BS IEC 62385-2007 Nuclear power plants - Instrumentation and control important to safety - Methods for assessing the performance of safety system instrument channels《核电站 对安全性重要的仪器和.pdf

1、 g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58safety Methods for assessing the performance of safety system instrument channelsICS 27.120.20Nucle

2、ar power plants Instrumentation and control important to BRITISH STANDARDBS IEC 62385:2007BS IEC 62385:2007This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 July 2007 BSI 2007ISBN 978 0 580 54101 8Amendments issued since publicationAmd. No.

3、Date CommentsCompliance with a British Standard cannot confer immunity from legal obligations.National forewordThis British Standard is the UK implementation of IEC 62385:2007.The UK participation in its preparation was entrusted to Technical Committee NCE/8, Reactor instrumentation.A list of organi

4、zations represented on this committee can be obtained on request to its secretary.This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application.INTERNATIONAL STANDARD IEC62385First edition2007-06Nuclear power plants Instrum

5、entation and control important to safety Methods for assessing the performance of safety system instrument channels Reference number IEC/CEI 62385:2007 BS IEC 62385:2007CONTENTS INTRODUCTION.4 1 Scope.6 2 Normative references .6 3 Terms and definitions .6 4 Requirements for performance verification

6、of process instruments .9 4.1 Background .9 4.2 General requirements9 4.3 Testing environment9 4.4 Test interval 10 4.5 Test location .10 4.6 Calibration of measurement and test equipment 10 4.7 Test results .10 4.8 Validation of test methods .10 4.9 Qualifications of test personnel .11 5 Acceptable

7、 means for instrument performance verification .11 5.1 Introduction .11 5.2 Calibration.11 5.3 Channel checks.12 5.4 Functional test.12 5.5 Response time testing.12 6 Methods to verify instrument calibration12 6.1 General considerations12 6.2 Cross-calibration (cross-validation) method.13 6.3 On-lin

8、e calibration monitoring14 6.3.1 Introduction .14 6.3.2 Principle of on-line calibration monitoring 14 6.3.3 Data acquisition requirements .14 6.3.4 Data qualification and data analysis requirements .15 6.3.5 Accounting for common mode drift.15 6.3.6 Data collection frequency 15 7 Methods for respon

9、se time testing 15 7.1 Response time testing of pressure transmitters .15 7.1.1 Ramp test16 7.1.2 Noise analysis technique .16 7.1.3 Power interrupt (PI) test 17 7.2 Response time testing of temperature sensors 17 7.2.1 Plunge test 17 7.2.2 LCSR test18 7.2.3 Self-heating test 19 7.2.4 Noise analysis

10、 .19 8 On-line detection of blockages and voids in pressure sensing lines 19 9 Verifying the performance of neutron detectors 20 BS IEC 62385:2007 2 Annex A (informative) RTD cross-calibration/cross-validation .21 Annex B (informative) On-line calibration monitoring.26 Annex C (informative) Response

11、 time testing techniques for pressure transmitters and neutron detectors28 Annex D (informative) Response time testing techniques for RTDs .31 Bibliography35 BS IEC 62385:2007 3 INTRODUCTION a) Technical background, main issues and organisation of the Standard This International Standard describes t

12、est methods for ensuring that safety system instrument channels in nuclear power plants comply with specifications for accuracy, response time and other performance characteristics. This Standard applies to those instruments whose primary sensors measure temperature, pressure, differential pressure,

13、 liquid level, flow and neutron flux. The focus of this Standard is on test methods that can be used remotely while the plant is on-line without a need to enter the reactor containment or physically access the instruments. b) Situation of the current Standard in the structure of the SC 45A standard

14、series IEC 62385 is the third level SC 45A document tackling the issue of assessing methods of performance of safety systems instrument channels. For more details on the structure of the SC 45A standard series, see item d) of this introduction. c) Recommendations and limitations regarding the applic

15、ation of this Standard The main interests to benefit from this international Standard are nuclear utilities that use on-line performance testing, suppliers who develop and install such systems, and regulatory authorities seeking documented industry consensus on successful practices. These users will

16、 benefit from the awareness of methods and practices considered appropriate by IEC experts and from the cost savings associated with the standardization of methods and practices. d) Description of the structure of the IEC SC 45A standard series and relationships with other IEC documents and other bo

17、dies documents (IAEA, ISO) The top-level document of the IEC SC 45A 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. They vary in length from a few metres to a few hundr

18、ed metres. Sensing lines may also include isolation and root valves and other piping hardware along their length. 3.9 in-situ test test of a sensor or a transmitter that is performed without removing the sensor or transmitter from its normal installed position in the system 3.10 noise analysis techn

19、ique method for in-situ response time testing of sensors, detectors, and transmitters and for on-line detection of blockages, voids, and leaks in pressure sensing lines BS IEC 62385:2007 7 3.11 on-line monitoring continuous or periodic measurement and recording of output of installed instrumentation

20、 3.12 outlier a sensor such as an RTD that has exceeded a prespecified deviation 3.13 performance monitoring (performance verification) process of demonstrating that an installed instrument channel continues to perform its intended function of monitoring the process variable with the expected accura

21、cy, response time, and stability 3.14 pressure transmitters pressure, level, and flow transmitters that are based on the principle of pressure or differential pressure measurement, and are collectively referred to in this Standard as pressure transmitters, pressure sensors, or just transmitters 3.15

22、 redundancy provision of alternative (identical or diverse) structures, systems or components, so that any one can perform the required function regardless of the state of operation or failure of any other IAEA Safety Glossary, Version 2.0, 2006 3.16 Resistance Temperature Detector (RTD) detector ge

23、nerally made up of a stainless steel cylindrical barrel protecting a platinum resistor whose resistance varies with temperature. This detector is placed in the piping containing the fluid whose temperature is measured in this way. It can be directly immersed in the fluid or protected by an intermedi

24、ate casing called the thermowell. IEC 62397 3.17 response time the period of time necessary for a component to achieve a specified output state from the time that it receives a signal requiring it to assume that output state IAEA Safety Glossary, Version 2.0, 2006 3.18 test interval the elapsed time

25、 between the initiation of identical tests on the same sensor and signal processing device, logic assembly or final actuation device IEC 60671 3.19 thermowell protective jacket for RTDs, thermocouples, and other temperature sensors. The thermowell is also used to facilitate replacement of the temper

26、ature sensor. BS IEC 62385:2007 8 3.20 time constant in the case of a first order system, the time required for the output signal of a system to reach 63,2 % of its final variation after a step change of its input signal. If the system is not first order system, the term “time constant“ is not appro

27、priate. For a system of a higher order, the term “response time“ should be used. IEC 62397 4 Requirements for performance verification of process instruments 4.1 Background The control and safety systems of nuclear power plants depend on process instrumentation which must provide reliable informatio

28、n to ensure plant safety and efficiency. Therefore, the performance of this instrumentation should be verified at predefined intervals during the plant life time. For this purpose, test methods have been developed, validated, and used in nuclear power plants. These methods include means to perform t

29、he tests in-situ and while the plant is operating (on-line testing). This clause gives the requirements for in-situ and on-line testing to verify that process instrumentation provides accurate and timely data and to identify faulty instruments. The focus of the Standard is on the process sensors tha

30、t measure temperature, pressure, liquid level, flow, and neutron flux. 4.2 General requirements Performance monitoring shall be conducted to verify that the safety system instrument channels in nuclear power plants are functioning within their performance specification limits. The tests that verify

31、performance characteristics shall be conducted in accordance with written procedures, and the test results shall be documented. The instrument channel should be tested in a single test. When the total channel is not tested in a single test, separate tests on groups of components or on single compone

32、nts encompassing the total instrument channel shall be combined to verify total channel performance. Performance monitoring encompasses the instrument channel portion of the overall safety system. Test boundaries shall include sensors and transmitters, sensing lines (impulse lines), thermowells, cab

33、les, and all other active and passive components that affect the overall instrument channel performance. If a performance index such as response cannot be identified exactly, a conservative estimate of the index shall be made by measurement and analysis and compared against the pertinent performance

34、 requirements to ensure that the performance is acceptable. 4.3 Testing environment In general, abnormal environmental conditions such as seismic events, radiation fields, extreme pressures, temperatures, and moisture conditions are covered by design qualification tests. As such, testing of equipmen

35、t for such environments is not within the scope of this Standard. However, the performance testing described in this Standard should be carried out within the bounds of the instruments environmental conditions (e.g., temperature, pressure, humidity, flow, etc.) If the test conditions vary widely, ap

36、propriate corrections shall be made for comparison or trending of data to compensate for performance due to variation in the environmental conditions or the effect of the environmental conditions on performance. BS IEC 62385:2007 9 In some cases, such as response time testing of temperature sensors,

37、 process operating conditions can have a strong influence on the result. In these cases, the tests shall be performed at or near normal operating conditions to provide the actual “in-service” performance of the sensors. Extrapolation from laboratory conditions to plant conditions should not be perfo

38、rmed in cases where the extrapolation results can have large and unquantifiable uncertainties. 4.4 Test interval The test intervals shall be established to detect unacceptable performance. The following factors should be considered in determining the test interval: a) technical specification require

39、ments; b) regulatory requirements; c) manufacturers recommendation and industry standards; d) margin between measured performance characteristics and allowable performance limits; e) rate-of-change of performance characteristics with time; and f) component failure rates and target reliability. 4.5 T

40、est location Testing should be performed in-situ to the extent practicable. Instrument removal for testing is acceptable only if such removal does not affect test results. In most cases of concern in this Standard, in-situ tests are performed remotely from the instrument cabinet in the control room

41、area. Procedures shall be implemented to confirm that equipment status is restored after testing. 4.6 Calibration of measurement and test equipment The calibration of measurement and test equipment used in verifying equipment performance characteristics shall be traceable to national standards and/o

42、r accepted values of natural physical phenomena. Written procedures shall be used to perform the calibration and the results of the calibration shall be documented. 4.7 Test results The test results shall be compared to the allowable performance limits. Allowances for uncertainties associated with t

43、he performance monitoring test shall be included in the test results or the establishment of performance limits. If the results are found to exceed the limit, or the rate of change in the performance characteristics are such that the allowable performance limits may be exceeded prior to the next tes

44、t, predetermined action should be taken to correct the problem. The accuracy of test results should be stated in terms of a percentage of the reported value or a band around the reported value. This accuracy should be determined from not only the equipment uncertainties, but also from the uncertaint

45、ies of the test and analysis techniques involved. If uncertainties cannot be identified objectively, it should be demonstrated that the test results are conservative. 4.8 Validation of test methods All performance monitoring test methods shall be validated. This validation shall be documented and sh

46、ould address the following considerations: BS IEC 62385:2007 10 a) Comparison of the test method with suitable laboratory tests, in-situ tests, or both tests to establish the validity of the method and quantify the accuracy of its results. The accuracy of the test method and results should be establ

47、ished by theoretical or experimental means, or both. The accuracy determination should consider all sources of error in the test method. b) Theoretical justification for the test method. c) That the assumptions and conditions to ensure validity of the test method are satisfied. Furthermore, if the t

48、est assumptions are not fully satisfied, it should be demonstrated that the results that are obtained will nevertheless be conservative. d) Any software used for data acquisition, data qualification, or data analysis should be designed and developed using a systematic approach according to accepted

49、industry standards for software development for nuclear power plants. All software packages should go through comprehensive verification and validation (V b) review of performance test procedures; c) equipment preparation for data acquisition; d) training on data acquisition and data analysis software; and e) interpretation and documentation of results. 5 Acceptable means for instrument performance verification 5.1 Introduction This clause gives the requirements for calibration, channel checks, functional tests, and resp