High Level Radioactive Waste Disposal: Background and The Canadian Proposal

Transcription

1 High Level Radioactive Waste Disposal: Background and The Canadian Proposal Adam McLean March 27, 2001

2 Outline of Presentation Where does new fuel come from? How is CANDU fuel used? What is high level radioactive waste? How much waste are we talking about? Where is the waste now? Principles of waste management The waste storage proposal Studies done so far The road ahead

3 Where Does New Fuel Come From? Uranium mines in Canada all found in Saskatchewan Cluff Lake (closed), McClean Lake, Midwest, Cigar Lake, McArthur River, Key Lake, Rabbit Lake Mined with open pit and underground techniques, from human/power hammer to pioneering work in completely automated mining. Fuel & Fuel Channel Analysis Department

4 How is CANDU Fuel Used? Manufactured at plants throughout Canada. Uranium from Cameco and Cogema corporations. Fuel components produced by Zircatec Precision Engineering and General Electric. Each bundle is 50cm long, 10cm in diameter and weighs 23 kilograms or 51 lbs. After transport to each reactor, all handling is remote and automatic.

5 What Is High Level Radioactive Waste? Includes fuel from power-production and research reactors, components from decommissioned reactors. Looks like fuel when it goes in - no visible change, no loss of structure. Less than 2% of Uranium atoms are changed in nuclear reactions. After removal from the reactor, it cannot be handled by hand. All radioactive components kept sequestered inside fuel bundles. 1 year after removal from the reactor, activity is ~1% original, after 10 years, 0.1%, after 100 years, 0.01%. Fuel & Fuel Channel Analysis Department

6 How Much Waste Are We Talking About? By the end of 2001, there will be approximately 1,600,000 used CANDU fuel bundles weighing 39,200 tonnes. This would fill four regulation-size hockey rinks up to the top of the boards. Produced 87% by OPG, 6% by NBPower, 5% by HQ, 2% by AECL. If reactors are constructed as old ones are retired to 2073, 10 million used bundles will be created.

7 Where is the Waste Now? At the reactor sites (Pickering, Bruce, Darlington) in watercooled pool for up to about 7 years when radioactivity and heat has reduced enough to transfer. Moved to modular, concrete, air-cooled, shielded, above ground dry storage on-site at each plant. Also, research reactor fuel and components stored at AECL Chalk River laboratory in shallow, underground sites.

8 IAEA Principles of Radioactive Waste Management Protection of human health Protection of the environment Protection beyond natural borders Protection of future generations Minimum burden on future generations National legal framework Control of radioactive waste generation Generation and management interdependencies Safety of facilities

9 The Waste Storage Proposal Partnership between AECL, OPG, NB Power, and Hydro-Quebec. In previous 30 years, have spent $700 million on the concept. AECL Whiteshell Research facility tests every aspect of disposal. Multiple barriers protect humans and the environment: Zircaloy bundle case has low solubility and is effective in containing radioactive and chemically toxic contaminants. Titanium-shelled container is designed to last >500 years with very low corrosion. Each container is placed in a borehole and surrounded by a clay buffer to limit dissolution of waste should groundwater seep in and retard movement of released contaminants (due to low permeability and high porosity) and provide seismic stability. Each room of boreholes is sealed with backfill of clay or cement, keeping the buffer securely in place. All tunnels, shafts, and exploration boreholes are ultimately sealed to make the facility passively safe.

10 What Does it Look Like? Using a location in the Canadian Shield provides a very stable seismic region and very low driving force for groundwater movement (mainly by diffusion). Site would be selected considering local geologic fracture zones, and groundwater chemistry. Disposal rooms are connected by extensive access tunnels which are connected to dual sets of ventilation and waste shafts to the surface, metres above. Designed to store 10 million used bundles at a cost of $13 billion.

11 What are the Risks? Facility will have an operating lifespan of 90 years. Natural background radiation in Canada is 3 msv / year. Current CNSC limit for radiation exposure to atomic radiation workers is 50 msv / year, and to public, 20 msv / year. Maximum dose to individual storage worker is 17 msv / year. For all times to 10,000 years, mean dose rate to public facility is < msv / year including natural env. penetration. Risk of inadvertent intrusion by exploratory drilling, meteor impact, etc. < / year assuming loss of institutional control after 500 years. Maximum dose rate to transport crew up to 10 msv / year. Maximum dose rate to public during transportation: road msv / year to people at truck stops rail msv / year to people living near railways water msv / year to boat following waste through canals Accident frequency with radioactive material release is less than / year for all methods of transport. Risk for dose of >10 msv during an accident is less than / year. Fuel & Fuel Channel Analysis Department

12 Is Transporting Spent Fuel Safe? Crash tests performed at Sandia National Labs in the US. Crash test into solid concrete wall - cask remains intact. Locomotive crash test - cask remains intact.

13 Studies Done So Far in Canada? 90,000+ computer simulations (VAULT, GEONET, BIOTRAC, and SYVAC) to study technical feasibility and safety of the proposal over the next 100,000 years. Submissions to Organization for Economic Co-operation and Devlopment (OECD), Nuclear Energy Agency Review Group, the Canadian Geotechnical Society, Natural Resources Canada, Health Canada, Royal Society of Canada Environmental Impact Statement Engineering Impact Statement Geosphere Model for Postclosure Assessment Biosphere Model for Postclosure Assessment Complete Environmental Assessment Panel review Ethical and Social Implications through the Canadian Coalition for Ecology, Ethics and Religion Public Involvement through Energy Probe, public hearings

14 What are the Alternatives? CANDU 1000MWe nuclear reactor uses 156 tonnes of uranium / year, with 156 tonnes of waste / year. Average 1000MWe coal-fired power station requires 3,200,000 tonnes of coal / year creating 7,000,000 tonnes of CO 2, 200,000 tonnes of SO2, and 200,000 tonnes of fly ash / year (including arsenic, cadmium, lead, vanadium and mercury). Fuel & Fuel Channel Analysis Department

15 What s Being Done in Other Countries? Waste Management for Spent Fuel from Nuclear Power Reactors Country Policy Facilities and progress towards final repositories Belgium Reprocessing Underground repository laboratory established Construction of repository to begin 2030 Canada Direct Disposal Underground repository laboratory established Repository planned for use 2025 Finland Direct Disposal Spent fuel storage in operation Five sites located for deep repository, one to be selected in 2010 for use by 2020 France Reprocessing Two facilities for storage of short-lived wastes Site selection studies underway for deep repository for commissioning 2020 Germany Reprocessing Low-level waste sites in use since 1975 (under review) High-level repository to be operational after 2010 India Reprocessing Investigating deep repository sites Japan Reprocessing Low-level waste repository in operation High-level waste storage facility under construction Investigations for final repository site begun Netherlands Reprocessing Central low-level waste repository in operation High-level waste storage facility under construction. Russia Reprocessing Sites for final disposal under investigation South Korea Undecided Low-level and intermediate-level waste site under investigation Spain Direct Disposal Low & intermediate-level waste repository in operation Final repository site selection program. Decision 2000, commissioning Sweden Direct Disposal Central spent fuel storage facility in operation since 1985 Final repository for low to intermediate waste in operation Underground research laboratory for high-level waste Site selection for repository, to begin disposal in Switzerland Reprocessing Central interim storage for all wastes under construction Underground research laboratory for high-level waste repository, with final deep repository to be finished by Low-level waste repository in operation since United Reprocessing High-level waste currently vitrified and stored, new underground repository Kingdom planned. Three low-level waste sites in operation USA Direct Disposal Investigations on national final repository at Yucca Mountain, EIS published mid 1999, possible opening Russia and Australia are considering constructing a storage facility for world-wide use.

16 Natural Evidence that Storage will be Safe? In 1972, very well preserved remains of 15 ancient natural nuclear reactors were found in the Oklo Uranium ore deposit in Gabon, Africa. Started billion years ago and ran from 100,000 to 1 million years. Plutonium has moved less than 10 feet from where it was formed.

17 The Road Ahead Canadian public acceptability is lacking, due to lack of information polling, lack of public trust in technology and regulator, and amount of social and political obstacles. CEAA recommended phases for the future include: Phase I: Setup federal policy statement, Aboriginal participation creation of Nuclear Fuel Waste Management Agency (NFWMA) public review of CNSC regulatory documents Phase II: Concept Acceptance public education through ongoing, interactive information and communication plan consideration of options for modified versions of the concept Phase III: Project Acceptance selection of site based on specific technical and environmental requirements Phase IV: Implementation measures to implement project

18 Closing The proposal for deep geologic high-level radioactive waste disposal facility is a safe storage concept with no long-term effects on the public and environment. Nuclear professionals must do their best to communicate this to the public. For more info Canadian Environmental Assessment Agency» Full environmental assessment viewable + executive summary» ceaa-acee.gc.ca Atomic Energy of Canada Limited» General and technical information on the proposal.» aecl.ca Toronto Branch of the Canadian Nuclear Society» Expert knowledge, local link to information world-wide» cns-snc.ca -> branches -> Toronto