1. HT 2005T8: Chain Reaction1 Chain Reaction Multiplication Criticality Conditions

2. HT 2005T8: Chain Reaction2 Overview Chain Reaction Conversion and Breeding Doubling Time Neutron Cycle in a Thermal Reactor Multiplication Factor k Simplified Fuel Cycle Fuel at Discharge

3. HT 2005T8: Chain Reaction3 Chain Reaction ν β γ γ β ν n

4. HT 2005T8: Chain Reaction4 Uranium Fuel 238 U 4.5 10 9 yr 235 U 0.7 10 9 yr 234 U 247000 yr Application U nat 99.27%0.72%0.006%CANDU (D 2 O) UE98-95%2-5%0.006%LWR (H 2 O) DU (UD)99.8%0.2%0.006% Fast Reactor (FR, FBR) Armour for tanks Armour-piercing

5. HT 2005T8: Chain Reaction5 Conversion or Breeding

6. HT 2005T8: Chain Reaction6 Conversion

7. HT 2005T8: Chain Reaction7 Conversion

8. HT 2005T8: Chain Reaction8 Neutron Cycle in Reactor n/fission N1N1 N2N2 Leakage Fast fission Resonance abs. Non-fuel abs. Leakage Non-fissile abs. Fission Slowing down Energy E 2 MeV 1 eV 200 MeV/fission ν ≈ 2.5

9. HT 2005T8: Chain Reaction9 Fast Fission

10. HT 2005T8: Chain Reaction10 Simple Criticality Calculations

11. HT 2005T8: Chain Reaction11 Fuel Cycle (Thermal) Fuel Factory Thermal Reactor DU Fissile Materials Actinides (MA) Fiss. Pr. (FP) Spent Fuel

12. HT 2005T8: Chain Reaction12 Fuel Cycle (Fast) Fuel Factory Fast Reactor FP+MA Spent Fuel DU

13. HT 2005T8: Chain Reaction13 Neutron Economy

14. HT 2005T8: Chain Reaction14 Breeding Factor 1 neutron absorbed in fuel η neutrons produced B neutrons captured in fertile Non-fuel capture and losses C+L 1 neutron to maintain chain reaction

15. HT 2005T8: Chain Reaction15 η Factor η Isotope (100%) Thermal (0.025eV) Fast (>0.5 MeV) 235 U2.072.35 233 U2.292.40 239 Pu2.152.90

16. HT 2005T8: Chain Reaction16 Fission Neutrons 239 Pu 235 U 233 U E = 1

17. HT 2005T8: Chain Reaction17 Conversion Factor If B < 1 it is called conversion factor, C. Number of 239 Pu created per 1 neutron absorbed Reactor System Initial Fuel Conversion Cycle Conversion Ration BWR 235 U (2-4%) 238 U → 239 Pu0.6 PWR 235 U (2-4%) 238 U → 239 Pu0.6 PHWR (CANDU)U nat 238 U → 239 Pu0.8 HTGR 235 U (5%) 232 Th → 233 U0.8 LMFBR 239 Pu (10-20%) 238 U → 239 Pu1.0 – 1.6

18. HT 2005T8: Chain Reaction18 Neutron Cycle in Reactor n/fission N1N1 N2N2 Leakage Fast fission Resonance abs. Non-fuel abs. Leakage Non-fissile abs. Fission Slowing down Energy E 2 MeV 1 eV 200 MeV/fission ν ≈ 2.5

19. HT 2005T8: Chain Reaction19 Chain Reaction in U nat ?

20. HT 2005T8: Chain Reaction20 Doubling Time T d for a breeder reactor is the amount of time required for the original fissile loading to double

21. HT 2005T8: Chain Reaction21 Doubling Time for FR

22. HT 2005T8: Chain Reaction22 Multiplication Factor

23. HT 2005T8: Chain Reaction23 Chain Reaction by Fast N. 235 U

24. HT 2005T8: Chain Reaction24 Time to Fission 1 kg 235 U

25. HT 2005T8: Chain Reaction25 Energy Comparison

26. HT 2005T8: Chain Reaction26 Distribution of FP Mass

27. HT 2005T8: Chain Reaction27

28. HT 2005T8: Chain Reaction28 Long-Lived Radio Isotopes

29. HT 2005T8: Chain Reaction29 Half-Lives of L.L. Isotopes

30. HT 2005T8: Chain Reaction30 The END