1. 4/2003 Rev 2 I.4.9h – slide 1 of 24 Session I.4.9h Part I Review of Fundamentals Module 4Sources of Radiation Session 9hFuel Cycle – Spent Fuel IAEA Post Graduate Educational Course Radiation Protection and Safety of Radiation Sources

2. 4/2003 Rev 2 I.4.9h – slide 2 of 24 Spent Fuel

3. 4/2003 Rev 2 I.4.9h – slide 3 of 24 What is the “Back End” of the Fuel Cycle  The back end has to do with post-reactor use of the (now) irradiated fuel  Irradiated fuel is extremely radioactive and generates heat  Clouded by politics, policy issues, national pride, NIMBY, BANANA, LULU etc.  Issue defused by excellent power plant records, longer fuel burnups, compact nature of waste  Economics clouded  No clear route driven by safety

4. 4/2003 Rev 2 I.4.9h – slide 4 of 24 Irradiated Fuel Spent nuclear fuel (SNF) being moved during refueling High Radiation Hazard - No people nearby

5. 4/2003 Rev 2 I.4.9h – slide 5 of 24 Typical SNF Properties  Round numbers, per tonne (MTIHM)  950 kg LEU (about 2% assay)  40 kg fission products  10 kg Pu isotopes (about 65% fissile)  very radioactive, 10s of Sv/hr  Generates heat - decays with time  after 1 year, about 5 KW/assembly (0.5 te)  after 5 years, about 1 KW/assembly  Only 3-5% is actually waste  94-96% is the original uranium  1% or so Pu can be used in MOX

6. 4/2003 Rev 2 I.4.9h – slide 6 of 24 How much SNF?  Currently over 60,000 tonnes (MTHM) in U.S  Accumulating at about 2,500 tonnes/yr  First repository limited to 70,000 MTHM by statute  Most US reactors expected to pursue license extension  In few years, likely to exceed statutory limit for first repository  Likely to exceed 100,000 MTHM within ten years  New plants/impacts?

7. 4/2003 Rev 2 I.4.9h – slide 7 of 24 Irradiated/SNF options  storage  wet or dry  at reactor or away  reprocessing  wet schemes - Purex  dry schemes  transmutation  disposal  repository/geologic  as SNF  as HLW

8. 4/2003 Rev 2 I.4.9h – slide 8 of 24 Wet Storage of SNF  Wet storage  “swimming pools,” sometimes borated  required for immediately discharged SNF  low temperature storage - 38 to 66 °C  shielding provided by water depth over SNF (6+ metres typical)  can be large, at site - “ISFSI” or away  water filters, pumps, IX  Requires active systems, some safety significant  Preferred method of long-term storage in most countries outside US countries outside US

9. 4/2003 Rev 2 I.4.9h – slide 9 of 24 Above Ground Dry Storage

10. 4/2003 Rev 2 I.4.9h – slide 10 of 24 Dry Storage of SNF  Dry storage  large metal/concrete containers: 1.5-3 m dia by 4.3-6.1 m High  requires minimum wet storage for cooling (5 yrs)  “high” temperature - 100-150 °C typical - in pressurized Helium  20-30 cm of steel or 1-1.2 m of concrete for shielding  Concrete requires air passages for cooling  Modular  not fully passive - seals, passages require routine inspections  preferred in U.S. for long-term storage

11. 4/2003 Rev 2 I.4.9h – slide 11 of 24 Other Dry Storage Items  Economics  $400 - 500 K for concrete cask  $1,000 - 1,500 K for metal casks  Vaults comparable to concrete costs per assembly  costs appear lower than wet storage  All currently loaded dry SNF storage casks will need to be unloaded for placement in SNF disposal cask  Some currently loaded casks will have to be unloaded for transportation

12. 4/2003 Rev 2 I.4.9h – slide 12 of 24 Dry Storage Issues  Big issues  creep of cladding  burnup/credits  thermal  life extension/20+ years  transportation  away from reactor storage  Repository  Dry storage easier than wet but many more issues  Under normal operating conditions, operator doses should be low for either wet or dry storage should be low for either wet or dry storage