CANDU Fundamentals CANDU Fundamentals CANDU Fundamentals Table of Contents 1 OBJECTIVES ............................................................................. 1 1.1 COURSE OVERVIEW ............................................................... 1 1.2 ATOMIC STRUCTURE.............................................................. 1 1.3 RADIOACTIVITY – SPONTANEOUS NUCLEAR PROCESSES ....... 1 1.4 NUCLEAR STABILITY AND INSTABILITY................................. 2 1.5 ACTIVITY ............................................................................... 2 1.6 NEUTRONS AND NEUTRON INTERACTIONS............................. 2 1.7 FISSION .................................................................................. 2 1.8 FUEL, MODERATOR, AND REACTOR ARRANGEMENT............. 2 1.9 NUCLEAR SAFETY.................................................................. 3 1.10 NUCLEAR POWER REACTORS................................................. 3 1.11 CANDU REACTOR CONSTRUCTION ...................................... 4 1.12 MODERATOR AND MODERATOR SYSTEM............................... 4 1.13 MODERATOR COVER GAS SYSTEM & MODERATOR AUXILIARY SYSTEMS......................................................................... 5 1.14 HEAT TRANSPORT SYSTEM .................................................... 6 1.15 HEAT TRANSPORT AUXILIARY SYSTEMS ............................... 6 1.16 REACTOR FUEL ...................................................................... 7 1.17 NEUTRON LIFE CYCLE ............................................................ 8 1.18 CRITICALITY AND NEUTRON MULTIPLICATION...................... 8 1.19 CHANGES IN REACTOR POWER WITH TIME .......................... 8 1.20 XENON: A FISSION PRODUCT POISON .................................... 8 1.21 REACTIVITY EFFECTS OF TEMPERATURE CHANGES ............... 9 1.22 NEUTRON FLUX CONTROL ..................................................... 9 1.23 REACTIVITY MECHANISMS .................................................... 9 1.24 EMERGENCY COOLANT INJECTION & CONTAINMENT ............ 9 1.25 CONVENTIONAL SIDE........................................................... 10 1.26 OTHER MAJOR SYSTEMS...................................................... 11 2 ATOMIC STRUCTURE.......................................................... 13 2.1 FUNDAMENTAL PARTICLES.................................................. 13 2.1.1 Proton ......................................................................... 13 2.1.2 Neutron ....................................................................... 13 2.1.3 Electron....................................................................... 14 2.2 STRUCTURE OF ATOMS........................................................ 14 2.3 ATOMIC NOTATION.............................................................. 14 2.4 ISOTOPES ............................................................................. 15 2.5 SUMMARY OF KEY IDEAS..................................................... 16 2.6 ASSIGNMENT ....................................................................... 18 i CANDU Fundamentals 3 RADIOACTIVITY - SPONTANEOUS NUCLEAR PROCESSES ..................................................................................... 19 3.1 TYPES OF EMISSIONS ........................................................... 19 3.1.1 Alpha Emissions.......................................................... 19 3.1.2 Beta Emissions............................................................ 19 3.1.3 Gamma Emissions....................................................... 20 3.2 INTERACTION OF RADIATION WITH MATTER........................ 21 3.2.1 Interactions of Alpha Particles ................................... 22 3.2.2 Interactions of Beta Particles ..................................... 22 3.2.3 Gamma Ray Interactions with Atoms ......................... 22 FIGURE 3.3....................................................................................... 24 COMPTON EFFECT............................................................................ 24 3.3 DIRECT AND INDIRECT IONIZATION ..................................... 25 3.4 SHIELDING ........................................................................... 25 3.5 SUMMARY OF KEY IDEAS..................................................... 26 3.6 ASSIGNMENT ....................................................................... 28 4 NUCLEAR STABILITY AND INSTABILITY ..................... 29 4.1 NEUTRON RICH NUCLIDES................................................... 30 4.2 INTERCHANGEABLE NUCLEONS ........................................... 31 4.3 NEUTRON DEFICIENT NUCLIDES .......................................... 32 4.4 HEAVY NUCLIDES................................................................ 32 4.5 SUMMARY OF KEY IDEAS..................................................... 33 4.6 ASSIGNMENT ....................................................................... 34 5 ACTIVITY AND HALF-LIFE ................................................ 35 5.1 THE LAW OF RADIOACTIVE DECAY ..................................... 35 5.2 HALF-LIFE............................................................................ 36 5.3 RANGE OF HALF-LIVES ........................................................ 39 5.4 SUMMARY OF KEY IDEAS..................................................... 39 5.5 ASSIGNMENT ....................................................................... 41 6 NEUTRONS AND NEUTRON INTERACTIONS................ 43 6.1 NEUTRON PRODUCTION ....................................................... 43 6.1.1 The Photoneutron Reaction ........................................ 43 6.2 NEUTRON INTERACTIONS..................................................... 43 6.3 ELASTIC SCATTERING—(N, N)............................................. 44 6.4 INELASTIC SCATTERING—(N, Nγ) ........................................ 44 6.5 TRANSMUTATION—(N, P), (N, α) ......................................... 45 6.5.1 Neutron-Proton Reaction (n, p) .................................. 45 6.5.2 Neutron-Alpha Reaction (n, α) ................................... 46 6.6 RADIATIVE CAPTURE—(N, γ)............................................... 46 6.7 FISSION ................................................................................ 47 6.8 SUMMARY OF KEY IDEAS..................................................... 48 ii CANDU Fundamentals 6.9 ASSIGNMENT ....................................................................... 49 7 FISSION..................................................................................... 51 7.1 ENERGY RELEASED BY FISSION ........................................... 51 7.2 FISSION FRAGMENTS............................................................ 54 7.3 CHAIN REACTION................................................................. 55 7.4 NEUTRONS ........................................................................... 56 7.4.1 Prompt and Delayed Neutrons.................................... 56 7.4.2 Neutron Energy........................................................... 57 7.4.3 Neutron Flux ............................................................... 57 7.5 NEUTRON CROSS-SECTIONS ................................................ 58 7.5.1 Effect of Composition.................................................. 59 7.5.2 Effect of Neutron Energy ............................................ 60 7.6 SUMMARY OF KEY IDEAS..................................................... 61 7.7 ASSIGNMENT................................................................... 62 8 FUEL, MODERATOR, AND REACTOR MANAGEMENT 63 8.1 MODERATOR........................................................................ 63 8.2 FRESH FUEL AND EQUILIBRIUM FUELLING .......................... 65 8.3 REACTOR ARRANGEMENT ................................................... 65 8.4 SUMMARY OF KEY IDEAS..................................................... 67 8.5 ASSIGNMENT ....................................................................... 69 9 NUCLEAR SAFETY................................................................ 71 9.1 INTRODUCTION .................................................................... 71 9.2 UNITS OF RADIATION EXPOSURE ......................................... 71 9.3 RADIATION .......................................................................... 72 9.4 CONVENTIONAL SAFETY...................................................... 75 9.5 ALARA - A PHILOSOPHY TOWARDS HAZARDS ................... 75 9.6 SELF-CHECKING .................................................................. 75 9.7 REACTOR SAFETY ................................................................ 75 9.8 DEFENCE IN DEPTH.............................................................. 76 9.8.1 Reliable Process Systems............................................ 77 9.8.2 Reliable Safety Systems............................................... 77 9.8.3 Multiple Barriers ........................................................ 77 9.8.4 Competent Operating and Maintenance Staff............. 78 9.8.5 Detect and Correct Failures ....................................... 79 9.9 BASIC RELIABILITY CONCEPTS ............................................ 79 9.9.1 Definitions................................................................... 79 9.9.2 Concepts...................................................................... 80 9.10 DOCUMENTATION ................................................................ 82 9.11 NUCLEAR STATION RADIOACTIVE EMISSIONS ..................... 83 9.12 THE