1. Nuclear Energy

2. Pitchblende or Uranium Oxide or U3O8

3. Pitchblende is a mixture of……..
235U & 234U & 238U Only 235U is fissionable

4. Uranium is common in the Earth’s crust
Uranium is common in the Earth’s crust. It is 35 times more common than silver!

5. First: Mine
Mine the pitchblende out of the ground (subsurface or surface)

6. Big Eagle Open Pit Uranium Mine (Wyoming)

7. Second: Mill
Milling. Mined uranium ores normally are milled by grinding the ore materials to a uniform particle size and then treating the ore to extract the uranium by heap leaching.
The milling process commonly yields dry powder-form material consisting of natural uranium, "yellowcake," which is sold on the uranium market as U3O8.

8. The result of milling is…..
Yellow Cake! Yummmmmmm

9. Uranium Milling Locations

10. Third: Conversion
Uranium conversion. Milled uranium oxide, U3O8, must be converted to uranium hexafluoride, UF6 (which can be enriched).

11. Fourth: Enriching
Enrichment. The concentration of the fissionable isotope, 235U is less than that required to sustain a nuclear chain reaction in reactor cores. Natural UF6 must be "enriched" in order for it to be used as nuclear fuel.

12. Gas centrifuge is the most commonly used uranium enrichment technology.
In the gas centrifuge process, the UF6 gas is spun at high speed in a series of cylinders. This acts to separate the 235UF6 and 238UF6 atoms based on their slightly different atomic masses.

13. The enriching process results in excess 238U that is called depleted uranium.

14. Depleted uranium is used in warheads
Depleted uranium is used in warheads . It is used because it carries a lot of kinetic energy (it is dense) and does a lot of damage on impact.

15. Depleted uranium (tailings)

16. Milling and Enriching

17. Highly Enriched 235U (in the hand’s of a fool)

18. Fifth: Fabrication
Fabrication. For use as nuclear fuel, enriched UF6 is converted into uranium dioxide (UO2) powder which is then processed into pellet form.

19. The pellets are then fired in a high temperature furnace to create hard, ceramic pellets of enriched uranium. The cylindrical pellets then undergo a grinding process to achieve a uniform pellet size.
The pellets are stacked, according to each nuclear core's design specifications, into tubes of corrosion-resistant metal alloy.

20. The tubes are sealed to contain the fuel pellets: these tubes are called fuel rods. The finished fuel rods are grouped in special fuel assemblies that are then used to build up the nuclear fuel core of a power reactor.

21. Fuel Rods (3% U-235; 97% U-238)
Fuel Assembly
Fuel Rods
Pellets

22. Fuel rods
Reactor Core

23. The Process

24. The nuclear reaction

25. Neutron
Fissionable U-235
Unstable U-236
Two fission fragments: Ba-141 & Kr-92
3 neutrons

27. The Fission Process
1 (of 3 neutrons) hit a U-235 = critical
< 1 neutron hits a U-235 = subcritical
> 1 neutron hits a U-235 = supercritical (yikes!)

28. Who Has the Uranium? Country Percentage of Uranium Australia 23%
Kazakhstan
16%
Canada
11%
United States
10%
South Africa 8%
Niger 6%
Namibia