1、Designation: D 7219 08An American National StandardStandard Specification forIsotropic and Near-isotropic Nuclear Graphites1This standard is issued under the fixed designation D 7219; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision,
2、 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 specification covers the classification, processing,and properties of nuclear grade graphite billets
3、 with dimen-sions sufficient to meet the designers requirements for fuelelements, moderator or reflector blocks, in a high temperaturegas cooled reactor. The graphite classes specified here wouldbe suitable for reactor core applications where neutron irradia-tion induced dimensional changes are a si
4、gnificant designconsideration.1.2 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard. (See IEEE/ASTM SI 10.)1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsi
5、bility 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:2C 559 Test Method for Bulk Density by Physical Measure-ments of Manufactured Carbon and Graphit
6、e ArticlesC 709 Terminology Relating to Manufactured Carbon andGraphiteC 781 Practice for Testing Graphite and Boronated GraphiteComponents for High-Temperature Gas-Cooled NuclearReactorsC 838 Test Method for Bulk Density of As-ManufacturedCarbon and Graphite ShapesC 1233 Practice for Determining Eq
7、uivalent Boron Con-tents of Nuclear MaterialsD 346 Practice for Collection and Preparation of CokeSamples for Laboratory AnalysisD 2638 Test Method for Real Density of Calcined Petro-leum Coke by Helium PycnometerIEEE/ASTM SI 10 American National Standard for Use ofthe International System of Units
8、(SI): The Modern MetricSystem2.2 ASME Standard:NQA-1 Quality Assurance Program Requirements forNuclear Facilities33. Terminology3.1 DefinitionsDefinitions relating to this specification aregiven in Terminology C 709.3.2 Definitions of Terms Specific to This Standard:3.2.1 baking/re-baking chargenumb
9、er of billets in abaking/re-baking furnace run.3.2.2 bulk densitymass of a unit volume of materialincluding both permeable and impermeable voids.3.2.3 extrusion forming lotnumber of billets of the samesize extruded in an uninterrupted sequence.3.2.4 green batchmass of coke, recycle green mix, re-cyc
10、le graphite, and pitch that is required to produce a forminglot.3.2.5 green mixpercentage of mix formulation, pitch andadditives required for the forming lot, which is processed andready to be formed.3.2.6 graphite billetextruded, molded, or iso-moldedgraphite artifact with dimensions sufficient to
11、meet the design-ers requirements for reactor components.3.2.7 graphite gradedesignation given to a material by amanufacturer such that it is always reproduced to the samespecification and from the same raw materials and mixformulation.3.2.8 graphitization chargenumber of billets of the samegrade in
12、a graphitizing furnace run.3.2.9 graphitizing furnace runtotal number of billetsgraphitized together in one graphitization furnace.3.2.10 high purity nuclear graphitenuclear graphite withan Equivalent Boron Content less than 2 ppm.3.2.11 impregnation chargenumber of billets in an auto-clave cycle.3.
13、2.12 isotropic nuclear graphitegraphite in which theisotropy ratio based on the coefficient of thermal expansion is1.00 to 1.10.1This specification is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.F0 on Manufactur
14、ed Carbon and Graphite Products.Current edition approved May 1, 2008. Published July 2008. Originally approvedin 2005. Last previous edition approved in 2005 as D 7219-05.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Ann
15、ual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from American Society of Mechanical Engineers (ASME), ASMEInternational Headquarters, Three Park Ave., New York, NY 10016-5990.1Copyright ASTM International, 100 Barr Harbor Drive
16、, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.2.13 low purity nuclear graphitenuclear graphite withan Equivalent Boron Content greater than 2 ppm but less than10 ppm.3.2.14 mix formulationpercentages of each specificallysized filler used to manufacture a graphite grade.3.2.15 mold
17、ing forming lotnumber of billets molded froma molding powder lot.3.2.16 molding powder lotsufficient quantity of re-milledand blended green batch produced from an uninterrupted flowof raw materials, or produced in a sequence of identicalmaterials batches, to produce a molding forming lot.3.2.17 near
18、 isotropic nuclear graphitegraphite in whichthe isotropy ratio based on the coefficient of thermal expansionis 1.10 to 1.15.3.2.18 nuclear graphite classdesignation of a nucleargraphite based upon its forming method, isotropy, purity anddensity (see Table 1).3.2.19 production lotspecified number of
19、billets made inaccordance with this specification and additional requirementsdetermined by the purchaser.3.2.20 purification chargenumber of billets in a purifica-tion run.3.2.21 recycle green mixground non-baked billets or nonused green mix manufactured in compliance with the mixformulation specifi
20、ed here.4. Significance and Use4.1 The purpose of this specification is to document theminimum acceptable properties and levels of quality assuranceand traceability for isotropic and near-isotropic nuclear gradegraphites.5. Materials and Manufacture5.1 Nuclear Graphite ClassesSee Table 1.5.2 Raw Mat
21、erials:5.2.1 Fillers:5.2.1.1 The filler shall consist of a near-isotropic or isotro-pic coke derived from a petroleum oil or coal tar.5.2.1.2 The coke shall have a coefficient of linear thermalexpansion (CTE), determined in accordance with PracticeC 781 and measured over the temperature range 25 to
22、500C,of between 3.5 3 10-6and 5.5 3 10-6C-1.5.2.1.3 The coke shall be sampled and distributed as de-scribed in Table 3.5.2.1.4 Graphite manufactured in compliance with thisspecification but failing to meet the property requirements ofSections 6 and 7 may be used as recycle material in the mixformula
23、tion.5.2.1.5 Recycle green mix manufactured from raw materialsin compliance with this specification may be used in the mixformulation.5.2.1.6 The maximum filler particle size used in the mixformulation shall be 1.68 mm.5.3 BinderThe binder(s) shall consist of coal tar pitch ofthe same grade from the
24、 same manufacturer. The specificbinder(s) used shall be identified to the purchaser and betraceable through the forming lot.5.4 ImpregnantThe impregnant(s) shall consist of a pe-troleum or coal tar pitch of the same grade from the samemanufacturer. The specific impregnant used shall be identifiedto
25、the purchaser and be traceable through the impregnationsteps.5.5 Manufacturing or Processing AdditivesAdditives (forexample, extrusion aids) may be used to improve the process-ing, quality and properties of the product, but only with theconsent and approval of the purchaser, and they must betraceabl
26、e through the forming lot.TABLE 1 ASTM Standard Classes of Nuclear GraphiteClassACTE Isotropy RatioB(aAG/aWG)PurityBulk Density,Cg/cm3(min)Class DesignationAsh Content,Bppm (max)Boron Equivalent,Dppm (max)Isomolded, isotropicHigh Purity 1.0-1.1 300 2 1.7 IIHPIsomolded, isotropicLow Purity 1.0-1.1 10
27、00 10 1.7 IILPIsomolded, near-isotropicHigh Purity 1.1-1.15 300 2 1.7 INHPIsomolded, near-isotropicLow Purity 1.1-1.15 1000 10 1.7 INLPExtruded, isotropicHigh Purity 1.0-1.1 300 2 1.7 EIHPExtruded, isotropicLow Purity 1.0-1.1 1000 10 1.7 EILPExtruded, near-isotropicHigh Purity 1.1-1.15 300 2 1.7 ENH
28、PExtruded, near-isotropicLow Purity 1.1-1.15 1000 10 1.7 ENLPMolded, isotropicHigh Purity 1.0-1.1 300 2 1.7 MIHPMolded, isotropicLow Purity 1.0-1.1 1000 10 1.7 MILPMolded, near-isotropicHigh Purity 1.1-1.15 300 2 1.7 MNHPMolded, near-isotropicLow Purity 1.1-1.15 1000 10 1.7 MNLPAThese classes may be
29、 further modified by the grain size as defined in Terminology C 709 (see Table 2).BDetermined in accordance with Practice C 781.CDetermined in accordance with Test Method C 559.DDetermined in accordance with Practice C 1233.TABLE 2 ASTM Graphite Grain Size Definitions fromTerminology C 709Graphite D
30、esignationDefinition ofGrains in the Starting Mix that are:AMedium Grained Generally4mmBFine Grained Generally 100 mSuperfine Grained Generally 50 mUltrafine Grained Generally 10 mMicrofine Grained Generally2mAGrain size as defined in Terminology C 709.BFor nuclear graphite, the maximum grain size i
31、s 1.68 mm in accordance with5.2.1.6.D72190825.6 Manufacture:5.6.1 FormulationThe mix formulation (as defined in3.2.14) and recycle green mix fraction (as defined in 3.2.21)inthe filler shall be recorded. This information shall be reportedto the purchaser if requested.5.6.2 FormingThe green mix may b
32、e formed by extru-sion, molding (including vibrationally molding), or iso-molding.5.6.3 Graphitization TemperatureThe graphitization tem-perature shall be determined on each billet using the proceduredescribed in Practice C 781. Each billet tested in accordancewith Practice C 781 shall have a Specif
33、ic Electrical Resistivity(SER) corresponding to a graphitization temperature of at least2700C.6. Chemical Properties6.1 Each graphite production lot shall be sampled in accor-dance with Section 11. The chemical impurities to be measuredshall be as agreed between the supplier and the purchaser. Themi
34、nimum list of elements to be measured and used for the EBCcalculation shall be B, Cd, Dy, Eu, Gd, and Sm.6.2 The boron equivalent shall be calculated in accordancewith Practice C 1233. The acceptance limits for the boronequivalent, as well as for ash content, are given in Table 1.6.3 Table X1.1 cont
35、ains a list of chemical impurities that aretypically measured depending on end-use requirements. Theimpurities are categorized as neutron absorbing impurities,oxidation promoting catalysts, activation relevant impurities,metallic corrosion relevant impurities, and fissile/fissionableelements.7. Phys
36、ical and Mechanical Properties7.1 Each graphite production lot shall be sampled in accor-dance with Section 11 and shall conform to the requirementsfor physical properties prescribed in Table 1 and Table 4 for theappropriate nuclear graphite class, and to the additional re-quirements of the purchase
37、r.7.2 The bulk density of each graphite billet shall be mea-sured as described in Test Method C 838.8. Other Requirements8.1 The graphitized billets shall be handled and stored suchthat they are protected from contaminants other than ambientair.8.2 Each graphite billet shall be marked with a unique
38、billetidentification number. Each billet shall be traceable throughthese identifying numbers to each of the following:8.2.1 Mix formulation,8.2.2 Coke batch,8.2.3 Recycle graphite batch,8.2.4 Forming lot,8.2.5 Molding powder lot,8.2.6 Baking charge,8.2.7 Impregnant charge,8.2.8 Graphitization furnac
39、e run,8.2.9 Position of billet in graphitization furnace,8.2.10 Purification step (if performed),8.2.11 Binder pitch,8.2.12 Impregnant pitch, and8.2.13 Additives used (if any).9. Dimensions9.1 Graphite billet dimensions are typically 0.4 to 0.6 mdiameter (extruded) or thickness (molded/extruded) of
40、0.6 by0.6 m cross-section (iso-molded) and 0.75 to 3.0 m length.10. Workmanship, Finish and Appearance10.1 Graphitized billets shall be brushed clean after removalfrom the graphitization furnace.11. Sampling and Cutting11.1 A statistical sampling plan shall be developed by thesupplier and agreed wit
41、h the purchaser. The plan shall describethe number of graphite billets to be sampled and the frequencyof sampling. The following minimum sampling frequencies arerecommended per production lot, depending on the number ofbillets per production lot.11.1.1 Sample four billets for each production lot con
42、tainingten or fewer billets.11.1.2 Sample one additional billet for every five additionalbillets per production lot, up to 50 billets.11.1.3 For production lots exceeding 50 billets the addi-tional sampling requirements should be agreed between thesupplier and the purchaser.11.1.4 During production
43、the sampling plan may be reevalu-ated based on statistical analysis of the production data. Anyrevised sampling plan must be agreed between the supplier andthe purchaser.11.2 A cutting plan shall be agreed between the purchaserand manufacturer. The cutting plan shall describe the type,location, numb
44、er, orientation of the test specimens, and anyrequired archive specimens needed for property determinationsas set forth in Sections 6 and 7 of this specification. The cuttingplan shall reflect property gradients and anisotropy introducedby forming and processing. In addition the number of each typeo
45、f specimen defined by the cutting plan shall be sufficient toyield statistically significant data.TABLE 3 Inspection Sampling and Testing of Filler CokesInspection Plan Sampling Procedure Tests and Test MethodsA representative sample of thecoke shall be taken prior to themixing step of manufactureSa
46、mple in accordance with Practice D 346 The procedure in Practice C 781 shall be used toprepare test specimens for the measurement ofcoke CTE.1. A sufficient sample for preparation of CTEtest specimens2. A sufficient sample will be taken foradditional testing. This sample shall be retainedfor a perio
47、d specified by the graphite purchaserMeasure the coke real density in accordancewith Test Method D 2638.D721908312. Finished Inspection12.1 Graphite billets shall be visually inspected for externalflaws. The allowable size, type, and number of flaws shall bedefined in agreement between the purchaser
48、 and the manufac-turer and be described in the purchase specification.12.2 It is recommended that all graphite billets are non-destructively tested to screen for internal defects. The allow-able size, type, and number of internal flaws should be definedin agreement between the purchaser and the manu
49、facturer andbe described in the purchase specification.13. Rejection and Rework13.1 Graphite billets failing on chemical purity (see Section6) may be purified/re-purified and subjected to retest.13.2 Graphite billets failing on SER (see 5.6.3) may bere-graphitized and subjected to retest.13.3 All other billets failing to meet the requirement ofSections 6 and 7 of this specification may be used as recyclegraphite in accordance with 5.2.1.4.14. Certification14.1 The manufacturer shall certify that the graphite meetsthe requirements of th
