6. Technical methods

In November 2002, Parliament passed the Nuclear Fuel Waste Act (NFWA). It required the major owners of used nuclear fuel in Canada to establish the NWMO. The initial phase of our mandate was to study approaches for the safe, long-term management of used nuclear fuel, and to recommend a preferred approach to the Government of Canada. The historical information about one part of that process is preserved here in line with our commitment to transparency.


    This series of papers is designed to provide general descriptions of the three methods for the long-term management of used nuclear fuel as defined in the Nuclear Fuel Waste Act (NFWA), as well as other possible methods and related system requirements.

    6.1 Status of Reactor Site Storage Systems for Used Nuclear Fuel

    SENES Consultants Ltd, ON CAN

    This report provides brief descriptions of used fuel storage systems at commercial reactor power sites in Canada. In addition, selected comments are provided on a variety of environmental and regulatory issues relevant to reactor site used fuel management systems. Current practice in Canada is to allow used fuel (i.e., fuel which has been irradiated in a reactor) to cool in used fuel bays (essentially water-filled pools) for ten years or more, and then to transfer the fuel to above-ground dry storage. While Ontario Power Generation is the largest producer of used fuel, the other nuclear utilities Hydro Quebec and New Brunswick Power also produce significant quantities of used fuel. Additional, but much smaller, quantities of used fuel have been produced from research activities by Atomic Energy of Canada and various research reactors in Canada. Recent Environmental Impact Statements to assess used fuel dry storage at Ontario Power Generation’s Darlington and Pickering (Phase II) sites demonstrate the increasing use of dry storage at reactor sites in Canada.

    Atomic Energy of Canada Limited (AECL) and Ontario Power Generation (OPG) began to investigate dry storage alternatives in the 1970’s. AECL has more than 25 years of experience with dry storage systems. The current design life of dry storage containers is 50 years; however, the actual life of dry storage containers is thought to be 100 years or more. In the event that centralized facilities for the management of used fuel are not available on a timely basis, extended use of dry storage would provide a reliable method of managing used fuel in the longer term. In such an event, regulatory and public communication issues would need to be revisited.


    Author Biography

    Dr. Douglas Chambers
    Dr. Douglas Chambers, Vice-President and Director of Radiation and Risk Studies at SENES. He has been a member of the Canadian delegation to the United Nations Scientific Committee on the Effects of Ionizing Radiation (UNSCEAR) since 1998. In 1993, Dr. Chambers was first appointed as a member of the former Advisory Committee on Radiological Protection (ACRP) which advised the Atomic Energy Control Board (now the Canadian Nuclear Safety Commission) Advisory Committee. He was Chairman of the Canadian Standards Association, Technical Committee on Environmental Radiation Protection for more than 10 years and is a member of the Canadian Standards Association Technical Committee on Risk Assessment. Dr. Chambers is also a member of Committee #85 on radon of the U.S. National Council on Radiation Protection and Measurements (NCRP). He is currently consultant to UNSCEAR on exposure to radon and potential associated health effects.

    Dr. Chambers is well recognized in Canada and internationally for his work in environmental radioactivity, pathways analysis, radioactive waste management and risk assessment.

    Among other activities, Dr. Chambers has directed or carried out evaluations for all stages of the nuclear fuel cycle. Dr. Chambers has also carried out numerous studies on radioactive wastes in Canada, the United States and Overseas.

    Examples of recent work include assisting the Federal German Environment Ministry (BMU) and the States of Saxony and Thüringia with the decommissioning of former uranium mining and processing facilities, the re-evaluation of radon progeny exposures to underground miners, the development of a regulatory guide for UF6 dispersion models for the U.S. Nuclear Regulatory Commission, the development of metrics for risk comparisons, and the evaluation of risks to lower form biota.

    Dr. Chamber has pioneered the development of tools for uncertainty analysis, dose reconstruction and radiation protection. He has contributed to more than 100 technical papers and presentations and has appeared at numerous commissions and inquiries on environmental and occupational radiological studies in Canada and the U.S. In 1997, the Canadian Nuclear Association recognized Dr. Chambers’ outstanding achievements in environmental radioactivity with the award of the W.B. Lewis medal. Dr. Chambers was the 2001 Morgan Lecturer for the Health Physics Society.

    6.2 Status of Centralized Storage Systems for Used Nuclear Fuel

    Mohan Rao & Dave Hardy, Hardy Stevenson and Associates, ON CAN

    This background paper reviews the status of centralized storage systems for used nuclear fuel. These are storage facilities to store used nuclear fuel in a central location built to provide effective management when there are many reactors producing used fuel. Often these are developed in a regional or a national context by the implementing organizations for the management of used fuel. This review finds that centralized storage systems are already operational and provide for interim storage in many countries that were reviewed. There are a number of technologies such as water pools, metal casks, concrete casks, silos and vaults. Dry storage casks (metal and concrete casks) seem to be the most preferred option. Current technologies for centralized storage systems were initially developed for an interim storage period of about 50 years. Many countries are now considering longer storage periods of 50-100 years. The role of centralized storage in the management of used fuel has been evolving over years and is considered in some countries as a technology for providing an alternative to disposal over timeframes of 50 to 300 years. For extended storage periods, the storage systems often need more research and development, and such programs are in progress in a number of countries and in co-operative international research programs.


    Author Biographies

    Dave Hardy

    Dave Hardy is the Principal of Hardy Stevenson and Associates Limited, a consulting firm specializing in Technical Services, Socio-Economic Impact Assessment, Ethical Analysis, Public Dialogue and Land-Use and Environmental Planning. The firm completes policy studies and assists in the environmental review and approval of energy, telecommunications, domestic waste, transportation, water and wastewater and other infrastructure projects. As a social scientist, Registered Professional Planner and trained facilitator, Mr. Hardy has taken a keen interest in how the interests of local communities are addressed in nuclear waste management decision-making. He has participated in approximately twenty-five spent fuel management and transportation projects and has authored several reports pertaining to the Canadian Nuclear Fuel Waste Management and Disposal program. He has a bachelor’s degree in sociology and masters’ degree in environmental studies specializing in community impact assessment. As an active volunteer, Mr. Hardy has held leadership and executive positions in a wide range of environmental and social policy organizations. In 2001 he was awarded a Paul Harris Fellowship.

    Dr. Mohan Rao
    Dr. Mohan Rao is Vice-President, Technical Services in Hardy Stevenson and Associates Limited. He was a Senior Advisor in nuclear waste management in Ontario Power Generation Inc. until the year 2000. His experience covers various aspects of waste management including low- and intermediate-level wastes, spent nuclear fuel and nuclear plant decommissioning including a number of studies in spent nuclear fuel storage. He also worked in a number of nuclear generation projects in the Indian Department of Atomic Energy and in the Atomic Energy of Canada Limited and in nuclear research and development in the Bhabha Atomic Research Centre in India. He has participated in several International Atomic Energy Agency studies on spent fuel management and in the Canadian Nuclear Fuel Waste Management and Disposal program. He has a bachelor’s degree in mechanical engineering, masters’ degrees in applied science and engineering, and a doctorate with specialization in nuclear sciences and engineering.

    6.3 Status of Geological Repositories for Used Nuclear Fuel

    McCombie, McCombie Consulting, Switzerland

    This report provides an objective appraisal of the development of the concept of geological disposal of radioactive wastes and of its current status. It is an overview document which addresses the key issues associated with geological disposal of used nuclear fuel and other high-level radioactive wastes. Some topical issues such as the siting of deep repositories are examined in detail because of their fundamental importance to geological disposal and the significant level of public interest. 

    Author Biography

    Charles McCombie

    Charles McCombie, is an independent strategic and technical advisor to various national and international waste management programmes. He has over 30 years experience in the nuclear field, 25 of which are in radioactive waste management. He is an author or co-author of over 150 published papers. For 20 years, he was scientific and technical director of Nagra, the Swiss Cooperative for the Disposal of Radioactive Waste. Currently one of his responsibilities is as Executive Director of the Arius Association. He has also held positions as a research scientist with the U.K. Atomic Energy Authority and with the Swiss Federal Institute for Reactor Research. His responsibilities have covered reactor safety, performance assessment for disposal, repository engineering and geological investigations and overall programme direction.

    He was the Swiss coordinator of collaborative work with numerous national programs and also with the IAEA, NEA and EU. He has served on a number of committees advising national and international organizations on radioactive waste management issues. He currently chairs the International Technical Advisory Committee of NUMO (the HLW organisation of Japan), is Vice-Chairman of the U.S. National Research Council’s Board on Radioactive Waste Management (BRWM) and chairs the Nuclear Advisory Committee of the Swiss Paul Scherrer Institute.

    Dr. McCombie received a B.Sc. degree in natural philosophy (physics) from the University of Aberdeen, Scotland and a Ph.D. degree in physics (material science) from the University of Bristol, England.


    6.4 Status of Nuclear Fuel Reprocessing, Partitioning and Transmutation

    David Jackson, David Jackson & Associates, ON CAN

    The basic concepts of the reprocessing, partitioning, conditioning and transmutation of nuclear fuel are explained. A Canadian context is established by discussing the characteristics of the fuel from CANDU reactors. The technology of reprocessing is introduced in terms of both the Purex and the dry reprocessing options. The world status of commercial reprocessing is reviewed with detail for the UK, France, Russia, Japan, India, the US and Canada. Current research on the transmutation of fission products and actinides is reported and the fundamental concepts of the fast reactor and Accelerator Driven System approaches presented. The technical aspects of reprocessing relevant to possible decisions on its application in Canada are summarized in issue related sections for easy reference.


    Author Biography

    Dr. David P. Jackson

    Dr. Jackson is currently Adjunct Professor of Engineering Physics at McMaster University where he teaches nuclear engineering courses. Since early 2001 he has been a primary player in establishing the University Network of Excellence in Nuclear Engineering, a consortium of universities and industry with the objective of preserving and enhancing nuclear education and research in Canadian universities.

    In addition to the technical aspects of his field, he is also interested with the broader issues of the management of technological systems and public communications with applications to the nuclear area. He is a research associate of the University of Ottawa’s Program on Research in International Management and Economy and was a member of McMaster’s theme school on Science, Technology, and Public Policy where he taught a course on Science and Technology in the Media and co-managed a Consensus Conference on municipal waste options for the city of Hamilton. He is coauthor with Hans Tammemagi of Unlocking the Atom:the Canadian Guide to Nuclear Technolgy, published in 2002, a book intended to explain to the layperson a broad gamut of nuclear technologies.

    Dr. Jackson obtained his Ph.D. in Engineering Physics from the University of Toronto in 1968. He then joined Atomic Energy of Canada Ltd. as a scientist at Chalk River Laboratories doing research in particle solid interactions phenomena including plasma-wall interactions. He has held a number of university and visiting scientist positions including a year as visiting scientist at the Max Planck Institute in Germany. In 1982, as manager, he initiated the fusion breeder blanket program at Chalk River Laboratories for the Canadian Fusion Fuels Technology Project (CFFTP) and became Manager, Fusion in 1985.

    From 1987-1997 he was Director of Canada's national fusion program and was the federal official responsible for CFFTP and the CCFM laboratory at Varennes, Quebec. He has represented Canada on a number of senior international committees including the International Fusion Research Council of the International Atomic Energy Agency of which he served as chair from, 1993 to 1998. With support from Natural Resources Canada, he continues to represent Canada on the International Energy Agency's Fusion Power Coordinating Committee. He was a member of the federal government’s Panel on Energy Research and Development from 1985 to 1997.

    He is a past President of the Canadian Nuclear Society, a Director of the Canadian Nuclear Association and a former member of the Partnership Group on Science and Engineering. He does consulting on nuclear and energy topics through his company David P. Jackson and Associates Limited and in 1999 he designed, coordinated and wrote a successful proposal to the Canadian Foundation for Innovation to establish an Institute for Applied Radiation Sciences based around the McMaster Nuclear Reactor.

    6.5 Range of Potential Management Options for Used Nuclear Fuel

    Phil Richardson & Marion Hill, Enviros Consulting Ltd, UK

    Methods for the long-term management of used nuclear fuel and other long-lived and highly active radioactive wastes have been under investigation in various countries for about the past forty years. This paper provides a summary of recent published assessments of management options for used fuel and, based on these assessments, suggests that they can be placed in three categories of differing levels of interest for further R&D. Sixteen fuel management options are considered in the paper. For each option there is a brief description and a summary of published assessments. These summaries use environmental, technical, economic and social and ethical criteria taken from other reviews of options.


    Author Biographies

    Marion Hill

    Marion has an MA in Natural Sciences (physics) from the University of Cambridge and an MSc in Medical Physics from the University of Aberdeen. She has 27 years experience in developing standards for and assessments of the radiological impact of the nuclear industry on the public and the environment, specialising in policies, strategies and standards for the management of radioactive wastes and radioactively contaminated land.

    During her career she has worked for the National Radiological Protection Board, Electrowatt, WS Atkins and Enviros, in addition to periods as an independent consultant. Marion currently works as an associate for Enviros Consulting.

    Phil Richardson
    Phil has a BSc in Geology from Hull University. He is a Chartered European Geologist and a Fellow of the Geological Society. Phil has over 27 years experience, including 13 years in the coal mining industry. He became an independent consultant in 1988, and has built up a detailed knowledge of national radioactive waste management programmes and a reputation as an independent reviewer of deep geological disposal. He took up a senior position as a Principal Consultant with Enviros Quantisci in 1999, and is now a Technical Manager at Enviros Consulting.

    Phil has advised Local and State Governments and national agencies in the United Kingdom, United States, Sweden, Japan, and Germany on global radioactive waste disposal issues, and currently maintains a subscription-based website supplying information on 18 national radioactive waste management programmes and nuclear site remediation.

    Within Enviros, Phil works on a wide range of projects dealing with public and stakeholder involvement and participation in siting hazardous facilities, as well as other technical issues related to geoscientific aspects of radioactive waste management and disposal.

    6.6 Status of Transportation Systems for High-level Radioactive Waste Management (HLRWM)

    Wardrop Engineering Inc, ON CAN

    Radioactive materials have been transported around the world for 40 years. In that time, there have been no accidents that resulted in the release of significant amounts of radioactivity.
    In the US, nearly 3000 shipments of commercial used fuel have been transported over 2.5 million km in the last 30 years. Approximately 4300 shipments (primarily by rail) are proposed within a 24-year period to Yucca Mountain beginning in 2010.

    The UK and France combined average 650 shipments of used fuel per year (primarily by rail), through countries much more densely populated than Canada. Used fuel and high level reprocessing waste has been transported by sea between Europe and Japan. The ships have covered over 4.5 million kilometres transporting used fuel without and incident resulting in the release of radiation to an individual or the environment.

    As yet, used fuel has not been transported off-site (other than for research purpose) in Canada, though it is a possibility in the future. In order to transport nuclear material in Canada, a CNSC license is required. The requirements of licensing ensure the risks to workers, the public, and the environment are as low as reasonably possible. The CNSC works in conjunction with Transport Canada to ensure the safe transport of radioactive material in Canada

    Advantages of road transport are flexibility, existing infrastructure and short turn-around times. The biggest disadvantage is the limit on payload. The design of the transport cask is the main safety feature in used fuel transport. Shipment by rail is practical for loads exceeding 40 tonnes and therefore large shipments are possible.

    One advantage of vessel transport is that all the reactor sites are located on a body of water. Another advantage is the existing technology and precedence. Most of the transportation by ship in Canada would be limited to in-land waters.

    In general, the transportation of used fuel is a contentious issue. The Seaborn panel concluded that Canadians were very mistrusting of nuclear technology in general, including transportation. Transportation of used fuel is probably best accepted in the UK, where regular shipments of used fuel by rail are transported through London.


    6.7 Status of Storage, Disposal and Transportation Containers for the Management of Used Nuclear Fuel

    Kinectrics, ON CAN

    This paper presents a factual description of the current status of storage, disposal and transportation containers for the long-term management of used fuel. Currently, Canadian used fuel is stored both in water-filled pools and increasingly also in dry storage containers. Dry storage is a preferred option for extended storage because of its lower maintenance requirements, lower need for monitoring and lower overall cost.

    Requirements for dry storage, disposal and transportation containers, and also their designs were examined. Both Canadian designs, which are specific to CANDU fuel, and designs for non-CANDU fuel were examined. Designs for storage and transportation of Canadian used fuel must accomodate the different forms in which fuel is presently stored at the various generation sites. Designs for disposal containers are relatively independent of this because the transported fuel will be re-packaged at the disposal site.

    Current dry storage technologies, which typically have a 50 year design life, can be adapted for the extended storage of used fuel. While it may be feasible to increase the design life of storage systems, the used fuel would nevertheless need to be repeatedly retrieved and repackaged into new storage systems over an extended storage period.

    The main types of dry storage systems currently in use are: 1) concrete vaults, which are large ventilated buildings and hold 600-2000 Mg fuel, 2) concrete containers and silos, which hold 5-15 Mg fuel, and 3) metal containers, which hold 10-17 Mg fuel. In Canada, concrete vaults, silos and dry storage container (DSC)s are, respectively, used at Gentilly-2, Point Lepreau and Ontario Power Generation (OPG) sites. In contrast to the rectangular DSC, container designs for light water reactor (LWR) fuel have a cylindrical configuration, which is not optimal for CANDU fuel because of its much shorter length.

    Geological disposal within the stable granitic rock of the Canadian Shield, at a depth of 500-1000 m, is considered to be generally acceptable for the permanent isolation of the Canadian used fuel. The reference Canadian used fuel container has a design life exceeding 100,000 years and has a capacity of 324 used fuel bundles. The design consists of an outer copper corrosion barrier vessel and an inner steel load-bearing vessel. The container will be encased in bentonite clay / sand mixtures for emplacement in disposal rooms or in boreholes. The Canadian design concept is similar in several respects to the Swedish and Finnish designs.

    Two designs exist for transporting Canadian used fuel, namely, the DSC and the Irradiated Fuel Transportation Container (IFTC). The IFTC is also rectangular but is made of stainless steel. It accommodates only half the DSC’s payload. While the DSC has a welded lid, is intended for single use and has a design life of 50 years, the IFTC has a bolted closure, is intended for repeat use and has a design life of 20 years. In contrast to the DSC and the IFTC, transportation containers for enriched LWR fuel have a multi-shell cylindrical structure (lead is sandwiched between inner and outer steel shells) which also incorporates neutron shielding.


    6.8 Review of the Fundamental Issues and Key Considerations Related to the Transportation of Spent Nuclear Fuel

    Gavin Carter, Butterfield Carter and Associates, LLC

    The process is underway in Canada to manage a range of technical and practical issues concerning the long-term management of spent fuel. Spent fuel could be transported from nuclear reactor sites to a central storage or disposal facility in Canada. In addition to road and rail transportation, it is conceivable that spent fuel could be transported by ships if Canada decides to reprocess its spent fuel overseas, to move spent fuel from one side of the country to the other, or to ship it via internal waterways.

    Experience overseas over the last forty years shows that the transportation of spent fuel can be managed safely. Spent fuel is shipped against a background of strict regulations and careful planning. There are a number of extensive technical papers that support the conclusion that spent fuel transport is a low risk activity.

    Author Biography
    Gavin Carter, Butterfield Carter and Associates, LLC
    Gavin Carter is a founding partner of Butterfield Carter and Associates, a consulting company based in Washington, DC that provides public relations, government relations and marketing services. Butterfield Carter and Associates has completed work for various nuclear organizations in the USA and Europe, including British Nuclear Fuels plc (BNFL), Areva/ Framatome and the Nuclear Energy Institute.

    Over the past ten years Mr. Carter has been closely involved in the communication and regulatory aspects of shipments of spent fuel, vitrified high level waste and mixed oxide fuel, within Europe and between Europe and Japan. While working for BNFL, Mr. Carter conceived the idea to create the World Nuclear Transport Institute (WNTI) and helped to establish it in 1998.

    Mr. Carter is an Economics and Politics graduate from the University of Leeds in England. He is the co-author of “The Return of Vitrified Residues to Japan: A Joint Experience”, Packaging and Transport of Radioactive Materials (PATRAM) Conference, Paris (1997) and is the author of “Managing the PR Aspects of International Nuclear Shipments”, PIME 1997 European Nuclear Society International Conference.


    6.9 Conceptual Designs for Used Nuclear Fuel Management

    The Nuclear Fuel Waste Act (NFWA) requires that the NWMO study include an assessment of three specific technical methods:

    • deep geological disposal in the Canadian Shield, based on the concept described by AECL in the Environmental Impact Statement on the Concept for Disposal of Canada’s Nuclear Fuel Waste and taking into account the views of the environmental assessment panel set out in the Report of the Nuclear Fuel Waste Management and Disposal Concept Environmental Assessment Panel dated February, 1998;
    • storage at nuclear sites; and
    • centralized storage, either above or below ground.

    Anticipating their responsibilities under the Act and prior to the establishment of NWMO, the Joint Waste Owners (Ontario Power Generation, Hydro Quebec, New Brunswick Power and AECL) commissioned a team of consultants in 2001 to develop conceptual designs and engineering cost estimates for the alternatives. These conceptual designs were provided to the NWMO in December 2003. The principal sources of information in developing the conceptual designs were:

    • the Joint Waste Owners - descriptions of current operations;
    • CTECH (a joint venture of CANATOM and AEA Technologies) - descriptions of siting considerations, construction, operation, monitoring, closure and decommissioning; and
    • Cogema Logistics - descriptions of retrieval from storage and transportation of used nuclear fuel.

    The overall engineering assumptions and cost estimation process used in developing the conceptual designs have been reviewed and validated for NWMO by an independent firm, ADH Technologies Inc.

    The conceptual designs are posted here for review. They are very large files which will be made available on CD-ROM disks upon request.

    Comprehensive summaries of the cost estimates are also posted for review. The complete cost estimate documents are much larger files which will be made available on CD-ROM disks upon request.

    In addition to the conceptual designs and the cost estimate summaries, an overview document describing the work and a Power Point presentation outlining it are provided below.


    6.9a Conceptual Designs for Reactor-site Extended Storage Facility Alternatives for Used Nuclear Fuel

    Used nuclear fuel is currently stored at seven sites in Canada, in both wet and dry storage facilities. Atomic Energy of Canada Limited (AECL) and Ontario Power Generation (OPG) began to investigate various options for dry storage in the 1970s. AECL has more than 25 years of experience with dry storage systems. Recent licensing of used nuclear fuel dry storage facilities at various reactor sites in Canada indicate general regulatory acceptance for the increasing use of dry storage at reactor sites as an interim method for managing used nuclear fuel.

    Extended storage can be defined as permanent or indefinite storage with the necessary ongoing maintenance and facility refurbishment. The current design life of dry storage containers is 50 years; however, the expected life of dry storage containers is thought to be 100 years or more. In the event that centralized facilities for the management of used fuel are not available on a timely basis, extended storage could be used indefinitely.

    Implementation of a reactor site extended storage (RES) alternative would involve the location of an extended dry storage facility at each reactor site. There are both surface and below-surface designs involving the use of casks, vaults and silos. Reactor site extended storage facilities would be designed to allow safe retrieval of used nuclear fuel from the storage complex at any point during the service life of the facility. After fuel receipt, all subsequent fuel movements would be under cover, minimizing effects of adverse weather and maximizing fuel container life. For all reactor site options, additional capacity would be provided by the construction of storage facilities on a rolling program (i.e., an ongoing, cyclical program of regular replacement and refurbishment activities).

    Storage in Casks - A cask is a mobile, durable container for enclosing and handling nuclear fuel waste for storage or transport. The cask wall shields radiation and heat is transferred by conduction through the wall. In the context of reactor site extended storage, a cask is equivalent to the dry storage container (DSC) used by OPG, as well as a variation of this design similar to the DSC for storing fuel in baskets.

    Storage in Vaults - The vault concept would involve the storage of fuel baskets confined in concrete vaults. The vaults would be constructed in the open on a concrete foundation slab. Fuel baskets would be transferred to the storage facility in a basket transfer flask. The basket transfer flask would deliver the basket to the dedicated vault on a powered transporter. Additional capacity would be provided by the construction of storage vaults on a rolling program. Cooling and ventilation to regulate the basket temperature inside the vault would be achieved by natural ventilation.

    Storage in Silos - The storage of used nuclear fuel inside sealed steel baskets, with the baskets housed within a concrete silo (canister) is a dry fuel storage system used in Canada and other countries for used fuel dry storage. The silos are situated outdoors and are passively cooled. The concrete silos are a cylindrical reinforced concrete shell with an internal liner of epoxy coated carbon steel. The liner has an internal diameter of 84.5 cm. The external diameter of the silo is 2.59 m and the height is 6.2 m. A shield plug is inserted into the silo liner after completion of the loading operations (nine baskets). Provision is made for IAEA safeguard seals to go over the shield plug such that the plug cannot be removed without breaking the seals.


    6.9b Conceptual Designs for Four Centralized Extended Storage Facility Alternatives for Used Nuclear Fuel

    Centralized storage systems are storage facilities and associated systems to store used nuclear fuel in a central location. Producers of used fuel may build such facilities to provide effective management when they have many reactors producing used fuel. These can be developed within a regional or a national context by the implementing organizations responsible for the management of used fuel.

    Centralized storage systems were initially developed as interim storage for periods of up to 50 years. These systems are already operational in twelve countries and used over a wide range of circumstances from providing common temporary storage for used fuel from a few reactors, to providing a fully centralized management system for used fuel at the national level. With increasing used fuel inventories, some countries are viewing centralized extended storage as a longer term management alternative which could encompass time periods of 50 to 300 years. As a result, more research and development is being undertaken on the durability of used fuel storage structures and the effectiveness of designs to ensure containment of radioactivity over extended timeframes.

    As previously noted, following its removal from the nuclear reactor, used nuclear fuel is highly radioactive and is stored for about a decade in water pool storage facilities at the reactors. Following this period, it is easier to handle and transport the used fuel and store it away from the reactor sites. Centralized storage becomes attractive as a storage option at this stage. This could be done either in wet storage (i.e. in water-filled pools) or in dry storage facilities. The latter have advantages including modularity and less ongoing maintenance. Although several centralized water pools have been built, dry storage seems to be the preferred option. The concept that has been developed and that has been considered in this assessment includes variations of dry storage, both above- and below-ground.

    Technologies for centralized dry storage of used fuel include metal casks, concrete casks, silos and vaults. Four alternatives for the Centralized Extended Storage Facility (CES) concept were selected by the Joint Waste Owners as representative of a range of possible centralized extended storage designs. The selected alternatives are:

    • Casks and Vaults in Storage Buildings (CVSB)
    • Surface Modular Vault (SMV)
    • Casks and Vaults in Shallow Trenches (CVST)
    • Casks in Rock Caverns (CRC).

    Site conditions should not be a major constraint in the implementation of these alternatives. Of the alternatives considered, two would comprise surface facilities, in which fuel is stored in a series of storage buildings built above grade. The remaining two alternatives would be below-ground facilities, one near-surface and mounded over and one at about 50m below ground surface in bedrock. The near-surface alternative, the Casks and Vaults in Shallow Trenches (CVST) would be passively ventilated, with the deeper alternative, Casks in Rock Caverns (CRC), ventilated using a forced system. Three of the alternatives (CVSB, CVST, CRC) would minimize repackaging of fuel upon receipt at the CES facility, which would allow higher fuel throughput and minimize cost.

    Centralized storage could be built at nuclear plant sites, adjacent to a geological repository or at a fully independent site. For the assessment, it is assumed that the CES facility would be located on a greenfield site. The CES facility would not rely on the services or provisions to other nuclear facilities, and would be considered as a standalone facility. It is assumed the facility would be constructed in the province of Ontario at a location with low earthquake risk and that the site would be relatively flat, be free draining, have stable soil structures, and have competent rock structures. Irrespective of the alternative under consideration, a CES facility would comprise a Processing Building and a Storage Complex. Each of the CES alternatives would provide sufficient storage for the full fuel bundle inventory. Each site layout would provide sufficient space to allow for the construction of used fuel storage and repackaging facilities. For all of the alternatives, additional capacity would be provided by the construction of storage facilities on a rolling program.


    6.9c Conceptual Design for a Deep Geologic Repository for Used Nuclear Fuel

    A deep geological repository is an engineered facility located within a naturally-occurring geological formation. Such facilities are widely, but not universally, regarded as having characteristics suitable for providing safe and secure the storage and/or disposal of used nuclear fuel well into the future. While uncertainties exist about the very long-term performance of repositories, many countries support the concept of deep geological disposal including, among others, Sweden, Italy, Spain, Japan, China and the United States.

    The design concept used in the assessment has been developed over a significant period of time and with considerable effort. A deep geologic repository for used CANDU fuel was developed by Atomic Energy of Canada Limited (AECL) during the period 1978-1996, under the Canadian Nuclear Fuel Waste Management Program. The results of that review are documented in the final report of the Environmental Assessment Panel, published in March of 1998. The Panel report summarized the concept review and recommended changes to address comments from a broad range of stakeholders, including the public. Since 1996, Ontario Hydro, and subsequently OPG and the other members of the Joint Waste Owners, have continued the development of the original AECL repository concept. Using the design parameters and specifications established through this work, together with information from existing repository design experience in Canada and internationally, a preliminary DGR design was produced to meet the following goals:

    • receive used nuclear fuel shipped from interim storage and/or from extended storage facilities;
    • encapsulate the used nuclear fuel in long-lived used fuel containers (UFCs) and place them in the DGR; and
    • retrieve the used fuel containers from the repository during the pre-closure phase, if required.

    The modified DGR concept developed by the Joint Waste Owners is a further development of the in-room emplacement configuration. The design would involve the encapsulation of the used nuclear fuel in copper/steel double-shell containers with a capacity of 324 bundles, and emplacement of these containers inside emplacement rooms, in a horizontal position. The containers would be arranged in two rows parallel to the longitudinal axis of the emplacement rooms and would be surrounded and supported by an assembly of pre-compacted blocks of buffer and dense backfill material. A system of monitoring the performance of the engineered barriers during the pre-closure phase would also be incorporated.

    It is assumed that the repository would be located in the Canadian Shield at a depth of 1000 meters. In developing the concept, different excavation techniques (including the drill and blast method and the use of tunnel boring machines) were assessed based on cost, design flexibility, proven capability and the effect on long term performance with respect to blast damage. The repository would be self-contained, except for the supply of materials, used fuel containers and their components. The facility design is based on the receipt, packaging and placement of CANDU used-fuel bundles at a rate of 120,000 per annum. The design assumes that these used-fuel bundles have been discharged from reactors and stored for 30 years prior to receipt at the DGR facility.

    Overall, the conceptual design developed by the Joint Waste Owners provides sufficient detail to confirm the engineering feasibility of a DGR and to allow the preparation of a conceptual cost estimate for its implementation, including its siting, construction, operation, decommissioning, closure and post-closure management. The concept is sufficiently well-developed to be considered in this assessment. Until the repository is operational, interim measures would be needed to effectively manage the used nuclear fuel and to ensure safety and security.


    6.9f Financing The Management of Nuclear Fuel Waste in Support of the Nuclear Fuel Waste Act - February 2005

    The Joint Waste Owners (Ontario Power Generation, Hydro Quebec, New Brunswick Power and AECL) have submitted to NWMO a proposal for financing the management of nuclear fuel waste, in response to the requirements laid out in the Nuclear Fuel Waste Act.


    6.9g Financing the Management of Nuclear Fuel Waste in Support of the Nuclear Fuel Waste Act – July 2005

    The Joint Waste Owners (Ontario Power Generation, Hydro Quebec, New Brunswick Power and AECL) have submitted to NWMO a proposal for financing the management of nuclear fuel waste, in response to the requirements laid out in the Nuclear Fuel Waste Act.


    6.10 Review of Conceptual Engineering Designs

    The overall engineering assumptions used in developing the conceptual designs for used nuclear fuel management have been reviewed and validated for NWMO by an independent firm, ADH Technologies Inc.


    Author Biographies

    ADH Technologies Inc.

    Mr. A. D. Hink, P. Eng. & President, ADH Technologies Inc. – Team Leader
    Mr. Hink is a Professional Engineer with many years experience managing major nuclear projects. His particular areas of expertise include engineering and project management of nuclear projects. He is highly respected as a developer of major nuclear projects from the initial marketing to proposal preparation, presentation to the clients, and through engineering to project completion. He has undertaken this responsibility for a number of nuclear facilities in the past. These projects have been successfully implemented. He has led the strategic planning function at the executive level for AECL and he was responsible for executive oversight of AECL’s waste management programs in this role.

    Mr. Pierre Galiungi, P.Eng.
    Mr. Galiungi is a Professional Engineer. He is a Fellow of the prestigious Institution of Civil Engineers, (FICE), and a Fellow of the Institution of Engineers of Australia (FIE) and carries the designation of European Engineer (Eur Ing). He has many years of hands-on experience as a construction manager and project manager with a true grasp of how projects are developed and executed. His experience extends to work on five continents and includes nuclear facilities, hydro- generation, heavy industrial and commercial projects and work in remote areas of the Canadian Arctic. Mr. Galiungi has particularly strong skills at cost management and cost control. These skills, combined with his experiences make Mr. Galiungi particularly well suited to reviewing projects with a view to judging their completeness and that proper consideration is given to risk elements and application of appropriate standards.

    Mr. Robert D. Gadsby, M. Sc. (Nuclear Physics)
    Mr. Robert Gadsby has over 30 years of experience in the Canadian nuclear industry and has served in a wide variety of senior management positions with Atomic Energy of Canada Limited (AECL).

    Most recently, Mr. Gadsby was General Manager, Waste Management and Decommissioning – with responsibility for directing the development of AECL’s Canadian and international waste management service business (including AECL’s cooperative programs with the IAEA and other international waste management organizations).

    Mr. Gadsby has extensive experience in reviewing client needs, evaluating and assessing technical options, and providing project management oversight of nuclear waste management projects. In addition, he has expertise in nuclear fuel cycle options and is familiar with the full spectrum of reactor fuel types (fuel handling, storage, transportation, security, waste management and disposal) which could potentially be used in Canada’s nuclear program (including Natural Uranium, SEU, DUPIC, MOX and even PWR fuel options).

    Mr. Gadsby has also been an “expert witness” regarding the Douglas Point safety and licensing at the Ontario Select Committee hearings into nuclear power.

    6.11 Validation of Cost Estimating Process for Long-Term Management of Used Nuclear Fuel

    The cost estimation process used in developing the conceptual designs for used nuclear fuel management has been reviewed and validated for NWMO by ADH Technologies Inc. and Charles River Associates.


    6.12 Long-Term Used Nuclear Fuel Waste Management - Geoscientific Review of the Sedimentary Sequence in Southern Ontario

    Martin Mazurek, Rock-Water Interaction, Institute of Geological Sciences, University of Bern, Switzerland

    This paper explores, from a geoscientific perspective, the suitability of sedimentary rock for hosting a deep geological repository based on a review of international waste management programs in sedimentary media and a complilation of existing geoscientific information. Although this report focuses on southern Ontario, the principal findings of the review may be applicable to sedimentary rocks in similar geologic settings within Canada. This paper was originally prepared for Ontario Power Generation, and is published here with permission of both Ontario Power Generation and the author.


    Author Biographies

    Martin Mazurek
    Martin Mazurek received his PhD at the University of Basel (Switzerland) as a metamorphic petrologist.

    Since then, he has been working for the Rock-Water Interaction Group at the Institute of Geological Sciences, University of Bern (Switzerland) in the fields of geochemistry and applied geology. He has 15 years of experience in the radioactive waste sector and participated in three Swiss safety cases for Nagra (Swiss National Cooperative for the Disposal of Radioactive Waste) targeted on crystalline and sedimentary rocks. He also worked on projects dealing with geochemical and structural aspects of underground rock laboratories (Grimsel, Switzerland; Äspö, Sweden; Tournemire, France). He was manager of an NEA (Nuclear Energy Agency, Paris) project dealing with the understanding of features, events and processes (FEPs) in argillaceous rocks and the relevance and representation of such FEPs in the safety assessment of geological disposal sites for radioactive waste.

    Martin Mazurek is father of a 4 years old son and lives with his family in Basel, Switzerland. His main hobbies are mountaineering, skiing and photography.

    6.13 Conceptual Designs for Used Nuclear Fuel Management – in Sedimentary Rock

    The Nuclear Fuel Waste Act (NFWA) requires that the NWMO study include an assessment of three specific technical methods. Anticipating their responsibilities under the Act and prior to the establishment of NWMO, the Joint Waste Owners (Ontario Power Generation, Hydro Quebec, New Brunswick Power and AECL) commissioned a team of consultants in 2001 to develop conceptual designs and engineering cost estimates for the alternatives. These conceptual designs were provided to the NWMO in December 2003 and are posted on the NWMO web site as part of Background Paper 6-9.

    Deep Geologic Repository in Sedimentary Rock
    The work of the Joint Waste Owners included an updated Canadian Deep Geologic Repository design and cost estimate based on the emplacement of used fuel containers within extended horizontal tunnels excavated in a granite pluton on the Canadian Shield, 1000 m below ground level – termed ‘in-room’ emplacement.

    During the course of its work, the NWMO identified a need to further examine different geologic formations that may be technically suitable alternative (non-crystalline rock) host geologies for a deep geologic repository (DGR) for used nuclear fuel. To address this need, the NWMO commissioned a high-level review of the potential changes to the ‘in-room’ DGR design and its cost estimate, as a consequence of locating a DGR in sedimentary rock that utilizes the proposed Nagra concept for used fuel disposal in a deep repository. The Nagra design for horizontal emplacement of used fuel containers in sedimentary rock was selected as a concept which has been developed specifically for sedimentary rock formations. The results of this report are summarized in the report: “Deep Geologic Repository in Sedimentary Rock, High-Level Review”.

    Centralized Extended Storage (CRC concept) in Sedimentary Rock
    The work of the Joint Waste Owners included conceptual designs and cost estimates for four alternatives for the extended storage of used nuclear fuel in a Centralized Extended Storage (CES) facility. One of these alternatives comprised the storage of Casks in Rock Caverns (CRC) some 50 m below the surface.

    During the course of its work, the NWMO identified a need to further examine different geologic formations and depths that may provide alternative host geologies for the extended storage of used nuclear fuel. To address this need, the NWMO commissioned a high-level review of the potential changes to the CRC design and its cost estimate, as a consequence of locating it at greater depth in a sedimentary rock formation. The report “Centralized Extended Storage in Sedimentary Rock – High Level Review” summarizes the design and operating features included in the CRC arrangement that require modification to accommodate the introduction of a CRC facility located in sedimentary rock at a depth of 500 m. The document also provides a scoping estimate for implementing these modifications and their effect tn the current CRC overall cost estimate.

    Selection of Sedimentary Rock Formation Type for review

    The report “Selection of a Single Representative Sedimentary Rock Formation for the Storage/Disposal of Used Nuclear Fuel” presents the rationale for the selection of the representative sedimentary rock sequences and depths used in the two high level reviews described above.


    6.14 Implications of Reprocessing, Partitioning and Transmutation on Long-term Management of Used Nuclear Fuel in Canada

    David P. Jackson, McMaster University
    This paper examines the economic and radiological implications of reprocessing, partitioning and transmutation (RP&T) in the context of the long-term management of used nuclear fuel in Canada. It is a sequel to Background Paper 6-4 which surveyed the basic technology of RP&T. This report further elaborates on some of the potential implications of reprocessing, partitioning and transmutation of used nuclear fuel in Canada and reports some recent progress in the field.


    6.15 Adaptive Phased Management: Draft Technical Description

    Nuclear Waste Management Organization

    This document provides a description of the Adaptive Phased Management Approach, as outlined in Appendix 3 of Choosing a Way Forward – Draft Study Report. A discussion of the potential appropriateness of Ordovician sedimentary rock as host geological media has been added to the end of this document.


    6.16 Adaptive Phased Management: Cost Summary

    Golder Associates Ltd., Gartner Lee Limited

    This paper documents and summarizes a cost estimation of the Adaptive Phased Management approach prepared by Golder Associates Limited/ Gartner Lee Limited. A description of this approach is contained in NWMO background paper 6-15.


    Author Biography

    John Davis, B.E.Sc., M.E.Sc., P. Eng., Golder Associates Ltd.
    Mr. Davis is a Senior Consultant and former Principal with Golder Associates Ltd. He has over four decades of practical consulting experience in the fields of geotechnical and environmental engineering, largely associated with solid municipal waste, hazardous industrial waste and radioactive waste management.

    During the late 1970’s and early 1980’s, Mr. Davis was the technical director of a multi-disciplinary project team responsible for the siting, design, licensing, and construction of all uranium mill tailings facilities associated with the expansion/reactivation of five uranium mines in Elliot Lake, Ontario.
    Mr. Davis continued to provide senior technical input to the project team during the operations and subsequent decommissioning of the tailings facilities until the late 1980’s. During that period, he was also responsible for all geotechnical aspects of the decommissioning of the Tennessee Valley Authority’s uranium mill and tailings facilities at Edgemont, South Dakota.

    Since the mid-1980’s, Mr. Davis has been involved in a senior management and technical advisory capacity for a series of multi-disciplinary studies for the safe long-term management of Canada’s historic low-level radioactive wastes. Work included waste and site characterization studies, disposal facility design studies and performance assessment studies for, initially, Eldorado Nuclear Ltd., then the federally constituted Siting Task Force, Low Level Radioactive Waste Management and currently the Low Level Radioactive Waste Management Office of AECL.

    Recently, Mr. Davis directed a geotechnical feasibility study for the safe long-term management of low and intermediate level wastes for Ontario’s Nuclear Power Stations at OPG’s Western Waste Management Facility at the Bruce Nuclear site in Kincardine, Ontario.

    Currently, Mr. Davis is a senior technical advisor/reviewer for a number of radioactive waste and energy related projects in Canada and abroad.

    6.17 Adaptive Phased Management: Validation of Cost Estimating Process for Adaptive Phased Management of the Long Term Management of Used Nuclear Fuel

    A.W. Hooker Associates Ltd.

    The cost estimation process used in developing the Adaptive Phased Management design for used nuclear fuel management has been reviewed and validated for NWMO by A. W Hooker Associates Ltd.


    6.18 Adaptive Phased Management: Technical Description

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    The Study

    NWMO background papers

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    NWMO background papers

    4. Science and environment