1、Designation: C 1128 01Standard Guide forPreparation of Working Reference Materials for Use in theAnalysis 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 or, in the cas
2、e of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This guide covers the preparation and characterizationof working reference materials (WRM)
3、 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 material.1.2 The inf
4、ormation 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 as thestandard.1.4 This standard does not purport to address all of the
5、safety 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. Referenced Documents2.1 ASTM Standards:C 859 Terminology Relating to
6、 Nuclear Materials2C 1009 Guide for Establishing a Quality Assurance Pro-gram for Analytical Chemistry Laboratories Within theNuclear Industry2C 1068 Guide for Qualification of Measurement Methodsby a Laboratory Within the Nuclear Industry2C 1215 Guide for Preparing and Interpreting Precision andBia
7、s Statements in Test Method Standards in the NuclearIndustry22.2 ISO Standards:ISO Guide to the Expression of Uncertainty in Measure-ment3ISO 17025 General Requirements for the Competence ofCalibration and Testing Laboratories3ISO Guide 30 Terms and Definitions Used in Connectionwith Reference Mater
8、ials33. Terminology43.1 Definitions of Terms Specific to This Standard:3.1.1 certified reference material (CRM)5a reference ma-terial with one or more property values that are certified by atechnically valid procedure, accompanied by or traceable to acertificate or other documentation that is issued
9、 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 material certificate is a docu-ment certifying one or more property value
10、s 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)5a material or substanceone or more properties of which are sufficiently well estab-lished to be used for the calibrati
11、on 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 control standard.3.1.3 working reference material (WRM)5a RM usuallyprepare
12、d 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.1.4. Summary of Guide4.1 This guide covers the preparation of WRMs fromnuclear fuel cycle materials. These materials are co
13、mpoundsand metal of uranium and plutonium, absorber materials such1This guide is under the jurisdiction of ASTM Committee C26 on Nuclear FuelCycle and is the direct responsibility of Subcommittee C26.8 on Quality AssuranceApplications.Current edition approved June 10, 2001. Published September 2001.
14、 Originallypublished as C 1128 89. Last previous edition C 1128 95.2Annual Book of ASTM Standards, Vol 12.01.3Available from American National Standards Institute, 11 W. 42nd St., 13thFloor, New York, NY 10036.4See C 859 for other terms specific to the nuclear fuel cycle.5It is important that a well
15、 defined uncertainty in the stated value(s) be given inthe certificate.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.as boron carbide, and cladding materials such as zirconium andstainless steel. The criteria governing the preparat
16、ion 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. Significance and Use5.1 Certified reference materials (
17、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 laboratory beinginvolved in making certification measure
18、ments. 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 reference materials (WRMs) need to havequality characteris
19、tics 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 values) assigned to WRMs, thus providingtraceability to
20、CRMs as required by ISO 17025. A WRM isnormally 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 sometimesused for calibration when available. However, CRM
21、s 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 thequantities needed for long-term, routine use. When pro
22、perlyprepared, 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 properties of the materials. Chemical instabilities,problems
23、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 the other criteria governing thepreparation of reli
24、able 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.Planning should include developing an outline or ge
25、neralscheme 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 thatshould be considered. These considerations and others, i.e.,initial planning, a production plan, and a statistical plan (seeFi
26、g. 2), are discussed in this section. Initial planning generallystarts with the application or need for a WRM and the quantityneeded. As planning progresses into the actual preparation, aFIG. 1 Quality Assurance of Analytical Laboratory DataFIG. 2 Producing a Working Reference MaterialC 11282product
27、ion 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 of uranium inuranium dioxide. If a standard is also required f
28、or the isotopicanalysis of uranium, it might be possible to prepare andcharacterize that WRM for isotopic analysis as well. During thepreparation of a WRM for the determination of a majorconstituent, it might be possible to add desired impurities andto establish values for those impurities. Careful
29、considerationshould be given to the preparation of multi-purpose WRMs,however, because they tend to be difficult to prepare andcharacterize.FIG. 3 United States Nuclear Measurement SystemC 112836.2.2 QuantityThe quantity of WRM prepared will de-pend on such factors as the length of time required for
30、 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 develop during the useof a WRM such as the exchange of materials with an
31、otherlaboratory 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 will be produced should be prepared during planning.The subjects discus
32、sed 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 thestatistical plan (see 6.4).6.3.1 MaterialsThe selection of materials is a
33、n importantpart of planning because proper selection is critical to achiev-ing credible WRMs. Selection depends on availability (source),cost, chemical and physical properties, and stability or repro-ducible stoichiometry. The material selected for a WRM mustbe as similar as possible to the sample m
34、aterial 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 the sample material. Probably the mostimportant criterion for selection
35、 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 unstable materials whose stoichiometries canbe reproduced easily can be u
36、sed 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 constituents andcertainly to analyze the prepared material during final cha
37、rac-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 inproducing a WRM may vary depending on its planned use.Usually, WRMs are
38、used for calibration and measurementcontrol. A common 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 control limits by using the same method and conditionsused for sample
39、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 (SeeAppendix X1). Characterization may include the analysis ofstarting materia
40、ls 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 degree of reliability required for a reference value. This willinvolve pl
41、anning 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 containers, uniquely identi-fying containers, sealing containers, and using
42、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. Inadequatepackaging may lead to loss of the WRMs integrity through
43、such 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 determined for each referencevalue. The statistical plan establishes how ch
44、aracterization 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 validation orcalibration of the measurement method to be used for charac-
45、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 a statisticalplan is an iterative process that will go on throughou
46、t 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 required for a WRM. For a givenWRM, the physical and chemical manipul
47、ations 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 MaterialsThe starting materials for thepreparation of WRMs may be the WRM fo
48、rms 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,
49、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 to urano-uranic oxide (U3O8) to prepare a WRM ormatrix material (see Appendix X2).7.3 WRM FormThe form of the WRM can be any stablestate of the element of interest or a somewhat unstable statewhose stoichiometry is easily reproducible. The forms mostcommonly used for nuclear materials have been oxides aspowder or pellets, metal, and nitrate solutions.7.4 ProcedureA prep
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