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1、| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | BRITISH STANDARD BS IEC 61501:1998 ICS 27.
2、120.10 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW Nuclear reactor instrumentation Wide range neutron fluence rate meter Mean square voltage method Licensed Copy: sheffieldun sheffieldun, na, Sun Nov 26 11:42:29 GMT+00:00 2006, Uncontrolled Copy, (c) BSI This British Stand
3、ard, having been prepared under the direction of the Engineering Sector Committee, was published under the authority of the Standards Committee and comes into effect on 15 July 2001 BSI 07-2001 ISBN 0 580 35396 6 BS IEC 61501:1998 Amendments issued since publication Amd. No.DateComments National for
4、eword This British Standard reproduces verbatim IEC 61501:1998 and implements it as the UK national standard. The UK participation in its preparation was entrusted to Technical Committee NCE/8, Reactor instrumentation, which has the responsibility to: aid enquirers to understand the text; present to
5、 the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed; monitor related international and European developments and promulgate them in the UK. A list of organizations represented on this committee can be obta
6、ined on request to its secretary. From 1 January 1997, all IEC publications have the number 60000 added to the old number. For instance, IEC 27-1 has been renumbered as IEC 60027-1. For a period of time during the change over from one numbering system to the other, publications may contain identifie
7、rs from both systems. Cross-references The British Standards which implement international or European publications referred to in this document may be found in the BSI Standards Catalogue under the section entitled International Standards Correspondence Index, or by using the Find facility of the B
8、SI Standards Electronic Catalogue. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summar
9、y of pages This document comprises a front cover, an inside front cover, the IEC title page, pages 2 to 40, an inside back cover and a back cover. The BSI copyright notice displayed throughout this document indicates when the document was last issued. Licensed Copy: sheffieldun sheffieldun, na, Sun
10、Nov 26 11:42:29 GMT+00:00 2006, Uncontrolled Copy, (c) BSI 1 egaP BS IEC 61501:1998 Licensed Copy: sheffieldun sheffieldun, na, Sun Nov 26 11:42:29 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BSI 07-2001 CONTENTS Page FOREWORD.3 INTRODUCTION .4 Clause 1 Scope .5 2 Normative references5 3 Definitions.
11、6 4 Abbreviations7 5 Principle of the mean square voltage method 7 6 Implementation of the mean square voltage method 8 6.1 Linear analogue method: quadratic amplifier 8 6.2 Logarithmic analogue method: logarithmic amplifier9 6.3 Digital method: digital mean square processor .9 7 Structure of a wide
12、 range channel .10 7.1 Single-detector WRC .11 7.2 Double-detector WRC 12 8 Technology of WRC 12 8.1 Analogue wide range channel.13 8.2 Digital wide range channel .13 9 Test conditions and test generators.14 9.1 Environmental test conditions.14 9.2 Test equipment14 10 Characteristics and test method
13、s for preamplifiers.15 10.1 Characteristics of the preamplifier15 10.2 Test methods for the preamplifier.16 11 Characteristics and test methods for quadratic amplifiers 20 11.1 Characteristics of the quadratic amplifier20 11.2 Test methods for the quadratic amplifier.20 12 Characteristics and test m
14、ethods for logarithmic amplifiers26 12.1 Characteristics of the logarithmic amplifier .26 12.2 Test methods for the logarithmic amplifier26 13 Characteristics and test methods for logarithmic summing amplifiers.31 13.1Characteristics of the summing amplifier31 13.2 Test methods for the summing ampli
15、fier.33 14 Characteristics and test methods for digital mean square processors (DMSP) .35 14.1 Characteristics of the digital mean square processor35 14.2 Test methods for the DMSP .36 Annex A (informative) Applications of WCRs.38 Bibliography 40 2 egaP 8991:10516 CEI SB Page 2 BS IEC 61501:1998 Lic
16、ensed Copy: sheffieldun sheffieldun, na, Sun Nov 26 11:42:29 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BSI 07-2001 INTERNATIONAL ELECTROTECHNICAL COMMISSION _ NUCLEAR REACTOR INSTRUMENTATION WIDE RANGE NEUTRON FLUENCE RATE METER MEAN SQUARE VOLTAGE METHOD FOREWORD 1)The IEC (International Electrote
17、chnical Commission) is a worldwide organization for standardization comprising all national electrotechnical committees (IEC National Committees). The object of the IEC is to promote international co-operation on all questions concerning standardization in the electrical and electronic fields. To th
18、is end and in addition to other activities, the IEC publishes International Standards. Their preparation is entrusted to technical committees; any IEC National Committee interested in the subject dealt with may participate in this preparatory work. International, governmental and non-governmental or
19、ganizations liaising with the IEC also participate in this preparation. The IEC collaborates 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 the IEC on t
20、echnical matters express, as nearly as possible, an international consensus of opinion on the relevant subjects since each technical committee has representation from all interested National Committees. 3)The documents produced have the form of recommendations for international use and are published
21、 in the form of standards, technical reports or guides and they are accepted by the National Committees in that sense. 4)In order to promote international unification, IEC National Committees undertake to apply IEC International Standards transparently to the maximum extent possible in their nationa
22、l and regional standards. Any divergence between the IEC Standard and the corresponding national or regional standard shall be clearly indicated in the latter. 5)The IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any equipment declared to be in conf
23、ormity with one of its standards. 6)Attention is drawn to the possibility that some of the elements of this International Standard may be the subject of patent rights. The IEC shall not be held responsible for identifying any or all such patent rights. This International Standard IEC 61501 has been
24、prepared by subcommittee 45A: Reactor instrumentation, of IEC technical committee 45: Nuclear instrumentation. The text of this standard is based on the following documents: FDISReport on voting 45A/338/FDIS45A/346/RVD Full information on the voting for the approval of this standard can be found in
25、the report on voting indicated in the above table. Annex A is for information only. 3 egaP 8991:10516 CEI SB Page 3 BS IEC 61501:1998 Licensed Copy: sheffieldun sheffieldun, na, Sun Nov 26 11:42:29 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BSI 07-2001 INTRODUCTION The response of a fission chamber
26、to a neutron is to produce a pulse of electrical charge and by counting these pulses it is possible to measure the neutron fluence rate. At higher levels the rate of pulse generation increases to the point where pulses merge (a phenomenon known as “pulse pile-up“) and the process of electronically c
27、ounting the pulses becomes impracticable. An alternative approach to processing is to consider the piled-up pulses as a fluctuating d.c. signal. Using Campbells theory it can be shown that the mean square of the signal amplitude, measured over a fixed bandwidth, is proportional to the initial pulse
28、rate. At low fluence rate levels the use of this approach is limited to 103 to 104 fissions per second by background noise in the electronics and in the fission chamber. The limit at high fluence rate levels is in the range 1010 to 1011 fissions per second because of non linearity caused by space ch
29、arge effects. This is the most common application of the MSV method. The use of the mean square voltage (MSV) measurement technique in combination with pulse counting permits the design of a system capable of measuring a neutron fluence rate over a range of more than 11 decades using a single fissio
30、n chamber with appropriate corrections. It is also possible to use two different detectors. 4 egaP 8991:10516 CEI SB Page 4 BS IEC 61501:1998 Licensed Copy: sheffieldun sheffieldun, na, Sun Nov 26 11:42:29 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BSI 07-2001 NUCLEAR REACTOR INSTRUMENTATION WIDE RA
31、NGE NEUTRON FLUENCE RATE METER MEAN SQUARE VOLTAGE METHOD 1 Scope This International Standard applies to instrument and measurement channels which generate a calculation of the mean square voltage (MSV) of a signal arising from a neutron detector, in order to extract from it information relating to
32、the neutron fluence rate of a nuclear reactor. After calibration, this information can be used to derive the relative power and the time constant, for example expressed in terms of period, doubling time, decades per minute or percent per second. The method used to calculate the mean square voltage o
33、f the signal is also known as “fluctuation treatment“ or “the Campbell method“. Associated with other techniques of measurement, such as pulse rate counting or current measurement, the calculation of the mean square voltage allows the assembly of a series of wide range neutron fluence rate measureme
34、nts for the simplification of nuclear instrumentation systems in the control of nuclear reactors. This standard describes the principles, the terminology, the characteristics, the requirements and the testing methods related to instrumentation and measurement of the neutron fluence rate using MSV te
35、chniques for nuclear reactor control. Typical examples of the application of the MSV techniques are given. 2 Normative references The following normative documents contain provisions which, through reference in this text, constitute provisions of this International Standard. At the time of publicati
36、on, the editions indicated were valid. All normative documents are subject to revision, and parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. Members of IEC and ISO
37、 maintain registers of currently valid International Standards. IEC 60050(101):1998, International Electrotechnical Vocabulary (IEV) Part 101: Mathematics IEC 60050(393):1996, International Electrotechnical Vocabulary (IEV) Chapter 393: Nuclear instrumentation: Physical phenomena and basic concepts
38、IEC 60050(394):1995, International Electrotechnical Vocabulary (IEV) Chapter 394: Nuclear instrumentation: Instruments IEC 60359:1987, Expression of the performance of electrical and electronic measuring equipment IEC 60527:1975, Direct current amplifiers; characteristics and test methods IEC 60650:
39、1979, Analogue counting ratemeters Characteristics and test methods IEC 60880:1986, Software for computers in the safety systems of nuclear power stations 5 egaP 8991:10516 CEI SB Page 5 BS IEC 61501:1998 Licensed Copy: sheffieldun sheffieldun, na, Sun Nov 26 11:42:29 GMT+00:00 2006, Uncontrolled Co
40、py, (c) BSI BSI 07-2001 3 Definitions For the purpose of this International Standard, the definitions given in IEC 60050(101), IEC 60050(393) and 60050(394), as well as the following apply. NOTE The principle of the method is based on the variations analysis of the output of a detector and amplifier
41、 channel. These variations have many origins: the pulses induced by the reactions of detection and the perturbations internal or external to the channel. To ensure clarity in the document, the terms which characterize the origin of the signal are defined. Generally the term “noise“ refers to the sig
42、nal variations linked to the perturbations. 3.1 fluctuations random variations of a physical quantity around its mean value NOTE In this standard, “fluctuations” means the variations of the measured signal induced by ionizing phenomena inside the detector. These variations are produced by the gamma
43、radiation, by the alpha emission of the sensitive coating or by the neutron reactions induced in the coating. For the considered applications only, the fluctuations from neutron reactions are useful. 3.2 electronic noise variation of a signal produced by the thermal agitation of the components of th
44、e electronic circuits. It is an internal perturbation of the measuring channel. 3.3 system noise all variations of the signal with an origin external to the measuring channel 3.4 white noise random process whereby the power density spectrum is constant and independent of the frequency 3.5 Poisson pr
45、ocess process defined according to the three following hypotheses: the number of events noted in a time interval T is independent of time and independent of any events which have already occurred; the probability of having one event, and one only, in a time interval T is proportional to T when T ? 0
46、; the probability of having more than one event in a time interval T tends towards 0 faster than T when T ? 0. The law of probability P is: P(,) () ! e K T aT K K aT ? ? where K is the number of considered events; T is the time interval considered; a is the mean number of events. It occurs in all nu
47、clear fission reactions. 6 egaP 8991:10516 CEI SB Page 6 BS IEC 61501:1998 Licensed Copy: sheffieldun sheffieldun, na, Sun Nov 26 11:42:29 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BSI 07-2001 3.6 pseudo-random signal periodic deterministic signal with spectral properties similar to those of Poisso
48、n processes. The pseudo-random signal provides a constant amplitude envelope at discrete frequencies within a certain frequency band. (The Poisson random signal tends to give a continuous spectrum.) 3.7 counting rate method signal processing method which applies to a signal having the form of separa
49、te pulses. The useful information representative of the neutron fluence rate is contained in the number of pulses per each unit of time (counting rate). 3.8 mean square voltage method signal processing method which applies to a random signal. The information representative of the neutron fluence rate is contained in the mean square value of the a.c. part of the detector signal. NOTE This method and its application for neutron fluence rate measurement are presented in this standard. 3.9 wide range channel detection assembly using at
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