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1、 Reference number ISO 18213-1:2007(E) ISO 2007 INTERNATIONAL STANDARD ISO 18213-1 First edition 2007-11-15 Nuclear fuel technology Tank calibration and volume determination for nuclear materials accountancy Part 1: Procedural overview Technologie du combustible nuclaire talonnage et dtermination du
2、volume de cuve pour la comptabilit des matires nuclaires Partie 1: Aperu gnral de la procdure Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=IHS Employees/1111111001, User=leee, leee Not for Resale, 11/22/2007 19:13:16 MSTNo reproduction or n
3、etworking permitted without license from IHS -,-,- ISO 18213-1:2007(E) PDF disclaimer This PDF file may contain embedded typefaces. In accordance with Adobes licensing policy, this file may be printed or viewed but shall not be edited unless the typefaces which are embedded are licensed to and insta
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6、lease inform the Central Secretariat at the address given below. COPYRIGHT PROTECTED DOCUMENT ISO 2007 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 mechanical, including photocopying and microfil
7、m, without permission in writing from either ISO at the address below or ISOs member body in the country of the requester. ISO copyright office Case postale 56 CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail copyrightiso.org Web www.iso.org Published in Switzerland ii ISO 2007
8、All rights reserved Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=IHS Employees/1111111001, User=leee, leee Not for Resale, 11/22/2007 19:13:16 MSTNo reproduction or networking permitted without license from IHS -,-,- ISO 18213-1:2007(E) ISO
9、 2007 All rights reserved iii Contents Page Foreword iv Introduction v 1 Scope . 1 2 Physical principles involved 1 3 The calibration model. 2 4 Equipment required 3 4.1 General. 3 4.2 The tank and its measurement systems. 3 4.3 Prover system . 6 4.4 Calibration liquid. 8 4.5 Calibration software .
10、8 5 A typical tank calibration procedure. 8 5.1 Calibration procedure. 8 5.2 Procedural notes. 9 6 Calibration planning and pre-calibration activities. 10 6.1 The calibration plan 10 6.2 Measurement requirements and preliminary error analysis 10 6.3 The tank and its measurement support systems 11 6.
11、4 Calibration equipment (prover system) 12 6.5 Reference operating conditions 13 6.6 Data acquisition and analysis . 15 6.7 The calibration plan 17 7 Volume determination 18 7.1 Overview 18 7.2 Steps for determining reference height 18 7.3 Steps for determining volume. 19 7.4 Compute uncertainty est
12、imates 20 7.5 Final note on heel volume 21 Bibliography. 22 Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=IHS Employees/1111111001, User=leee, leee Not for Resale, 11/22/2007 19:13:16 MSTNo reproduction or networking permitted without licens
13、e from IHS -,-,- ISO 18213-1:2007(E) iv ISO 2007 All rights reserved Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technic
14、al committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely wi
15、th the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft Inte
16、rnational Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements of this document ma
17、y be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 18213-1 was prepared by Technical Committee ISO/TC 85, Nuclear energy, Subcommittee SC 5, Nuclear fuel technology. ISO 18213 consists of the following parts, under the general titl
18、e Nuclear fuel technology Tank calibration and volume determination for nuclear materials accountancy: Part 1: Procedural overview Part 2: Data standardization for tank calibration Part 3: Statistical methods Part 4: Accurate determination of liquid height in accountancy tanks equipped with dip tube
19、s, slow bubbling rate Part 5: Accurate determination of liquid height in accountancy tanks equipped with dip tubes, fast bubbling rate Part 6: Accurate in-tank determination of liquid density in accountancy tanks equipped with dip tubes Copyright International Organization for Standardization Provid
20、ed by IHS under license with ISO Licensee=IHS Employees/1111111001, User=leee, leee Not for Resale, 11/22/2007 19:13:16 MSTNo reproduction or networking permitted without license from IHS -,-,- ISO 18213-1:2007(E) ISO 2007 All rights reserved v Introduction ISO 18213 deals with the acquisition, stan
21、dardization, analysis, and use of calibration data to determine liquid volumes in process tanks for the purpose of nuclear materials accountability. This part of ISO 18213 complements the other parts, which include ISO 18213-2 (data standardization), ISO 18213-3 (statistical methods), ISO 18213-4 (s
22、low bubbling rate), ISO 18213-5 (fast bubbling rate), and ISO 18213-6 (in-tank determination of liquid density). Accurate determinations of volume are a fundamental component of any measurement-based system of control and accountability in a facility that processes or stores nuclear materials in liq
23、uid form. Volume determinations are typically made with the aid of a calibration or volume measurement equation that relates the response of the tanks measurement system to some independent measure of tank volume. The ultimate purpose of the calibration exercise is to estimate the tanks volume measu
24、rement equation (the inverse of the calibration equation), which relates tank volume to measurement system response. The steps carried out to acquire data for estimating the tanks calibration or volume measurement equation are collectively described as the process of tank calibration. The methods pr
25、esented in this part of ISO 18213 apply to tanks equipped with bubbler probe systems for measuring liquid content. With such systems, gas (air) is forced through a dip tube (probe) submerged in the tank liquid. Measurements of the pressure required to induce bubbling are used to determine the height
26、 of the column of liquid in the tank above the tip of the probe. During the calibration process, these determinations of liquid height are related to an independent measure of the tanks liquid content for some (calibration) liquid whose density has been precisely determined. An estimate of the volum
27、e measurement equation obtained from these data is subsequently used to determine process liquid volumes from measures of the pressure that these liquids exert at the tip of the dip tube. This part of ISO 18213 is intended to serve as a procedural overview for the tank calibration and volume determi
28、nation process, the main elements of which are presented. Selected steps that require further amplification are discussed in detail in other parts of ISO 18213 as noted. Tank calibration and volume measurement data are sensitive to variations in measurement conditions and especially to changes in li
29、quid and air temperatures. Therefore, it is necessary to standardize these data to a fixed set of reference conditions to minimize variability and ensure comparability. Standardization is required whenever measurement conditions change during a calibration exercise. Standardization is also necessary
30、 for comparing or combining data obtained during several calibration periods over which the measurement conditions are not constant. Finally, it is essential to standardize measurements of process liquid used to determine volumes for accountability purposes, because process measurement conditions ar
31、e typically quite different from those that prevail during the calibration exercise. Data standardization steps are presented in ISO 18213-2. A key step for both calibration and volume determination is to determine the height of a column of liquid above some reference point from a measure of the pre
32、ssure that liquid exerts at the tip of a submerged probe. Procedures for making accurate liquid height determinations from pressure measurements are presented for slow and fast bubbling rates in ISO 18213-4 and ISO 18213-5, respectively. Statistical methods for (i) examining the consistency of a set
33、 of data obtained during the calibration process, (ii) deriving an estimate of a tanks measurement or calibration equation from a set of calibration data and (iii) estimating the uncertainty of a volume determination obtained from this equation are presented in ISO 18213-3. In tanks equipped with tw
34、o or more dip tubes, the procedures of this part of ISO 18213 can be used to obtain (differential) pressure measurements for each probe. These measurements can, in turn, be used to make very accurate determinations of liquid density. Methods for making accurate determinations of density from in-tank
35、 measurements are presented in ISO 18213-6. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=IHS Employees/1111111001, User=leee, leee Not for Resale, 11/22/2007 19:13:16 MSTNo reproduction or networking permitted without license from IHS -,-,-
36、 ISO 18213-1:2007(E) vi ISO 2007 All rights reserved Taken together, the six parts of ISO 18213 provide a comprehensive state-of-the-art methodology that addresses all the factors known to significantly affect the uncertainty of volume determinations obtained by means of a tank calibration equation.
37、 This methodology can be used to produce high-quality calibrations for tanks from which very precise volume determinations are required, such as key input and output accountability tanks. For various reasons (inadequate instrumentation, lack of time or other resources), it might not be possible for
38、an operator to meet all the prescribed conditions set forth herein, even for key accountability tanks. Moreover, it is typically not necessary for the operator to meet these conditions for all the tanks in a facility. Under these circumstances, this part of ISO 18213 provides a starting framework fr
39、om which to develop a suitable “reduced” calibration model for each tank. The first step for any calibration is to establish appropriate uncertainty limits for the resulting volume determinations. Next, each potentially significant factor is evaluated relative to its effect on calibration results, a
40、nd specifically for its contribution to the total uncertainty of volume determinations (see ISO 18213-3:, Annex D). A reduced model is obtained by ignoring factors found to have a negligible effect on total uncertainty in subsequent calculations pertaining to that calibration possibly by fixing them
41、 at suitable constant values; see either ISO 18213-4:, Annex A (slow bubbling) or ISO 18213-5:, Annex A (fast bubbling) for examples. Other factors are, of course, retained. Thus, for a key accountability tank for which very precise volume measurements are required, a suitable model retains (nearly)
42、 all potentially significant factors in subsequent standardization and uncertainty calculations. For tanks with less restrictive measurement requirements, a model that includes terms which involve only one or two of the most influential factors, such as temperature and density, is often sufficient.
43、The user is reminded at numerous points throughout this International Standard that it is required of the user to determine whether or not to retain a particular variable. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=IHS Employees/111111100
44、1, User=leee, leee Not for Resale, 11/22/2007 19:13:16 MSTNo reproduction or networking permitted without license from IHS -,-,- INTERNATIONAL STANDARD ISO 18213-1:2007(E) ISO 2007 All rights reserved 1 Nuclear fuel technology Tank calibration and volume determination for nuclear materials accountan
45、cy Part 1: Procedural overview 1 Scope This part of ISO 18213 describes procedures for tank calibration and volume determination for nuclear process tanks equipped with pressure-measurement systems for determining liquid content. Specifically, overall guidance is provided for planning a calibration
46、exercise undertaken to obtain the data required for the measurement equation to estimate a tanks volume. The key steps in the procedure are also presented for subsequently using the estimated volume-measurement equation to determine tank liquid volumes. The procedures presented apply specifically to
47、 tanks equipped with bubbler probe systems for measuring liquid content. Moreover, these procedures produce reliable results only for clear (i.e. without suspended solids), homogeneous liquids that are at both thermal and static equilibrium. 2 Physical principles involved The pressure measurement sy
48、stems for determining liquid height described in this part of ISO 18213 are based on the fundamental hydrostatic principle which states that the pressure, P, exerted by a column of liquid at its base is related to the height of the column and the density of the liquid as given in Equation (1): P = gHMM (1) where HM is the height of the liquid column (at temperature Tm)1); M is the average density of the liquid in the column (at temperature Tm); g is the local acceleration due to gravity. If the density of the liquid is known, Equation (1) can be