1、 IEC 61226Edition 3.0 2009-07INTERNATIONAL STANDARD NORME INTERNATIONALENuclear power plants Instrumentation and control important to safety Classification of instrumentation and control functions Centrales nuclaires de puissance Instrumentation et contrle-commande importants pour la sret Classement
2、 des fonctions dinstrumentation et de contrle-commande IEC61226:2009 THIS PUBLICATION IS COPYRIGHT PROTECTED Copyright 2009 IEC, Geneva, Switzerland All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or m
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16、ication ou si vous avez des questions, visitez le FAQ du Service clients ou contactez-nous: Email: csciec.ch Tl.: +41 22 919 02 11 Fax: +41 22 919 03 00 IEC 61226Edition 3.0 2009-07INTERNATIONAL STANDARD NORME INTERNATIONALENuclear power plants Instrumentation and control important to safety Classif
17、ication of instrumentation and control functions Centrales nuclaires de puissance Instrumentation et contrle-commande importants pour la sret Classement des fonctions dinstrumentation et de contrle-commande INTERNATIONAL ELECTROTECHNICAL COMMISSION COMMISSION ELECTROTECHNIQUE INTERNATIONALE VICS 27.
18、120.20 PRICE CODECODE PRIXISBN 2-8318-1052-1 Registered trademark of the International Electrotechnical Commission Marque dpose de la Commission Electrotechnique Internationale 2 61226 IEC:2009 CONTENTS FOREWORD.3 INTRODUCTION.5 1 Scope.8 2 Normative references .8 3 Terms and definitions .9 4 Abbrev
19、iations .13 5 Classification scheme.13 5.1 General .13 5.2 Background .14 5.3 Description of categories.14 5.3.1 General .14 5.3.2 Category A 15 5.3.3 Category B 15 5.3.4 Category C 15 5.4 Assignment criteria16 5.4.1 General .16 5.4.2 Category A 16 5.4.3 Category B 16 5.4.4 Category C 17 6 Classific
20、ation procedure .17 6.1 General .17 6.2 Identification of design basis .18 6.3 Identification and classification of functions.18 7 Assignment of technical requirements to categories .21 7.1 General requirements21 7.2 Requirements related to functions .21 7.2.1 Basic requirements21 7.2.2 Specific req
21、uirements 22 7.3 Requirements related to I 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 collaborates closely wit
22、h 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 the relevant subj
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25、ossible 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 provides no marking procedure to indicate its approval and cannot be rendered responsible for any eq
26、uipment declared to be in conformity with an IEC Publication. 6) All users should ensure that they have the latest edition of this publication. 7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and members of its technical committees and
27、 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 expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC Publications. 8) At
28、tention 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) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of patent rights.
29、 IEC shall not be held responsible for identifying any or all such patent rights. International Standard IEC 61226 has been prepared by subcommittee 45A: Instrumentation and control of nuclear facilities, of IEC technical committee 45: Nuclear instrumentation. This third edition cancels and replaces
30、 the second edition published in 2005 and constitutes a technical revision. The main changes with respect to the previous edition are listed below: to introduce a definition for “non-hazardous stable state”; to clarify limits of categories; to clarify requirements related to equipment used for beyon
31、d design events. 4 61226 IEC:2009 The text of this standard is based on the following documents: FDIS Report on voting 45A/745/FDIS 45A/767/RVDFull information on the voting for the approval of this standard can be found in the report on voting indicated in the above table. This publication has been
32、 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 maintenance result date indicated on the IEC web site under “http:/webstore.iec.ch“ in the data related to the specific publication. At this dat
33、e, the publication will be reconfirmed, withdrawn, replaced by a revised edition, or amended. 61226 IEC:2009 5 INTRODUCTION a) Technical background, main issues and organisation of the standard This International Standard responds to an International Atomic Energy Agency (IAEA) requirement1to classi
34、fy nuclear power plants instrumentation and control systems according to their importance to safety. With distributed computer based I assign specification and design requirements to I b) the consequences of failure to perform the function; c) the probability that it (the I d) the time following a P
35、IE at which, or the period throughout which it (the I b) those structures, systems and components that prevent anticipated operational occurrences from leading to accident conditions; c) those features which are provided to mitigate the consequences of malfunction or failure of structures, systems o
36、r components. IAEA Safety Glossary: 2007 NOTE Items important to safety considered in this standard are mainly I the time for which alternative actions can be taken; the timeliness by which hidden faults can be detected and remedied. This standard extends the classification strategy presented in IAE
37、A Safety Guide NS-G-1.3, and establishes the criteria and methods to be used to assign the I b) functions, the failure or spurious actuation of which would lead to unacceptable consequences, and for which no other category A function exists that prevents the unacceptable consequences; c) functions r
38、equired to provide information and control capabilities that allow specified manual actions necessary to reach the non-hazardous stable state. 5.4.3 Category B An I b) functions required to provide information or control capabilities that allow specified manual actions necessary after the non-hazard
39、ous stable state has been reached to prevent a DBE from leading to unacceptable consequences, or mitigate the consequences; c) functions, the failure of which during normal operation, would require the operation of a category A function to prevent an accident whose study is required; d) functions to
40、 reduce considerably the frequency of a DBE as claimed in the safety analysis; e) plant process control functions operating so that the main process variables are maintained within the limits assumed in the safety analysis, if these control functions are the only means of control of these variables.
41、 If different means are provided, clause 5.4.4 a) may apply; f) functions used to prevent or mitigate a radioactive release or fuel degradation outside of the limits and conditions of normal operation as defined in the safety analysis; NOTE 1 This refers to functions that are not already covered by
42、the analysis of DBE leading to category A classification. 61226 IEC:2009 17 g) functions that provide continuous or intermittent tests or monitoring of functions in category A to indicate their continued availability for operation and alert control room staff to their failures, if no alternative mea
43、ns (e.g. periodic tests) are provided to verify their availability4. NOTE 2 Where the monitoring function is the only means of detecting otherwise unrevealed failures, then assigning the function to category B ensures that the equipment providing the function is suitably qualified. 5.4.4 Category C
44、An I NOTE 1 According to national practices a possible acceptable application of clause 5.4.4 a) is the combination of a regulation function and suitable manual actuation based on independent alarms including a justification of the use of manual action. b) functions used to prevent or mitigate a min
45、or radioactive release, or minor degradation of fuel, within the NPP design basis; NOTE 2 A minor release or minor fuel degradation is considered to be that which falls within the normal limits and conditions of operation (e.g. discharge limits). c) functions that provide continuous or intermittent
46、tests or monitoring of functions in category A and B to indicate their continued availability for operation and alert control room staff to their failures, and are not classified category B according to 5.4.3 g); d) functions necessary to reach the safety probabilistic goals including those to reduc
47、e the expected frequency of a DBE; e) functions to reduce the demands on a category A function, as claimed in the safety analysis; f) functions to monitor and take mitigating action following internal hazards within the NPP design basis (e.g. fire, flood); g) functions to warn personnel or to ensure
48、 personnel safety during or following events that involve or result in release of radioactivity in the NPP, or risk of radiation exposure; h) functions to monitor and take mitigating action following natural events (e.g. seismic disturbance, extreme wind); i) functions provided for the benefit of th
49、e accident management strategy to reach and maintain a safe state for beyond design accidents; j) functions provided to minimise the consequences of severe accidents; k) functions which provide access control for the NPP. 6 Classification procedure 6.1 General An outline of the procedure is shown in Figure 1. 4 Subclause 4.2.6 of IEC 60671 provides further guidance on the class of equipment used to implement such f
