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  1. 1. Chapter 7. Nuclear Waste 1.Nuclear Waste Disposal: Amounts of Waste Categories of Nuclear Waste Wastes from Commercial Reactors Hazard Measures for Nuclear Wastes 2. Storage and Disposal of Nuclear Wastes Stages in Waste Handling Deep Geologic Disposal Alternatives to Deep Geologic Disposal Worldwide Status of Nuclear Waste Disposal Plans
  2. 2. IAEA Safety Standards: Geological disposal of radioactive waste 1.1 Categories of Nuclear Waste The Nature of the Problem Military and Civilian Wastes Wastes from commercial nuclear reactors raise more critical issues the amounts are greater, their production continues Form Half lifetime Radioactivity level As with all radioactive sources, radioactive waste is potentially hazardous to health. Therefore, it must be managed in a safe way to protect people and the environment
  3. 3. Good waste management begins before the waste is generated: the starting point for all activities that produce radioactive waste is to avoid or reduce waste generation at its source. Minimizing primary waste generation also minimizes the quantity of waste requiring disposal.
  4. 4. Bad News: Wastes from commercial nuclear reactors raise more critical issues the amounts are greater, their production continues Good News: The world has over half a centurys knowledge and experience on how to deal with nuclear waste. When the characteristics of the waste are known, it can be managed. -IAEA
  5. 5. Types of Waste High-level waste (HLW) Transuranic waste (TRU) Low-level waste (LLW) Uranium Mill Tailings This categorization varies slightly from country to country, but in principle the main criteria for determining the type of waste are derived from radioactive content and half-life, i.e. the time taken for the waste to lose half of its radioactivity.
  6. 6. Types of Waste High-Level Waste The most dangerous radioactive waste Spent fuel comes from nuclear reactors (52,000 tons) liquid and solid waste from plutonium production (91 million gallons). About 70 percent of the available storage space is now filled with used fuel assemblies at Turkey Point.
  7. 7. Types of Waste Transuranic Waste Includes clothing, tools, and other materials contaminated with plutonium, neptunium, and other man-made elements heavier than uranium.
  8. 8. Types of Waste Low and Mixed Low-Level Waste Includes radioactive and hazardous wastes from hospitals, research institutions, and decommissioned power plants (472 million cubic feet)
  9. 9. Uranium Mill Tailings Residues left from the extraction of uranium ore (265 million tons)). Types of Waste
  10. 10. Mining Uranium ore is usually located aerially; core samples are then drilled and analyzed by geologists. The uranium ore is extracted by means of drilling and blasting. Mines can be in either open pits or underground. Uranium concentrations are a small percentage of the rock that is mined, so tons of tailings waste are generated by the mining process.
  11. 11. Production in 2000 Canada 10,682 Australia 7,578 Niger 2,895 Namibia 2,714 Uzbekistan 2,350 Russia (est) 2,000 Kazakhstan 1,752 USA 1,456 South Africa 878 China (est) 500 Ukraine (est) 500 Czech Republic 500 India (est) 200 France 319 others 422 Total world 34,746 company tonnes U Cameco 7218 Cogema 6643 WMC 3693 ERA 3564 Navoi 2400 Rossing 2239 KazAtomProm 2018 Priargunsky 2000 Source: http://www.world-nuclear.org/search/index.htm
  12. 12. Whatever the type of the radioactive waste, all of it has to be disposed of in a safe manner! It is a common misbelief that radioactive waste takes up a lot of space. However, all the spent fuel generated by two 860 MW reactors during their 40 years of operation would fit into three 10 metre by ten metre pools.
  13. 13. Measures of Waste Magnitudes Mass: The most common mass measure for nuclear waste is the mass of the uranium in the initial fuel, more broadly designated as metric tonnes of initial heavy metal (MTIHM or MTHM) Volume: The volume of the fuel can be inferred from the UO2 mass and density (about 10 tonnes/m3 ). Radioactivity: in terms of the activity (in curies or becquerels) taken either for the radionuclides individually or for their sum. radionuclides differ in the types of particles emitted, their energy, the half-lives, and the possibility of their reaching the biosphere. Nonetheless, it provides some overall perspective. Heat output: on the scale of 6 kW of heat are produced per megacurie of activity
  14. 14. 1.2 Wastes from Commercial Reactors Mass and Volume per GWyr
  15. 15. Activity of selected radionuclides in spent fuel versus time since discharge of fuel from reactor
  16. 16. Activity of selected radionuclides as a function of time
  17. 17. Heat Production The handling of the nuclear wastes is significantly complicated by the heat generated in the decay of the radionuclides The heat generation per unit activity depends on the energy carried by the emitted particles. 1 megacurie 5.93 kW (at 1 MeV per disintegration).
  18. 18. Decay of spent fuel from 1 GWyr of PWR operation, for burnup of 40 GWd/t (28.5 MTHM): activity and thermal output as a function of time since discharge.
  19. 19. 1.3 Hazard Measures for Nuclear Wastes Total System Performance Assessments (TSPAs) The maximum permissible concentration is established as the maximum level acceptable for drinking water is closely related to the annual limit on intake (ALI). 20 mSv/yr The water dilution volume (in cubic meters) is the amount of water required to dilute the radionuclide to the maximum permissible concentration.
  20. 20. Illustration of use of water dilution volume: WDV of radionuclides in PWR spent fuel, as a function of time
  21. 21. Chapter 7. Nuclear Waste 1.Nuclear Waste Disposal: Amounts of Waste Categories of Nuclear Waste Wastes from Commercial Reactors Hazard Measures for Nuclear Wastes 2. Storage and Disposal of Nuclear Wastes Stages in Waste Handling Deep Geologic Disposal Alternatives to Deep Geologic Disposal Worldwide Status of Nuclear Waste Disposal Plans
  22. 22. Waste Storage Alternatives Leave It Where It Is Deep Geologic Disposal Yucca Mountain, Nevada Salt Cave Disposal WIPP near Carlsbad, New Mexico Very Deep Holes (6 miles) Ice-Sheet Disposal Space Disposal Sub-Seabed Disposal Island Geologic Disposal Deep-Well Injection Disposal Vitrification (Glass Waste) Reprocessing It is better to have used nuclear fuel in one location
  23. 23. NIMBY: Not In My Back Yard Fear of radiation because they dont understand it Concern that the waste facility will release long-term contamination Worry that property values will be reduced with construction of a waste facility Belief that power companies are the ones responsible for storing their own waste People dont want dumped on by other peoples waste Belief that nuclear power should just go away and be replaced by other energy resources Environmental concerns
  24. 24. Current Waste Disposal At this time, radioactive wastes are being stored at the Department of Energys facilities around the country High level wastes are stored in underground carbon or stainless steel tanks Spent nuclear fuel is put in above-ground dry storage facilities and in water-filled pools
  25. 25. Current High-Level Waste Storage in the US
  26. 26. www.nei.org
  27. 27. 2.2 Deep Geologic Disposal In every option, deep geological disposal is the preferred final end point. The principle of geological disposal is to isolate the waste deep inside a suitable host formation, e.g. granite , salt or clay. The waste is placed in an underground facility or disposal facility, designed to ensure that a system of natural and multiple artificial barriers work together to prevent radioactivity from escaping.
  28. 28. Yucca Mountain The Future of Nuclear Waste Storage
  29. 29. Yucca Mountain Project: Nuclear Fuel and High Level Waste Repository Much more secure repository than leaving high level waste at 60 reactor sites around the country. On old atomic bomb testing base, inside a mountain. The storage is above the water table. The Yucca Mountain site would be 60% filled by present waste. US has legal commitment to the reactor industry. Site has been studied extensively by scientists for over 20 years. Will store waste during its 10,000 year decay time. Questions of how to deflect dripping water around and under the storage vessels. Questions of radioactive decay weakening storage containers. A solution would be to build containers that can be opened and reincased, or to which surrounded casings could be added.
  30. 30. Transportation Concerns
  31. 31. Artists conception of transportation cask and carrier for truck transport; total length = 18 m (56 ft).
  32. 32. Typical Low-Level Waste Disposal Site Hanford (Nuclear News, November 2004)
  33. 33. Country Facility name / Region Geology Depth Status Belgium HADES Underground Research Facility / Mol plastic clay 223 m in operation 1982 Canada AECL Underground Research Laboratory / Pinawa granite 420 m 1990-2006 Finland ONKALO / Olkiluoto granite 400 m under construction France Meuse/Haute Marne Underground Research Laboratory / Bure mudstone 500 m in operation 1999 Japan Horonobe Underground Research Lab / Horonobe sedimentary rock 500 m under construction Japan Mizunami Underground Research Lab / Mizunami granite 1000 m under construction Korea Korea Underground Research Tunnel granite 80 m in operation 2006 Sweden Aspo Hard Rock Laboratory granite 450 m in operation 1995 Switzerland Grimsel Test Site granite 450 m in operation 1984 Switzerland Mont Terri Rock Laboratory / Mont Terri claystone 300 m in operation 1996 USA Yucca Mountain nuclear waste repository / Nevada tuff, ignimbrite 50 m 1997-2008 2.4 Worldwide Status


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