1、BSI Standards PublicationNuclear powers plants Instrumentation and controlimportant to safety Management of ageing of sensors and transmittersPart 1: Pressure transmittersBS IEC 62765-1:2015National forewordThis British Standard is the UK implementation of IEC 62765-1:2015.The UK participation in it
2、s preparation was entrusted to TechnicalCommittee NCE/8, Reactor instrumentation.A list of organizations represented on this committee can be obtained onrequest to its secretary.This publication does not purport to include all the necessary provisions ofa contract. Users are responsible for its corr
3、ect application. The British Standards Institution 2015.Published by BSI Standards Limited 2015ISBN 978 0 580 77967 1ICS 27.120.20Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the authority of theStandards Policy and Strateg
4、y Committee on 30 April 2015.Amendments/corrigenda issued since publicationDate Text affectedBRITISH STANDARDBS IEC 62765-1:2015IEC 62765-1 Edition 1.0 2015-04 INTERNATIONAL STANDARD NORME INTERNATIONALE Nuclear powers plants Instrumentation and control important to safety Management of ageing of se
5、nsors and transmitters Part 1: Pressure transmitters Centrales nuclaires de puissance Instrumentation et contrle-commande importants pour la sret Gestion du vieillissement des capteurs et des transmetteurs Partie 1: Transmetteurs de pression INTERNATIONAL ELECTROTECHNICAL COMMISSION COMMISSION ELECT
6、ROTECHNIQUE INTERNATIONALE ICS 27.120.20 ISBN 978-2-8322-2629-2 Registered trademark of the International Electrotechnical Commission Marque dpose de la Commission Electrotechnique Internationale Warning! Make sure that you obtained this publication from an authorized distributor. Attention! Veuille
7、z vous assurer que vous avez obtenu cette publication via un distributeur agr. colourinside 2 IEC 62765-1:2015 IEC 2015 CONTENTS FOREWORD . 4 INTRODUCTION . 6 1 Scope 8 2 Normative references 8 3 Terms and definitions 9 4 Abbreviations 12 5 Background . 12 5.1 General . 12 5.2 Type of transmitter an
8、d interface. 12 5.2.1 Type of transmitters . 12 5.2.2 Interface between sensing part and process 13 5.3 Reasons for transmitter ageing management 13 5.4 Environmental stressors 14 5.4.1 General . 14 5.4.2 Radiation . 14 5.4.3 Temperature 15 5.4.4 Humidity 15 5.4.5 Pressure transients 15 5.4.6 Vibrat
9、ion 15 5.4.7 Corrosive chemical reaction . 15 5.5 Sensing line problems to be considered with transmitter ageing 16 5.6 Techniques for detecting pressure transmitter ageing . 16 6 Ageing management of transmitters . 17 6.1 General . 17 6.2 Methodology of ageing management . 17 6.3 Identification of
10、ageing by performance verification test 18 6.4 Test and inspection interval 18 6.5 Test location . 19 6.6 Calibration of measurement and test equipment 19 6.7 Test and inspection results . 19 6.8 Validation of test methods . 19 6.9 Classification of condition monitoring system and its software . 19
11、6.10 Replacement of transmitter or its parts 19 7 Acceptable means for transmitter testing . 20 8 Relationship between initial qualification and transmitter ageing management . 20 Annex A (informative) Calibration for type tests or periodic tests . 21 A.1 General . 21 A.2 Configuration for calibrati
12、on of transmitters . 21 A.3 Uncertainty and TDF between M any IEC National Committee interested in the subject dealt with may participate in this preparatory work. International, governmental and non-governmental organizations liaising with the IEC also participate in this preparation. IEC collabora
13、tes closely with the International Organization for Standardization (ISO) in accordance with conditions determined by agreement between the two organizations. 2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international consensus of opinion on th
14、e relevant subjects since each technical committee has representation from all interested IEC National Committees. 3) IEC Publications have the form of recommendations for international use and are accepted by IEC National Committees in that sense. While all reasonable efforts are made to ensure tha
15、t the technical content of IEC Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any misinterpretation by any end user. 4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications transparently to the m
16、aximum extent possible in their national and regional publications. Any divergence between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in the latter. 5) IEC itself does not provide any attestation of conformity. Independent certification bodi
17、es provide conformity assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any services carried out by independent certification bodies. 6) All users should ensure that they have the latest edition of this publication. 7) No liability shall attach to
18、IEC or its directors, employees, servants or agents including individual experts and members of its technical committees and IEC National Committees for any personal injury, property damage or other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
19、expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC Publications. 8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is indispensable for the correct application of this publication. 9)
20、Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of patent rights. IEC shall not be held responsible for identifying any or all such patent rights. International Standard IEC 62765-1 has been prepared by subcommittee 45A: Instrumentation, con
21、trol and electrical systems of nuclear facilities, of IEC technical committee 45: Nuclear instrumentation. The text of this standard is based on the following documents: FDIS Report on voting 45A/1001/FDIS 45A/1015/RVD Full information on the voting for the approval of this standard can be found in
22、the report on voting indicated in the above table. BS IEC 62765-1:2015IEC 62765-1:2015 IEC 2015 5 This publication has been drafted in accordance with the ISO/IEC Directives, Part 2. The committee has decided that the contents of this publication will remain unchanged until the stability date indica
23、ted on the IEC website under “http:/webstore.iec.ch“ in the data related to the specific publication. At this date, the publication will be reconfirmed, withdrawn, replaced by a revised edition, or amended. IMPORTANT The colour inside logo on the cover page of this publication indicates that it cont
24、ains colours which are considered to be useful for the correct understanding of its contents. Users should therefore print this document using a colour printer. BS IEC 62765-1:2015 6 IEC 62765-1:2015 IEC 2015 INTRODUCTION a) Technical background, main issues and organisation of the standard With the
25、 majority of NPPs over 20 years old, the management of ageing of transmitters (pressure, level, flow) is currently a relevant topic, especially for those plants that have extended their operating licenses or are considering this option. This standard is intended to be used by operators of NPPs (util
26、ities), systems evaluators, and by licensors. b) Situation of the current standard in the structure of the IEC SC 45A standard series IEC 62765 is the third level IEC SC 45A document comprising several parts to tackle the specific issue of management of ageing of sensors and transmitters in nuclear
27、power plants (NPPs) for I steps to be followed to establish pressure transmitter testing requirements for an ageing management program for NPP instrumentation systems; and relationship between on-going qualification analysis and ageing management program with regards to pressure transmitters. It is
28、recognised that testing and monitoring techniques used to evaluate the ageing condition of NPPs transmitters are continuing to develop at a rapid pace and that it is not possible for a standard such as this to include references to all modern technologies and techniques. This standard identifies min
29、imum requirements aimed at ensuring that any potential impacts on NPP safety due to ageing of pressure transmitters of NPP can be identified and that suitable actions are undertaken to demonstrate that the safety of the plant will not be impaired. To ensure that this standard will continue to be rel
30、evant in future years, the emphasis has been placed on issues of principle, rather than specific technologies. d) Description of the structure of the IEC SC 45A standard series and relationships with other IEC documents and other bodies documents (IAEA, ISO) The top-level document of the IEC SC 45A
31、standard series is IEC 61513. It provides general requirements for I impulse lines/sensing lines are usually used to connect pressure, level, and flow transmitters to the process Note 1 to entry: They vary in length from a few metres to a few hundred metres. Sensing lines may also include isolation
32、and root valves and other piping hardware along their length. SOURCE: IEC 62385:2007, 3.8 3.12 pressure transmitter PT pressure, level, and flow transmitters that are based on the principle of pressure or differential pressure measurement, and are collectively referred in this standard as pressure t
33、ransmitters, pressure sensors, PT, or just transmitters SOURCE: IEC 62385:2007, 3.14 BS IEC 62765-1:2015IEC 62765-1:2015 IEC 2015 11 3.13 qualified life period for which a structure, system or component has been demonstrated, through testing, analysis or experience, to be capable of functioning with
34、in acceptance criteria during specific operating conditions while retaining the ability to perform its safety functions in a design basis accident or earthquake SOURCE: IAEA Safety Glossary, 2007 edition 3.14 response time period of time necessary for a component to achieve a specified output state
35、from the time that it receives a signal requiring it to assume that output state SOURCE: IAEA Safety Glossary, 2007 3.15 routine test conformity test made on each individual item during or after manufacture 3.16 test interval elapsed time between the initiation of identical tests on the same sensor
36、and signal processing device, logic assembly or final actuation device SOURCE: IEC 60671:2007, 3.13 3.17 turn down factor TDF URL (Upper Range Limit) divided by the calibrated span of the device, which is a ratio, i.e. dimensionless quality SOURCE: ISA67.04.02 3.18 type test conformity test made on
37、one or more items representative of the production 3.19 verification process of ensuring that an equipment fulfils the specified conditions Note 1 to entry: The IEC 61513 verification definition which applies to activities differs and reads “confirmation by examination and by provision of objective
38、evidence that the results of an activity meet the objectives and requirements defined for this activity”. This verification definition applies not to activities but to equipment. 3.20 system validation confirmation by examination and provision of other evidence that a system fulfils in its entirety
39、the requirement specification as intended (functionality, response time, fault tolerance, robustness) Note 1 to entry: In this standard, to apply this definition pressure transmitters are considered as systems. SOURCE: IEC 61513:2011, 3.59 BS IEC 62765-1:2015 12 IEC 62765-1:2015 IEC 2015 4 Abbreviat
40、ions AFV As-found Value ALV As-left Value AV1 Allowable Value AV2 Analytical Value DBE Design Basis Event EUT Equipment Under Test FT Flow Transmitter LT Level Transmitter M increase the viscosity of fill fluids; and affect the transmitters electronics, especially the integrated circuit components.
41、BS IEC 62765-1:2015IEC 62765-1:2015 IEC 2015 15 5.4.3 Temperature Temperature is one of the dominant stressors in pressure transmitters. Temperature predominantly affects the transmitters electronics. Long-term exposure to high temperatures is detrimental to the life of the transmitter. Temperature
42、also increases the effect of humidity because it increases the rate at which moisture diffuses through seals. 5.4.4 Humidity Humidity affects the operation of a transmitters electronics and can cause corrosion in other parts of a transmitter. Moisture sources and sinks exist within the transmitter a
43、nd are therefore unavoidable. The humidity levels inside a nuclear power plant may be as high as 100 %, particularly in areas where there are water or steam leaks during normal plant operation. Some moisture will leak into transmitters because the organic polymer seals used in most transmitters cann
44、ot provide perfect sealing under long-term exposure to the temperatures that exist around pressure transmitters. A significant degrading effect of humidity is short circuits in the transmitter electronics. In addition, moisture weakens the dielectric strength of insulators. 5.4.5 Pressure transients
45、 Pressure transmitters are continuously exposed to small pressure fluctuations during normal operation and large pressure surges during reactor trips and other events. Water hammer, for example, is a well-known phenomenon in NPPs, which can degrade the performance of PT. Other pressure-induced degra
46、dations occur during calibration and maintenance when transmitters are inadvertently over-pressurised or cycled with pressures that are above or below their normal range. Cyclic pressures accelerate wearing and loosening of parts in the mechanical systems of transmitters. 5.4.6 Vibration Vibration g
47、enerated by nearby machinery during plant operation is transmitted to pressure transmitters through the building structure. Normal vibration can produce mechanical fatigue and loosen or disintegrate the transmitter components. 5.4.7 Corrosive chemical reaction Chemicals or sludge in process fluids c
48、an cause blockages in sense lines, fouling or erosion and corrosion of primary elements or sensing parts. Corrosion of sense element diaphragms may dilute oil fills. Any of these effects may cause changes in calibration accuracy or time response. BS IEC 62765-1:2015 16 IEC 62765-1:2015 IEC 2015 Tabl
49、e 2 Examples of environmental stressors with potential to damage transmitters Ageing stressor Affected component Consequence Radiation Electronics Changes in values of electronic components Seals Embrittlement and cracking of seals allowing moisture into transmitter electronics Fill Fluid Viscosity changes degrading fill fluid Temperature Electronics Shorten transmitters life, change in values of electronic components Seals Failure of seals, allowing moisture into transmitter electr
