Risk and Safety Analysis of Nuclear Systems

by Lee, John C.; McCormick, Norman J.

• ISBN13: 9780470907566
• ISBN10: 0470907568
• Edition: 1st
• Format: Hardcover
• Copyright: 2011-07-05
• Publisher: Wiley

Summary

The book has been developed in conjunction with NERS 462, a course offered every year to seniors and graduate students in the University of Michigan NERS program.The first half of the book covers the principles of risk analysis, the techniques used to develop and update a reliability data base, the reliability of multi-component systems, Markov methods used to analyze the unavailability of systems with repairs, fault trees and event trees used in probabilistic risk assessments (PRAs), and failure modes of systems. All of this material is general enough that it could be used in non-nuclear applications, although there is an emphasis placed on the analysis of nuclear systems.The second half of the book covers the safety analysis of nuclear energy systems, an analysis of major accidents and incidents that occurred in commercial nuclear plants, applications of PRA techniques to the safety analysis of nuclear power plants (focusing on a major PRA study for five nuclear power plants), practical PRA examples, and emerging techniques in the structure of dynamic event trees and fault trees that can provide a more realistic representation of complex sequences of events. The book concludes with a discussion on passive safety features of advanced nuclear energy systems under development and approaches taken for risk-informed regulations for nuclear plants.

Author Biography

John C. Lee, PhD, has been Professor of Nuclear Engineering at the University of Michigan since 1974, following five years of employment at Westinghouse Electric Corporation and General Electric Company. He has written for approximately 180 publications on broad areas of nuclear reactor physics and engineering, including nuclear systems analysis and diagnostics. Dr.Lee is a Fellow of the American Nuclear Society. Norman J. McCormick, PhD, is an emeritus professor of mechanical engineering at the University of Washington who retired in 2003. From 1966 until the early 1990s, he was a professor of nuclear engineering. Dr. McCormick is the author of the book Reliability and Risk Analysis Methods and Nuclear Power Applications (upon which part of NERS 462 is based) and has authored approximately 150 journal articles. He is a Fellow of the American Nuclear Society.

Table of Contents

Preface	p. xii
Permissions and Copyrights	p. xiv
List of Tables	p. xvi
List of Figures	p. xviii
Risk and Safety of Engineered Systems	p. 1
Risk and Its Perception and Acceptance	p. 1
Overview of Risk and Safety Analysis	p. 6
Two Historical Reactor Accidents	p. 8
Definition of Risk	p. 9
Reliability, Availability, Maintainability, and Safety	p. 10
Organization of the Book	p. 12
References	p. 13
Probabilities of Events	p. 15
Events	p. 15
Event Tree Analysis and Minimal Cut Sets	p. 17
Probabilities	p. 19
Interpretations of Probability	p. 19
Axiomatic Approach to Probabilities	p. 20
Intersection of Events	p. 21
Union of Events	p. 22
Decomposition Rule for Probabilities	p. 25
Time-Independent Versus Time-Dependent Probabilities	p. 25
Time-Independent Probabilities	p. 26
Introduction	p. 26
Time-Independent Probability Distributions	p. 27
Normal Distribution	p. 32
Reliability Functions	p. 35
Time-Dependent Probability Distributions	p. 41
Erlangian and Exponential Distributions	p. 42
Gamma Distribution	p. 43
Lognormal Distribution	p. 44
Weibull Distribution	p. 46
Generalized ôBathtubö Distribution	p. 47
Selection of a Time-Dependent Probability Distribution	p. 48
Extreme-Value Probability Distributions	p. 50
Probability Models for Failure Analyses	p. 52
References	p. 53
Exercises	p. 53
Reliability Data	p. 59
Estimation Theory	p. 59
Moment Estimators	p. 60
Maximum Likelihood Estimators	p. 61
Maximum Entropy Estimators	p. 64
Comparison of Estimators	p. 65
Bayesian Updating of Data	p. 65
Bayes Equation	p. 65
Applications of the Bayes Equation	p. 67
Central Limit Theorem and Hypothesis Testing	p. 70
Interpretation of the Central Limit Theorem	p. 71
Hypothesis Testing with the Central Limit Theorem	p. 72
Reliability Quantification	p. 74
Central Limit Theorem for Reliability Quantification	p. 74
Engineering Approach for Reliability Quantification	p. 76
X2-Distribution for Reliability Quantification	p. 77
Three-Way Comparison and Concluding Remarks	p. 78
References	p. 80
Excercises	p. 80
Reliability of Multiple-Component Systems	p. 85
Series and Active-Parallel Systems	p. 86
Systems with Independent Components	p. 86
Systems with Redundant Components	p. 88
Fail-to-Safety and Fail-to-Danger Systems	p. 90
Systems with Standby Components	p. 93
Decomposition Analysis	p. 96
Signal Flow Graph Analysis	p. 100
Cut Set Analysis	p. 101
References	p. 104
Exercises	p. 104
Availability and Reliability of Systems with Repair	p. 109
Introduction	p. 109
Markov Method	p. 111
Markov Governing Equations	p. 111
Solution of Markov Governing Equations	p. 113
An Elementary Example	p. 116
Availability Analyses	p. 118
Rules for Constructing Transition Rate Matrices	p. 118
Availability Transition Rate Matrices	p. 119
Time-Dependent Availability Examples	p. 123
Steady-State Availability	p. 127
Reliability Analyses	p. 128
Reliability Transition Rate Matrices	p. 129
Time-Dependent Reliability Examples	p. 130
Mean Time to Failure	p. 130
Additional Capabilities of Markov Models	p. 133
Imperfect Switching Between System States	p. 134
Systems with Nonconstant Hazard Rates	p. 136
References	p. 137
Exercises	p. 137
Probabilistic Risk Assessment	p. 141
Failure Modes	p. 142
Classification of Failure Events	p. 143
Primary, Secondary, and Command Failures	p. 143
Common Cause Failures	p. 144
Human Errors	p. 148
Failure Data	p. 150
Hardware Failures	p. 150
Human Errors	p. 150
Combination of Failures and Consequences	p. 152
Inductive Methods	p. 152
Event Tree Analysis	p. 154
Fault Tree Analysis	p. 156
Introduction	p. 156
Fault Tree Construction	p. 157
Qualitative Fault Tree Analysis	p. 157
Quantitative Fault Tree Analysis	p. 160
Common Cause Failures and Fault Tree Analysis	p. 165
Master Logic Diagram	p. 165
Uncertainty and Importance Analysis	p. 168
Types of Uncertainty in PRAs	p. 168
Stochastic Uncertainty Analysis	p. 169
Sensitivity and Importance Analysis	p. 170
References	p. 172
Exercises	p. 172
Computer Programs for Probabilistic Risk Assessment	p. 179
Fault Tree Methodology of the SAPHIRE Code	p. 179
Gate Conversion and Tree Restructuring	p. 180
Simplification of the Tree	p. 180
Fault Tree Expansion and Reduction	p. 182
Fault and Event Tree Evaluation with the SAPHERE Code	p. 183
Other Features of the SAPHIRE Code	p. 185
Other PRA Codes	p. 185
Binary Decision Diagram Algorithm	p. 187
Basic Formulation of the BDD Algorithm	p. 187
Generalization of the BDD Formulation	p. 189
Zero-Suppressed BDD Algorithm and the FTREX Code	p. 193
References	p. 194
Exercises	p. 195
Nuclear Power Plant Safety Analysis	p. 197
Engineered Safety Features of Nuclear Power Plants	p. 197
Pressurized Water Reactor	p. 198
Boiling Water Reactor	p. 210
Accident Classification and General Design Goals	p. 215
Plant Operating States	p. 217
Accident Classification in 10 CFR 50	p. 217
General Design Criteria and Safety Goals	p. 219
Design Basis Accident: Large-Break LOCA	p. 220
Typical Sequence of a Cold-Leg LBLOCA in PWR	p. 221
ECCS Specifications	p. 225
Code Scaling, Applicability, and Uncertainty Evaluation	p. 227
Severe (Class 9) Accidents	p. 231
Anticipated Transients Without Scram	p. 233
History and Background of the ATWS Issue	p. 233
Resolution of the ATWS Issues	p. 235
Power Coefficients of Reactivity in LWRs	p. 237
Radiological Source and Atmospheric Dispersion	p. 241
Radiological Source Term	p. 242
Atmospheric Dispersion of Radioactive Plume	p. 243
Simple Models for Dose Rate Calculation	p. 247
Biological Effects of Radiation Exposure	p. 250
References	p. 252
Exercises	p. 254
Major Nuclear Power Plant Accidents and Incidents	p. 259
Three Mile Island Unit 2 Accident	p. 260
Sequence of the Accident-March 1979	p. 260
Implications and Follow-Up of the Accident	p. 260
PWR In-Vessel Accident Progression	p. 263
Core Uncovery and Heatup	p. 265
Cladding Oxidation	p. 266
Clad Melting and Fuel Liquefaction	p. 268
Molten Core Slumping and Relocation	p. 270
Vessel Breach	p. 271
Chernobyl Accident	p. 272
Cause and Nature of the Accident-April 1986	p. 272
Sequence of the Accident	p. 274
Estimate of Energy Release in the Accident	p. 275
Accident Consequences	p. 275
Comparison of the TMI and Chernobyl Accidents	p. 276
Fukushima Station Accident	p. 277
Sequence of the Accident-March 2011	p. 277
March 2011 Perspectives on the Fukushima SBO Event	p. 278
Salem Anticipated Transient Without Scram	p. 279
Chronology and Cause of the Salem Incident	p. 279
Implications and Follow-Up of the Salem ATWS Event	p. 281
LaSalle Transient Event	p. 283
LaSalle Nuclear-Coupled Density-Wave Oscillations	p. 283
Simple Model for Nuclear-Coupled Density-Wave Oscillations	p. 287
Implications and Follow-Up of the LaSalle Incident	p. 289
Davis-Besse Potential LOCA Event	p. 291
Background and Chronology of the Incident	p. 291
NRC Decision to Grant DB Shutdown Delay	p. 293
Causes for the Davis-Besse Incident and Follow-Up	p. 295
References	p. 297
Exercises	p. 300
PRA Studies of Nuclear Power Plants	p. 303
WASH-1400 Reactor Safety Study	p. 304
Assessment of Severe Accident Risks: NUREG-1150	p. 311
Background and Scope of the NUREG-1150 Study	p. 311
Overview of NUREG-1150 Methodology	p. 313
Accident Frequency Analysis	p. 315
Accident Progression Analysis	p. 320
Radionuclide Transport Analysis	p. 324
Offsite Consequence Analysis	p. 327
Uncertainty Analysis	p. 330
Risk Integration	p. 331
Additional Perspectives and Comments on NUREG-1150	p. 337
Simplified PRA in the Structure of NUREG-1150	p. 340
Description of the Simplified PRA Model	p. 340
Parametric Studies and Comments on the Simplified PRA Model	p. 344
References	p. 345
Exercises	p. 347
Passive Safety and Advanced Nuclear Energy Systems	p. 349
Passive Safety Demonstration Tests at EBR-II	p. 349
EBR-II Primary System and Simplified Model	p. 350
Unprotected Loss-of-Flow and Loss-of-Heat-Sink Tests	p. 357
Simplified Fuel Channel Analysis	p. 361
Implications of EBR-II Passive Safety Demonstration Tests	p. 362
Safety Characteristics of Generation III+ Plants	p. 364
AP1000 Design Features	p. 364
Small-Break LOCA Analysis for AP1000	p. 366
Economic Simplified Boiling Water Reactor	p. 371
Reliability Quantification of SBWR Passive Safety Containment	p. 375
Generation IV Nuclear Power Plants	p. 382
Sodium-Cooled Fast Reactor	p. 383
Hypothetical Core Disruptive Accidents for Fast Reactors	p. 387
VHTR and Phenomena Identification and Ranking Table	p. 393
References	p. 396
Exercises	p. 399
Risk-Infoimed Regulations and Reliability-Centered Maintenance	p. 401
Risk Measures for Nuclear Plant Regulations	p. 402
Principles of Risk-Informed Regulations and Licensing	p. 402
Uncertainties in Risk-Informed Decision Making	p. 405
Other Initiatives in Risk-Informed Regulations	p. 406
Reliability-Centered Maintenance	p. 406
Optimization Strategy for Preventive Maintenance	p. 407
Reliability-Centered Maintenance Framework	p. 409
Cost-Benefit Considerations	p. 410
References	p. 413
Exercises	p. 415
Dynamic Event Tree Analysis	p. 417
Basic Features of Dynamic Event Tree Analysis	p. 418
Continuous Event Tree Formulation	p. 421
Derivation of the Stochastic Balance Equation	p. 421
Integral Form of the Stochastic Balance Equation	p. 423
Numerical Solution of the Stochastic Balance Equation	p. 425
Cell-to-Cell Mapping for Parameter Estimation	p. 426
Derivation of the Bayesian Recursive Relationship	p. 427
CCM Technique for Dynamic Event Tree Construction	p. 430
Diagnosis of Component Degradations	p. 434
Bayesian Framework for Component Diagnostics	p. 434
Implementation of the Probabilistic Diagnostic Algorithm	p. 437
References	p. 441
Exercises	p. 442
Reactor Radiological Sources	p. 443
Fission Product Inventory and Decay Heat	p. 443
Health Effects of Radiation Exposure	p. 446
References	p. 448
Some Special Mathematical Functions	p. 449
Gamma Function	p. 449
Error Function	p. 451
References	p. 451
Some Failure Rate Data	p. 453
Linear Kalman Filter Algorithm	p. 457
References	p. 461
Answers to Selected Exercises	p. 462
Index	p. 467
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