Hashemian Maintenance of Process Instrumentation in Nuclear Power Plants H. Hashemian Maintenance of Process Instrumentation in Nuclear Power Plants With 131 Figures H. Hashemian Analysis and Measurement Services Corporation, AMS Cross Park Drive 9111 37923 Knoxville, TN USA hash@ams-corp.com Library of Congress Control Number: 2006926431 ISBN-10 3-540-33703-2 Springer Berlin Heidelberg New York ISBN-13 978-3-540-33703-4 Springer Berlin Heidelberg New York This work is subject to copyright. All rights are reserved, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broad- casting, reproduction on microfilm or in other ways, and storage in data banks.
Duplication of this publication or parts thereof is permitted only under the provisions of the German Copyright Law of September 9, 1965, in its current version, and permission for use must always be obtained from Sprin- ger. Violations are liable to prosecution under German Copyright Law. Springer is a part of Springer Science+Business Media springer.com © Springer-Verlag Berlin Heidelberg 2006 Printed in Germany The use of general descriptive names, registered names, trademarks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant pro- tective laws and regulations and therefore free for general use.
Typesetting: digital data supplied by author Final processing: PTP-Berlin Protago-TEX-Production GmbH, Berlin (www.com) Cover-Design: deblik, Berlin Printed on acid-free paper 62/3141/Yu – 5 4 3 2 1 0 This book is dedicated to my wonderful daughter, Nikki Hashemian. Hashemian Knoxville, Tennessee USA Preface 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 verification 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.2 On-Line Monitoring of Process Instruments Calibration .3 Dynamic Testing of Pressure Transmitters and Sensing Lines .4 On-Line Detection of Venturi Fouling .5 Measuring the Vibration of Reactor Internals .6 Detecting Core Flow Anomalies .7 CANDU Reactor Applications .8 In-Situ Response-Time Testing of Temperature Sensors .9 Testing Cables In-Situ.
15 2 Origins of This Book .5 ISA and IEC Standards. 25 3 Maintenance of Nuclear Plant Instrumentation. 27 4 Nuclear Plant Temperature Instrumentation .1 History of RTDs .2 Nuclear-Grade RTDs .3 Nuclear Plant Temperature Measurement Terminology .4 Problems with Nuclear-Grade RTDs .2 Failure of Extension Leads .3 Low Insulation Resistance .5 Wrong Calibration Tables .6 Loose or Bad Connections .7 Large EMF Errors .9 Thinning of Platinum Wire .10 Lead-Wire Imbalance .11 Seeping of Chemicals into Thermowell .12 Cracking of Thermowell .5 Problems with Core-Exit Thermocouples. 48 5 Cross-Calibration Technique .3 Sources of Cross-Calibration Data .1 Dedicated Data Acquisition System .2 Plant Computer Data .4 Detailed Analysis of Cross-Calibration Data .1 Correcting Cross-Calibration Data .5 Presenting Cross-Calibration Results .6 Effect of Corrections on Cross-Calibration Results .7 Automated Software for Cross-Calibration .8 Uncertainty of Cross-Calibration Results .1 Uncertainty with Dedicated Data Acquisition System .2 Uncertainties with Plant Computer Data .9 Validating the Cross-Calibration Technique .10 Uncertainty in Cross-Calibrating Three-Wire RTDs .1 Cross-Calibration Procedure for Three-Wire RTDs .2 Cross-Calibration Validation for Three-Wire RTDs .11 Validation of Dynamic Cross-Calibration .12 Cross-Calibrating Core-Exit Thermocouples .2 New Calibration Table .3 Uncertainty of Recalibration Results .14 NRC Position on RTD Cross-Calibration.
84 6 Response-Time Testing of RTDs and Thermocouples .1 Reasons for Test .3 Analyzing LCSR Data .4 LCSR Validation for RTDs .5 LCSR Validation for Thermocouples .6 Optimizing LCSR Parameters .7 Accuracy of LCSR Results .8 Effect of LCSR Heating Current .9 Effect of Temperature Stratification .10 LCSR Testing at Cold Shutdown .4 Self-Heating Test .3 Self-Heating Error in RTDs .5 Noise Analysis Technique .2 In-Plant Validation .7 Factors Affecting Response Time .1 Ambient Temperature Effect .2 Effect of Fluid Flow Rate .3 Ambient Pressure Effect. 141 7 Nuclear Plant Pressure Transmitters .2 Transmitter Population and Application .3 Nuclear Qualification .1 Qualification Procedure .2 Qualified Life .2 Foxboro/Weed Transmitters .5 Smart Pressure Transmitters .6 Fiber-Optic Pressure Transmitters .7 Wireless Pressure Transmitters. 175 8 Characteristics of Pressure Sensing Lines .1 Design and Installation .2 Sensing Lines for Transmitters Inside Containment .3 Sensing Lines for Transmitters Outside Containment .4 Sensing-Line Problems .1 Blockages, Voids, and Leaks .2 BWR Level Measurement .3 Shared Sensing Lines .4 Use of Snubbers .5 Sensing-line Dynamics .1 Effect of Length on Response Time .2 Effect of Blockages on Response Time .3 Effect of Void on Response Time. 193 9 Measurement of Pressure Sensor and Sensing-Line Dynamics .1 Noise Analysis Technique: Description .2 Data Qualification .2 Noise Analysis Technique: Assumptions .3 Noise Analysis Technique: Validation .2 In-Plant Validation .4 Pink Noise Technique .5 Accuracy of Noise Analysis Technique .6 Experience from Testing in Nuclear Power Plants .7 Oil Loss in Nuclear Plant Pressure Transmitters .8 Oil Loss Diagnostics .1 Effect of Oil Loss on Transmitter Linearity .2 Oil Loss in Transmitters Other than Rosemount .9 Response Time Degradation.
220 10 On-line Detection of Sensing Line Problems .1 Sensing Line Blockages .2 Air in Sensing Lines .3 Detecting Sensing Line Leaks .4 Problems with Shared Sensing Lines. 235 About the Author. 239 Acronyms and Abbreviations. 303 List of Figures Fig.
A loop of a PWR plant and its typical sensors. On-line monitoring data from four redundant transmitters in a nuclear power plant. Results of transmitter calibration verification over a wide range. On-line detection of sensing-line blockages.
Results of search of LER database. Example of on-line monitoring results for detecting venturi fouling. Cross-sectional view of a PWR plant. PSD containing vibration signatures of reactor internals.
Illustration of cross-correlation principle involving a neutron detector and a core-exit thermocouple to determine transit time (τ ). BWR core flow diagnostics using an existing column of in-core neutron detectors. Sagging of a fuel channel in a CANDU reactor. Typical LCSR transient for a nuclear plant RTD.
Nuclear plant RTD circuit and corresponding TDR signatures .14 Rod drop-time measurement results for a bank of eight rods. Results of automated testing of CRDMs and calculation of timing events. Simplified diagram of a primary coolant loop of a PWR. Illustration of RTD response to a step change in temperature in the reactor.
Nuclear-grade direct-immersion RTDs. X-rays and cross-sectional drawing of Rosemount Model 176 RTD. Photograph and x-rays of direct-immersion Rosemount Model 177GY RTDs. 36 XIV List of Figures Fig.
Photograph and x-ray of Rosemount Model 177HW RTD. Silver-plated RdF RTD for nuclear power plants. Components of a complete RTD/thermowell assembly (Rosemount Model 104). Internal wiring of Rosemount Model 104 RTD of the type used in PWR plants (four-wire RTD including a dummy loop for lead-wire compensation).
Examples of RTD thermowells of the type used in nuclear power plants. Electron microscope photo of platinum element in a nuclear-grade RTD. Electron microscope photo of an open platinum wire in a nuclear-grade RTD. Erratic behavior preceding the failure of a primary coolant RTD at a PWR plant.
On-line monitoring results for a group of core-exit thermocouples. Data acquisition options for cross-calibration. Equipment setup for cross-calibration. Flowchart of cross-calibration procedure using a dedicated data acquisition system.
Block diagram of cross-calibration data retrieval from the plant computer. Effect of instability correction on cross-calibration data. Cross-calibration results before and after correcting for plant temperature instability and nonuniformity. Raw cross-calibration data and results of analysis from automated software for data retrieval and data analysis.
Example of cross-calibration data before and after correcting for process temperature fluctuations. Difference between the hot-leg and cold-leg temperatures in each loop of a two-loop PWR. Example of a temperature measurement channel and corresponding sources of uncertainties that may be involved in RTD cross-calibration using data from plant computer. Error between linear fit and quadratic equation over a narrow temperature range.
Three-wire and four-wire RTD configurations. Results of recalibration of an outlier using automated software. 83 List of Figures XV Fig. Extrapolation errors when the Callendar or a quadratic equation is used.
Extrapolation errors when a linear fit is used. Wheatstone bridge for LCSR testing of RTDs. Field data from LCSR testing a direct-immersion and a thermowell-mounted RTD. Diagram for a multichannel LCSR test unit.
LCSR data acquisition software screen. Equipment setup for LCSR testing of thermocouples. LCSR transients from laboratory and in-plant testing of thermocouples. Comparison of raw and transformed LCSR data with corresponding plunge-test transient from laboratory testing of an RTD.
Single and average LCSR transients. Ensemble averaging of LCSR transients. LCSR correction factor. Central geometry of sensing element.
Illustration of radial heat transfer from RTD sensing element. Simplified schematic of EdF loop for validating LCSR technology. RTD and thermocouple installation in the EdF loop. Test section of EdF loop used in LCSR validation tests.
Potential swirling effect in the primary coolant system of PWRs. Deviation of redundant hot-leg RTDs due to temperature stratification. Temperature stratification error as a function of reactor power. Primary coolant system of a PWR plant with RTD bypass manifolds.
Sampling scoops in the primary coolant pipes of Westinghouse PWRs. Primary coolant system of a PWR plant after removal of RTD bypass manifolds. Temperature stratification effect on LCSR data. LCSR transients for an RTD in two different operating cycles in a PWR plant.
Effect of temperature stratification on LCSR data depending on orientation of the RTD in the pipe. LCSR data acquisition screen showing individual LCSR transients and the average of these transients. 128 XVI List of Figures Fig. Typical self-heating curve of an RTD from testing in a PWR plant.
Computer screen with results of a self-heating test. PSD of Rosemount 177 HW RTD from data acquired at the EdF loop. PSDs of an RTD and a thermocouple from testing in a PWR plant at normal operating conditions. Example of important pressure transmitters in a loop of a PWR plant.
Principle of gauge, absolute, and differential pressure measurement. Example of some of the important pressure transmitters in a BWR plant. Pressure transmitter current loop. Safety classification of nuclear power plant equipment (Source: IAEA-TECDOC-1402).
Example of qualified life versus operating temperature for a nuclear-grade pressure transmitter. Barton Model 752 Transmitter (the electronics housing of a Barton Model 753 is similar in appearance). Barton Model 764 Transmitter (the electronics housing of a Barton Model 763 is similar in appearance). Simplified diagram of a Barton double-bellows differential pressure transmitter.
Photograph and drawing of the displacement sensor in Barton transmitters. Sensing Module of Barton Transmitter Model 752. Diagram of Barton Model 753 transmitter. Body styles of three models of Foxboro (Weed) transmitters.
Diagram of a Foxboro transmitter and its sensing element that is made of a diaphragm capsule. Diagram of a Foxboro transmitter and its sensing element that is made of a Bourdon tube. Diagram of a Foxboro transmitter and its sensing element that is made of a bellows capsule. Rosemount commercial and nuclear-grade transmitters.
Diagram of sensing module of a Rosemount pressure transmitter. Diagram of Tobar absolute pressure transmitter. Structure of sensing module of Tobar transmitters. 170 List of Figures XVII Fig.
Body styles of Tobar (Weed) transmitters. Rosemount smart sensor modules. Rosemount Model 3051N smart pressure transmitter for nuclear service. Circuit arrangement and electronic components of a smart Rosemount sensor.
Operation principle of simple fiber-optic pressure sensors. Typical pressure sensing line for steam and water service inside a nuclear reactor containment. Typical pressure sensing line with a provision to isolate the transmitter from the process fluid. Sensing line for water and steam service outside containment .