Corrosion Monitoring in Nuclear Systems: Research and Applications: (EFC 56)

Annotation. Corrosion remains one of the key issues affecting the performance and availability of nuclear power plants. Therefore, reliable in-plant corrosion monitoring methods are essential both for the future operation of existing plants and to ensure the safety of future nuclear waste disposal systems. In two parts, this book was stimulated by a workshop organised by EFC Working Party 4 on Nuclear Corrosion and the European Cooperative Group on Corrosion Monitoring of Nuclear Materials (EGC-COMON). The first part deals mainly with research into the detection of stress corrosion crack initiation in nuclear power plant environments (essentially high temperature water at 300) by various methods, particularly the electrochemical noise technique but also including the electrochemical impedance, acoustic emission and direct current potential drop methods. The second part addresses the goal to develop in-situ techniques and includes examples of the application of electrochemical corrosion potential monitoring. This book will be of particular interest to scientists and engineers concerned with the mitigation of corrosion in nuclear power plants and the long-term storage of radioactive waste Copyright ......Page 3 Most important abbreviations......Page 10 Preface......Page 7 Table of Contents ......Page 5 1.3 Probes for corrosion monitoring......Page 11 1.4 Accuracy of electrochemical methods......Page 13 1.5 Epilogue and answers to the questions......Page 14 2.1.1 Electrochemical techniques......Page 15 2.1.2 Non-electrochemical techniques......Page 16 2.2.1 Corrosion potential......Page 17 2.2.2 Tafel extrapolation......Page 20 2.2.3 Linear polarisation resistance......Page 21 2.2.4 Electrochemical impedance spectroscopy......Page 23 2.2.5 Harmonic analysis......Page 28 2.2.6 Intermodulation distortion technique......Page 32 2.3 Conclusions......Page 35 References......Page 38 3.1 Introduction......Page 42 3.2 Repassivation with the Scratch Technique......Page 44 3.3.2 Example 2......Page 47 3.3.3 Example 3......Page 48 3.4 Electrochemical Noise Generator Based on Repassivation Kinetics......Page 49 Conclusions......Page 53 References......Page 55 4.1 Introduction......Page 56 4.2.2 Experimental Procedure......Page 57 4.2.2.1 Electrochemical Noise Measurements......Page 59 4.2.2.2 Direct Current Potential Drop Measurements......Page 61 4.3 Results and Discussion......Page 62 Acknowledgement......Page 71 References......Page 72 5.1 Introduction......Page 73 5.2.1 Materials......Page 74 5.2.3 Electrochemical Noise Instrumentation......Page 75 5.3 Results......Page 76 References......Page 89 6.1 Introduction......Page 91 6.2 Experimental......Page 92 6.3.1 Microscopic Analysis......Page 93 6.3.2 Electrochemical Noise Analysis......Page 95 References......Page 104 7.1 Introduction......Page 106 7.2 Experimental......Page 107 7.3.2 Impedance Measurements......Page 109 7.3.2.1 Impedance of Oxide Layer......Page 112 7.3.2.2 Polarisation Resistance and Double Layer Capacitance......Page 118 7.3.2.3 Diffusion Impedance......Page 123 Conclusions......Page 125 Acknowledgement......Page 127 References......Page 128 8.1 Introduction......Page 130 8.2 Experimental Set-up......Page 131 8.3.1 Potential and Current Transient Response to SCC Initiation and Propagation......Page 132 8.3.2 Interpretation of R614 Results......Page 133 8.3.3 Estimate of Charge Transferred during Localised Corrosion Events for R614......Page 136 8.3.4 Additional Tests Interrupted after First Large Transient......Page 137 8.3.5 Analysis of Charge Associated with Transients for R628......Page 140 8.3.7 Interrupted Test Completion for R628......Page 142 8.3.8 Analysis of Charge Sizes for Specimen R628......Page 143 8.4.1 AE Results for R614......Page 145 8.4.3 Interpretation of AE Results for R614......Page 147 8.4.4 AE Results for Specimen R628......Page 148 8.4.5 Analysis of Acoustic Emission Results for R628......Page 149 Conclusions......Page 150 Acknowledgements......Page 151 References......Page 152 9.2.1 Materials and Solutions......Page 153 9.2.2 Reference Electrode......Page 154 9.3.1 Corrosion Monitoring......Page 155 9.3.3 Time Evolution of the Transfer Conductance at 90°C......Page 158 9.3.4 Time Evolution of the Transfer Conductance at 50°C......Page 159 9.3.5 Corrosion Products at 150°C......Page 160 9.3.6 Corrosion Products at 90°C......Page 161 9.4 Discussion......Page 163 Conclusions......Page 165 References......Page 166 10.2 Requirements for In-Line Water Chemistry Sensors......Page 168 10.3 High-Temperature Water Chemistry Sensors......Page 172 10.4 Experience with High-Temperature Water Chemistry Sensors in Operating Plants......Page 176 References......Page 178 11.1 Introduction......Page 181 11.2 Description of Test Loops......Page 182 11.3 On-Line Crack Growth Rate Measurements......Page 183 11.4 Crack Initiation Measurements......Page 185 11.5 Irradiation Creep and Stress Relaxation Measurements......Page 189 11.6 In-Core ECP Measurements......Page 191 11.7 In-Core Conductivity Measurements......Page 196 11.8.1 On-Line Potential Drop Corrosion Monitor......Page 199 11.8.2 Electrochemical Impedance Spectroscopy......Page 201 References......Page 202 12.2.1 ECP Monitoring in BWR......Page 204 12.2.2 Crack Growth Rate Measurements......Page 207 12.2.3 Electrochemical Noise Monitoring during a Decontamination Process......Page 209 12.2.4 ECP Monitoring in PWR Secondary Water......Page 213 12.2.6 Pipe-Thinning Monitor......Page 215 Conclusions......Page 218 References......Page 220 13.1 Introduction......Page 221 13.2 Previous Experience......Page 222 13.2.1 Measurements at the Ringhals PWRs in Sweden......Page 223 13.2.2 Comparison between In-Pipe and Side-Stream Autoclave Measurements......Page 224 13.3 The New Electrode Arrangement......Page 228 References......Page 229 14.1 Introduction......Page 231 14.2 Experimental Techniques......Page 232 14.3.2 Redox and Corrosion Potentials......Page 238 14.3.3 Transport of Particulate Iron......Page 241 14.3.5 Iron Redox States at Different Hydrazine Concentrations......Page 242 14.3.7 Comparison of Measured and Calculated Redox Potentials......Page 244 References......Page 247 15.1 Introduction......Page 249 15.2.1 Control of Corrosive Conditions......Page 250 15.2.3 In-situ Measurements......Page 251 15.3.2 In-situ Corrosive Condition Measurements......Page 252 15.3.3 Anodic Polarisation Current Measurements......Page 253 15.4.2 Effects of Hydrogen Peroxide and Oxygen on ECP and FDCI......Page 254 15.4.4 Equivalent Circuit Analysis......Page 256 15.5.1 Sensor Array......Page 258 15.5.2 Reference Electrode......Page 259 15.5.3 Alternative Data Processing......Page 260 Acknowledgements......Page 262 References......Page 263 Index ......Page 265 Corrosion remains one of the key issues affecting the performance and availability of nuclear power plants. Therefore, reliable in-plant corrosion monitoring methods are essential both for the future operation of existing plants and to ensure the safety of future nuclear waste disposal systems.In two parts, this book was stimulated by a workshop organised by EFC Working Party 4 on Nuclear Corrosion and the European Cooperative Group on Corrosion Monitoring of Nuclear Materials (EGC-COMON). The first part deals mainly with research into the detection of stress corrosion crack initiation in nuclear power plant environments (essentially high temperature water at around 300 °C) by various methods, particularly the electrochemical noise technique but also including the electrochemical impedance, acoustic emission and direct current potential drop methods. The second part addresses the goal to develop in-situ techniques and includes examples of the application of electrochemical corrosion potential monitoring.This book will be of particular interest to scientists and engineers concerned with the mitigation of corrosion in nuclear systems.