REPROCESSING AND RECYCLE REQUIREMENTS TO SUPPORT THE ONGOING SUSTAINABLE DEVELOPMENT OF NUCLEAR POWER

Transcription

1 EPOCESSING AND ECYCLE EQUIEMENTS TO SUPPOT THE ONGOING SUSTAINABLE DEVELOPMENT OF NUCLEA POWE Dunn, M.J. Commercial Manager British Nuclear Group Sellafield, Spent Fuel Services 1. Introduction Sustainable development has been defined as a development that meets the needs of the present without compromising the ability of future generations to meet their own needs (ef 1). Sustainable development essentially focuses on the long-term future by integrating the requirement of three key areas: economics, environmental impact and social welfare. Sustainability is increasingly becoming one of the key factors utilised in strategic decision processes. If nuclear power is going to continue to play a significant role in meeting the world s energy needs, it must fulfil the requirements of a sustainable energy system. The continued sustainable development of nuclear power is dependent upon the sustainability of the nuclear fuel cycle. One of the key decisions relating to the nuclear fuel cycle is the selection of an option for the back end. It is generally recognised that two options for spent fuel management exist at present, a once-through cycle requiring the direct disposal of spent fuel and a closed cycle with reprocessing of spent fuel and the recycle of recovered products. A sub option is also available:- deferral of the decision as to which of the previous options to choose, the wait and see strategy. Selection of a spent fuel management route may be a matter of national policy and as such the reactor operator may be constrained to one particular option. However some utilities are not constrained in this manner and are free to choose the appropriate spent fuel management route. Various analyses have been published over the years claiming to demonstrate the advantage of the once through option over the recycle option or visa versa. In reality there is no one option that is preferred in all cases. For some utilities/customers the reprocessing and recycle option is the more attractive and for others the once through cycle best meets their needs. This paper will not compare and contrast the two main fuel cycle options in detail but will review the specific issues associated with recycle from a sustainability viewpoint. In reviewing the sustainability of the recycle option the future of the reprocessing industry will be considered and a brief overview of the UK situation will be provided. 2. Transport Transport is an important activity in the nuclear fuel cycle. egardless of whether spent fuel is reprocessed, interim stored in a central facility or stored at reactor awaiting a decision as to its ultimate management route, transport will be required. Spent fuel, Mox fuel and wastes have been transported both nationally and internationally, under international safeguards, for many years (including more than 40 years of spent fuel transports) without a single accident with radiological consequences to the public or the environment. Despite this excellent safety and security record, the transport of nuclear material has been the focus of much political opposition. It is imperative that national and international transport routes for all nuclear materials are maintained as the development of the back end of the fuel cycle can not be maintained if transport routes are not available. The maintenance of transport routes for wastes, returned to customers or to storage facilities or to repositories for disposal,

2 is equally as important as the maintenance of spent fuel transports in supporting the sustainability of the nuclear fuel cycle. Transport of materials is the enabler of world market prices for front end services and also allows the economies of scale associated with large scale reprocessing plants offering international services to be made available to individual utilities and/or countries. British Nuclear Groups (formerly BNFL), and PNTL/NTL experience in maintaining these transport routes spans over 40 years. During this time 4000tU of fuel has been transported from Japan to Europe for reprocessing, with subsequent waste and product returns. One of the most important aspects of maintaining these routes is managing the interface with stakeholders. In carrying out the various transports we maintain an interface with over 40 Governments, 50 egulators, some 4 international organisations and various other key stakeholders. 3. Interim storage Interim storage is an integral part of the fuel cycle in that it is required regardless of the choice of fuel management option. Historically the predominant technology for interim storage has been wet storage, however it appears that the future technology will be predominantly dry storage. One of the arguments in favour of dry storage for longer-term storage, is that it benefits from the potential for passive cooling and requires less support services, i.e. water treatment facilities. However for existing licensed facilities, such as those in the UK, France and Sweden, wet storage is a flexible, economic and acceptable technology. Simple arithmetic demonstrates that interim storage or a wait and see strategy will be the most widespread spent fuel management option for the foreseeable future. Each year approximately 10,000tU of irradiated nuclear fuel is discharged from reactors and at best approximately only 15% of this material is destined for reprocessing. Currently there is some 200,000tU of spent fuel in storage and this, together with the fact that repositories for final fuel disposal appear to be some way off, dictate that interim storage will be the predominant spent fuel management strategy for the foreseeable future. Siting of interim storage facilities is likely to become a major issue in terms of the sustainability of the option. Long-term storage on the reactor site may or may not be politically acceptable at the local level once the economic benefit to the community of power generation has ceased, whilst storage on a national or international level will be subject to the issue of NIMBY (Not in My Back Yard). National or sub-national (local) governments are increasingly refusing to accept the perceived detriments they believe are associated with the storage of non-indigenous spent nuclear fuel. This will undoubtedly affect the economics of interim storage and the potential for economies of scale to be delivered via large scale international facilities. Siting and public acceptability issues associated with spent fuel storage will be the predominant factors determining the availability of interim storage. 4. eprocessing Commercial reprocessing commenced in the 1950 s. Since then more than 85,000 tonnes of commercial spent fuel have been reprocessed. At the present time, reprocessing is undertaken on both a national and international basis with international services offered by UK, France and ussia. The current reprocessing capacity available is about 5000tHM per annum, this represents about half the amount of yearly spent fuel arisings. During the next 20/30 years it is anticipated that most of the current reprocessing facilities will come to the end of their lifetimes. If the current level of capacity is to be maintained into the future, new facilities will be required. The following table details the past, current and planned reprocessing plant capacities in the world. (ef 2)

3 Country Site Plant Fuel start Close Capacity present thm Capacity future thm Belgium Mol Eurochemic LW China Jiuquan PP LW? 25 Lanzhou LW 2020 ** 800 France Marcoule APM FB Marcoule UP1 GC La Hague UP2 LW La Hague UP3 LW Germany Karslruhe WAK LW India Trombay PP ese arch Tarapur PEFE 1 PHW Kalpakkam PEFE 2 PHW Kalpakkam PEFE 3A PHW Tarapur PEFE 3B PHW Japan Tokai -mura PNC TP LW okkasho P LW ussian Federation Chelyabinsk T1 WW E Krasnoyarsk T2 WW E To be determine d UK Sellafield B205 GC Sellafield Thorp LW /AG Dounraey UKAEA P FB USA West Valley NFS LW Hanford ockwell U metal Savannah S U iver metal Idaho Falls U-Al Allo y Total Capacity ** Authors note: Pilot reprocessing plant due to commence operation this year, throughput approx 100tU/yr The above table includes planned future capacity in China and ussia. There has been speculation recently that the USA may be considering reprocessing on account of waste management issues. eprocessing is a widespread industrialised activity and will remain so for the next 20 years or so.

4 Existing reprocessing plants are all operating on the 50 year old Purex technology. It is unlikely that new separation technology will be back fitted to existing plant and thus Purex will be the predominant reprocessing technology for the next 20 years or so. Development work on new and improved separation technologies for inclusion in the next generation of reprocessing plants is underway. Most of these technologies are linked to specific advanced fuel cycle systems; such as fast reactors, partitioning and transmutation etc. The technologies currently being developed include both advanced aqueous systems and dry techniques. The driver for developing advanced fuel cycles is the need to adapt to the changing utility management, public acceptance and regulatory requirements whilst maintaining an economic, environmentally acceptable and safe reprocessing service. From an environmental impact point of view current reprocessing technology is a sustainable technology. Many studies have found that there is little or no difference in environmental impact between the recycle and once through fuel cycles. eprocessing and recycle can also contribute up to about 30% saving in natural uranium requirements even if the products of reprocessing are used only in thermal systems. The technology is also sustainable from an economic point of view with customers making the choice to reprocess based on their own economic assessments where they are not constrained by political guidelines. If the reprocessing and recycle option does not meet the decision making criteria of the electricity utilities, then the utilities will choose not to reprocess. It is up to the reprocessing and recycle service providers to offer a service that does meet the requirements of the utilities. From a sustainability perspective no single utility that is continuing to operate reactors has committed all its spent fuel to reprocessing and thus by definition both reprocessing and recycle and long term interim storage are being pursued. Some commentators raise proliferation concerns regarding the reprocessing and recycle industry. In response to these concerns it should be noted that reprocessing services are undertaken to stringent safety and security requirements under international safeguards. eprocessing facilities are designed and constructed to satisfy all relevant national and international standards for the safekeeping of nuclear material. A range of physical security measures are utilised including; fences, patrol guards, personnel vetting, restricted access, surveillance and sophisticated electronic detection systems. There has never been any material diverted from civil reprocessing, taking place under international contracts, operated under international safeguards. It is highly improbable that civil reprocessing programmes operating under international safeguards will ever contribute to weapons programmes as any misuse of material under safeguards would have a high probability of detection and thus prevention. A country that takes the political decision to embark on a weapons programme would use facilities and materials outside the safeguards regime. A recent phenomenon which has undermined maintenance of the reprocessing and recycle technology is the short-term views that have driven the electricity generation market. Whilst utilities have had the option of following a wait and see policy, for either local/national political reasons or short term economic pressures of say an increasingly deregulated market, they will inevitably follow this option. This is because by definition doing nothing with the fuel other than storing it, in say an existing reactor pond subject to local/technical constraints will cost less than any active treatment option. If this position alone continued to prevail the implications are that in a short period of time reprocessing may cease to be offered on an international basis, the plants in the UK, France and ussia may well close and as such utilities will be left by definition with only a single spent fuel management route. Once reprocessing ceases to be offered on an international basis it would be very difficult to re start the infrastructure required to resurrect the service. ecent developments in various energy

5 markets suggest that the short termism that has been prevalent in some markets over the last 10 years or so seems to be being replaced with an acceptance that the long term sustainability of energy supply is of high importance. The reprocessing of spent fuel and recycle of plutonium is undertaken on timescales that may stretch into decades. Because of the long timescales associated with the service it is difficult to respond to short term fluctuations in the fuel and electricity markets. Over the last 20 years the headline price of reprocessing has fallen dramatically because of the depreciation of existing plant and increased competition in the market. Uranium resource availability is unlikely to constrain the development of nuclear power over the next 50 years as there appears to be sufficient readily available resource to meet even expanded future programmes. However, just because there is sufficient resource does not mean that it will be available at an attractive price. Uranium prices have doubled over the last couple of years; this has had the impact of increasing fuel cycle costs by some 25% and thus levelised generation costs by 5%. As security of supply and self-sufficiency become increasingly important over the coming decades, the use of recovered uranium and plutonium will be key to supporting the sustainability of the fuel cycle. 5. Plutonium ecycle Plutonium has been successfully recycled in the form of MOX fuel in thermal reactors for more than thirty years. Experience has demonstrated that the performance of MOX fuel is similar to that of uranium fuel. Currently, the use of MOX fuel has been established on an industrial scale in a number of countries with thermal reactors licensed to use MOX fuel at levels of up to 30% of the reactor core. The current stockpile of separated civil plutonium is approximately 200tes. It is stored safely and securely under international safeguards at various reprocessing plants awaiting recycle as MOX fuel or stored as a potential future asset. Within the next decade or so the inventory could be reduced to a level determined only by the working stocks required by MOX fabrication plants. The continued industrialisation of MOX recycle is a priority in reducing the plutonium stockpile and improving the economics of MOX. ecent modelling undertaken by IAEA using the VISTA model has described a long range forecast for separated plutonium stocks up to The modelling assumed a low level of increase in nuclear generation, three reprocessing scenarios (0%, 30% and 70% of arisings reprocessed) and a medium MOX utilisation scenario based on historic utilisation rates up to 2004, for 2004 to 2009, 2010 to % of LWs power generation from MOX thereafter rising to 7% in 2050.(ef 3). The following results were derived from the above assumptions. Pu (t) Cumulative Pu Stocks, P1-0-M2 P1-1-M2 P1-3-M2 INFCIC 549 (excl. mil.) Nuc. Pow er (MV) Nuclear Power (GWe) Year

6 As can be seen from the above modelling, a low level of industrialisation of MOX utilisation together with a low level of reprocessing can easily accommodate existing and future stocks of separated plutonium. In reality the separated plutonium stocks will never fall to zero if there is an ongoing programme of recycle as a float of separated plutonium equating to approximately 2 years throughput will be held by MOX fabricators for operational purposes. 6. Situation in UK The UK has a mixture of reactor operating systems and also a mixture of spent fuel management strategies for dealing with the different type of fuel arisings. The first generation of reactors that were constructed in the UK are the Magnox reactors. All Magnox spent fuel is planned to be reprocessed through the Magnox reprocessing plant (B205) at Sellafield by The second generation of nuclear reactors in the UK are the AG type. A proportion of the AG fuel will be reprocessed. The remainder will undergo long term storage with a view to eventual disposal or reprocessing. The third generation of nuclear reactor in the UK is the Sizewell PW. This plant was constructed with approximately 18 years pond storage capacity, which has been re- racked to provide approximately 30 years capacity. Spent PW fuel will be interim stored prior to a decision being made about its ultimate treatment route. In the UK all management options are being followed, full reprocessing, reprocessing and storage and long term interim storage or wait and see. 7. Conclusions It is imperative that the industry continues to demonstrate that fuel cycle facilities are managed to the highest safety standards and that the appropriate security and safeguards standards are applied to national and international movements of materials. To ensure the availability of fuel cycle facilities it is important that the internationalisation of the fuel cycle continues and is supported. The potential for short term national or local political pressures to adversely impact the international market are great. eprocessing is a widespread industrialised activity and will remain so for the next 20 years or so. The replacement of existing facilities in 20 or 30 years time may well be by regional or joint venture international facilities as the market consolidates and economics of scale are sought. The sustainable development of the back end of the fuel cycle is manageable, however the acceptance both politically and publicly and the short termism of the current situation will have to be changed for the continued sustainable development of nuclear power. A relatively low level of industrialisation of MOX utilisation together with a low level of reprocessing can accommodate existing and future stocks of separated plutonium. 8. eferences: 1.World Commission on Environment and Development (WCED). Our common future. Oxford University press 1987, p.43.

7 2. Fissile Materials Management Strategies for Nuclear Energy: Back End Fuel Cycle Working Group. Bairiot et al to be published by IAEA Forecast of fissile material inventories in back end fuel cycle. Fukuda and Ceyhan to be published by IAEA 2006.