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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
城市放射性废物管理办法
IAEA Safety Standards: Geological disposal of radioactive waste
1.1 Categories of Nuclear Waste
The Nature of the Problem
Military and Civilian WastesWastes from commercial nuclear reactors raise more critical issues the amounts are greater, their production continues…
FormHalf lifetimeRadioactivity 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
Good waste management begins before the wasteis 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.
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 century’s knowledge and experience on how to deal with nuclear waste. When the characteristics of the waste are known, it can be managed. -IAEA
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.
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.
Types of Waste
Transuranic Waste
– Includes clothing, tools, and other materials contaminated with plutonium, neptunium, and other man-made elements heavier than uranium.
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)
Uranium Mill Tailings•Residues left from the extraction of uranium ore (265 million tons)).
Types of Waste
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.
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
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.
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 thebiosphere. Nonetheless, it provides some overall perspective.
Heat output: on the scale of 6 kW of heat are produced per megacurie of activity
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).
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.
1.3 Hazard Measures for Nuclear WastesTotal 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.
Illustration of use of water dilution volume: WDV of radionuclides in PWR spent fuel, as a function of time
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
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
NIMBY: Not In My Back Yard
• Fear of radiation because they don’t 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 don’t want dumped on by other
peoples’ waste• Belief that nuclear power should just go
away and be replaced by other energyresources
• Environmental concerns
Current Waste Disposal
• At this time, radioactive wastes are being stored at the Department of Energy’s 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
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(花岗岩) , 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.
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.
Artist’s conception of transportation cask and carrier for truck transport;total length = 18 m (56 ft).
Country Facility name / Region Geology Depth StatusBelgium HADES Underground Research Facility
/ Molplastic 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 of Nuclear Waste Disposal Plans
Korea Gyeongju L&ILW — 80 m under construction
SwedenSFR /
Forsmark63,000
m3 L&ILWgranite 50 m in operation 1988
Sweden Forsmark spent fuel granite 450 m licence application 2011
Switzerland
—high-level
wasteclay — siting
United Kingdom
—high-level
waste— — under discussion
USA
Waste Isolation Pilot Plant / New
Mexico
transuranic waste
salt bed 655 m in operation 1999
USA
Yucca Mountain Project / Nevada
70,000 ton HLW
ignimbrite 200-300 m proposed, canceled 2010
高放废物地质处置研究开发规划指南
国防科学技术工业委员会 科 学 技 术 部 国 家 环 境 保 护 总 局
2006
我国高放废物地质处置规划研究的总体思路是:统筹规划、协调发展、分步决策、循序渐进。
研究开发和处置库工程建设包括三个阶段:试验室研究开发和处置库选址阶段( 2006 - 2020)、地下试验阶段( 2021 - 2040)、原型处置库验证与处置库建设阶段( 2041-本世纪中叶)
甘肃北山 3个预选地段(旧井、野马泉、向阳山 -新场)
In terms of good practices of radioactive waste management, responsibility covers all the steps from ‘cradle to grave’.
Energy Source Death Rate deaths per TWhr deaths per GWyr
Coal – world average 161 1410 (26% of world energy, 50% of electricity)
Coal – China 278 2435 Coal – USA 15 131 Oil 36 315 (36% of world energy)
Natural Gas 4 35 (21% of world energy)
Biofuel/Biomass 12 105 Peat 12 105
Solar (rooftop) 0.44 3.85 (less than 0.1% of world energy)
Wind 0.15 1.31 (less than 1% of world energy)
Hydro 0.10 .88 (europe death rate, 2.2% of world energy)
Hydro - world including Banqiao)
1.4 12 (about 2500 TWh/yr and 171,000 Banqiao dead)
Nuclear 0.04 .35 (5.9% of world energy)
Living is not a risk-free endeavour to be sure.
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