Title: Nuclear Fuel Production Fissile Nuclei Uranium and Plutonium
1Nuclear Fuel ProductionFissile NucleiUranium
and Plutonium
2Uranium
- Two isotopes
- 99.3 238U not useful for energy production
- 0.7 235U useful for energy production
- For a nuclear reactor Need 4 235U
- For a fission bomb Need 90 235U
3Reacting the Fuel Fission Reactions
4Chain Reactions
5Controlling the Reactions Control Rods
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7Producing Uranium Fuel
- U ore contains small amounts of UO2 and UO3.
- Step 1. Oxidize UO2 to UO3
- Step 2. Solubilize U by reacting with H2SO4
-
- UO3(s) 2 H(aq) ? UO22(solid salt) H2O(l)
- UO22(solid salt) 3 SO42-(aq) ? UO2(SO4)34-(aq)
- Key Uranium is solubilized and is leached out of
the rock.
8- Step 3. More Reactions, eventually to yield UO3.
- 2R3N H2SO4 ? (R3NH)2SO4
- 2 (R3NH)2SO4 UO2(SO4)34- ? (R3NH)4UO2(SO4)3
(aq) 2SO42- (aq) - (R3NH)4UO2(SO4)3 2(NH4)2SO4 ? 4R3N
(NH4)4UO2(SO4)3 2H2SO4 - 2NH3 2UO2(SO4)34- (aq) ? (NH4)2U2O7 (s)
4SO42- (aq) - (NH4)2U2O7 (s) ? U3O8(s) H2O(l) NH3(g)
- U3O8 is then reacted to make pure UO3.
- Key UO3 formed is pure.
9Step 4. Formation of UF6
- UO3(s) H2(g) gt UO2(s) H2O
- UO2(s) 4HF(g) gt UF4(s) 2H2O(l)
- UF4(s) F2(g) gt UF6(l or g)
- Key UF6 has a boiling point near 50 oC.
10Step 5. Fuel-Level Enrichment 4
11Efficiencies diffusion 1.002/stage Final
Fraction 0.7 x (1.002)cycles gas centrifuge
1.2/stage Final Fraction 0.7 x (1.2)cycles
12Plutonium Fuel Made inside Uranium
Nuclear Reactors
Fast neutron reactors (Also called fast breeder
reactors)
13235U
14Artificial Transmutations
15Creation of Transuranium Elements
16Exploring for yourself.Kirk-Othmer Encylopedia
of Chemical TechnologyActinides and
Transactinides
17Most made by neutron addition
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20Nuclear Explosions Fast n addition
238U ? 255U ? 255Np ? 255Pu ? ? 255Fm
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22Ultra Heavy Elements Beyond the Actinides
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25Radioactive Dating
http//pubs.usgs.gov/gip/geotime/radiometric.html
table
First-order Reaction
26Specifics for Dating of Earth and Previously
Living Things
Units of Radioactivity Curie, Ci 3.7 x 1010
disintegrations/sec Becquerel, Bq 1
disintegration/sec
C-14 N-14
5730 years
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