Maintenance of Process Instrumentation in Nuclear Power Plants

This book is written for the instrumentation and control engineers, technicians, and managers in nuclear power plants. It focuses on process temperature and pressure sensors and the veri?cation of these sensors’ calibration and response time. It also provides examples of typical problems and solutions with temperature and pressure measurements in nuclear power plants. Contents 1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1. 1 Reference Plant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1. 2 On-Line Monitoring of Process Instruments Calibration . . . . . . . . . . 3 1. 3 Dynamic Testing of Pressure Transmitters and Sensing Lines . . . . . . 3 1. 4 On-Line Detection of Venturi Fouling . . . . . . . . . . . . . . . . . . . . . . . . . . 6 1. 5 Measuring the Vibration of Reactor Internals . . . . . . . . . . . . . . . . . . . . 8 1. 6 Detecting Core Flow Anomalies . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . 10 1. 7 CANDU Reactor Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 1. 8 In-Situ Response-Time Testing of Temperature Sensors . . . . . . . . . . . 12 1. 9 Testing Cables In-Situ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 1. 10 Automated Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 2 Origins of This Book . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 2. 1 Collaborative R&D . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 2. 2 Government R&D . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 2. 3 Utility R&D . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 2. 4 IAEA Guidelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 2. 5ISA and IEC Standards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 3 Maintenance of Nuclear Plant Instrumentation . . . . . . . . . . . . . . . . . . . 27 4 Nuclear Plant Temperature Instrumentation . . . . . . . . . . . . . . . . . . . . . 29 4. 1 History of RTDs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 4. 2 Nuclear-Grade RTDs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 4. 3 Nuclear Plant Temperature Measurement Terminology . . . . . . . . . . . 34 4. 4 Problems with Nuclear-Grade RTDs . . . . . . . . . . . . . . . . . . . . . . . . . . . 42 4. 4. 1 Dynamic Response . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 4. 4. 2 Failure of Extension Leads . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 4. 4. 3 Low Insulation Resistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 4. 4. 4 Premature Failure . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . 44 4. 4. 5 Wrong Calibration Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 X Contents 4. 4. 6 Loose or Bad Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . .