Thermal analysis of pressurized water reactors Third ed

CONTENTS Preface to Third Edition, xv Nomenclature, xvi Glossary, xix Chapter 1 Power Generation 1.1 Reactor Configurations, 1 1 1 Basic Concept (Conventional PWR), 1 .1 .2 Other Reactor Concepts, 18 1 1.3 Advanced Reactors with Passive Safety Features, 24 1 1.4 Status of Various Concepts, 29 1.2 Steady-State Power Generation and Distribution in Conventional PWR Cores, 30 1.2.1 Power Distribution in Unperturbed Uniformly Loaded Cores, 30 1.2.2 Effect of Fuel Loading, 32 1.2.3 Effect of Control Rods, Water Slots, Voids, and Burnable Absorbers, 41 1.2.4 Nuclear Hot-Channel Factors, 48 1.2.5 Heat Generation Within Fuel Elements, 52 1.2.6 Distribution of Power Among Fuel, Moderator, and Structure, 55 1.3 Methods for Estimation of Steady-State Core Power in Conventional PWRs, 58 1.3.1 Pin-by-Pin Diffusion Computations, 58 1.3.2 Nodal Methods, 60 1.3.3 Effective Fast Group Methods, 66 1.4 Power Generation and Distribution in Pressure Tube-Type Cores, 68 1.4.1 Overall Power Distribution, 68 1.4.2 Power Generation Within Fuel Clusters, 70 1.4.3 Effect of Refueling Procedures, 72 1.5 Transient Power Generation and Distribution, 74 1.5.1 Power Distribution Following a Load Change, 74 1.5.2 Power Generation During Shutdown, 79 Generation in Reactor Structure and Moderator, 85 1.6.1 Structure, 85 1 .6.2 Moderator, 87 1.7 Thermal Design Basis, 87 References, 88 Chapter 2 Fuel Elements 2.1 Fuel Element Characteristics, 93 2.1.1 Fuels and Their Thermal Properties, 93 2.1.2 Fuel Element Cladding and Assembly Designs, 114 2.2 Behavior of U02 Fuel Elements, 127 2.2.1 Mechanical Properties of U02, 127 2.2.2 Fuel Densification and Restructuring, 130 2.2.3 Fuel Swelling, 135 2.2.4 Fission Gas Release and Internal Pressure, 139 2.2.5 Thermal Resistance of Fuel and Fuel-Cladding Gap, 150 2.2.6 Mechanical Behavior of Cladding, 164 2.2.7 Accuracy of Fuel Element Property and Behavior Models, 168 2.3 Steady-State Conduction Under Idealized Conditions, 169 2.3.1 Heat Generation Within a Fuel Plate, 169 2.3.2 Heat Generation Within a Fuel Rod, 172 2.3.3 Annular Fuel Elements, 182 2.4 Realistic Evaluation of Steady-State Temperatures, 183 2.4.1 Rigid Pellet, No Fuel-Pellet Friction, 184 2.4.2 Rigid Pellet, Fuel-Pellet Friction Considered, 187 2.4.3 Behavior Considering Pellet Plasticity, 190 2.5 Fuel Performance, 196 2.5.1 Typical Reactor Operating Conditions, 196 2.5.2 Fuel Behavior, 197 2.5.3 Improved Fuel Rod Design, 202 2.5.4 Evaluation of Fuel Performance During Normal Operation, 204 2.6 Transient Fuel Rod Behavior, 209 2.6.1 Fuel Rod Temperature Transients, 209 2.6.2 Cladding Behavior During Transients, 222 2.6.3 Fuel Melting, 230 References, 232 Chapter 3 Hydrodynamics 3.1 Basic Flow Characteristics, 242 3.1.1 Transport Equations for Single-Phase Flow, 242 3.1.2 Single-Phase Flow Friction, 244 3.1.3 Simple Flow Transients, 257 3.1 .4 Pump Behavior, 258 3.2 Reactor Component Hydrodynamics, 261 3.2.1 Velocity Profiles and Turbulence in Fuel Rod Bundles, 261 3.2.2 Flow in Plenums, 270 3.2.3 Flow-Induced Vibration, 274 3.2.4 Hydraulic Design of Control Rods, 282 3.3 Two-Phase Flow, 283 3.3.1 Two-Phase Flow Structure (Flow Patterns), 284 3.3.2 Void Fraction, 290 3.3.3 Two-Phase Pressure Drop, 300 3.3.4 Basic Two-Phase Flow Modeling, 309 3.3.5 Sonic Velocity and Critical Flow, 319 3.3.6 Pump Behavior with Two-Phase Flow, 342 3.4 Flow Instability, 342 3.4.1 Nature of Various Flow Instabilities, 343 3.4.2 Effects of Various Parameters on Flow Instability, 350 3.4.3 Dynamic Instability Analysis, 350 3.4.4 Parallel Channel Instability, 356 3.4.5 Flow Pattern Instability, 359 3.4.6 PWR Instability Concerns, 359 3.4.7 Recommended Methods of Analysis, 361 3.5 Liquid-Vapor Separation, 362 3.5.1 Entrainment and Carry-Over, 362 3.5.2 De-Entrainment, 368 3.5.3 Carry-Under, 371 3.5.4 Flooding, 372 3.5.5 Primary Steam Separation, 375 3.5.6 Phase Separation in Branching Conduits, 378 References, 382 Chapter 4 Heat Transfer and Transport 4.1 Heat Transport Assuming One-Dimensional Behavior, 395 4.1.1 Steady-State Enthalpy Rise Along a Closed Coolant Channel, 396 4.1.2 Transient Heat Transport, 401 4.1.3 Heat Transfer Via Natural Ccmvection, 418 4.2 Heat Transport in the Presence of Interacting Channels, 419 4.2.1 Subchannel Analysis, 419 4.2.2 Porous Media Approach, 447 4.3 Forced Convection Heat Transfer in Single-Phase Flow, 456 4.3.1 Empirical Equations for Single-Phase Heat Transfer, 456 4.3.2 Surface Roughness Effects on Heat Transfer, 460 4.3.3 Turbulence Promoter and Grid Spacer Effects, 461 4.4 Boiling Heat Transfer, 462 4.4.1 Flow Boiling Heat Transfer, 462 4.4.2 The Boiling Crisis or Critical Heat Flux, 466 4.4.3 Effects of Crud Deposition, 497 4.4.4 Post-C HF Heat Transfer, 499 4.4.5 Recommended Approaches to Boiling Heat Transfer Estimation, 512 4.5 Condensation, 514 4.5.1 Basic Models, 514 4.5.2 Reflux Condensatior:1, 516 4.5.3 Spray Condensation, 517 4.5.4 Direct Contact Condensation on Flowing Liquid Streams, 518 4.5.5 Steam Condensation on Containment Surfaces, 519 4.6 Heat Transfer in Reactor System Components, 519 4.6.1 Heat Transfer in Steam Generators, 519 4.6.2 Pressurizer Heat Transfer, 528 4.7 Cooling of Structure and Solid Moderator, 530 4.7.1 Temperature Distributiom Wilthin Core Structure, 530 4.7 .2 Temperature Distributiom Wilthin a Solid Moderator, 533 References, 535 Chapter 5 Reactor Thermal and Hydraulic Performance 5.1 Basic Thermal Design, 546 5.1.1 Thermal Design Limitations and Approaches, 546 5.1.2 Fuel Rod Design, 548 5.1.3 Preliminary Core Design, 552 5.1.4 Hot-Channel Factor Evaluation for Conservative Core Design, 557 5.1.5 Effect of Anticipated Operating Occurrences (AOOs) and Major Accidents on Core Design, 567 5.2 Analysis of Core Performance During Normal Operation, 563 5.2.1 Optimal System Performance, 563 5.2.2 Effect of Core Flow Arrangement on Core Performance, 568 5.2.3 Interaction of Thermal-Hydraulic Design with Other Areas, 569 5.3 Subchannel Analysis Methods for Core Thermal-Hydraulic Design, 572 5.3.1 Objectives of Subchannel Analysis Procedures, 572 5.3.2 Sequential or Chain Subchannel Procedures, 573 5.3.3 Single-Pass Computational Methods, 574 5.3.4 DNB Computations Using Subchannel Analysis Procedures, 577 5.4 Stochastic Thermal Analysis Procedures, 582 5.4.1 Assessment of Correlation Accuracy, 582 5.4.2 Stochastic Design Methods Based on the Total DNB Ratio, 583 5.4.3 Assessment of DNB Failure Probability at Operating Conditions, 586 5.5 Computer-Based Analysis of Pressure Tube Reactor Cores, 587 5.6 Reactor Protection and Core Monitoring, 589 5.6.1 Safety Criteria, 589 5.6.2 Core Monitoring Instrumentation, 592 5.6.3 Core Protection, 594 5.6.4 Set-Point Analysis (Conventional PWRs), 598 5.6.5 Thermal Protection in Pressure Tube Reactors, 606 5.6.6 Alternative DNB Design Limit, 607 5.7 Advanced PWRs, 608 5.7.1 Design Objectives and Specific Goals, 608 5.7.2 Core Modifications in Advanced Design Reactors, 609 5.7.3 Primary System Component Modifications, 613 5.8 Future Design Directions, 614 References, 615 Chapter 6 Safety Analysis 6 .1 Safety Approaches, 618 6.1.1 Safety Philosophy, 618 6.1.2 Safety Criteria, 619 6 .2 Accident Evaluation Approaches, 621 6.2.1 Thermal-Hydraulics Approaches, 621 6.2.2 Neutronic Modeling, 623 6.2.3 Computer Configurations, 627 6.3 Anticipated Operating Occurrences, 627 6.3.1 Loss-of-Flow Accident (LOFA), 628 6.3.2 Undercooling Transients, 631 6.3.3 Reactivity and Power Distribution Anomalies, 633 6.3.4 Overcooling Transients, 634 6.3.5 Changes in Reactor Coolant Inventory, 634 6.4 Accidents Due to Secondary System Rupture (Steam-Line Breaks), 635 6.5 Large-Break Loss-of-Coolant Accident (LBLOCA), 636 6 .5.1 System Behavior, 636 6.5.2 Regulatory Requirements, 639 6.5.3 Key LOCA Phenomena, 640 6.5.4 Fluid-Structure Interactions, 655 6.5.5 Evaluation Models for LBLOCA Analysis, 659 6.5.6 Best Estimate Computer Models for L BLOCA Analysis, 665 6.5.7 Initial Conditions for Conventional PWRs, 668 6.5.8 Long-Term Recovery Following LBLOCA, 668 6.5.9 LBLOCA in CANDU Reactors, 670 6 .6 Small-Break Loss-of-Coolant Accident (SBLOCA), 672 6 .6 .1 Breaks Actuating Accumulator Flow, 673 6 .6 .2 Medium-Size Small Breaks, 673 6 .6 .3 Very Small Size Breaks, 674 6 .6 .4 Break Location Effects, 678 6.6.5 SBLOCA Analysis, 679 6.6.6 SBLOCA in CANDU Reactors, 681 6.7 Anticipated Transients Without Scram, 681 6 .7 .1 Regulatory Requirements, 681 6.7.2 Characteristics of ATWS Events, 682 6 .7 .3 Loss-of-Feedwater ATWS, 682 6 .7 .4 ATWS Analysis Procedures, 684 6 .8 Severe Accidents, 685 6 .8 .1 Overall Perspective, 685 6 .8 .2 Severe Accident Causes, 687 6 .8 .3 Severe Accident Sequences in Conventional PWRs, 688 6 .8 .4 Severe Accident Sequences in CANDU Reactors, 691 6 .8 .5 Important Physical Phenomena in Severe Accidents, 693 6 .8 .6 Computer Programs for Analysis of Severe Accidents, 707 6 .8 .7 Severe Accident Management, 709 6 .8 .8 Probabilistic Risk Assessment, 709 6 .9 Vapor Container Analysis, 712 6 .9 .1 Containment Systems, 712 6 .9 .2 Licensing Analysis, 713 6 .9 .3 Vapor Containment During Severe Accidents, 720 6.10 Safety Features of Advanced Designs, 722 6 .10.1 Redesigned Conventional PWRs, 722 6 .10.2 Hybrid Safety System Approach, 724 6.10.3 Approaches Placing Primary Rei iance on Passive Safety Systems, 725 6.11 Safety Analysis Techniques for Advanced Reactors, 727 References, 728 Author Index 735 Subject Index 740