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Flashcards in Radioactive Deck (32):
1

A. 3 basic types of radiation

1. Alpha Particles (most dangerous, cannot get thru skin, lethal if internalized
2. Beta Particles (high Energy e, stopped by plywood)
3. Gamma Rays (high Energy electromagnetic Radiation, m of concrete or H2O

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A. Half-life

the time a radionuclide decays to a more stable form

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B. Hazards of Radionuclides

- alter the chem and physical properties of the material when passed thru (DNA)
- When inhaled or ingested, some can bioaccumulate in the body where they will continue to emit radiation

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C. 5 Natural Sources of Radionuclides

1. Inhalation (depends on where you live)
2. medical diagnosis
3. comic radiation
4. gamma rays from soils and Rx
5. internal sources

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C. Industrial Sources
NORMs may be an issue for employees

1. oil and gas industry
2. mineral extraction -> processing
3. Forestry production
4. water treatment facilities
5. tunnelling + underground waste

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D. radioactive waste Catelogies

1. NORM (Naturally Occurring Radioactive Materials)
2. radioactive wastes resulting from the nuclear fuel cycle
3. atomic weapons produced from plutonium

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D1. NORM

-radioactive elements found naturally in our environment or their decay products
-low concentration in earth (U and Th)
-concentrate NORM -> TENORM (technology-enhanced)
has a higher radiation levels

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D2.1. The Nuclear Fuel Cycle

- Uranium mining and milling
- Refining and uranium enrichment
- Fuel fabrication
- Fuel consumption in nuclear reactors
- Fuel reprocessing
- Waste solidification
- Burial of solidified waste or reprocessing

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D2.1. Uranium mining and milling

- Concentrated ore
- Large piles of waste rock and tailings, low level source of radioactivity

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Fuel consumption

Produce low level radioactive (reactor wastes) which consist discarded equipment

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Fuel consumption

long half life ->> difficult to deal w as a waste ->> takes long to become Nonhazardous to the envi

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Fuel reprocessing

try to decrease the hazard of waste -> disposal (spent fuel and removes 235U & 239Pu)

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Burial of solidified waste or reprocessing

final disposal options

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High Level of Radioactive Waste (HLRW)

produces ionizing radiation with a strong ability to penetrate matter
Eg. spent nuclear, reactor fuel, small amount of medical isotopes

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Intermediate Level (ILRW)

-requires isolation and containment beyond several hundred years
Eg. radiation therapy; used radioactive component

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Low level (LLRW)

-losses all or most radiation in about 300yr
Eg. paper tower, floor sweeping, glassware...

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Uranium mine and Mil waste

-waste generated by the mining and milling of uranium ore

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D2.2. Levels of RW

1. High level
2. Intermediate level
3. Low Level
4. Uranium Mine and Mill Waste

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E. Disposal option for RW

-based on the time frame of the isolation and include:
+interim Storage
+Long Term Storage

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Long Term storage

-maintain integrity in 1000s year or much longer
-Goal: no long term monitoring required and negligible risk to the biosphere at anytime in future

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Short term storage safety requirements

i) cooling mechanisms (H2O/air)
ii) shielding mechanisms. (3mof H2O, 1mof concrete)

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CANOO Reactors

-duel bundles
-deemed waste after 1 year
-30m away from an unshielded bundles
-dose 50-60 Sv/yr
-annual Rad Dose: 2mSv/yr

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E1. Interim Storage of HLRW

- # of Fuel rod about 2M
- the fuel is placed in wet storage (deep water pools with both cooling and shielding process, 10yr)
- Once cooled, then transferred to dry storage
+ still radioactive
+ steel or concrete container, above grd -> air cooling
+ 1 container = 70T, life = 50yr
+ above grd dry storage

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E1.2. Long term storage of HLRW - site criteria

site must be:
-geomorphically and structurally stable (area w no seismic activity, no volcanic activity, protect waste from landscape erosion)
-isolated from fractured bedrock (containment issue, if fractures, hard to clean up)
- isolated from grd H2O and grd h20 flow (no contamination to grd water)

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E1.2. Long-term storage of HLRW - Disposal site considered in past

i) burital within the Antarctic ice cap
ii) Placement on the ocean floor at subduction zones
+when the barrels transferred to the subduction zone, at high P ruptured the barrels and release content to the ocean
+ if not subducted, barrels become apart of accretionary wedge
iii) Deep Geo Disposal (Terminal Storage)
+ store RW in engineered repositories within geo units where it will be isolated from zones of active grd H2O flow
+ mornitor the site for 1-2 gen and if goes well, permanent disposal of the waste

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E1.2.3 Deep Geological Disposal consideration

1. deep crystallize Rx (intrusive granite)
2. Deep salt beds (halite)
3. Deep shale beds
4. thick unsaturated zones

27

Adv and Disad of deep salt beds

Ad: i) dry and impermeable to H2O
ii) can dissipate large amt of heal
iii) fracture that develops to self-seal
Dis: i) can dissolve to create large cavern
ii) can dissolve to create brines which corrosive
iii) salt flow - halite flow toward to the surface wehen heated

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3 storage options in canadian

1.deep underground storage in canadian shield
2.decentralized storage at reactor sites
3.centralized storage in a disposal area
*Federal gov accept combo 1 & 3 : a centralized repository deep undergrd in the canadian shield in Disposal Vaults

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Adaptive Phase management

1.waste will be retrievable indefinitely
2. waste will be mornitored continuously

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Disposal Vault Design

-Lithology: Granite of the Canadian Shield
-Mineral Value: low,
-Depth: 500-1000m
-Storage containers: corrosion resistant, containers last for 1000yr
-GrdH2O flow: low exposure, k & K
-Buffer material: material to surround the barrels to retard grdh2o flow if it entered the repositories
-Backfill: Vaults tunnels + shift at closure

31

Cigar Lake Uranium Deposit

- Located in nothern Sas
- 11% of the world's uranium deposit, 430m below the Earth's surface (very permeable sandstone)
- High grade ore is encased in clays which formed 1.3 Byr ago

32

US Department of Defense Isolation Pilot Plant

- world's 3 deepest DGR, licensed for research and production of nuclear weapons
-Location: 26km East of Carlbad New Mexico
Depth: 650
-Lithology: Halite which is 900m thick
-Material Accepted: Tranuranic low level (still Radioactive 24000yr)