Nuclear Corrosion Modeling (eBook)

Front Cover 1
Nuclear corrosionModeling 4
Coyright Page 5
Contents 6
Preface 12
Introduction 14
1. Why Do We Care? 14
2.. Bounding the Discussion 14
The Reactor 15
Materials of Construction 15
pH Control Agents and Coolant Additives 16
Clarifying the Definition 16
3. The Analytical Domain 17
Chapter 1: The Corrosion Source 20
1. The Process 20
2. The Form 21
3. Why a Double-Layered Film? 22
4. Ion Site Preference 24
5. Kinetics 26
Modeling the Behavior 26
A Closer Look at kp 28
Temperature 28
Zinc in the Aqueous Phase 29
Surface Condition 30
The Experimental Technique 32
Elemental Speciation of kp and kr 39
Computation of the Actual kr 39
Elemental Speciation 40
Adjusting Kinetics for the Presence of Zinc 41
6. The Cobalt Source 41
Tramp Cobalt in Construction Material 42
High Cobalt Content Alloys 43
Stellite 44
The Cobalt Source Mechanism 46
Modeling the Cobalt Source 48
7. A Place to Start 49
Chapter 2: Framing the Vision of the General Equation Set 52
1. Mass Balances 53
2. Physicochemical Processes 54
3. Nuclear Processes 54
4. Dependent Variables 58
5. Modeling Coolant Additives and pH Control Agents 58
Chapter 3: Building Block Fluxes for the General Equation Set 62
1. Corrosion Growth and Release 63
2. Particulate Deposition and Erosion 64
Water Purity 67
Practical Measurements of kdp and ke 67
3. Hydrothermal Crystallization/Dissolution 69
Saturated or Equilibrium Coolant Concentrations 70
Vanishing Dependent Variables 73
Parsing the Hydrothermal Mass Transfer 74
Modeling of Boiling Phenomena 75
Boiling Enhanced Hydrothermal Crystallization 76
Boiling Enhanced Particulate Deposition 77
4. Hydrothermal Particulate Crystallization/Dissolution 77
Saturation Enhancement Factor 78
Hydrothermal Particulate Mass Transfer Coefficient 80
5. Building Block Models for Radioactive Buildup and Decay 81
Effective Thermal Neutron Production Cross Sections 81
Chapter 4: The General Equation Set 84
1. Chromite Sublayer Equations 85
Iron- and Nickel-Based Alloys 85
Stellite 85
Zircaloy 85
Discussion 85
2. Ferrite Layer Equations 86
Discussion 87
3. Particulate Aqueous Phase Equations 87
Discussion 88
4. Aqueous Soluble Phase Equations 88
Iron- and Nickel-Based Alloy Soluble Equations 88
Zircaloy Base Metal Soluble Equations 89
Stellite Base Metal Soluble Equations 90
Discussion 90
Chapter 5: Framing the Vision of the Media Equation Set 92
1. Reactor Coolant Purification Systems 92
2. Modeling Media 93
Filtration Building Block Model 94
Discussion 95
Modeling lambdaf and beta 96
A Simpler Approach 97
Ion-Exchange Building Block Model 99
Discussion 100
Chapter 6: The Media Equation Set 104
1. Media Ionic Subsurface Equations (Ion Exchangers Only) 105
Discussion 105
2. Media Surface Phase (Filtered Mass) Equations 106
Discussion 106
3. Media Particulate Equations 106
Discussion 107
4. Media Soluble Equations 108
Discussion 109
Chapter 7: A Solution Method 110
1. Linearizing the Equation Sets 111
2. Finite Differencing 113
General Equations for Iron in Iron- and Nickel-Based Alloys 114
Simplified Linearized Iron Equations 115
Discussion 115
How Does Finite Differencing Work? 117
Defining Y(n) and b(n, m) 119
3. Subordinate or Secondary Models and Correlations 123
FORTRAN or C Algorithms for the Thermodynamic Properties of Steam and Water 124
Computation of pH (Log of the H+ Ion Concentration) 124
Single-Phase Hydraulic Friction Factor 124
Chapter 8: Defining the Input Architecture for NOC 126
1. System Defaults and Program Control Inputs 126
Finite Difference Mesh 127
2. Time-Independent Part (or Region) Inputs 129
3. Operating History Histogram Inputs 133
The Modeling of Time 134
4. Time-Dependent Inputs 135
Time-Dependent Loop Connection Table Inputs 136
Time-Dependent Part Inputs 136
Nuclear Inputs and Power Shapes 138
5. Program Design and Suggestions 139
Chapter 9: Program Architecture 142
1. Input Module 142
Full Input Processing 143
Input Prescanning 143
Full Input Summary Edits 145
Automesh Generation 146
Initial Dependent Variable Boundary Conditions 148
Restart Input Processing 150
The Restart File Structure 151
2. Analysis Module 154
Loop 1-Operating Steps 154
Keeping Track of Time 156
Loop 2-Temporal Power Rows 157
Loop 3-Descending the Loop Connection Table 157
Loop 4-The Innermost Loop over Mesh Cells 158
Dynamic Solution Repair 159
Consider a Freezing Strategy 160
Row Convergence 161
A Word about Convergence 161
Preserving the Mass Balance 162
Partial Row Rebalance 164
Oscillatory Solutions 165
Special Case Mass Rebalance 169
Wrapping Up the Problem 171
Summary Tables 171
3. Output Module 172
4. Summary 173
Chapter 10: Pre- and Postprocessing (the GUI Interface) 176
1. Postprocessing Functionality 177
Special Solution Edits 178
Simulation Graphical Trends 179
2. Summary 179
Chapter 11: Design Applications 182
1. Optimizing a Coolant Purification System 182
2. Designing a More Effective Purification System 185
How Does One Model an Absolute Filter? 187
What Can Be Learned by Simulation Testing of This Design? 187
3. Selecting New Structural Materials 188
Afterword 192
Appendix 194
Nickel Equilibria 194
Cobalt Equilibria 194
Zinc Equilibria 194
Nomenclature 196
Dependent variables 196
Subscripts relating to dependent variables 196
Superscripts relating to dependent variables 196
Steam table and related hydraulic quantities 196
Nuclear quantities 197
Dimensionless numbers 197
Glossary 198
References 200
About the Author 202
Index 204