1. The Nuclear Fuel Cycle ?
2. Open and Closed Fuel Cycle
3. Open and Closed Fuel Cycle
4. AREVA in the Fuel Cycle
5. Mining and Milling ore 0.1-2 % U
Reduced by chemical leaching or solvent extraction to U3O8 (yellowcake)
Mill tailings still contain some U and therefore emit radon
Tailings are placed underground or capped
6. Uranium Concentrations
8. Uranium Deposits & Milling Sites
9. Uranium Ore and Yellowcake
10. World Uranium Production
11. Enrichment Natural U is 0.72% U-235
Power plants use 3-5% enriched
Gaseous diffusion - most common
Gas centrifuges
Aerodynamic separation - too expensive
Electromagnetic separation
Laser isotope
12. Conversion Capacity in T U/y
13. Uranium Hexafluoride
14. Fuel Fabrication UF6 is converted into UO2 clad then grouped into fuel bundles
15. International Fabrication Capacity (LWR, Uranium Oxide)
[t U/year] nominal capacity
1. USA 3500
2. Russia 2020
3. Kazakhstan 2000
4. Japan 1674
5. France 970
6. Belgium 750
7. Germany 650
8. Sweden 600
9. Korea, Rep. 400
10. Unit. Kingd. 330 11. Spain 300
12. China,cont'l 100
13. India 25
14. Algeria 0
16. Reactor Fuel Management
Remain critical while fuel composition and reactivity changes
Shape the power density to max power output
Maximize heat production from fuel
Uniform irradiation of fuel
Maximize productive use of neutrons
17. Fuel shuffle Every year PWR-1/3 or BWR 1/4 of the core is removed and the core is reloaded
New fuel is shuffled into the core
Zone loading
Scattering loading
Modified scatter loading
18. Zone Loading
19. Scattering Loading
20. Modified Scatter Loading
21. Spent fuel storage Still contains fuel
180 kg of fissile Pu + 22,000 kg of U-235 at each refueling (435 MW and 420MW)
Also contains 100s of fission products -7 have half-lives greater than 25 yrs.
Stored on site in water then dry storage
No permanent US storage yet
22. Waste Disposal High level - fission products separated in the first stage of reprocessing
Mine and Mill tailings
Transuranic (TRU)
actinides with concentrations
> 100 nCi/g
Low level waste - no shielding required
< 100 nCi/g
class A - 0.1 Ci/ft3
class B - 2 Ci/ft3
class C - 7 Ci/ft3
Intermediate level -
vaguely defined between low and high
23. Reprocessing Objectives
Recover U, Pu, and Th to be used as fuel
Separate radioactive and neutron-absorbing fission products
Convert the radioactive waste into suitable forms for safe storage
The US does not have reprocessing facilities
24. Types of Reprocessing Bismuth Phosphate
Redox
Trigly
Butex
Purex - most common
Thorex
Pyro-processes
Urex+ - most recent
