1. 4/2003 Rev 2 I.4.7 – slide 1 of 48 Session I.4.7 Part I Review of Fundamentals Module 4Sources of Radiation Session 7Nuclear Reactors IAEA Post Graduate Educational Course Radiation Protection and Safety of Radiation Sources

2. 4/2003 Rev 2 I.4.7 – slide 2 of 48 Overview  In this session we will discuss Nuclear Reactors including  Types  Basic Elements

3. 4/2003 Rev 2 I.4.7 – slide 3 of 48 The Beginning

4. 4/2003 Rev 2 I.4.7 – slide 4 of 48 Fossil vs Nuclear

5. 4/2003 Rev 2 I.4.7 – slide 5 of 48 Nuclear Reactors  Types of Nuclear Reactors:  Light Water Reactors (LWR)  Heavy Water Reactors (HWR)  Gas-Cooled Reactors  Fast Neutron Reactors  Fast Breeder Reactors

6. 4/2003 Rev 2 I.4.7 – slide 6 of 48 Boiling Water (BWR) Nuclear Reactors

7. 4/2003 Rev 2 I.4.7 – slide 7 of 48 Pressurized Water (PWR) Nuclear Reactors

8. 4/2003 Rev 2 I.4.7 – slide 8 of 48  The next five slides display the main components of a Nuclear Power Plant:  Control Building  Containment Building  Turbine Building  Fuel Building  Diesel Generator Building  Auxiliary Building Components of a Nuclear Plan

9. 4/2003 Rev 2 I.4.7 – slide 9 of 48 Control Building

10. 4/2003 Rev 2 I.4.7 – slide 10 of 48 Containment Building

11. 4/2003 Rev 2 I.4.7 – slide 11 of 48 Turbine Building

12. 4/2003 Rev 2 I.4.7 – slide 12 of 48 Fuel Building

13. 4/2003 Rev 2 I.4.7 – slide 13 of 48 Diesel Generator and Auxiliary Buildings

14. 4/2003 Rev 2 I.4.7 – slide 14 of 48 Protective Barriers

15. 4/2003 Rev 2 I.4.7 – slide 15 of 48 Steam Generator

16. 4/2003 Rev 2 I.4.7 – slide 16 of 48 Nuclear Reactors

17. 4/2003 Rev 2 I.4.7 – slide 17 of 48 Advanced Reactors  The first advanced reactors are now operating in Japan; others under construction in several countries  Nine new nuclear reactor designs either approved or at advanced stages of planning  Advanced reactors incorporate safety improvements and are simpler to operate, inspect, maintain and repair

18. 4/2003 Rev 2 I.4.7 – slide 18 of 48  The new generation of reactors have:  a standardized design to expedite licensing and reduce capital cost and construction time  enhanced safety systems to further reduce the possibility of core melt accidents  higher availability and longer operating life  higher burn ‑ up to reduce fuel use and the amount of waste, and  will be economically competitive in a range of sizes Advanced Reactors

19. 4/2003 Rev 2 I.4.7 – slide 19 of 48  More 'passive' safety features which rely on gravity, natural convection, etc., to avoid accidents  Two broad categories:  Evolutionary - basically new models of existing, proven designs  Developmental - depart more significantly from today’s plants and require more testing and verification before large ‑ scale deployment Advanced Reactors

20. 4/2003 Rev 2 I.4.7 – slide 20 of 48 CANDU Reactors  CANDU stands for "Canada Deuterium Uranium“  It is a pressurized heavy ‑ water, natural ‑ uranium power reactor designed first in the late 1950s by a consortium of Canadian government and private industry  All power reactors in Canada are CANDU type  The CANDU designer is AECL (Atomic Energy of Canada Limited), a federal crown corporation

21. 4/2003 Rev 2 I.4.7 – slide 21 of 48 CANDU Reactors

22. 4/2003 Rev 2 I.4.7 – slide 22 of 48  On ‑ power refueling is one of the unique features of the CANDU system  Due to the low excess reactivity of a natural ‑ uranium fuel cycle, the core is designed to be continuously "stoked" with new fuel, rather than completely changed in a batch process (as in LWRs)  This reduces core excess reactivity, and the requirement for burnable poisons, which in turn increases fuel burnup (decreases the fuel throughput rate) CANDU Reactors

23. 4/2003 Rev 2 I.4.7 – slide 23 of 48  Other advantages of on ‑ power refueling include:  increased capacity factors (on-line availability)  ability to "fine ‑ tune" the power distribution  ability to detect and remove defective fuel  minimization of power perturbations  On ‑ power refuelling is achieved with two identical fuelling machines that latch on to opposing ends of a designated channel  Each machine, operated remotely from the control room, includes a magazine capable of either discharging new fuel or accepting spent fuel CANDU Reactors

24. 4/2003 Rev 2 I.4.7 – slide 24 of 48 Heavy Water

25. 4/2003 Rev 2 I.4.7 – slide 25 of 48 High Temperature Gas Cooled Reactors

26. 4/2003 Rev 2 I.4.7 – slide 26 of 48 Pebble Bed Reactor

27. 4/2003 Rev 2 I.4.7 – slide 27 of 48 Pebble Bed Reactor

28. 4/2003 Rev 2 I.4.7 – slide 28 of 48 Pebble Bed Reactor Potential Problems (according to some groups)  It has no containment building  It uses flammable graphite as a moderator  It produces more high level nuclear wastes than current nuclear reactor designs

29. 4/2003 Rev 2 I.4.7 – slide 29 of 48 Pebble Bed Reactor Potential Problems (according to some groups)  It relies heavily on nearly perfect fuel pebbles  It relies heavily upon fuel handling as the pebbles are cycled through the reactor  There's already been an accident at a pebble bed reactor in Germany due to fuel handling problems

30. 4/2003 Rev 2 I.4.7 – slide 30 of 48 Reactors of the Future  Future reactors - known as Generation IV  Lead-alloy, liquid-metal cooled fast reactor system (LFR)  Molten salt reactor system (MSR)  Sodium liquid-metal cooled fast reactor  Very high temperature gas-cooled reactor system (VHTR)  Supercritical water-cooled reactor system

31. 4/2003 Rev 2 I.4.7 – slide 31 of 48 Where to Get More Information  Cember, H., Johnson, T. E., Introduction to Health Physics, 4th Edition, McGraw-Hill, New York (2008)  Martin, A., Harbison, S. A., Beach, K., Cole, P., An Introduction to Radiation Protection, 6 th Edition, Hodder Arnold, London (2012)  Glasstone, S., Sesonske, A. Nuclear Reactor Engineering, 4 th Edition, Dordrecht:Kluwer Academic Publishers (1995)  The six Generation IV reactor designs were taken from Nuclear News, Nov 2002  More information at: http://www.world- nuclear.org/info/inf08.html