Automation protects against both unsafe conditions and human errors. It is the key to safety in the nuclear power industry. This is the message of this book, written by Béla Lipták, a consultant with more than 50 years’ experience in automation and industrial safety. After reviewing the Three Mile Island, Chernobyl, and Fukushima accidents, he not only concludes that safety automation could have prevented all three, but also explains why they occurred and what was needed to prevent them. In this book, he analyses these accidents and the industry as a whole, concluding that the next Fukushima is unavoidable unless the safety controls of the operating 438 ageing plants around the world are updated and fully automated. He believes that extending their operating licenses without adding the safety systems that are described in this book is irresponsible. He recommends that nuclear power plants be given operating licenses or license extensions only if they satisfy the following design and automation requirements: The plant has the ability to automatically shut down the reactors even when both internal and external electric power supplies have failed and regardless of what management or the operators do. The energy needed to automatically cool and safely shut down the reactors is made available in an uninterruptible form, such as gravity, and this energy supply is backed up by the always available energy of decay steam. All primary containments are inerted and both the primary and secondary containments are protected against explosions by detecting both the presence of hydrogen and high pressure steam and by automatically triggering filtered venting, if either rises beyond safe limits. The automatic shutdown systems are so designed (like an airbag in a car) that they cannot be turned off by anybody or anything, including cyber-terrorist attacks. Lipták believes that part of the nuclear safety problem is our “manual safety culture,” because we still tend to trust humans more than we trust automation. This is wrong: we should automatically protect our processes also from human errors, we should prevent pilots from flying into buildings (9/11) or ship captains to hit islands (Costa Concordia, Italy). He feels that automation should – and must – be used to make the nuclear power industry safer by providing protection against intentional or unintentional operator actions or from their failure to act.

Table of Contents:
Preface xiii Introduction xv Reading Material xvi Chapter 1: Nuclear Power Generation 1 1.1 History 1 1.2 Energy from Splitting Atoms 5 1.2.1 The Fission of Uranium-235 6 1.2.2 The Moderation of Fast Neutrons 8 1.2.3 Fission, Isotopes and Nuclear Fuels 9 1.2.4 Controlling the Reactor 11 1.3 Power Plant Design Variations 12 1.3.1 Boiling Water Reactors (BWR) 14 1.3.2 Emergency Core Cooling System 17 1.3.3 BWR Pressure Transients 18 1.3.4 Pressurized Water Reactors (PWR) 18 1.4 Nuclear Waste Storage and Disposal 21 1.4.1 Types of Nuclear Wastes 21 1.4.2 Reprocessing of Nuclear Wastes 22 1.4.3 Temporary Storage 22 1.4.4 Decommissioning 24 1.4.5 Transportation 24 1.4.6 Permanent Disposal 25 1.4.7 Reading Material 26 Chapter 2: Safety Automation Instruments 27 2.1 The Tools Of Safety 28 2.1.1 Redundancy, Backup, and Self-Diagnostics 28 2.1.2 Data Transmission 29 2.1.3 Digital Transmission and Smart Transmitters 32 Contents viii 2.2 Level Measurement 34 2.2.1 Unreliable D/P Level Measurement 35 2.2.2 The Fukushima Design 38 2.2.3 Obtaining Reliable Ex-Core Level Measurement 39 2.2.4 Thermal Ex-Core Level Measurement 42 2.2.5 In-Core Level Measurement 45 2.2.6 Newer Developments in In-Core Level Measurement 47 2.2.7 Reading Material 47 2.3 Radiation and Neutron Detectors 50 2.3.1 Radiation Exposure 50 2.3.2 Radiation Monitoring 52 2.3.3 Personal Dosimeters 53 2.3.4 Portable Radiation Detectors 55 2.3.5 Ionization Chambers 56 2.3.6 Neutron Detectors 58 2.3.7 Scintillation Neutron Detectors 59 2.3.8 Geiger-Müller Tubes 61 2.3.9 Reading Material 62 2.4 Reactor Power Measurement 65 2.4.1 Measuring Fission Power by Neutron Flux Detection 66 2.4.2 In-Core Flux Detectors 67 2.4.3 Total Fission Rate of the Reactor 68 2.4.4 Thermal Power Measurement 69 2.4.5 Maximum Operating Thermal Power 70 2.4.6 Measurement Uncertainty Recapture 70 2.4.7 Reading Material 70 2.5 Flow Measurement 71 2.5.1 Flow Units 73 2.5.2 Specifying the Required Accuracy 73 2.5.3 Temperature and Pressure Effects 77 2.5.4 Rangeability and Automatic Range Switching 79 2.5.5 The Reynolds Number 80 2.5.6 Head Type Flowmeters 82 2.5.7 Orifice Plate 86 2.5.8 Elbow Taps 90 2.5.9 Magnetic Flowmeters 92 2.5.10 Coriolis Mass Flowmeters 98 2.5.11 Pitot Tubes 100 2.5.12 Ultrasonic Flowmeters 102 2.5.13 Venturi Tubes 106 2.5.14 Flow Tubes 108 2.5.15 Flow Nozzles 111 2.5.16 Vortex Shedding and Swirl Meters 112 2.5.17 Flowmeter Calibration and Maintenance 115 2.5.18 Operating Energy Costs 116 2.5.19 Comparing the Relative Merits of Flowmeters 119 2.5.20 Reading Material 122 2.6 Temperature Measurement 124 2.6.1 Resistance Temperature Detectors 126 2.6.2 Thermocouples 131 2.6.3 Fiber Optic Thermometers 137 2.6.4 Ultrasonic Thermometers 139 2.6.5 Reading Material 141 2.7 Pressure Measurement 143 2.7.1 Pressure Gauges and Transmitters 144 2.7 2 Differential Pressure Transmitters 151 2.7.3 Electronic Pressure Sensors 153 2.7.4 Optical Transducers 159 2.7.5 Reading Material 160 2.8 Hydrogen Detection 161 2.8.1 Catalytic Combustion Type Sensors 162 2.8.2 Solid-State Hydrogen Detectors 167 2.8.3 Reading Material 169 2.9 Steam Quality (Dryness) Monitoring 171 2.9.1 Throttling Calorimeter and Other Methods 173 2.9.2 Reading Material 175 2.10 Pressure Relief Systems and Devices 175 2.10.1 Steam Pressure Relief 177 2.10.2 Containment Structure Protection 182 2.10.3 Conventional Pressure Relief Valves 184 2.10.4 Pilot Operated Relief Valves 191 2.10.5 PRV Specification Form 195 2.10.6 Rupture Discs 197 2.10.7 Reading Material 200 Chapter 3: How Automation Would Have PreventedThree Mile Island, Chernobyl, and Fukushima 203 3.1 The Main Safety Concerns 203 3.1.1 Cyber-Terrorism 205 3.2 Three Mile Island 207 3.2.1 The Accident: Operator Errors 210 3.2.2 The Role of the PORV 213 3.2.3 Further Operator Errors 216 3.2.4 Conclusions 217 3.2.4 Reading Material 218 3.3 Chernobyl 221 3.3.1 The Process and the RBMK Reactor 222 3.3.2 Design Errors, Positive Void Coefficient 225 3.3.3 Control Rod Design Errors 226 3.3.4 Operator Errors 227 3.3.5 Automation Would Have Prevented the Accident 228 3.3.6 Conclusions 230 3.3.7 Reading Material 230 3.4 Fukushima 232 3.4.1 Unused “Time Windows” 235 3.4.2 The Chronology of Events 237 3.4.3 The Approximate Layout of Unit 1 240 3.4.4 Semi-Manual Controls 242 3.4.5 Unreliable Water Level Measurement 244 3.4.6 Semi-Automatic Emergency Cooling System 246 3.4.7 High Pressure Coolant Injection (HPCI) System 246 3.4.8 Isolation Condenser System Controls 249 3.4.9 Unreliable Pressure Controls 251 3.4.10 Unreliable Hydrogen Explosion Protection 254 3.4.11 The Fukushima Disaster Was Preventable 256 3.4.12 Reading Material 259 Chapter 4: Summary and Lessons to Learn 263 4.1 General Design Requirements for Safety 264 4.2 The Future 266 4.3 Conclusions 267 Appendix 269 A-1 Definitions 269 A-2 Acronyms and Abbreviations 285 A-3 Organizations 289 A-4 Conversion Tables 290 Table A4-1 Conversion Among Flow Units 290 Table A4-2 Conversion Among Engineering Units 292 A-5 Steam Tables 303 Table A5-1 Dry and Saturated Steam Table 303 Table A5-2 Superheated Steam Table 305 A-6 Water Table 310 Table A6-1 Water Table 310 A-7 Nuclear Power Plant Accidents 311 Nuclear power plant accidents and incidents with multiple fatalities and/or more than US$100 million in property damage, 1952–2011 311 A-8 Nuclear Reactor Attacks 313 Cyber-Attacks, Cybersecurity 313 Index 315 About the Author 331