Fuel Cycle Options Research Articles

Nuclear technology and its challenges in India

India has a strong technology base for its comprehensive nuclear energy programme. A glimpse of this capability is given in this paper, starting with uranium exploration and mining to fuel reprocessing and nuclear waste management. India has chosen a closed fuel cycle option, and the plutonium recovered from spent fuel will soon be manufactured into fuel elements for its 500 MWe Prototype Fast Breeder Reactor, which is under construction. A modest programme to develop systems for thorium utilisation is being pursued. The nuclear energy development programme includes accelerator-based nuclear reactor systems. India is also a party to the 500 MW nuclear fusion machine ITER, which is under construction at Cadarache, France, under an international cooperation framework.

THE IMPACT OF FUEL CYCLE OPTIONS ON THE SPACE REQUIREMENTS OF A HLW REPOSITORY

Because of increasing concerns regarding global warming and the longevity of oil and gas reserves, the importance of nuclear energy as a major source of sustainable energy is gaining recognition worldwide. To make nuclear energy truly sustainable, it is necessary to ensure not only the sustainability of the fuel supply but also the sustained availability of waste repositories, especially those for high-level radioactive waste (HLW). From this perspective, the effort to maximize the waste loading density in a given repository is important for easing repository capacity problems. In most cases, the loading of a repository is controlled by the decay heat of the emplaced waste. In this paper, a comparison of the decay heat characteristics of HLW is made among the various fuel cycle options. It is suggested that, for a future fast breeder reactor (FBR) cycle, the removal and burning of minor actinides (MA) would significantly reduce the heat load in waste and would allow for a reduction of repository size by half.

WITHDRAWN: DUPIC and other advanced fuel cycle options in Korea

This article has been withdrawn at the request of the editor. The Publisher apologizes for any inconvenience this may cause. The full Elsevier Policy on Article Withdrawal can be found at http://www.elsevier.com/locate/withdrawalpolicy .

Rethinking the Thorium Fuel Cycle: an Industrial Point of View

The use of thorium as a fertile material in combination with a fissile material (either U233, U235 or plutonium) as an alternative to the uranium fuel cycle received a great deal of attention in many venues from the 1950s to the mid 70s. More recently, new studies have been carried out on this cycle for transmutation purposes and several countries such as India still continue to consider the thorium cycle as an attractive option within the framework of their national nuclear programs. The purpose of this paper is to provide an updated overview of the potential of the thorium cycle, taking into account the renewed interest in the development of nuclear energy as currently under consideration for future energy systems. In this paper many of the issues related to the use of thorium at each stage of the nuclear fuel cycle are reviewed from the standpoint of industrial feasibility and economy. First, past experience with using thorium as a fuel for prototype or commercial nuclear reactors, particularly in high temperature reactors, is examined. The neutronic and physic aspects of the thorium in various reactors will be overviewed. Second, updated data on world-wide thorium resources and supplies is presented. Then, the sustainability issues of nuclear energy development with regard to the future availability of natural resources (uranium and thorium) are addressed. After that follows a discussion of the pros and cons of radiological/ nuclear/chemical characteristics of thorium as it relates to the implementation of fuel cycle industrial processes and impacts on the wastes. In particular, the technical aspects of back end fuel cycle issues are examined for both open and closed fuel cycles including reprocessing and recycling technical issues. Also examined are proliferation issues related to the use of the thorium cycle. Accompanying this examination is a comprehensive analysis of the technical features of various thorium fuel cycle options from the standpoint of proliferation resistance. Finally, economical aspects of the thorium fuel cycle are addressed. In summary, these analyses permit the reader to draw some general conclusions regarding the use of the thorium cycle for the development of a sustainable nuclear energy system.

Fuel Cycle Options for the Production and Utilization of Denatured Plutonium

Denatured reactor plutonium with a 238Pu isotopic content of ˜6% or somewhat more can be produced in a suitably adapted fuel cycle. Several such fuel cycle options are proposed. Reenriched reprocessed 235U/236U/238U, which can be blended with some low-enriched 235U/238U fuel, leads, after one burnup cycle of 50 to 60 GWd/tonne in a pressurized water reactor (PWR) core, to denatured reactor plutonium with more than 8% 238Pu isotopic content. Presently existing reactor plutonium with ˜2.8% 238Pu from spent fuel with a burnup of 50 GWd/tonne can also be converted in PWRs, during one or two burnup cycles over 50 to 60 GWd/tonne into denatured reactor plutonium. This is also demonstrated by burnup calculations for different fuel cycle scenarios using, e.g., reenriched reprocessed uranium, thorium, and minor actinides. Denatured reactor plutonium with 6% or somewhat more 238Pu isotopic content can be considered as a proliferation-resistant fuel and could be treated like low-enriched (<20% 235U) uranium fuel. It can be incinerated by multiple recycling in PWRs or fast reactors. Advanced aqueous reprocessing or pyroprocessing as well as related refabrication methods, as they are being developed for transmutation scenarios of the minor actinides, would be best suited for such adapted fuel cycle options. Safeguards needs and aspects for the different proposed fuel cycle options are discussed.

Scenario Analyses of Future UK Fuel Cycle Options

As an international nuclear company and one which is involved throughout the nuclear fuel cycle, a complete (holistic) understanding of the technicalities and economics of a range of nuclear fuel cycles is an important part of Nexia Solutions' business. To this end, Nexia Solutions has developed the capability to model and assess a range of reactor systems and fuel cycles using both “off the shelf” as well as bespoke software, including tools developed in-house. This paper presents a range of potential United Kingdom (UK) specific nuclear fuel cycle options for current, near, medium and long-term deployment that have been evaluated using these analysis tools and capabilities. These fuel cycles illustrate how the UK could utilize the plutonium stockpile and highlights some of the key issues for UK new nuclear build scenarios in the near, medium and long term.

Proliferation Resistance Assessment Methodology for Nuclear Fuel Cycles

A methodology, based on the multiattribute utility analysis, for the assessment of diverse fuel cycles for proliferation resistance was developed. This methodology is intended to allow for the assessment of the effectiveness of safeguards implementation at facilities within a large-scale fuel cycle and allow for the ability to choose technologies based in part on their effectiveness to deter the proliferation of nuclear materials. Fuel cycle facilities under consideration include nuclear reactors, reprocessing facilities, fuel storage facilities, enrichment plants, fuel fabrication plants, uranium conversion plants, and uranium mining and milling operations. The method uses a series of attributes (for example, Department of Energy attractiveness level, weight fraction of even Pu isotopes, measurement uncertainty, etc.) to determine a proliferation resistance measure for each step in a process flow sheet. Each of the attributes has a weighting that determines its importance in the overall assessment. Each attribute also has an associated utility function derived from both expert knowledge and physical characteristics that relates changes in the value of the attribute to its overall effect on the proliferation resistance measure. A method for aggregating proliferation resistance values for each process in a flow sheet into an overall nuclear security measure for the complete cycle was also developed. This method is focused on preventing host nation diversion; however, a similar technique could be used to analyze the risk due to theft by an insider or outsider. This methodology has been applied successfully for example fuel cycles to demonstrate its viability as an assessment methodology and its capability in discriminating diverse fuel cycle options.

Scenario Analyses of Future UK Fuel Cycle Options

As an international nuclear company and one which is involved throughout the nuclear fuel cycle, a complete (holistic) understanding of the technicalities and economics of a range of nuclear fuel cycles is an important part of Nexia Solutions' business. To this end, Nexia Solutions has developed the capability to model and assess a range of reactor systems and fuel cycles using both “off the shelf” as well as bespoke software, including tools developed in-house. This paper presents a range of potential United Kingdom (UK) specific nuclear fuel cycle options for current, near, medium and long-term deployment that have been evaluated using these analysis tools and capabilities. These fuel cycles illustrate how the UK could utilize the plutonium stockpile and highlights some of the key issues for UK new nuclear build scenarios in the near, medium and long term.

A Physics Study on Thorium Fuel Recycling in a CANDU Reactor Using Dry Process Technology

Dry process fuel technology has high proliferation resistance, which is one of the important goals of the Generation-IV nuclear energy system developments. It is expected that dry process fuel technology can be applied not only to existing but also to future nuclear systems. In this study, the homogeneous ThO2-UO2 fuel cycle and the heterogeneous ThO2-DUPIC fuel cycle options of a Canada deuterium uranium (CANDU) reactor were assessed, which included a neutronic feasibility analysis of recycling spent fuels. Parametric calculations were also performed for reactivity coefficients and isotopic content changes for various initial fuel conditions. The results of the physics calculations have shown that it is feasible to recycle the thorium fuel through the dry process option in the CANDU reactor, which in turn significantly improves natural uranium savings and diminishes spent fuel. However, further investigation of the dry process option, which is technically and economically feasible for thorium-abundant dioxide fuel, is required.

New Fuel Cycle and Fuel Management Options in Heavy Liquid Metal–Cooled Reactors

Fast reactors cooled by lead or lead-bismuth alloy offer new interesting fuel cycle and fuel management options by virtue of the superb neutronics and safety features of these heavy liquid metal (HLM) coolants. One option is once-for-life cores having relatively low power density. These cores are fueled in the factory; there is no refueling or fuel shuffling on site. A second option is very long-life cores being made of a fissioning zone and a natural uranium blanket zone. The fissioning zone very slowly drifts toward the blanket. A third option is multirecycling of light water reactor (LWR) discharged fuel without partitioning of transuranics (TRUs) in fuel-self-sustaining reactors. LWR spent fuel could provide the initial fuel loading after extracting fission products and ~90% of its uranium. The makeup fuel is natural or depleted uranium. A fourth option is the high-burnup once-through fuel cycle using natural or depleted uranium feed. The initial fuel loading of this reactor is a mixture of enriched and natural uranium. The natural uranium utilization is 10 to 20 times higher than that of a once-through LWR. A fifth option is transmutation of TRUs from LWRs using critical HLM-cooled reactors; such reactors could be designed to have the same high actinide burning capability of accelerator-driven systems and have comparable safety, but at a substantially lower cost. These novel reactor designs and fuel management options are hereby reviewed.

The Economics of Reprocessing versus Direct Disposal of Spent Nuclear Fuel

We assess the economics of reprocessing versus direct disposal of spent fuel. The uranium price at which reprocessing spent fuel from light water reactors (LWRs) and recycling the resulting plutonium and uranium in LWRs would become economic is estimated for a range of reprocessing prices and other fuel cycle costs. The contribution of both fuel cycle options to the cost of electricity is also estimated. A similar analysis is performed to compare fast neutron reactors (FRs) with LWRs. We review available information about various fuel cycle costs, as well as the quantities of uranium likely to be recoverable at a range of future prices. We conclude that the once-through LWR fuel cycle is likely to remain significantly cheaper than recycling in either LWRs or FRs for at least the next 50 yr, even with substantial growth in nuclear power.

Confidence-building and security-building measures in the nuclear area with relevance for South Asia

This paper addresses some relevant issues concerning whether it is possible to envision arms control and confidence-building and security-building measures (CSBMs) in South Asia, a region characterized by highly competitive and extremely adversarial political relationships. It makes the case that, despite mutual hostility, competing nuclear weapon development programmes and opposing strategic cultures, both India and Pakistan could usefully consider and implement a series of CSBMs in the realm of arms control. These include a unilateral joint protocol to the nuclear Non-proliferation Treaty, regional nuclear fuel cycle options, and CSBMs in the nuclear field.

Critical Power Performance of Tight Lattice Bundle

An innovative fuel cycle system concept named BARS (BWR with an Advanced Recycle System) has been proposed as a future fuel cycle option aiming at enhanced utilization of uranium resources and reduction of radioactive wastes. In BARS, the spent fuel from conventional light water reactors (LWRs) is recycled as a mixed oxide (MOX) fuel for a BWR core with the fast neutron spectrum by means of oxide dry-processing and vibro-packing fuel fabrication. The fast neutron spectrum is obtained by means of triangular tight fuel lattice. Further study on BARS, especially on tight lattice MOX fuel, has been initiated as a joint study by Toshiba and Gifu University. The objective of this paper is to show the latest progress of the study on BARS, especially concerning the thermal-hydraulics measurements for tight lattice bundle.

A comparative physics study of alternative long-term strategies for closure of the nuclear fuel cycle

The appropriate management of radioactive waste arising from the nuclear fuel cycle is considered to be a key issue in the development of future, more sustainable nuclear energy systems. In this context, the partitioning and transmutation of actinides could play an important role through the achievement of very significant reductions in the actinide content and radiotoxicity of the high-level waste requiring geological disposal. The current paper reports on the results of a detailed physics study carried out to compare the pros and cons of alternative strategies for closure of the nuclear fuel cycle. Different long-term “steady-state” scenarios have been considered, involving the deployment, to varying degrees, of light water reactors (LWRs) and advanced fast-spectrum systems. The same nuclear data and calculation methods have been used throughout, so that a consistent and reliable comparison of the relative performance of the three basic fuel cycle options (once-through, plutonium recycle, and recycling of all actinides) has been made possible. In addition, with transmutation having been considered employing both critical and accelerator-driven fast-spectrum systems, the study has provided an evaluation of the advantages and disadvantages of these two different advanced system types.

Advantages of Irradiated DUPIC Fuels from the Perspective of Environmental Impact

This study compares some properties of irradiated Direct Use of Spent Pressurized Water Reactor (PWR) Fuel In Canada Deuterium Uranium reactor (CANDU) (DUPIC) fuels with properties of other fuel cycles. The properties include the radiotoxicity, decay heat, activity, and actinide content embedded in various spent fuels or high-level wastes, which could be measures of the effectiveness of waste management. From radiotoxicity analysis of fuel cycles, the toxicity of the DUPIC option based on 1 GW(electric)·yr is much smaller than those of other fuel cycle options such as the PWR once-through mode, mixed oxide fuel recycling mode, and CANDU once-through mode. The analysis shows that the value is just about half the order of magnitude of other fuel cycles until decayed to a level below the toxicity of initial ore. This means that the DUPIC option could have an indirect benefit on the environmental effects of long-term spent-fuel disposal. From total activity analysis of various fuel cycle options, the activity per metric ton heavy metal of spent fuel is the lowest in natural uranium CANDU fuel, but in the case of activity based on 1 GW(electric)·yr, the DUPIC option has the smallest activity. In the meanwhile, from the activity analysis of 99Tc and 237Np, which are important to the long-term transport in geologic media, the DUPIC option was being contained in only about half of those other options. In conclusion, compared to other fuel cycle cases, the irradiated DUPIC fuels would have good properties from the perspective of environmental effects.

Assessment of Homogeneous Thorium/Uranium Fuel for Pressurized Water Reactors

The homogeneous ThO2-UO2 fuel cycle option for a pressurized water reactor (PWR) of current technology is investigated. The fuel cycle assessment was carried out by calculating the main performance parameters: natural uranium and separative work requirements, fuel cycle cost, and proliferation potential of the spent fuel. These performance parameters were compared with a corresponding slightly enriched (all-U) fuel cycle applied to a PWR of current technology. The main conclusion derived from this comparison is that fuel cycle requirements and fuel cycle cost for the mixed Th/U fuel are higher in comparison with those of the all-U fuel. A comparison and analysis of the quantity and isotopic composition of discharged Pu indicate that the Th/U fuel cycle provides only a moderate improvement of the proliferation resistance. Thus, the overall conclusion of the investigation is that there is no economic justification to introduce Th into a light water reactor fuel cycle as a homogeneous ThO2-UO2 mixture.

Radioactive Waste Arisings from Various Fuel Cycle Options

This study examines all kinds of waste volumes from various fuel cycle options including DUPIC (Direct Use of Spent PWR Fuel In CANDU) fuel cycle and compares each other. The fuel cycle option considered the PWR (Pressurized Water Reactor) once-through cycle, the PHWR (Pressurized Heavy Water Reactor) once-through cycle and the thermal recycling option using an existing PWR with MOX (Mixed Oxide) fuel. This study focuses on the radioactive wastes including mill waste, low-level waste and high-level waste generated by all fuel cycle steps, which can be one of the effectiveness measures of waste management. All waste disposition volume is estimated in terms of m3/GWe-yr. We find in the estimation of radioactive waste volume that PWR-MOX option has the lowest mill tailings and spent fuel volumes among the options, but the option has high volume of ILW and HLW. Mill tailings and spent fuel volumes of the DUPIC fuel cycle are lower than those of other competitive options such as PWR-PHWR once-through cycle. PWR once-through cycle has the lowest LLW and ILW volume among the options, but has high mill tailings and spent fuel volume. The data obtained in this study would be helpful to further estimate environmental effect and/or waste disposition costs in various fuel cycle options.

Decision-making of nuclear energy policy: application of environmental management tool to nuclear fuel cycle

This study aims to evaluate and estimate the environmental impacts of nuclear fuel cycles and to support the decision-making of nuclear energy policy, relating to a selection of environmentally preferred nuclear fuel cycle for the environmentally sound and sustainable development of nuclear energy. To achieve this objective, life cycle assessment (LCA) as an environmental management tool is applied to the nuclear fuel cycle alternatives of a once-through fuel cycle, the direct use of PWR spent fuel in CANDU (DUPIC) cycle and recycling with plutonium and uranium recovery by extraction (PUREX) process. The assessments provide a comparison of the environmental impacts of the three nuclear fuel cycle options and the environmentally most significant stages of each nuclear fuel cycle are identified. As a result, the recycling with PUREX process turned out to impose less-significant environmental impact than did the DUPIC and once-through options. The environmentally dominant stage was found to be mining/milling stage and the most radiologically significant pathway could be an internal exposure. The results are useful for making a decision of nuclear energy policy by an estimation of environmental impacts of nuclear fuel cycle options and the application of LCA to nuclear energy is very significant eco-labeling according to the advent of international standard organization 14,000 series. Finally, this approach also makes it possible to obtain the environmental data relating to the nuclear energy and to examine the environmental impacts of chemical effluents discharged from a nuclear facility. From this result, therefore, the comparative assessment of nuclear and non-nuclear energy sources including radiological and non-radiological aspects may be further developed.

Radioactive Waste Arisings from Various Fuel Cycle Options.

This study examines all kinds of waste volumes from various fuel cycle options including DUPIC (Direct Use of Spent PWR Fuel In CANDU) fuel cycle and compares each other. The fuel cycle option considered the PWR (Pressurized Water Reactor) once-through cycle, the PHWR (Pressurized Heavy Water Reactor) once-through cycle and the thermal recycling option using an existing PWR with MOX (Mixed Oxide) fuel. This study focuses on the radioactive wastes including mill waste, low-level waste and high-level waste generated by all fuel cycle steps, which can be one of the effectiveness measures of waste management. All waste disposition volume is estimated in terms of m3/GWe-yr. We find in the estimation of radioactive waste volume that PWR-MOX option has the lowest mill tailings and spent fuel volumes among the options, but the option has high volume of ILW and HLW. Mill tailings and spent fuel volumes of the DUPIC fuel cycle are lower than those of other competitive options such as PWR-PHWR once-through cycle. PWR once-through cycle has the lowest LLW and ILW volume among the options, but has high mill tailings and spent fuel volume. The data obtained in this study would be helpful to further estimate environmental effect and/or waste disposition costs in various fuel cycle options.

Economic Analysis on Direct Use of Spent Pressurized Water Reactor Fuel in CANDU Reactors—IV: DUPIC Fuel Cycle Cost

This study examines the economics of the DUPIC fuel cycle using unit costs of fuel cycle components estimated based on conceptual designs. The fuel cycle cost (FCC) was calculated by a deterministic method in which reference values of fuel cycle components are used. The FCC was then analyzed by a Monte Carlo simulation to get the uncertainty of the FCC associated with the unit costs of the fuel cycle components. From the deterministic analysis on the equilibrium fuel cycle model, the DUPIC FCC was estimated to be 6.21 to 6.34 mills/kW·h for DUPIC fuel options, which is a little smaller than that of the once-through FCC by 0.07 to 0.27 mills/kW·h. Considering the uncertainty (0.40 to 0.44 mills/kW·h) of the FCC estimated by the Monte Carlo simulation method, the cost difference between the DUPIC and once-through fuel cycle is negligible. On the other hand, the material balance calculation has shown that the DUPIC fuel cycle can save natural uranium resources by ~20% and reduce the spent fuel arising by ~65% compared with the once-through fuel cycle. In conclusion, the DUPIC fuel cycle is comparable with the once-through fuel cycle from the viewpoint of FCC. In the future, it should be important to consider factors such as the environmental benefit owing to natural uranium savings, the capability of reusing spent pressurized water reactor fuel, and the safeguardability of the fuel cycle when deciding on an advanced nuclear fuel cycle option.