1、Designation: D 7301 08An American National StandardStandard Specification forNuclear Graphite Suitable for Components Subjected toLow Neutron Irradiation Dose1This standard is issued under the fixed designation D 7301; the number immediately following the designation indicates the year oforiginal ad
2、option 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 specification covers the classification, processing,and propertie
3、s of nuclear grade graphite billets with dimen-sions sufficient to meet the designers requirements for reflec-tor blocks and core support structures, in a high temperaturegas cooled reactor. The graphite classes specified here wouldbe suitable for reactor core applications where neutron irradia-tion
4、 induced dimensional changes are not a significant designconsideration.1.2 The purpose of this specification is to document theminimum acceptable properties and levels of quality assuranceand traceability for nuclear grade graphite suitable for compo-nents subjected to low irradiation dose. Nuclear
5、graphitesmeeting the requirements of Specification D 7219 are alsosuitable for components subjected to low neutron irradiationdose.1.3 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.2. Referenced Documents2.1 ASTM Standards:2C
6、559 Test Method for Bulk Density by Physical Measure-ments of Manufactured Carbon and Graphite 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 fo
7、r Bulk Density of As-ManufacturedCarbon and Graphite ShapesC 1233 Practice for Determining Equivalent 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 Pycn
8、ometerD 7219 Specification for Isotropic and Near-isotropicNuclear GraphitesIEEE/ASTM SI 10 American National Standard for Use ofthe International System of Units (SI): The Modern MetricSystem2.2 ASME Standards:3NQA-1 Quality Assurance Program Requirements forNuclear Facilities3. Terminology3.1 Defi
9、nitionsDefinitions relating to this specification aregiven in Terminology C 709. See Table 1.3.2 Definitions of Terms Specific to This Standard:3.3 anistropic nuclear graphite, ngraphite in which theisotropy ratio based on the coefficient of thermal expansion isgreater than 1.15.3.4 baking/re-baking
10、 charge, nnumber of billets in abaking/re-baking furnace run.3.5 bulk density, nmass of a unit volume of materialincluding both permeable and impermeable voids.3.6 extrusion forming lot, nnumber of billets of the samesize extruded in an uninterrupted sequence.3.7 green batch, nmass of coke, recycle
11、green mix,recycle graphite, and pitch that is required to produce aforming lot.3.8 green mix, npercentage of mix formulation, pitch andadditives required for the forming lot, which is processed andready to be formed.3.9 graphite billet, nextruded, molded, or iso-moldedgraphite artifact with dimensio
12、ns sufficient to meet the design-ers requirements for reactor components.3.10 graphite grade, ndesignation given to a material bya manufacturer such that it is always reproduced to the samespecification and from the same raw materials and mixformulation.3.11 graphitizing furnace run, ntotal number o
13、f billetsgraphitized together in one graphitization furnace.1This specification is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.F0 on Manufactured Carbon and Graphite Products.Current edition approved July 1, 200
14、8. Published August 2008.2For 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 of
15、Mechanical Engineers (ASME), ASMEInternational Headquarters, Three Park Ave., New York, NY 10016-5990, http:/www.asme.org.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.12 graphitization charge, ntotal number of billetsgraphitized
16、 together in one graphitization furnace.3.13 high purity nuclear graphite, nnuclear graphite withan Equivalent Boron Content less than 2 ppm.3.14 impregnation charge, nnumber of billets in an auto-clave cycle.3.15 low purity nuclear graphite, nnuclear graphite withan Equivalent Boron Content greater
17、 than 2 ppm but less than10 ppm.3.16 mix formulation, npercentages of each specificallysized filler used to manufacture a graphite grade.3.17 molding forming lot, nnumber of billets moldedfrom a molding powder lot.3.18 molding powder lot, nsufficient quantity of re-milledand blended green batch prod
18、uced from an uninterrupted flowof raw materials, or produced in a sequence of identicalmaterials batches, to produce a molding forming lot.3.19 nuclear graphite class, ndesignation of a nucleargraphite based upon its forming method, isotropy, purity anddensity (see Table 2).3.20 production lot, nspe
19、cified number of billets made inaccordance with this specification and additional requirementsdetermined by the purchaser.3.21 purification charge, nnumber of billets in a purifi-cation run.3.22 recycle green mix, nground non-baked billets ornon-used green mix manufactured in compliance with the mix
20、formulation specified here.4. Materials and Manufacture4.1 Nuclear Graphite ClassesSee Table 2.4.2 Raw Materials:4.2.1 Fillers:4.2.1.1 The filler shall consist of a coke derived from apetroleum oil or coal tar.4.2.1.2 The coke shall have a coefficient of linear thermalexpansion (CTE), determined in
21、accordance with PracticeC 781 and measured over the temperature range 25 to 500C,less than 5.5 3 10-6C-1.4.2.1.3 The coke shall be sampled and distributed as de-scribed in Table 3.4.2.1.4 Graphite manufactured in compliance with thisspecification but failing to meet the property requirements ofSecti
22、ons 5-7 may be used as recycle material in the mixformulation.4.2.1.5 Recycle green mix manufactured from raw materialsin compliance with this specification may be used in the mixformulation.4.2.1.6 The maximum filler particle size used in the mixformulation shall be 1.68 mm.4.3 BinderThe binder sha
23、ll consist of coal tar pitch of thesame grade from the same manufacturer. The specific binder(s)used shall be identified to the purchaser and be traceablethrough the forming lot.4.4 ImpregnantThe impregnant shall consist of a petro-leum or coal tar pitch of the same grade from the samemanufacturer.
24、The specific impregnant(s) used shall be identi-fied to the purchaser and be traceable through the impregnationsteps.4.5 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
25、 and approval of the purchaser, and they must betraceable through the forming lot.4.6 Manufacture:4.6.1 FormulationThe mix formulation (as defined in3.16) and recycle green mix fraction (as defined in 3.22)inthefiller shall be recorded. This information shall be reported tothe purchaser if requested
26、.4.6.2 FormingThe green mix may be formed by extru-sion, molding (including vibrationally molding), or iso-molding.4.6.3 Graphitization TemperatureThe graphitization tem-perature shall be determined on each billet using the proceduredescribed in Practice C 781. Each billet tested in accordanceTABLE
27、1 ASTM Graphite Grain Size Definitions fromTerminology C 709GraphiteDesignationDefinition of Grains inthe Starting Mix that are:AMedium Grained Generally1.15 300 2 1.7 IAHPIsomolded, anisotropic-LP 1.15 1000 10 1.7 IALPExtruded, anisotropic-HP 1.15 300 2 1.7 EAHPExtruded, anisotropic-LP 1.15 1000 10
28、 1.7 EALPMolded, anisotropic-HP 1.15 300 2 1.7 MAHPMolded, anisotropic-LP 1.15 1000 10 1.7 MALPAThese classes may be further modified by the grain size as defined in Terminology C 709.BDetermined in accordance with Practice C 781.CDetermined in accordance with Test Method C 559.DDetermined in accord
29、ance with Practice C 1233.D7301082with Practice C 781 shall have a Specific Electrical Resistivity(SER) corresponding to a graphitization temperature of at least2700C.5. Chemical Properties5.1 Each graphite production lot shall be sampled in accor-dance with Section 10. The chemical impurities to be
30、 measuredshall be agreed upon between the supplier and the purchaser.The minimum list of elements to be measured and used for theEBC calculation shall be B, Cd, Dy, Eu, Gd, and Sm.5.2 The boron equivalent shall be calculated in accordancewith Practice C 1233. The acceptance limits for the boronequiv
31、alent as well as for ash content are given in Table 2.5.3 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,metall
32、ic corrosion relevant impurities, and fissile/fissionableelements.6. Physical and Mechanical Properties6.1 Each graphite production lot shall be sampled in accor-dance with Section 10 and shall conform to the requirementsfor physical properties prescribed in Table 2 and Table 4 for theappropriate nu
33、clear graphite class, and to the additional re-quirements of the purchaser.6.2 The bulk density of each graphite billet shall be mea-sured as described in Test Method C 838.7. Other Requirements7.1 The graphitized billets shall be handled and stored suchthat they are protected from contaminants othe
34、r than ambientair.7.2 Each graphite billet shall be marked with a unique billetidentification number. Each billet shall be traceable throughthese identifying numbers to each of the following:7.2.1 Mix formulation,7.2.2 Coke batch,7.2.3 Recycle graphite batch,7.2.4 Forming lot,7.2.5 Molding powder lo
35、t,7.2.6 Baking charge,7.2.7 Impregnant charge,7.2.8 Graphitization furnace run,7.2.9 Position of billet in graphitization furnace,7.2.10 Purification step (if performed),7.2.11 Binder pitch,7.2.12 Impregnant pitch, and7.2.13 Additives used (if any).8. Dimensions8.1 Graphite billet dimensions are typ
36、ically 0.4 to 0.6 m indiameter (extruded) or thickness (molded/extruded) of 0.6 by0.6 m cross-section (iso-molded) and 0.75 to 3.0 m in length.9. Workmanship, Finish and Appearance9.1 Graphitized billets shall be brushed clean after removalfrom the graphitization furnace.10. Sampling and Cutting10.1
37、 A statistical sampling plan shall be developed by thesupplier and agreed upon with the purchaser. The plan shalldescribe the number of graphite billets to be sampled and thefrequency of sampling. The following minimum samplingfrequencies are recommended per production lot depending onthe number of
38、billets per production lot.10.1.1 Sample 4 billets for each production lot containing10 or fewer billets.10.1.2 Sample one additional billet for every 5 additionalbillets per production lot up to 50 billets.TABLE 3 Inspection Sampling and Testing of Filler CokesInspection Plan Sampling Procedure Tes
39、ts and Test MethodsA representative sample of the cokeshall be taken prior to the mixing stepof manufactureSample in accordance with Practice D 346 The procedure in Practice C 781 shall be usedto prepare test specimens for the measurement of coke CTE1. A sufficient sample for preparation of CTE test
40、 specimens2. A sufficient sample will be taken for additional testing.This sample shall be retained for a period specified bythe graphite purchaserMeasure the coke real density in accordance withTest Method D 2638TABLE 4 Physical and Mechanical Properties for Nuclear GraphiteStrength,AWG, MPa, minCl
41、assBCoefficient of Thermal Expansion Thermal Conductivity at 25C Tensile Flexural Compressive Dynamic Elastic Modulus, WGPracticeCC 781 C 781 C 781 C 781 C 781 C 781IAHP Less than 5.5 3 10-680 20 30 55 8IALP Less than 5.5 3 10-680 20 30 55 8EAHP Less than 5.5 3 10-6100 13 20 43 8EALP Less than 5.5 3
42、 10-6100 13 20 43 8MAHP Less than 5.5 3 10-690 8 11 24 4MALP Less than 5.5 3 10-690 8 11 24 4AAt least one of the three strength measurements should be selected for production lot acceptance in agreement with the supplier and the purchaser.BWG = With Grain; AG = Against Grain.CEquivalent practices m
43、ay be used by manufacturers based outside the United States.D730108310.1.3 For production lots exceeding 50 billets the addi-tional sampling requirements should be agreed upon by thesupplier and the purchaser.10.1.4 During production the sampling plan may be re-evaluated based on statistical analysi
44、s of the production data.Any revised sampling plan must be agreed upon between thesupplier and the purchaser.10.2 A cutting plan shall be agreed upon by the purchaserand manufacturer. The cutting plan shall describe the type,location, number, orientation of the test specimens, and anyrequired archiv
45、e specimens needed for property determinationsas set forth in Sections 5-7 of this specification. The cuttingplan shall reflect property gradients and anisotropy introducedby forming and processing. In addition the number of each typeof specimen defined by the cutting plan shall be sufficient toyiel
46、d statistically significant data.11. Finished Inspection11.1 Graphite billets shall be visually inspected for externalflaws. The allowable size, type, and number of flaws shall bedefined in the agreement between the purchaser and themanufacturer and be described in the purchase specification.11.2 It
47、 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 the agreement between the purchaser and the manufacturerand be described in the purchase specification.12. Rejection and
48、Rework12.1 Graphite billets failing on chemical purity (see Section5) may be purified/re-purified and subjected to retest.12.2 Graphite billets failing on SER (4.6.3) may be re-graphitized and subjected to retest.12.3 All other billets failing to meet the requirement ofSections 5-7 of this specifica
49、tion may be used as recyclegraphite in accordance with 4.2.1.4.13. Certification13.1 The manufacturer shall certify that the graphite meetsthe requirements of this specification and the purchase speci-fication.14. Product Marking14.1 Each billet shall be marked with a permanent uniquenumber, which shall be traceable to the production history asspecified in 7.2.15. Packaging and Storage15.1 Packaging of the finished billet shall be in accordancewith the purchase specification.15.2 Storage of the finished billets prior to shipping shall besuch that no
