1、BSI Standards PublicationNuclear facilities Electrical equipment important to safety QualificationBS IEC/IEEE 60780-323:2016National forewordThis British Standard is the UK implementation of IEC/IEEE 60780-323:2016.It supersedes BS IEC 60780:1998 which is withdrawn.The UK participation in its prepar
2、ation was entrusted to TechnicalCommittee NCE/8, Instrumentation, Control 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 preparatio
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15、blication. Use of the referenced publications is indispensable for the correct application of this publication. 9) Attention is drawn to the possibility that implementation of this IEC/IEEE Publication may require use of material covered by patent rights. By publication of this standard, no position
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18、 risk of infringement of such rights, is entirely their own responsibility. International Standard IEC/IEEE 60780-323 has been prepared by subcommittee 45A: Instrumentation, control and electrical systems of nuclear facilities, of IEC technical committee 45: Nuclear instrumentation, in cooperation w
19、ith the Nuclear Power Engineering Committee of the Power those features that are provided to mitigate the consequences of malfunction or failure of structures, systems and components. A) For usage consistent with IEC 61226, equipment important to safety are as follows: all I for equipment important
20、to safety, qualification is essential to the following: electric equipment and systems that are essential to emergency reactor shutdown, containment isolation, reactor core cooling, and containment and reactor heat removal, or electric equipment that are otherwise essential in preventing significant
21、 release of radioactive material to the environment. Note 1 to entry: Users of this standard are advised that Class 1E is a functional term. Equipment and systems are to be classified Class 1E only if they fulfill the functions listed in the definition. Identification of systems or equipment as Clas
22、s 1E based on anything other than their function is an improper use of the term and should be avoided. 3.13 equipment qualification generation and maintenance of evidence to ensure that equipment will operate on demand to meet system performance requirements during normal and abnormal service condit
23、ions and postulated design basis events SOURCE: IAEA Safety Glossary, 2007 3.14 equipment similarity demonstration of physical, operational and dynamic equivalency between equipment being qualified and equipment previously qualified BS IEC/IEEE 60780-323:2016IEC/IEEE 60780-323:2016 11 IEC/IEEE 2016
24、3.15 harsh environment environment that significantly changes as a result of a design basis event, e.g., loss-of-coolant accident (LOCA), high-energy line break (HELB), and main steam line break (MSLB) SOURCE: IEEE Standards Dictionary Online 3.16 interfaces shared boundary between structures, syste
25、ms and components that includes physical attachments, mounting, auxiliary components, and connectors (electrical and mechanical) to the equipment 3.17 margin difference between service conditions and the conditions used for equipment qualification SOURCE: IEEE Standards Dictionary Online 3.18 mild e
26、nvironment environment that would at no time be significantly more severe than the environment that would occur during normal plant operation, including anticipated operational occurrences 3.19 qualified condition condition of equipment, prior to the start of a design basis event, for which the equi
27、pment was demonstrated to meet the design requirements for the specified service conditions. This could include certain post accident cooling and monitoring systems that are expected to remain operational. 3.20 qualified life period for which an equipment has been demonstrated, through testing, anal
28、ysis and/or experience, to be capable of functioning within acceptance criteria during specific operating conditions while retaining the ability to perform its safety functions in accident condition or earthquake Note 1 to entry: This note applies to the French language only. SOURCE: IAEA Safety Glo
29、ssary, 2007 3.21 service conditions actual physical states or influences during the service life of equipment, including normal operating conditions, abnormal operating conditions, design basis event conditions and conditions following a design basis event and design extension conditions Note 1 to e
30、ntry: In 2007-edition of IAEA safety glossary, accident conditions include both design basis accident and beyond design basis accident. This second notion has been replaced within IAEA by the notion of design extension conditions (AIEA, SSR-2/1). It explains the need of changing the definition. SOUR
31、CE: IAEA Safety Glossary, 2007, modified 3.22 service life period from initial operation to final withdrawal from service of a structure, system or component BS IEC/IEEE 60780-323:2016 12 IEC/IEEE 60780-323:2016 IEC/IEEE 2016 SOURCE: IAEA Safety Glossary, 2007 3.23 severe accident accident condition
32、s more severe than a design basis event and involving significant core degradation SOURCE: IAEA Safety Glossary, 2007 3.24 significant ageing mechanism ageing mechanism that, under normal and abnormal service conditions, causes degradation of equipment that progressively and appreciably renders the
33、equipment vulnerable to failure to perform its safety function(s) during the design basis event conditions SOURCE: IEEE Standards Dictionary Online 4 Symbols and abbreviations DBE Design Basis Event EM Electromagnetic EMC Electromagnetic Compatibility EMI Electromagnetic Interference HELB High Energ
34、y Line Break I however analysis alone shall not be used to demonstrate qualification. Qualification should comprise a logical assessment, similarity evaluation or a valid mathematical model of the equipment to be qualified. The bases for analysis typically include physical laws, results of test data
35、 (including those collected during type test performed on equipment from the plant see 6.2.3 and condition measurement) and operating experience. 6.1.4 Combined methods Equipment may be qualified by combinations of type test, operating experience, and analysis. For example, where type test of a comp
36、lete assembly is not possible, component testing supplemented by analysis may be used. 6.2 Reassessing qualified life 6.2.1 General Environmental qualification may yield a qualified life that is less than the anticipated service life of the equipment. For example, the qualified life may be limited d
37、ue to the use of moderate ageing acceleration factors to achieve realistic simulation of degradation in service during available testing time. Such moderate ageing acceleration factors may result in the condition of the equipment under test falling short of its required end-of-life condition and hen
38、ce limiting service life. The methods that follow may be used for reassessing and extending equipment qualified life. The method chosen shall be justified and the application shall be sufficiently documented to give confidence in the extended qualified life. BS IEC/IEEE 60780-323:2016IEC/IEEE 60780-
39、323:2016 15 IEC/IEEE 2016 6.2.2 Method 1: Using conservatism Evaluation of conservatisms in original assumptions for environmental conditions, failure criteria, and acceleration factors may identify that actual conditions are less severe, and the qualified life may be adjusted accordingly with due c
40、onsideration of the required margins addressed in 7.3.5. Limitations of use of accelerating factors shall be considered (e.g. time period extrapolation, synergy between effect of temperature and radiation, dose rate effect). Ageing models shall be properly verified. Environmental conditions shall be
41、 properly assessed. 6.2.3 Method 2: Type test on aged samples from the plant Install additional qualified equipment in identical service conditions or use qualified equipment aged in the plant. Remove before the end of the qualified life of equipment in-service and demonstrate its safety function pe
42、rformance during DBE(s) after further age conditioning to establish additional qualified life. 6.2.4 Method 3: Performing type test for longer qualified life A longer qualified life can be achieved by either retain and continue ageing the test sample from the initial program for additional duration
43、or begin ageing a new sample while the qualified equipment is in service. Equipment safety function is then demonstrated by successfully passing accident condition test. 6.2.5 Method 4: Component replacement Identify age-sensitive components and replace them with new, identical components to extend
44、qualification. Consideration shall be given to time required to have the component accessible for the replacement. This method shall not be used if the disassembly of the equipment can alter its performance in service conditions (including accident conditions). 6.3 Condition monitoring Condition mon
45、itoring for equipment qualification purposes monitors one or more condition indicators to determine whether equipment remains in a qualified condition. The trend of the condition indicator shall be determined during age conditioning of the test specimen for qualification testing or on another simila
46、r specimen (same model, same materials, same supplier, same hardware/software, etc.) submitted to the same age conditioning tests. The condition indicator shall be measurable, change monotonically with time, be correlated with the safety function performance under DBE conditions, be linked to the fu
47、nctional degradation of the qualified equipment, and have a consistent trend from unaged through the limit of the qualified pre-accident condition. Condition indicators are dependent on technology. Such condition indicators cannot always be defined in practice, even if such indicators would be benef
48、icial. Condition-based qualification is an adjunct to type testing. To use condition-based qualification, age conditioning shall be performed incrementally and condition indicators shall be measured at each increment to establish data for comparison with observations of the same indicators during se
49、rvice. In particular, it is required to establish the condition of the condition indicator(s) at the conclusion of age conditioning, prior to testing to accident conditions. If the qualification programme has been completed, age conditioning may be replicated on another sample by performing incremental condition indicator measurements. Since measurements for condition indicators may be taken at one temperature, additional data may be required to provide a correlation with time and temperature. Condition indicators shall be leading indicators of ad
