Presentation to NAS Workshop Oct 2016 M. Garamszeghy, NWMO, Canada

Transcription

1 Presentation to NAS Workshop Oct 2016 M. Garamszeghy, NWMO, Canada

2 The opinions given in this presentation represent my own views and observations from more than 35 years of experience in the field of radioactive waste management in Canada and internationally. They are not intended to be construed as official views of the NWMO, the government of Canada or any of the institutions that may be mentioned herein. 2

3 Background Responsibilities Radioactive Waste Classifications Waste Management Status in Canada Issues & Challenges Waste Management Considerations 3

4 The Government of Canada Policy Framework for Radioactive Waste specifies that: The Government of Canada is responsible for developing policy and regulating and overseeing radioactive waste producers and owners to ensure that they comply with legal requirements and that they meet their operational and funding responsibilities in accordance with approved long-term waste management (disposal) plans. Waste producers and owners are responsible, in accordance with the polluter pays principle, for funding, organizing, managing and operating long-term waste management facilities and other facilities required for their waste. The policy framework recognizes that arrangements may be different for the broad categories of radioactive waste found in Canada, namely nuclear fuel waste, low- and intermediate-level radioactive waste and uranium-mine waste rock and mill tailings. 4

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6 Prior to 2008, the official radioactive waste classifications were: Nuclear fuel waste (used fuel) Uranium mining and milling waste Low-level waste (everything else not included above) Broad LLW definition not sufficient for waste owners for designing and operating waste management facilities Each owner developed their own sub-classes of LLW, based on their needs and capabilities, and developed their waste management infrastructure around these individual definitions No consistency across the industry e.g. what one owner consider to be LLW, another might consider to be ILW 6

7 Current Canadian waste classifications (LLW, ILW and HLW) are based mainly on operational needs (e.g. processing and storage of the wastes). Main drivers are: Beta-Gamma dose rates for worker safety during handling and for design and operation of storage facilities Physical properties for waste processing Tritium content for air and water releases Individual radionuclides are not generally important for handling, processing and storage except how they contribute to dose rates and worker exposures. One of the main radionuclides for disposal safety case in the Canadian NPP context is C-14. This is not a contributor to dose rate, is difficult to measure non-destructively and is present in a significant fraction of the NPP wastes. In general, classifications defined in a CSA standard match IAEA GSG-1 Numeric boundaries between waste classes can be different for different waste owners 7

8 Clearance is allowed under regulations Case-by-case approval is required by regulator Case can be based on single object, specific waste stream or wider waste management program. Most major waste owners have an approved likely clean program that diverts materials away from radioactive waste streams. Some considerations Generic limits are available, based on IAEA RS-G-1.7 derived nuclide-by-nuclide limits and a sum of fractions addition rule. Tends to be very conservative. Case-specific clearance is allowed by presenting appropriate safety case to regulator. Clearance limits generally higher for this option. National standard (CSA N292.5) is available to provide additional guidance. 3R s currently encouraged and may be made mandatory by proposed new regulations 8

9 Sources of waste: Reactor operations, decommissioning, research, medical, industrial, historic activities Compacted & uncompacted DAW, incinerator ash, solidified sludges, soils, building rubble, etc. Criteria: Operational: low dose rates (generally less than ~2 msv/h unshielded) Disposal: no significant quantities of long-lived nuclides (no fixed numeric boundary, depends on safety case for disposal concept), no significant heat generation Planned Disposal Options: Deep geological disposal, combined with ILW Near surface disposal being considered for some lower activity wastes Specific management options: Current practice: storage in above ground or below ground facilities Packaged, but not normally solidified 9

10 Sources of waste: Reactor moderator and coolant purification circuits (IX resins, filters; primary nuclide of concern: C-14) Irradiated core components from reactor refurbishment and decommissioning (primary nuclides of concern: Zr-93 & Nb-94) Isotope production (various nuclides, e.g. Co-60) Criteria: Operational: high dose rates (generally greater than ~10 msv/h unshielded) Disposal: significant quantities of long-lived nuclides (no fixed numeric boundary, depends on safety case for disposal concept), no significant heat generation Planned Disposal Options: Deep geological disposal, combined with LLW or SF/HLW Specific management options: Current practice: storage in above ground or below ground facilities Packaged, but not normally solidified 10

11 Canada currently does not have any disposal facilities for L&ILW or used fuel. However, progress is being made towards implementation: LLRWMO has a licence and is constructing a facility for historic wastes OPG is currently well advanced in the licensing process for a single DGR for all of its operational L&ILW. CNL is in the preliminary licensing stages of a NSF for AECL-owned VLLW/LLW. NWMO is in the siting process for a used fuel DGR (based on a well-informed, voluntary host community). There is a single organization (NWMO) with the legislated mandate for long-term management of used (spent) nuclear fuel. There is no single national entity with a mandate for long-term management of L&ILW, as each waste owner is responsible for the funding and long-term management of their own waste. All wastes are currently stored by their owners in facilities of various designs (both above ground and below ground) at various locations. Waste management facilities have separate licences from NPPs. Licence conditions and waste acceptance criteria (WAC) are facility-specific. 11

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13 Who owns the waste? (each waste owner is responsible for disposal of their waste) How much is there? (small waste quantities may require different disposition than large amounts) Where is it? (if waste is already stored in one location, why move it?) What are the local community preferences? (community acceptance is important, you need to consider what they are comfortable with) What are the total system costs? (since each waste owner can control their lifecycle costs, there is a strong incentive for integrated solutions, i.e. balancing costs of processing, packaging, storage, transport and disposal) 13

14 What types of waste require disposal? (it is usually less costly to build one combined facility than several waste specific facilities) What other hazards are associated with the waste? (non-radiological / mixed waste) How is the waste currently packaged and stored? (it is usually more cost effective to build additional engineered barriers into the disposal facility than to re-condition and/or re-package large amounts of existing waste) How well is the waste characterized? ( over designing a disposal facility to a higher class of waste may be more cost effective than package-by-package characterization to exclude non-compliant packages from a lower class facility) 14

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