1 / 18

Nuclear Fuel Cycle: Mining, Enrichment, and Fuel Fabrication

Nuclear Fuel Cycle: Mining, Enrichment, and Fuel Fabrication. Randall Fielding, INL Email: randall.fielding@inl.gov Phone: (208) 533-7015. Presentation Summary. Nuclear Electricity 7 th Ed., Ian Hore-Lacy, Uranium Information Centre and World Nuclear Association . Mining: Surveying .

liam
Download Presentation

Nuclear Fuel Cycle: Mining, Enrichment, and Fuel Fabrication

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Nuclear Fuel Cycle: Mining, Enrichment, and Fuel Fabrication Randall Fielding, INL Email: randall.fielding@inl.gov Phone: (208) 533-7015

  2. Presentation Summary Nuclear Electricity 7th Ed., Ian Hore-Lacy, Uranium Information Centre and World Nuclear Association

  3. Mining: Surveying • Surveying • Geological and satellite surveys • Very high level • Aircraft surveys • After areas of interest are seen with satellite a more detailed survey is done using planes and helicopters • Surface surveys • Prospector and his donkey

  4. Mining: Minerals of interest • Several uranium bearing minerals of interest for mining • Grades usually vary from 0.5% - 0.03%

  5. Mining: Types of mining • Open pit mine • Most common • Underground • Must have adequate ventilation because of radon, sometimes necessitating remote equipment • In-situ leaching (solution mining) • Leaching solution pump down one hole and dissolved U3O8 pump up adjacent holes • Somewhat experimental, ground water contamination concerns

  6. Mining: Milling • During milling the U3O8 from the mine is concentrated • Incoming ore is crushed • Roasted to dive off organics • U3O8 is leached or recovered through Sx/ion exchange • U3O8 is precipitated out, washed, dried, and packaged • Finished product is termed “yellow cake”

  7. U3O8 HF F2 UO2 UF4 UF6 Reduction Hydofluorination Fluorination Distillation H2+N2 Pure UF6 Solvent U3O8 Heat H2+N2 HF UO3 UO2 Hydro-fluorination Digestion Sx Calcination Reduction HNO3 UF4 F2 Fluorination Pure UF6 Enrichment: Conversion from U3O8 to UF6 Dry Hydrofluor Process Wet Solvent Extraction Process

  8. Enrichment: 235U Enrichment • Gaseous Diffusion • 235U molecules are faster, hence diffuse through a hole in a barrier more quickly • Centrifugal method • Centrifugal forces compress the gas at the centrifuge wall, but thermal agitation separates lighter elements to the center of the chamber • Atomic Vapor Laser Isotope Separation • A laser selectively excites 235U atoms. UV light kicks some excited electrons free and ionizes the atoms. Ions are collected on a negatively charge Faraday cup.

  9. Fuel Fabrication: UO2 Production • Fuel manufacturers receive the UF6 which is solid at room temperature and convert it to UO2 • Bubble UF6 gas through water to form UO2F2 • UO2F2 is added to ammonia water to precipitate (NH4)2U2O2 • (NH4)2U2O2 is calcined to form U3O8 • U3O8 is reduced with H2 to form UO2

  10. Fuel Fabrication: Pellet Production • UO2 is crushed and ground to a fine powder and mixed with an organic binder (e.g.. polyvinyl alcohol) • Powder is pressed into pellets and sintered • Sintering • Hydrogen • 1650° C for 24 hours • Final density: 94% theoretical density

  11. Fuel Fabrication: Pellet Production • Pellet final diameter: ~10 mm diameter • Pellets are ground to final diameters • Ends are be cupped and corners chamfered • Grinding will reduce mechanical interaction during irradiation • Each pellet is inspected

  12. Fuel Fabrication: Pellet Production

  13. Fuel Fabrication: Fuel Rod Production • Pellets are segregated into stacks and weighed • Loaded into zirconium alloy tubes • Pressurized to 1000-2000 p.s.i. with helium and seal welded http://www.euronuclear.org/info/encyclopedia/f/fuel-rod.htm

  14. Fuel Fabrication: Assembly Fabrication • Fuel rods are then bundled into fuel assemblies

  15. Jacket hardware Spacer wire wrap Bottom endplug welding Sodium Loading Inspections Load jackets with fuel Settle slugs Weld top endplug Fuel Fabrication: Metal Fuel Trimmings to casting furnace Trimmings to chemistry Fuels feedstock Alloy production Injection casting Break molds Trim slugs Inspection Bonding Furnace Weld inspection Final inspection Bonding Assembly hardware Fabricate fuel assemblies Final inspection Pull test Flow test

  16. Fuel Fabrication: Metal Fuel • Sodium bonded fuel • Provides good heat conduction • Metal fuel is compatible with Na • LMFBR use sodium as the coolant

  17. Fuel Fabrication: Metal Fuel • Metal fuel is injection cast • Alloys are melted under vacuum • Evacuated molds are lowered into melt and furnace is pressurized • Metal is forced up into the molds where it cools and solidifies • Fuel slugs are then removed from the molds • Remaining fabrication steps similar to UO2 fuel

  18. References: • The Nuclear Fuel Cycle: Analysis and Management by R.G. Cochran and N. Tsoulfanidis • Figures were found on www.wikipedia.org (unless otherwise noted)

More Related