1、Designation: C 1128 01 (Reapproved 2008)Standard Guide forPreparation of Working Reference Materials for Use inAnalysis of Nuclear Fuel Cycle Materials1This standard is issued under the fixed designation C 1128; the number immediately following the designation indicates the year oforiginal adoption
2、or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This guide covers the preparation and characterizationof working reference ma
3、terials (WRM) that are produced by alaboratory for its own use in the analysis of nuclear materials.Guidance is provided for establishing traceability of WRMs tocertified reference materials by a defined characterizationprocess. The guidance provided is generic; it is not specific fora given materia
4、l.1.2 The information provided by this guide is found in thefollowing sections:SectionPlanning 6Preparation 7Packaging and Storage 8Characterization 9Statistical Analysis 10Documentation 111.3 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in
5、thisstandard.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.
6、 Referenced Documents2.1 ASTM Standards:2C 859 Terminology Relating to Nuclear Materials3C 1009 Guide for Establishing a Quality Assurance Pro-gram for Analytical Chemistry Laboratories Within theNuclear IndustryC 1068 Guide for Qualification of Measurement Methodsby a Laboratory Within the Nuclear
7、IndustryC 1215 Guide for Preparing and Interpreting Precision andBias Statements in Test Method Standards Used in theNuclear Industry2.2 ISO Standards:4ISO Guide to the Expression of Uncertainty in Measure-mentISO 17025 General Requirements for the Competence ofCalibration and Testing Laboratories4I
8、SO Guide 30 Terms and Definitions Used in Connectionwith Reference Materials43. Terminology53.1 Definitions of Terms Specific to This Standard:3.1.1 certified reference material (CRM)6a reference ma-terial with one or more property values that are certified by atechnically valid procedure, accompani
9、ed by or traceable to acertificate or other documentation that is issued by a certifyingbody (as defined by ISO Guide 30). A certifying body is atechnically competent body (organization or firm, public orprivate) that issues a reference material certificate (as definedby ISO Guide 30). A reference m
10、aterial certificate is a docu-ment certifying one or more property values for a certifiedreference material, stating that the necessary procedures havebeen carried out to establish their validity (as defined by ISOGuide 30).3.1.2 reference material (RM)6a material or substanceone or more properties
11、of which are sufficiently well estab-lished to be used for the calibration of an apparatus, theassessment of a measurement method, or assigning values tomaterials (as defined by ISO Guide 30). A reference materialmay be referred to in this guide also as a standard, such ascalibration standard or con
12、trol standard.3.1.3 working reference material (WRM)6a RM usuallyprepared by a single laboratory for its own use as a calibrationstandard, as a control standard, or for the qualification of ameasurement method (see Guide C 1068) as indicated in Fig.1.1This guide is under the jurisdiction of ASTM Com
13、mittee C26 on Nuclear FuelCycle and is the direct responsibility of Subcommittee C26.08 on Quality Assur-ance, Statistical Applications, and Reference Materials.Current edition approved June 1, 2008. Published July 2008. Originally approvedin 1989. Last previous edition approved in 2001 as C 1128 01
14、.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Withdrawn.4Available from American National Standards Insti
15、tute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.5See C 859 for other terms specific to the nuclear fuel cycle.6It is important that a well defined uncertainty in the stated value(s) be given inthe certificate.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box
16、C700, West Conshohocken, PA 19428-2959, United States.4. Summary of Guide4.1 This guide covers the preparation of WRMs fromnuclear fuel cycle materials. These materials are compoundsand metal of uranium and plutonium, absorber materials suchas boron carbide, and cladding materials such as zirconium
17、andstainless steel. The criteria governing the preparation of reli-able WRMs are identified and discussed. Because this guide isgeneric, requirements and detailed information for specificnuclear materials are not given. A flow diagram to illustrate anapproach to producing WRMs is given in Fig. 2.5.
18、Significance and Use5.1 Certified reference materials (CRMs) prepared fromnuclear materials are generally of high purity, possessingchemical stability or reproducible stoichiometry. Usually theyare certified using the most unbiased and precise measurementmethods available, often with more than one l
19、aboratory beinginvolved in making certification measurements. CRMs aregenerally used on a national or international level, and they areat the top of the metrological hierarchy of reference materials.A graphical representation of a national nuclear measurementsystem is shown in Fig. 3.5.2 Working ref
20、erence materials (WRMs) need to havequality characteristics that are similar to CRMs, although therigor used to achieve those characteristics is not usually asstringent as for CRMs. Where possible, CRMs are often usedto calibrate the methods used for establishing the concentrationvalues (reference v
21、alues) assigned to WRMs, thus providingtraceability to CRMs as required by ISO 17025.AWRMisnormally prepared for a specific application.5.3 Because of the importance of having highly reliablemeasurement data from nuclear materials, particularly forcontrol and accountability purposes, CRMs are someti
22、mesused for calibration when available. However, CRMs preparedfrom nuclear materials are not always available for specificapplications. Thus, there may be a need for a laboratory toprepare WRMs from nuclear materials. Also, CRMs are oftentoo expensive, or their supply is too limited for use in thequ
23、antities needed for long-term, routine use. When properlyprepared, WRMs will serve equally well as CRMs for mostapplications, and using WRMs will preserve supplies ofCRMs.5.4 Difficulties may be encountered in the preparation ofRMs from nuclear materials because of the chemical andphysical propertie
24、s of the materials. Chemical instabilities,problems in ensuring stoichiometry, and radioactivity arefactors involved, with all three factors being involved withsome materials. Those preparing WRMs from nuclear materi-als must be aware of how these factors affect preparation, aswell as being aware of
25、 the other criteria governing thepreparation of reliable WRMs.6. Planning6.1 Producing a WRM requires forethought to ensure thecredibility of the completed WRM. Planning also ensures thatthe necessary resources are available. Time, funding, andmaterials can be wasted easily without thorough planning
26、.Planning should include developing an outline or generalscheme for preparing the WRM. The intended use of theWRM, the sources available for obtaining needed materials,and the equipment required are some areas of planning thatFIG. 1 Quality Assurance of Analytical Laboratory DataFIG. 2 Producing a W
27、orking Reference MaterialC 1128 01 (2008)2should be considered. These considerations and others, i.e.,initial planning, a production plan, and a statistical plan (seeFig. 2), are discussed in this section. Initial planning generallystarts with the application or need for a WRM and the quantityneeded
28、. As planning progresses into the actual preparation, aproduction plan and a statistical analysis plan will be devel-oped.6.2 Initial Planning:6.2.1 Application of WRMA WRM can be prepared for asingle method of analysis or for several methods. For example,one might be prepared for the determination
29、of uranium inuranium dioxide. If a standard is also required for the isotopicanalysis of uranium, it might be possible to prepare andcharacterize thatWRM for isotopic analysis as well. During theFIG. 3 United States Nuclear Measurement SystemC 1128 01 (2008)3preparation of a WRM for the determinatio
30、n of a majorconstituent, it might be possible to add desired impurities andto establish values for those impurities. Careful considerationshould be given to the preparation of multi-purpose WRMs,however, because they tend to be difficult to prepare andcharacterize.6.2.2 QuantityThe quantity of WRM p
31、repared will de-pend on such factors as the length of time required for its use,the frequency of use, the amount of material available, and theWRMs anticipated shelf life. Consideration should be given tothe amount of WRM that will be needed for characterizationand for archival purposes. Needs may d
32、evelop during the useof a WRM such as the exchange of materials with anotherlaboratory for an interlaboratory testing program. For this andother possible contingencies, the preparation of a quantity overthe anticipated amount should be planned.6.3 Production PlanAn outline that specifies how theWRM
33、will be produced should be prepared during planning.The subjects discussed in 6.2 and in this section should beconsidered and addressed if appropriate. A preparation proce-dure should be written and included as a part of the productionplan (see 7.4). The production plan must be integrated with thest
34、atistical plan (see 6.4).6.3.1 MaterialsThe selection of materials is an importantpart of planning because proper selection is critical to achiev-ing credibleWRMs. Selection depends on availability (source),cost, chemical and physical properties, and stability or repro-ducible stoichiometry. The mat
35、erial selected for a WRM mustbe as similar as possible to the sample material in chemical andphysical properties, particularly in those that will affect themethod of analysis. One way to achieve similarity in compo-sition is to prepare the WRM material by the same or similarprocess used to prepare t
36、he sample material. Probably the mostimportant criterion for selection is stability. The WRM com-position must be sufficiently stable to make the preparation ofthe WRM cost effective, and the stability must be known wellenough to establish a shelf life with a high degree of confi-dence. Somewhat uns
37、table materials whose stoichiometries canbe reproduced easily can be used for WRMs.6.3.2 EquipmentGenerally, standard laboratory equip-ment will be involved in preparing a WRM. Analytical setupsand instrumentation will be required, possibly to analyzestarting materials for impurities and other const
38、ituents andcertainly to analyze the prepared material during final charac-terization of the WRM. Depending on packaging requirements,equipment may be required for such things as sealing glassampoules or packaging a WRM in a special atmosphere.6.3.3 UseThe degree of attention given to some steps inpr
39、oducing a WRM may vary depending on its planned use.Usually, WRMs are used for calibration and measurementcontrol.Acommon approach to producing a control standard isto take material from a batch of production material, treat it asnecessary to ensure homogeneity, and establish initial measure-ment co
40、ntrol limits by using the same method and conditionsused for sample analysis. To produce a calibration standard,more care in preparation and rigor in characterization arerequired.6.3.4 Characterization of MaterialsPlanning must pro-vide for the characterization of materials used for a WRM (SeeAppend
41、ix X1). Characterization may include the analysis ofstarting materials for impurities and major constituents. Itshould include a scheme for establishing the value to beassigned (reference value) to each constituent of interest. Inplanning for characterization, consideration must be given tothe degre
42、e of reliability required for a reference value.This willinvolve planning for the statistical collection and analysis ofcharacterization data (see 6.4).6.3.5 PackagingPackaging of the WRM should beplanned. Decisions need to be made concerning the division ofthe WRM into portions, selecting container
43、s, uniquely identi-fying containers, sealing containers, and using additionalmeans to protect the integrity of the WRM. It may be necessaryto package some WRMs soon after preparation to preserveintegrity; in that case, packaging materials and equipmentshould be readied prior to material preparation.
44、 Inadequatepackaging may lead to loss of the WRMs integrity throughsuch consequences as contamination, evaporation, degradationand absorption.6.4 Statistical PlanA statistical plan for characterizationshould be developed during planning. Such a plan is necessaryto allow an uncertainty to be determin
45、ed for each referencevalue. The statistical plan establishes how characterization willbe done. It includes sampling of the WRM, the frequency andnumber of measurements to be made of the WRM, anyreference material to be measured with the WRM, and theorder of measurements (see 9.3 and 9.4). The valida
46、tion orcalibration of the measurement method to be used for charac-terization may be addressed in the plan also (see 9.2.3). It isessential to have a qualified statistician involved in developingthe plan, and the statistician should be brought into theplanning process early (see Fig. 2). Developing
47、a statisticalplan is an iterative process that will go on throughout planning,and it must be integrated with the production plan (see 6.3).7. WRM Preparation7.1 The objective of preparation is to make physical andchemical manipulations so as to produce a homogeneous andstable material in the form re
48、quired for a WRM. For a givenWRM, the physical and chemical manipulations that will beused depend on the starting material(s), the WRM formrequired, and the physical and chemical properties of thematerials involved. Various aspects of preparation are dis-cussed in this section.7.2 Starting Materials
49、The starting materials for thepreparation of WRMs may be the WRM forms desired or maybe other materials that are processed into those forms. In theformer case, the starting material is process material. Forexample, a batch of uranium dioxide pellets, boron carbidepowder, or plutonium nitrate solution might be taken directlyfrom a process run, treated as necessary, characterized, andpackaged as a WRM. In the latter case, various approaches areused to produce the form desired. For example, high-purityuranium hexafluoride might be dissolved and the solutionconverted t
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