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Session I.4.9a

Part I Review of Fundamentals

Module 4 Sources of Radiation

Session 9a Fuel Cycle - Overview

IAEA Post Graduate Educational CourseRadiation Protection and Safety of Radiation Sources

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Overview

In this session we will discuss the Nuclear Fuel Cycle including:

Mining Milling Conversion Enrichment Fuel Fabrication Power Generation Spent Fuel Reprocessing Waste Disposal

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Energy Resources

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Energy Resources

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ppmSource (part per million)

High‑grade ore (2% U) 20,000

Low‑grade ore (0.1% U) 1,000

Fertiliser 400

Coal deposits 100

Granite (60% of earths crust) 4

Sedimentary rock 2

Seawater 0.003

Typical Uranium Concentrations

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Country tonnes percentage of world

Australia 863,000 28%

Kazakhstan 472,000 15%

Canada 437,000 14%

South Africa 298,000 10%

Namibia 235,000 8%

Brazil 197,000 6%

Russian Fed. 131,000 4%

USA 104,000 3%

Uzbekistan 103,000 3%

World Total 3,107,000

Known RecoverableUranium Resources

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Uranium Decay Chain

Primary Isotopes 238U -

alpha emitter 235U and 234U –

alpha/gamma emitters

Decay Products 231Th and 234Th -

beta/gamma emitters 234mPa -

beta/gamma emitter

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Decommissioned Nuclear Weapons

over 90% 235U (must be downblended for commercial fuel)

Thorium

coverts to 233U after neutron capture 3 times more abundant than uranium

Other Sources of Fuel

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Natural uranium consists of three isotopes:

Isotope % Abundance Half Life (106 years)

238U 99.284 4,500235U 0.711 704234U 0.005 0.245

Properties of Natural Uranium

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Uranium Properties

238U is most abundant

234U increases with enrichment

Note activity ratios

0.00010.0010.01

0.1

110

100

Nat

ura

lUranium Isotope

Percent

U-238

U-235

U-234

LE

U

Dep

lete

d

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Uranium Specific Activity

Type (enrichment) Specific Activity(Bq/gram)

Depleted (0.2%) 1.5 x 104

Natural (0.71%) 2.6 x 104

Enriched (4%) 8.9 x 104

Enriched (93%) 4.1 x 106

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Uranium Compounds

UF6 produced at conversion plants

U3O8 is yellowcake from milling

UO2 is dominant fuel type (ceramic) used

to produce pellets

UF4 is intermediate form in conversion

Uranyl nitrate is important in recovery

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Fuel Cycle

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Fuel Cycle Around the World