal. Quantitative assessments have been made of the impact of the liquid and gaseous discharges to the environment from all stages in the fuel cycle. An upper limit to the possible health effects is readily obtained using the codified recommendations of the International Commission on Radiological Protection. This contrasts with the lack of knowledge concerning the health effects of many other pollutants, including those resulting from the burning of fossil fuels. Most of the liquid and gaseous discharges result at the reprocessing stage and although their impact on the environment and on human health is small, they have given rise to much public concern. Reductions in discharges at Sellafield over the last few years have been quite dramatic, which shows what can be done provided the necessary very large investment is undertaken. The cost-effectiveness of this investment must be considered. Some of it has gone beyond the point of justification in terms of health benefit, having been undertaken in response to public and political pressure, some of it on an international scale. The potential for significant off-site impact from accidents in the fuel cycle has been quantitatively assessed and shown to be very limited. Waste disposal will also have an insignificant impact in terms of risk. It is also shown that it is insignificant in relation to terrestrial radioactivity and therefore in relation to the human environment. 14 refs, 5 figs, 2 tabs

  19. Fuel cycle and waste management: A perspective from British nuclear fuels plc

    International Nuclear Information System (INIS)

    Holmes, R.G.G.; Fairhall, G.A.; Robbins, R.A.

    1996-01-01

    The phrase fuel cycle and waste management implies two separate and distinct activities. British Nuclear Fuels plc (BNFL) has adopted a holistic approach to the fuel cycle that integrates the traditional fuel cycle activities of conversion to uranium hexafluoride, fuel fabrication, power generation, and reprocessing with waste arisings, its subsequent treatment, and disposal

  20. IAEA Activities in the Area of Fast Reactors and Related Fuels and Fuel Cycles

    International Nuclear Information System (INIS)

    Monti, S.; Basak, U.; Dyck, G.; Inozemtsev, V.; Toti, A.; Zeman, A.

    2013-01-01

    Summary: • The IAEA role to support fast reactors and associated fuel cycle development programmes; • Main IAEA activities on fast reactors and related fuel and fuel cycle technology; • Main IAEA deliverables on fast reactors and related fuel and fuel cycle technology

  1. Nuclear Fuel Cycle Options Catalog FY15 Improvements and Additions

    International Nuclear Information System (INIS)

    Price, Laura L.; Barela, Amanda Crystal; Schetnan, Richard Reed; Walkow, Walter M.

    2015-01-01

    The United States Department of Energy, Office of Nuclear Energy, Fuel Cycle Technology Program sponsors nuclear fuel cycle research and development. As part of its Fuel Cycle Options campaign, the DOE has established the Nuclear Fuel Cycle Options Catalog. The catalog is intended for use by the Fuel Cycle Technologies Program in planning its research and development activities and disseminating information regarding nuclear energy to interested parties. The purpose of this report is to document the improvements and additions that have been made to the Nuclear Fuel Cycle Options Catalog in the 2015 fiscal year.

  2. Nuclear Fuel Cycle Options Catalog: FY16 Improvements and Additions

    Energy Technology Data Exchange (ETDEWEB)

    Price, Laura L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Barela, Amanda Crystal [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Schetnan, Richard Reed [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Walkow, Walter M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2016-08-31

    The United States Department of Energy, Office of Nuclear Energy, Fuel Cycle Technology Program sponsors nuclear fuel cycle research and development. As part of its Fuel Cycle Options campaign, the DOE has established the Nuclear Fuel Cycle Options Catalog. The catalog is intended for use by the Fuel Cycle Technologies Program in planning its research and development activities and disseminating information regarding nuclear energy to interested parties. The purpose of this report is to document the improvements and additions that have been made to the Nuclear Fuel Cycle Options Catalog in the 2016 fiscal year.

  3. Nuclear Fuel Cycle Options Catalog FY15 Improvements and Additions.

    Energy Technology Data Exchange (ETDEWEB)

    Price, Laura L. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Barela, Amanda Crystal [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Schetnan, Richard Reed [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Walkow, Walter M. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)

    2015-11-01

    The United States Department of Energy, Office of Nuclear Energy, Fuel Cycle Technology Program sponsors nuclear fuel cycle research and development. As part of its Fuel Cycle Options campaign, the DOE has established the Nuclear Fuel Cycle Options Catalog. The catalog is intended for use by the Fuel Cycle Technologies Program in planning its research and development activities and disseminating information regarding nuclear energy to interested parties. The purpose of this report is to document the improvements and additions that have been made to the Nuclear Fuel Cycle Options Catalog in the 2015 fiscal year.

  4. Significance of the Nuclear Fuel Cycle in the 21st Century

    International Nuclear Information System (INIS)

    Nash, Kenneth L.; Lumetta, Gregg J.; Clark, Sue B.; Friese, Judah I.

    2006-01-01

    The combined effects of increasing industrialization around the world, the threat of global climate change, and decreasing availability of 'clean' fossil fuels will make the development of alternative energy sources more important in the coming decades. For fission-based nuclear power to contribute significantly to future energy supplies, it will be essential to maintain the improvements that have been made in plant operational efficiency, to license geological repositories for waste disposal, and to consider again the issue of recycling of spent nuclear fuels to recover its fuel value and to reduce the long-term radiotoxicity of the wastes. In this chapter, we present an overview of the nuclear fuel cycle from spent fuel recycling through the repository performance in the context of its importance to energy production in the 21st Century

  5. World nuclear fuel cycle requirements 1989

    International Nuclear Information System (INIS)

    1989-01-01

    This analysis report presents the projected requirements for uranium concentrate and uranium enrichment services to fuel the nuclear power plants expected to be operating under two nuclear supply scenarios. These two scenarios, the Lower Reference and Upper Reference cases, apply to the United States, Canada, Europe, the Far East, and other countries in the World Outside Centrally Planned Economic Areas (WOCA). A No New Orders scenarios is also presented for the Unites States. This report contains an analysis of the sensitivities of the nuclear fuel cycle projections to different levels and types of projected nuclear capacity, different enrichment tails assays, higher and lower capacity factors, changes in nuclear fuel burnup levels, and other exogenous assumptions. The projections for the United States generally extend through the year 2020, and the WOCA projections, which include the United States, are provided through 2010. The report also presents annual projections of spent nuclear fuel; discharges and inventories of spent fuel. Appendix D includes domestic spent fuel projections through the year 2020 for the Lower and Upper Reference cases and through 2036, the last year in which spent fuel is discharged, for the No New Orders case

  6. Vertical integration in the nuclear fuel cycle

    International Nuclear Information System (INIS)

    Mommsen, J.T.

    1977-01-01

    Vertical integration in the nuclear fuel cycle and its contribution to market power of integrated fuel suppliers were studied. The industry subdivision analyzed is the uranium raw materials sector. The hypotheses demonstrated are that (1) this sector of the industry is trending toward vertical integration between production of uranium raw materials and the manufacture of nuclear fuel elements, and (2) this vertical integration confers upon integrated firms a significant market advantage over non-integrated fuel manufacturers. Under microeconomic concepts the rationale for vertical integration is the pursuit of efficiency, and it is beneficial because it increases physical output and decreases price. The Market Advantage Model developed is an arithmetical statement of the relative market power (in terms of price) between non-integrated nuclear fuel manufacturers and integrated raw material/fuel suppliers, based on the concept of the ''squeeze.'' In operation, the model compares net profit and return on sales of nuclear fuel elements between the competitors, under different price and cost circumstances. The model shows that, if integrated and non-integrated competitors sell their final product at identical prices, the non-integrated manufacturer returns a net profit only 17% of the integrated firm. Also, the integrated supplier can price his product 35% below the non-integrated producer's price and still return the same net profit. Vertical integration confers a definite market advantage to the integrated supplier, and the basic source of that advantage is the cost-price differential of the raw material, uranium

  7. A Review of RedOx Cycling of Solid Oxide Fuel Cells Anode

    Science.gov (United States)

    Faes, Antonin; Hessler-Wyser, Aïcha; Zryd, Amédée; Van Herle, Jan

    2012-01-01

    Solid oxide fuel cells are able to convert fuels, including hydrocarbons, to electricity with an unbeatable efficiency even for small systems. One of the main limitations for long-term utilization is the reduction-oxidation cycling (RedOx cycles) of the nickel-based anodes. This paper will review the effects and parameters influencing RedOx cycles of the Ni-ceramic anode. Second, solutions for RedOx instability are reviewed in the patent and open scientific literature. The solutions are described from the point of view of the system, stack design, cell design, new materials and microstructure optimization. Finally, a brief synthesis on RedOx cycling of Ni-based anode supports for standard and optimized microstructures is depicted. PMID:24958298

  8. A Review of RedOx Cycling of Solid Oxide Fuel Cells Anode

    Directory of Open Access Journals (Sweden)

    Jan Van herle

    2012-08-01

    Full Text Available Solid oxide fuel cells are able to convert fuels, including hydrocarbons, to electricity with an unbeatable efficiency even for small systems. One of the main limitations for long-term utilization is the reduction-oxidation cycling (RedOx cycles of the nickel-based anodes. This paper will review the effects and parameters influencing RedOx cycles of the Ni-ceramic anode. Second, solutions for RedOx instability are reviewed in the patent and open scientific literature. The solutions are described from the point of view of the system, stack design, cell design, new materials and microstructure optimization. Finally, a brief synthesis on RedOx cycling of Ni-based anode supports for standard and optimized microstructures is depicted.

  9. Quantitative Characterization of the Surface Evolution for LiNi0.5Co0.2Mn0.3O2/Graphite Cell during Long-Term Cycling.

    Science.gov (United States)

    Zheng, Huiyuan; Qu, Qunting; Zhu, Guobin; Liu, Gao; Battaglia, Vincent S; Zheng, Honghe

    2017-04-12

    Many factors have been brought forward to explain the capacity degradation mechanisms of LiNi x Co y Mn z O 2 (NCM)/graphite cells at extreme conditions such as under high temperature or with high cutoff voltage. However, the main factors dominating the long-term cycling performance under normal operations remain elusive. Quantitative analyses of the electrode surface evolution for a commercial 18650 LiNi 0.5 Co 0.2 Mn 0.3 O 2 (NCM523)/graphite cell during ca. 3000 cycles under normal operation are presented. Electrochemical analyses and inductively coupled plasma-optical emission spectroscopy (ICP-OES) confirm lithium inventory loss makes up for ca. 60% of the cell's capacity loss. Electrochemical deterioration of the NCM523 cathode is identified to be another important factor, which accounts for more than 30% of the capacity decay. Irregular primary particle cracking due to the mechanical stress and the phase change aroused from Li-Ni mixing during repetitive cycles are identified to be the main contributors for the NCM cathode deterioration. The amount of transition metal dissolved into electrolyte is determined to be quite low, and the resulting impedance rise after about 3000 cycles is obtained to be twice that of the reference cell, which are not very significant affecting the long-term cycling performance under normal operations.

  10. Long-term radiotoxicity, in the framework of the ICRP-48, of high level wastes and spent fuels produced by light water reactors: impact of burn-up extension and of the use of mixed oxide fuels

    International Nuclear Information System (INIS)

    Elayi, A.G.; Schapira, J.P.

    1987-01-01

    The time evolution of radiotoxicities of spent fuels and high-level wastes have been calculated up to 10 7 years, in the framework of the recent I.C.R.P.-48 guideline, in which the ratio dose/ingested-activity has been divided by 10 for Np, multiplied by 10 for Pu and by 2 for Am, Cm and Cf, with respect to the previous I.C.R.P.-30 values. In the case of burn-up extension of the standard 33,000 MWd/t enriched uranium fuel, and in the case of plutonium recycle in light-water reactors, one shows that the spent fuel radiotoxicity is now dominated by its plutonium content, most of the time up to about 10 5 years. Possible incineration effects are discussed within these two fuel cycle options

  11. A multi-nuclide approach to quantify long-term erosion rates and exposure history through multiple glacial-interglacial cycles

    DEFF Research Database (Denmark)

    Strunk, Astrid; Larsen, Nicolaj Krog; Knudsen, Mads Faurschou

    possible to resolve the complex pattern of exposure history under a fluctuating ice sheet. In this study, we quantify long-term erosion rates along with durations of multiple exposure periods in West Greenland by applying a novel Markov Chain Monte Carlo (MCMC) inversion approach to existing 10Be and 26Al......) interglacial periods characterized by zero shielding due to overlying ice and a uniform interglacial erosion rate, and ii) glacial periods characterized by 100 % shielding and a uniform glacial erosion rate. We incorporate the exposure/burial history in the model framework by applying a threshold value...... to the global marine benthic d18O record and include the threshold value as a free model parameter, hereby taking into account global changes in climate. The other free parameters include the glacial and interglacial erosion rates as well as the timing of the Holocene deglaciation. The model essentially...

  12. IFR fuel cycle demonstration in the EBR-II Fuel Cycle Facility

    International Nuclear Information System (INIS)

    Lineberry, M.J.; Phipps, R.D.; Rigg, R.H.; Benedict, R.W.; Carnes, M.D.; Herceg, J.E.; Holtz, R.E.

    1991-01-01

    The next major milestone of the IFR (Integral Fast Reactor) program is engineering-scale demonstration of the pyroprocess fuel cycle. The EBR-II Fuel Cycle Facility has just entered a startup phase which includes completion of facility modifications, and installation and cold checkout of process equipment. This paper reviews the design and construction of the facility, the design and fabrication of the process equipment, and the schedule and initial plan for its operation. (author)

  13. Study on the FBR cycle introduction scenario. 4. Evaluation of the FBR cycle introduction scenario from the viewpoints of the fuel cycle requirements

    International Nuclear Information System (INIS)

    Ono, Kiyoshi; Shiotani, Hiroki; Hirao, Kazunori

    2003-07-01

    This report is intended to explain the outline of the scenario studies on FBR (Fast Breeder Reactor) cycle introduction. Recently, people value the reduction of environmental impact in addition to the recycle of energy resources and the energy security in these scenario studies. This report summarizes the analysis about the necessity of plutonium recycling in LWR (Light water Reactor) from short-term view and about the necessity of FBR cycle introduction from a long-term view in Japan, by comparing 'FBR scenario' with 'LWR once-through scenario' and 'Pu recycle in LWR scenario', from the viewpoints of cumulative uranium demand, spent fuel storage, radioactive waste arising, etc. It becomes clear that the plutonium recycling in LWR has a good effect on the reduction of spent fuel storage and the cumulative natural uranium demand before FBR cycle introduction, from short-term view (20-30 years). On the other hand, this analysis also shows that there is much effect of FBR deployment not only on saving amount of uranium use and energy security but also on reduction of high-level radioactive waste (spent fuels and vitrified waste) and minor actinide arising, from long-term view (100-200 years). (author)

  14. Life-cycle of fuel peat

    International Nuclear Information System (INIS)

    Leijting, J.; Silvo, K.

    1998-01-01

    The share of peat in the primary energy supply in Finland in 1996 was about 6.5 % and the area used for peat production was about 535 km 2 , corresponding to about 0.5 % of the original peatland area of Finland. Fuel peat production is hence a significant form of using natural resources. About 1.4 % of the total peatland area has been reserved for peat production. Approximately 95 % of the peat excavated in Finland is used as fuel peat, and 5 % as horticultural peat. As raw material and fuel peat can be considered to be slowly renewable material. The environmental impacts of fuel peat production, transportation and peat combustion were evaluated in this research by methods used in life-cycle assessment. Preparation and production phases of peat production areas, fuel peat transportation to power plants, combustion of peat in power plants, and disposal of the ashes formed the basis for the investigation. Data collected in 1994-1996 was used as the basic material in the research. Special attention was paid to the estimation of greenhouse gas balance when using a virgin bog and the forest drained peatland areas as starting points. Post-production use of peatlands were not inspected in the life-cycle assessment. The work was carried out in 1997 in cooperation with Vapo Oy. The regional environmental centers, VTT and Helsinki and Joensuu Universities assisted significantly in acquisition of the material and planning of the work 3 refs

  15. Economics analysis of fuel cycle cost of fusion–fission hybrid reactors based on different fuel cycle strategies

    Energy Technology Data Exchange (ETDEWEB)

    Zu, Tiejun, E-mail: tiejun@mail.xjtu.edu.cn; Wu, Hongchun; Zheng, Youqi; Cao, Liangzhi

    2015-01-15

    Highlights: • Economics analysis of fuel cycle cost of FFHRs is carried out. • The mass flows of different fuel cycle strategies are established based on the equilibrium fuel cycle model. • The levelized fuel cycle costs of different fuel cycle strategies are calculated, and compared with current once-through fuel cycle. - Abstract: The economics analysis of