1、Designation: D7219 08 (Reapproved 2014) An American National StandardStandard Specification forIsotropic and Near-isotropic Nuclear Graphites1This standard is issued under the fixed designation D7219; the number immediately following the designation indicates the year oforiginal adoption or, in the
2、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 specification covers the classification, processing,and properties of nuclear grade
3、 graphite billets 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
4、 changes are a significant 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.
5、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:2C559 Test Method for Bulk Density by Physical Measure-ments of Manufactured Ca
6、rbon and Graphite ArticlesC709 Terminology Relating to Manufactured Carbon andGraphiteC781 Practice for Testing Graphite and Boronated GraphiteMaterials for High-Temperature Gas-Cooled Nuclear Re-actor ComponentsC838 Test Method for Bulk Density of As-ManufacturedCarbon and Graphite ShapesC1233 Prac
7、tice for Determining Equivalent Boron Contentsof Nuclear MaterialsD346 Practice for Collection and Preparation of CokeSamples for Laboratory AnalysisD2638 Test Method for Real Density of Calcined PetroleumCoke by Helium PycnometerIEEE/ASTM SI 10 American National Standard for Use ofthe International
8、 System of Units (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 C709.3.2 Definitions of Terms Specific to This Standard:3.2.1 baking/re-b
9、aking chargenumber 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 g
10、reen mix, recyclegraphite, and pitch that is required to produce a forming lot.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
11、 sufficient to 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 th
12、e samegrade in 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.1This specification is under the jurisdiction of ASTM
13、Committee D02 onPetroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility ofSubcommittee D02.F0 on Manufactured Carbon and Graphite Products.Current edition approved May 1, 2014. Published July 2014. Originally approvedin 2005. Last previous edition approved in 2008 as D7219
14、08. DOI: 10.1520/D7219-08R14.2For 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.3Available from American Society
15、 of Mechanical Engineers (ASME), ASMEInternational Headquarters, Three Park Ave., New York, NY 10016-5990.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.2.11 impregnation chargenumber of billets in an auto-clave cycle.3.2.12 isotro
16、pic nuclear graphitegraphite in which theisotropy ratio based on the coefficient of thermal expansion is1.00 to 1.10.3.2.13 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 f
17、iller used to manufacture a graphite grade.3.2.15 molding 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
18、 batches, to produce a molding forming lot.3.2.17 near 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 (
19、see Table 1).3.2.19 production lotspecified number of 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 manu
20、factured in compliance with the mixformulation specified 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 Manufact
21、ure5.1 Nuclear Graphite ClassesSee Table 1.5.2 Raw Materials: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 Practi
22、ceC781 and measured over the temperature range 25 to 500C, ofbetween 3.5 10-6and 5.5 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
23、may be used as recycle material in the mixformulation.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 co
24、nsist of coal tar pitch ofthe same grade from the same manufacturer. The specificbinder(s) used shall be identified to the purchaser and betraceable through the forming lot.TABLE 1 ASTM Standard Classes of Nuclear GraphiteClassA CTE Isotropy RatioB(AG/WG)PurityBulk Density,Cg/cm3(min)Class Designati
25、onAsh 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 1000 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, isotropic
26、High 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 ENHPExtruded, 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 1
27、0 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 further modified by the grain size as defined in Terminology C709 (see Table 2).BDetermined in accordance with Practice C781.CDetermined in accordance wi
28、th Test Method C559.DDetermined in accordance with Practice C1233.TABLE 2 ASTM Graphite Grain Size Definitions from TerminologyC709Graphite DesignationDefinition ofGrains in the Starting Mix that are:AMedium Grained Generally4mmBFine Grained Generally 100 mSuperfine Grained Generally 50 mUltrafine G
29、rained Generally 10 mMicrofine Grained Generally2mAGrain size as defined in Terminology C709.BFor nuclear graphite, the maximum grain size is 1.68 mm in accordance with5.2.1.6.D7219 08 (2014)25.4 ImpregnantThe impregnant(s) shall consist of a petro-leum or coal tar pitch of the same grade from the s
30、amemanufacturer. The specific impregnant used shall be identifiedto the purchaser and be traceable through the impregnationsteps.5.5 Manufacturing or Processing AdditivesAdditives (forexample, extrusion aids) may be used to improve theprocessing, quality and properties of the product, but only witht
31、he consent and approval of the purchaser, and they must betraceable through the forming lot.5.6 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 purchas
32、er if requested.5.6.2 FormingThe green mix may be formed byextrusion, 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 C781. Each billet tested in acco
33、rdancewith Practice C781 shall have a Specific 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 b
34、etween the supplier and the purchaser. Theminimum 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 C1233. The acceptance limits for the boronequivalent, as well as for ash conten
35、t, are given in Table 1.6.3 Table X1.1 contains 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 impuriti
36、es, and fissile/fissionableelements.7. Physical 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 t
37、he additional re-quirements of the purchaser.7.2 The bulk density of each graphite billet shall be mea-sured as described in Test Method C838.8. Other Requirements8.1 The graphitized billets shall be handled and stored suchthat they are protected from contaminants other than ambientair.8.2 Each grap
38、hite billet shall be marked with a unique 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 Imp
39、regnant charge,8.2.8 Graphitization furnace 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 (ex
40、truded) or thickness (molded/extruded) of 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
41、 be developed by thesupplier and agreed with 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 Samp
42、le four billets for each production lot containingten 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
43、and the purchaser.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 manufactureSample in accordance with Practice D346 The procedure in Practice C781 shall be us
44、ed toprepare test specimens for the measurement ofcoke CTE.1. A sufficient sample for preparation of CTE testspecimens2. A sufficient sample will be taken for additionaltesting. This sample shall be retained for a pe-riod specified by the graphite purchaserMeasure the coke real density in accordance
45、 withTest Method D2638.D7219 08 (2014)311.1.4 During production 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 manuf
46、acturer. The cutting plan shall describe the type,location, number, 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 introduce
47、dby forming and processing. In addition the number of each typeof specimen defined by the cutting plan shall be sufficient toyield statistically significant data.12. Finished Inspection12.1 Graphite billets shall be visually inspected for externalflaws. The allowable size, type, and number of flaws
48、shall bedefined in agreement between the purchaser 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 defi
49、nedin agreement between the purchaser and the manufacturer 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
