4/2003 Rev 2 I.4.9a – slide 1 of 14
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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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