Sources of Radiation Nuclear Power Reactors

1. Sources of Radiation Nuclear Power Reactors Day 4 – Lecture 3

2. Objective To discuss about Nuclear Power Reactors including their Types and Basic Elements

3. Contents • Types of Nuclear Reactors • PWRs • BWRs • CANDU • Advanced Nuclear Reactors • Components of a Nuclear Power Plant

4. The Beginning

5. Fossil vs Nuclear

6. Nuclear Reactors • Types of Nuclear Reactors: • Light Water Reactors (LWR) • Heavy Water Reactors (HWR) • High-Temperature Gas-Cooled Reactors • Fast Neutron • Fast Breeder

7. Primordial Nuclides

8. Slow Neutron Interactions Fission 1n + 235U  fission products available for more fission the mean number of neutrons released per fission for U-235 is 2.5). This leads to a self-sustaining chain reaction or “critical mass.”

9. Boiling Water (BWR) Nuclear Reactors

10. Pressurized Water (PWR) Nuclear Reactors

11. Components of a Nuclear Plant • 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

12. Control Building

13. Containment Building

14. Turbine Building

15. Fuel Building

16. Diesel Generator and Auxiliary Buildings

17. Protective Barriers

18. Steam Generator

19. Nuclear Reactors

20. Advanced Reactors • The first advanced reactors now operating in Japan • Nine new nuclear reactor designs either approved or at advanced stages of planning • Incorporate safety improvements and are simpler to operate, inspect, maintain and repair

21. Advanced Reactors • The new generation of reactors have: • a standardised design to expedite licensing, reduce capital cost and reduce construction time • higher availability and longer operating life, will be economically competitive in a range of sizes, further reduce the possibility of core melt accidents • higher burn‑up to reduce fuel use and the amount of waste

22. Advanced Reactors • More 'passive' safety features which rely on gravity, natural convection to avoid accidents • Two broad categories: • Evolutionary - basically new models of existing, proven designs • Developmental - depart more significantly from today¹s plants and require more testing and verification before large‑scale deployment

23. 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

24. CANDU Reactors

25. CANDU Reactors

26. High Temperature Gas Cooled Reactors

27. High Temperature Gas Cooled Reactors

28. Pebble Bed Reactor In the 1950s, Dr Rudolf Schulten ( 'father' of the pebble bed reactor) had an idea. The idea was to compact silicon carbide coated uranium granules into hard billiard-ball-like graphite spheres to be used as fuel for a new high-temperature, helium-cooled type of reactor. The idea took root, and in due course, the AVR, a 15 MW (megawatt) demonstration pebble bed reactor, was built in Germany. It operated successfully for 21 years.

29. Pebble Bed Reactor

30. 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

31. 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

32. Where to Get More Information • Cember, H., Johnson, T. E, Introduction to Health Physics, 4th Edition, McGraw-Hill, New York (2009) • More information at: • http://www.pbmr.co.za/index.htm