1、American National Standardfor Methods of Nuclear Material Control Measurement Control Program Nuclear MaterialsAnalytical Chemistry LaboratoryANSI N15.51-2007An INMM Sponsored DocumentANSIN15.51-2007ANSIN15.51-2007Revision ofANSI N15.51-1990 (R2006)American National Standardfor Methods ofNuclear Mat
2、erial Control Measurement Control Program Nuclear MaterialsAnalytical Chemistry LaboratorySecretariatInstitute of Nuclear Materials ManagementApproved October 31, 2007American National Standards Institute, Inc.Approval of an American National Standard requires review by ANSI that therequirements for
3、 due process, consensus, and other criteria for approval havebeen met by the standards developer.Consensus is established when, in the judgement of the ANSI Board ofStandards Review, substantial agreement has been reached by directly andmaterially affected interests. Substantial agreement means much
4、 more thana simple majority, but not necessarily unanimity. Consensus requires that allviews and objections be considered, and that a concerted effort be madetowards their resolution.The use of American National Standards is completely voluntary; theirexistence does not in any respect preclude anyon
5、e, whether he has approvedthe standards or not, from manufacturing, marketing, purchasing, or usingproducts, processes, or procedures not conforming to the standards.The American National Standards Institute does not develop standards andwill in no circumstances give an interpretation of any America
6、n NationalStandard. Moreover, no person shall have the right or authority to issue aninterpretation of an American National Standard in the name of the AmericanNational Standards Institute. Requests for interpretations should beaddressed to the secretariat or sponsor whose name appears on the titlep
7、age of this standard.CAUTION NOTICE: This American National Standard may be revised orwithdrawn at any time. The procedures of the American National StandardsInstitute require that action be taken periodically to reaffirm, revise, orwithdraw this standard. Purchasers of American National Standards m
8、ayreceive current information on all standards by calling or writing the AmericanNational Standards Institute.American National StandardPublished byAmerican National Standards Institute, Inc.25 West 43rd Street, New York, NY 10036Copyright 2008 by American National Standards Institute, Inc.All right
9、s reserved.No part of this publication may be reproduced in anyform, in an electronic retrieval system or otherwise,without prior written permission of the publisher.Printed in the United States of AmericaiContentsPageForeword . iii0 Introduction. 11 Scope and purpose 12 Normative references . 23 De
10、finitions. 24 Technical Aspects of a Measurement Control Program . 55 Administrative Aspects of a Measurement Control Program 10AnnexesA Measurement methods procedure requirements 13B Target values for uncertainty components in fissile isotope and element assay 14C Target values for random uncertain
11、ties in sampling and element assay of nuclear materials 15D Target values and measurement system performance 16E Method development and qualification report. 17F Sampling plan. 18G Packaging instruction requirements . 19H Identification and labeling . 20J Considerations for data records . 21K Storag
12、e of samples. 22L Considerations for laboratory documentation. 23M Program records considerations. 24N Measurement request and report form considerations. 25P Sample, laboratory, and data records requirements 26Q Example of control charts . 27R Management of a measurement control program 29S Essenti
13、als of a measurement control program . 30T Functional responsibilities for a measurement control program . 31U Training criteria for laboratory personnel 32V Recommended qualification program for analysts . 33W Review and audit of measurement control . 34iiPageX Documentation . 37Y Response to out-o
14、f-control situations. 38Z Objectives/purposes of Interlaboratory Comparison Programs 39AA Bibliography 40iiiForeword (This foreword is not part of American National Standard ANSI N15.51-2007.)This standard was revised under the procedures of the American National StandardsInstitute by Accredited Sta
15、ndards Committee N15 on Methods of Nuclear MaterialControl. The secretariat of N15 is held by the Institute of Nuclear Materials Manage-ment (INMM). Committee N15 has the following scope:Standards for the protection, control, and accounting of special nuclear ma-terials in all phases of the nuclear
16、fuel cycle, including analytical procedureswhere necessary and special to this purpose, except that physical protectionof special nuclear materials within a nuclear power plant is not included.The Institute of Nuclear Materials Management has long recognized the importanceof measurement quality for
17、maintaining adequate protection, control, and account-ability (MPC shipments; measured discards; transfers into, out of, or between material balance areas, item control areas, or both; and total material on current inventory. 3.2 accuracy: A measure of the agreement between the measured value and th
18、e true (or assigned) value. See bias. 3.3 assigned value: A value assigned to a standard used for calibrating and/or controlling a NM measurement device or system. 3.4 ASTM International: Formerly the acronym for the American Society for Testing and Materials; now used by the Society as its complete
19、 name. 3.5 audit: An examination of current activities to assure that they are in compliance with program policies and procedures. 3.6 bias: A systematic error that can be estimated by comparison of the sample mean of a series of measurements with a true or reference value, in which case a correctio
20、n can be applied to remove the effect of the bias on the measurements. 2Available from the ANSI Electronic Standards Store (ESS) at www.webstore.ansi.org. 3Available from ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959. 4Available from the Superintendent of Documents, U.S. Government P
21、rinting Office, 732 North Capitol Street, NW, Washington, DC 20401 or the U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001. 2 ANSI N15.51-2007 3.7 calibration: The process of determining the numerical relationship between the observed output of a measurement system and the actual value
22、of the characteristic being measured based upon a certified reference material. 3.8 certified reference material (CRM): A reference material that is certified for the value of one or more of its properties by a technically valid procedure and accompanied by, or traceable to, a certificate or other d
23、ocumentation that is issued by a certifying body. 3.9 chain of custody: A means of assuring that a sample is continually under control to prevent inadvertent or deliberate tampering from the time the sample is taken until its disposal and requiring signed receipts at each point where responsibility
24、for the sample is transferred. (See also custody.) 3.10 confirmatory measurement: A measurement made to test whether some attribute or characteristic of nuclear material is consistent with the expected response for that material when no significant change in the NM content or concentration has occur
25、red. 3.11 control standards: Standards that are representative of the process material being measured. These standards are measured periodically in order to monitor system reliability and to estimate any bias associated with the measurements of the process material. 3.12 custody: A sample is in cust
26、ody if it is either: in ones actual physical possession, in ones view after being in ones physical possession, in ones physical possession and subsequently secured so that tampering is excluded, or is kept in a secure area that is restricted to authorized personnel. 3.13 distribution: The relative s
27、patial location of components of a mixture; A well-defined universe of possible measurements arising from a property or relationship under study. 3.14 diversion: The unauthorized removal of nuclear material from its approved use or authorized location. 3.15 documentation: The collection of records t
28、hat describe the purpose, use, structure, details, and operational requirements of a program, and the performance of activities. 3.16 an estimate: The particular value yielded by a rule or method of estimating a parameter of a parent population. 3.17 homogeneous: A description of a substance that is
29、 sufficiently blended to ensure that any sample taken from it is representative of the entire substance. 3.18 Inventory difference (ID): The difference between the quantity of NM on-hand according to accounting records and the quantity of NM on-hand as determined by a physical inventory. 3.19 ISO: T
30、he acronym for the International Organization for Standardization. 3.20 limit of error (LE): The boundaries computed as the measured value plus or minus twice its standard deviation (uncertainty). Relative to the uncertainties of the measurement method, the underlying true value of the attribute bei
31、ng determined will lie within such limits for a specified proportion of potential measured values, that is, for approximately 0.95, or 95% of them. 3 ANSI N15.51-2007 3.21 machine readable: Material (label, tag, etc.) that is capable of being read by an electronic device. 3.22 matrix: The form or co
32、mposition of a material that best represents the generic physical makeup of the material with regard to impact on measurement response. 3.23 MC The quantity being estimated. 3.30 physical inventory: A determination by physical means (visual and measurement) of the quantity of nuclear material on-han
33、d at a specified point in time. 3.31 precision: A quantitative measure of the variability of a set of repeated measurements. 3.32 procedure: A document that specifies or describes how an activity is to be performed. 3.33 qualification: Demonstration (through specific test requirements) of adequate k
34、nowledge and experience for the performance of a task 3.34 random error: The specific variation encountered in a single measurement, characterized by the random occurrence of a positive or negative deviation from the mean value of the measurement. 3.35 reference material (RM): A material or substanc
35、e one or more properties of which are sufficiently well established to be used for the calibration of an apparatus, the assessment of a measurement method, or the assignment of values to materials. 3.36 replicate samples: Two or more samples taken independently from the same population. 3.37 shelf-l
36、ife: The time that elapses before a stored material or device is rendered inoperative or unusable for its intended purpose due to age or deterioration. 4 ANSI N15.51-2007 3.38 special nuclear material (SNM): U-233, uranium enriched in U-233 and/or U-235, plutonium, or any combination thereof, and an
37、y other material which, pursuant to the provisions of Section 51 of the Atomic Energy Act of 1954, as amended, has been determined to be special nuclear material, but does not include source material; it also includes any material artificially enriched by any of the foregoing, not including source m
38、aterial as defined by the Atomic Energy Act, Title 42, U. S. Code, Section 2002, et. seq. 3.39 standard deviation: The positive square root of the variance. 3.40 standard error (of a parameter estimate): The standard deviation of the parameter estimate. 3.41 statistical sampling: A statistically val
39、id technique used to select elements from a population, including probability sampling, simple random sampling, systematic sampling, stratified sampling, and cluster sampling. 3.42 systematic error: The mean that would result from an infinite number of measurements of the same measurand carried out
40、under the same conditions of measurement minus a true value of the measurand. 3.43 tare: The weight of a container or wrapper that is deducted from the gross weight to obtain the net weight. 3.44 traceability: The ability to relate individual measurement results to national standards (primary standa
41、rds) or nationally accepted measurement systems through an unbroken chain of comparisons. 3.45 uncertainty: A concept employed to describe the inability of a measurement process to measure the true value exactly. 3.46 variance: A measure of the dispersion of a set of results. 3.47 variance propagati
42、on: The determination of the value to be assigned as the uncertainty of a given quantity using mathematical formulas for the combination of uncertainty components. Variance propagation involves many considerations, and the computational formulas for computing the uncertainty depend upon the function
43、al relationships of the measurement parameters involved. 3.48 verification measurement: A quantitative measurement to verify an existing measured value as previously recorded. 3.49 verisimilitude: A concept applied to standards that represent the material to be analyzed, characterized, or tested as
44、closely as necessary. 4 Technical aspects of a measurement control program 4.1 Methods 4.1.1 Introduction. A measurement control program provides assurance that data produced from a measurement system are acceptable for meeting established measurement performance requirements. For the measurement co
45、ntrol program to have any value, it must generate data that represents (or reflects) the quality of measurements performed on process materials. Thus, one first selects a measurement method to meet the desired level of performance, and then uses 5 ANSI N15.51-2007 a measurement control program to ve
46、rify (or detect the lack of) such performance, both initially and on a continuing basis. 4.1.2 Selection 4.1.2.1 General. A method that contains the following characteristics shall be selected: technically sound; specific for the property being measured; free from interferences (or be correctable fo
47、r interferences); have an acceptable measurement range for the property being measured; capable of producing data that will meet established precision and accuracy requirements. 4.1.2.2 Target values. The required level of performance of each analytical chemistry laboratory measurement system is det
48、ermined by its specific needs. As a guideline to laboratories in estimating the appropriate level of performance, international “target values” for uncertainty components in isotopic and element assay have been developed. For individual facilities, the performance-level requirements may exceed or be
49、 less than the target values depending on their needs and requirements. These target values provide estimates of the capability that could reasonably and realistically be expected from industrial-type laboratories on a routine basis. (See annex B.) Target values attempt to describe a reasonably achievable “state of the practice” as opposed to “state of the art,” which may be considerably better. Further, it is universally recognized that uncertainties associated with the sampling operation can also contribute significantly to the overall uncertainty of the measureme
