Nuclear Fuel Production Fissile Nuclei Uranium and Plutonium

1
Nuclear Fuel ProductionFissile NucleiUranium
and Plutonium

• 235U
• 239Pu

2
Uranium

• 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

3
Reacting the Fuel Fission Reactions
4
Chain Reactions
5
Controlling the Reactions Control Rods
6
(No Transcript)
7
Producing 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.

9
Step 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.

10
Step 5. Fuel-Level Enrichment 4
11
Efficiencies Diffusion method
1.002/stage Final Fraction 0.70 x
(1.002)cycles Calculate cycles to make 4.0
235U Calculate cycles to make 90.0 235U
12
Efficiencies Centrifuge method
1.2/stage Final Fraction 0.70 x
(1.2)cycles Calculate cycles to make 4.0
235U Calculate cycles to make 90.0 235U
13
Plutonium Fuel Made inside Uranium
Nuclear Reactors
Fast neutron reactors (Also called fast breeder
reactors)
14
235U
15
Artificial Transmutations
16
Creation of Transuranium Elements
17
(No Transcript)
18
(No Transcript)
19
(No Transcript)
20
(No Transcript)
21
(No Transcript)
22
(No Transcript)
23
(No Transcript)
24
Radioactive Dating
http//pubs.usgs.gov/gip/geotime/radiometric.html
table
First-order Reaction
25
Specifics 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
26
(No Transcript)