1. 4/2003 Rev 2 I.4.9f – slide 1 of 50 Session I.4.9f Part I Review of Fundamentals Module 4Sources of Radiation Session 9fFuel Cycle – Fuel Fabrication IAEA Post Graduate Educational Course Radiation Protection and Safe Use of Radiation Sources

2. 4/2003 Rev 2 I.4.9f – slide 2 of 50 Object is to convert enriched UF 6 into UO 2 fuel pellets, suitable for use as fuel in a reactor Fuel Fabrication

3. 4/2003 Rev 2 I.4.9f – slide 3 of 50 Fuel Fabrication Overview  Large, industrial-type facilities  Generally good construction  Confinement not containment of Special Nuclear Material (SNM)  No shielded areas  Generally operators/people involved/intertwined with the process  Low radiation and airborne hazards

4. 4/2003 Rev 2 I.4.9f – slide 4 of 50 Basic Chemical Approaches  “Wet” process chemistry  hydrolyze UF 6 in solution  precipitate with ammonia compounds  calcine/reduce to UO 2  ADU = ammonium diuranate  “Dry” process chemistry  hydrolyze UF 6 with steam  convert to UO 2 with steam/H 2  IDR = Integrated Dry Route (BNFL term)

5. 4/2003 Rev 2 I.4.9f – slide 5 of 50  Low-enriched (<10%) uranium facilities  Framatome, Richland WA  Framatome, Lynchburg VA  Westinghouse, Columbia SC  Global, Wilmington NC  High-enriched (>20%) uranium facilities  NFS, Erwin TN  BWXT, Lynchburg VA US Fuel Fabrication Facilities

6. 4/2003 Rev 2 I.4.9f – slide 6 of 50 US Fuel Fabrication Facilities

7. 4/2003 Rev 2 I.4.9f – slide 7 of 50 Importance of Fuel  First two layers of confinement:  Fuel form itself  (Metal) cladding  Must be high quality - “Perfect”  Leakers often require reactor shutdown  Special handling/canning of leaking spent nuclear fuel (SNF)  Money, radiation dose and waste if wrong

8. 4/2003 Rev 2 I.4.9f – slide 8 of 50 Importance of Fuel  Fuel around for “decades”  about 1 year after fabrication  usually 3 cycles (about 5 years) in reactor  minimum of 5 years in wet SNF storage  minimum of 20 years in dry SNF storage  some power reactor fuel 35+ years old  Repository - 100+ years  Fuel is the “tail that wags the dog”

9. 4/2003 Rev 2 I.4.9f – slide 9 of 50 Fuel Considerations  Enriched UF 6 not suitable for fuel  Requires chemical conversion to more stable and robust form  Requires mechanical activities, cladding, and assembly  Fuel requires high density to achieve adequate nucleonics and properties

10. 4/2003 Rev 2 I.4.9f – slide 10 of 50 Chemical Forms of Uranium Fuel  UO 2 (a compromise) is used in most power reactors (LWRs, PHWRs, AGRs, RMBKs) as cylindrical pellets  Pebble bed would use coated UO 2 and would probably be a UO 2 /UC mix

11. 4/2003 Rev 2 I.4.9f – slide 11 of 50 Nuclear Fuel Enrichment  Enrichment Levels  PWR: 2.5-4.5%  BWR: 3-5%  CANDU/PHWR: 0.71%  Naval/Research: up to 100%  Gas/graphite: 0.71-20%  FBR/LMFBR/IFR - 0.2 (blanket) to 30% (driver); 15-25% fissile (Pu) typical

12. 4/2003 Rev 2 I.4.9f – slide 12 of 50 Nuclear Fuel Core Time and Quantities  Core irradiation time, years  CANDU/PHWR: < 1  PWR/BWR: 4-5  Naval/research: 1 - 20+  Gas/graphite: 0.5-3 typical, some > 5  FBR/LMFBR/IFR: 3-5 (driver)  Physical quantities small  about 10,000 MTHM/yr world  about 2,000 MTHM/yr US  U.S. SNF about 50,000 tonnes  All U.S. SNF would fit on a football field 7.6 m deep, subcritical

13. 4/2003 Rev 2 I.4.9f – slide 13 of 50 Typical PWR Fuel Load  1,000 MWe nominal  193 assemblies  51,000 fuel rods  18,000,000 fuel pellets  Typical reject/rework rates  1-3% on pellets  0.1-0.3% on rods  very low for assemblies

14. 4/2003 Rev 2 I.4.9f – slide 14 of 50 PBMR Fuels  “Tennis ball” pebble fuel - 60 mm dia  5 mm outer graphite layer  15,000 coated UO 2 particles, 9 g U/pebble  UO 2 is 0.5 mm  330,000 fuel + 110,000 pure graphite pebbles in core  UO 2 pressed into pebbles  Assay would be 8% enrichment

15. 4/2003 Rev 2 I.4.9f – slide 15 of 50 UF 6 received from enrichment facility in cylinders Cylinders removed from package, weighed, and transferred to UF 6 storage pad UF 6 Cylinders Arriving at Facility Fuel Fabrication

16. 4/2003 Rev 2 I.4.9f – slide 16 of 50 Typical Cylinders at Fuel Fabrication Facilities

17. 4/2003 Rev 2 I.4.9f – slide 17 of 50 Typical Autoclaves

18. 4/2003 Rev 2 I.4.9f – slide 18 of 50 Typical UO 2 Powder Brown/Black appearance

19. 4/2003 Rev 2 I.4.9f – slide 19 of 50 Greatest Environmental Hazards in Fuel Fabrication  Whether wet or dry …  chemical conversion of UF 6 into UO 2  chemical operations in scrap/recovery

20. 4/2003 Rev 2 I.4.9f – slide 20 of 50 Ceramic Process and Final Fuel Fabrication  Ceramic Process  Pretreat  Pelletize (green)  Sinter  Grind  Wash/dry  Inspect

21. 4/2003 Rev 2 I.4.9f – slide 21 of 50 Sample Sintered Pellets

22. 4/2003 Rev 2 I.4.9f – slide 22 of 50 Pellet Trays

23. 4/2003 Rev 2 I.4.9f – slide 23 of 50 Machined pellets are typically about 0.5 inch in length & about 0.33 inch in diameter. They are "dished" slightly on each end. End taper allows pellets to expand and contract through drastic temperature changes inside reactor without damaging fuel or cladding materials Fuel Fabrication

24. 4/2003 Rev 2 I.4.9f – slide 24 of 50 What are Burnable Poisons?  Materials in fuel that limit reactivity for part of the reactor operating cycle (absorb some neutrons)  “Poison Rod”  like a weak control rod  no fuel, just the neutron poison  “Poisoned Rod”  contains fuel and poison  poison in fuel pellets or as separate pellets in rod  Gadolinia and erbia typical poisons due to large neutron cross-sections

25. 4/2003 Rev 2 I.4.9f – slide 25 of 50 Mechanical Process Steps  Mechanical Process  Prepare rods  Load pellets  Seal rods  Make assemblies/Inspect  Store, prior to transportation

26. 4/2003 Rev 2 I.4.9f – slide 26 of 50 Why zirconium?  Capable of withstanding high T, P, rad for years  Structural strength (for tubing)  Corrosion resistance in most coolant environments  Low thermal neutron absorbance  Zr 0.185 b (1 barn = 1E-24 cm 2 )  Hf 10.2 (common impurity)  Reactor grade Zr requires < 100 ppm Hf  Alloys (mainly Zr, some Sn - 1%)  Zircaloy-2 (BWR typical)  Zircaloy-4 (PWR typical)  Others - “Zirlo”

27. 4/2003 Rev 2 I.4.9f – slide 27 of 50 Fuel Pellet “Stacks”

28. 4/2003 Rev 2 I.4.9f – slide 28 of 50 Fuel Rods

29. 4/2003 Rev 2 I.4.9f – slide 29 of 50 Spacer Grids Skeleton Assemblies BWR Grid PWR BWR

30. 4/2003 Rev 2 I.4.9f – slide 30 of 50 The completed fuel assembly is washed and inspected Fuel Assembly in Fixture Fuel Assembly Clean Check Assemblies

31. 4/2003 Rev 2 I.4.9f – slide 31 of 50 Visual Inspection PWRAssembly

32. 4/2003 Rev 2 I.4.9f – slide 32 of 50 Storage  Assemblies stored in racks to  preclude water accumulation  maintain minimal separation/distances

33. 4/2003 Rev 2 I.4.9f – slide 33 of 50 Fuel Assemblies  1,000 MWe Reactor - about 100 MTHM in core  30-34 MTHM in refueling, every 18 months  60-70 assemblies per refueling (PWR)  PWR and BWR assemblies different  BWR smaller size, weight, but about same height  BWR more void space and channels  PWR assembly about 0.5 MTHM  BWR assembly about 0.2 MTHM

34. 4/2003 Rev 2 I.4.9f – slide 34 of 50 PWR/BWR Assemblies PWR 17 x 17 BWR 9 x 9

35. 4/2003 Rev 2 I.4.9f – slide 35 of 50 Typical Scrap Materials  Off-specification pellets  Solids, residues, cleanout from processes (ADU, UOx)  Filter materials, blowback  Machined scrap - from grinding etc.  Dust from the ceramic process  hammer mills, attritors  granulating/slugging anything containing uranium even incinerator ash

36. 4/2003 Rev 2 I.4.9f – slide 36 of 50 Upon final acceptance of the fuel assembly, units are packed in shipping containers for transfer to utility power reactor site Fuel Assembly Packing Shipping Container Loading Fuel Fabrication

37. 4/2003 Rev 2 I.4.9f – slide 37 of 50 Assembly is shock-mounted so that damage does not occur during transport (usually by truck) to customer Fuel Fabrication

38. 4/2003 Rev 2 I.4.9f – slide 38 of 50 Assembled Fuel Bundle At the Nuclear Power Plant, new fuel assemblies are inspected and loaded into the reactor core where the 235 U in the fuel pellets fissions producing heat for electric power generation Fuel Fabrication

39. 4/2003 Rev 2 I.4.9f – slide 39 of 50 CountryOwnerPlantCapacity (MTU/year) BelgiumFBFCDessel750 BrazilFEC (INB)Resende100 ChinaCNNCYibin100 FranceFBFCRomans ‑ sur ‑ Isère820 SICNVeurey ‑ Voroise150 GermanyAdvanced Nuclear FuelsLingen650 IndiaNuclear Fuel ComplexHyderabad25 JapanJapan Nuclear Fuel Co.Yokosuka City750 Mitsubishi Nuclear FuelTokai ‑ Mura440 Nuclear Fuels IndustriesKumatori284 Tokai ‑ Mura200 KazakhstanUlba Metallurgical CoKamenogorsk2,000 LWR Fuel Fabrication Facilities Uranium Oxide Fuel Fabrication

40. 4/2003 Rev 2 I.4.9f – slide 40 of 50 CountryOwnerPlantCapacity (MTU/year) South KoreaKNFCTaejon400 PakistanPAECKundian? RussiaJSC TVELElektrostal620 Novosibirsk1,000 SpainENUSAJuzbado300 SwedenBNFL/West. AtomVästerås600 United KingdomBNFLSpringfields, Lancashire330 United StatesFramatome ANP, IncLynchburg, Virginia400 WestinghouseHematite, Missouri (closed)450 Columbia, S. Carolina1,150 Framatome ANPRichland, Washington700 Global Nuclear FuelWilmington, N. Carolina1,200 Total13,419 LWR Fuel Fabrication Facilities Uranium Oxide Fuel Fabrication

41. 4/2003 Rev 2 I.4.9f – slide 41 of 50 What is MOX?  MOX contains plutonium  Mixed uranium-plutonium OXide fuel  Can be reactor or weapons grade Pu  A one-third core approach “essentially” same as LEUO 2  Matrix is sintered DUO 2 pellets  5-8% Pu in pellets

42. 4/2003 Rev 2 I.4.9f – slide 42 of 50 Experience with MOX  European experience positive:  over 20 reactors licensed for MOX (one-third)  over 15 reactors using MOX  MOX burnup license limit: 42,000 MWD/MTHM  several fuel fabrication facilities  Melox/France is the largest - dry powder processing (about 200 MTHM/yr capacity; licensed at 105)  several minor incidents but no accidents  U.S. experience limited  test assemblies, FBR fuel  wet processing, generally OK  some contamination concerns

43. 4/2003 Rev 2 I.4.9f – slide 43 of 50 MOX Trends?  French, Swiss - continuing  Germany - “some MOX activities”  Britain - “waiting”  Japan - “planning”  Russia/FSU - valuable resource  Environmental Safety and Health impact:  low, no discernable trend  fuel fab. doses, impact comparable to U facilities

44. 4/2003 Rev 2 I.4.9f – slide 44 of 50 What is Weapons Pu?  Short irradiation and low burnup  Uses Pu from dismantled weapons  Typically 90%+ fissile Pu  Requires purification from Ga, Am-241 in-growth  Weapons Pu starts as metal, not as the oxide

45. 4/2003 Rev 2 I.4.9f – slide 45 of 50 How Much Weapons Pu?  About 35 tonnes each (U.S. and Russia)  U.S. currently identified 25 tonnes to MOX  remainder for immobilization  Additional treaties may increase this  Additional problems may decrease this  Technically straightforward but highly politicized program

46. 4/2003 Rev 2 I.4.9f – slide 46 of 50 Which reactors use MOX?  All LWRs are essentially 1% MOX after 6 months  about 50% of power comes from Pu  MOX can be used in LWRs  many applications (>20) in Europe using PWRs  proposed for U.S. at McGuire and Catawba plants  typically one-third of core reload  Fast reactors (usually 15%+ Pu)  LWRs can have full MOX cores  more extensive control system changes

47. 4/2003 Rev 2 I.4.9f – slide 47 of 50 ES&H Concerns  Pu and MOX powder more radiotoxic than UO 2 fuel powder  Room release example: 1 mg in nominal room, 1 minute exposure, nitrate = 35 rem inhalation dose  Ground release example: at 100 meters, 0.32 g, 1 hour exposure = 100 rem (from Pu-239)  Uranium quantities would be 100 times larger for same doses  More radioactive/gamma, particularly for reactor Pu  Criticality  Once pelletized, sintered, in rods  essentially no impact

48. 4/2003 Rev 2 I.4.9f – slide 48 of 50 CountryOwnerPlantCapacity (MTIHM/year) BelgiumBelgonucléaire SADessel37 FranceCOGEMACadarache40 MELOXMarcoule195 IndiaDAETarapur50 JapanJNCTokai ‑ Mura10 United KingdomBNFLSellafield128 Total460 LWR Fuel Fabrication Facilities Mixed Oxide (MOX) Fuel

49. 4/2003 Rev 2 I.4.9f – slide 49 of 50 CountryOwnerPlantCapacity (MTU/year) ArgentinaPecom ‑ Nuclear/CNEAEzeiza160 CanadaZircatec Port Hope, Ontario1,500 General Electric CanadaPeterborough, Ontario1,200 IndiaDAE Nuclear Fuel ComplexHyderabad135 Trombay135 South KoreaKNFCTaejon400 PakistanPAECChashma20 Total3,550 Heavy Water Reactor Fuel Fabrication Facilities

50. 4/2003 Rev 2 I.4.9f – slide 50 of 50  UF 6 release  Criticality  Chemicals used in process Fuel Fabrication Hazards