1、Designation: D7301 11An American National StandardStandard Specification forNuclear Graphite Suitable for Components Subjected toLow Neutron Irradiation Dose1This standard is issued under the fixed designation D7301; the number immediately following the designation indicates the year oforiginal adop
2、tion 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 properties
3、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 i
4、nduced 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 gr
5、aphitesmeeting the requirements of Specification D7219 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:2C559
6、Test Method for Bulk Density by Physical Measure-ments of Manufactured Carbon 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 Metho
7、d for Bulk Density of As-ManufacturedCarbon and Graphite ShapesC1233 Practice 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 Pycnome
8、terD7219 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 Definiti
9、onsDefinitions relating to this specification aregiven in Terminology C709. See Table 1.3.2 Definitions of Terms Specific to This Standard:3.2.1 anistropic nuclear graphite, ngraphite in which theisotropy ratio based on the coefficient of thermal expansion isgreater than 1.15.3.2.2 baking/re-baking
10、charge, nnumber of billets in abaking/re-baking furnace run.3.2.3 bulk density, nmass of a unit volume of materialincluding both permeable and impermeable voids.3.2.4 extrusion forming lot, nnumber of billets of thesame size extruded in an uninterrupted sequence.3.2.5 green batch, nmass of coke, rec
11、ycle green mix,recycle graphite, and pitch that is required to produce aforming lot.3.2.6 green mix, npercentage of mix formulation, pitchand additives required for the forming lot, which is processedand ready to be formed.3.2.7 graphite billet, nextruded, molded, or iso-moldedgraphite artifact with
12、 dimensions sufficient to meet the design-ers requirements for reactor components.3.2.8 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.1This specification is under the jur
13、isdiction 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 Oct. 1, 2011. Published November 2011. Originallyapproved in 2008. Last previous edition approved in 2008 a
14、s D730108. DOI:10.1520/D7301-11.2For 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 Soci
15、ety of 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.3.2.9 graphitizing furnace run, ntotal number of billets
16、graphitized together in one graphitization furnace.3.2.10 graphitization charge, ntotal number of billetsgraphitized together in one graphitization furnace.3.2.11 high purity nuclear graphite, nnuclear graphitewith an Equivalent Boron Content less than 2 ppm.3.2.12 impregnation charge, nnumber of bi
17、llets in anautoclave cycle.3.2.13 low purity nuclear graphite, nnuclear graphitewith an Equivalent Boron Content greater than 2 ppm but lessthan 10 ppm.3.2.14 mix formulation, npercentages of each specificallysized filler used to manufacture a graphite grade.3.2.15 molding forming lot, nnumber of bi
18、llets moldedfrom a molding powder lot.3.2.16 molding powder lot, nsufficient quantity of re-milled and blended green batch produced from an uninter-rupted flow of raw materials, or produced in a sequence ofidentical materials batches, to produce a molding forming lot.3.2.17 nuclear graphite class, n
19、designation of a nucleargraphite based upon its forming method, isotropy, purity anddensity (see Table 2).3.2.18 production lot, nspecified number of billets madein accordance with this specification and additional require-ments determined by the purchaser.3.2.19 purification charge, nnumber of bill
20、ets in a puri-fication run.3.2.20 recycle green mix, nground non-baked billets ornon-used green mix manufactured in compliance with the mixformulation 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 o
21、f 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 accordance with PracticeC781 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-s
22、cribed in Table 3.4.2.1.4 Graphite manufactured in compliance with thisspecification but failing to meet the property requirements ofSections 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 b
23、e 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 shall 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
24、the forming lot.4.4 ImpregnantThe impregnant shall consist of a petro-leum or coal tar pitch of the same grade from the samemanufacturer. The specific impregnant(s) used shall be identi-fied to the purchaser and be traceable through the impregnationsteps.4.5 Manufacturing or Processing AdditivesAddi
25、tives (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 betraceable through the forming lot.4.6 Manufacture:4.6.1 FormulationThe mix formulation (as defined in3.2.14) and r
26、ecycle green mix fraction (as defined in 3.2.20)inthe filler shall be recorded. This information shall be reportedto the purchaser if requested.4.6.2 FormingThe green mix may be formed by extru-sion, molding (including vibrationally molding), or iso-molding.4.6.3 Graphitization TemperatureThe graphi
27、tization tem-perature shall be determined on each billet using the proceduredescribed in Practice C781. Each billet tested in accordanceTABLE 1 ASTM Graphite Grain Size Definitions fromTerminology C709GraphiteDesignationDefinition of Grains inthe Starting Mix that are:AMedium Grained Generally1.15 3
28、00 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 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 defi
29、ned in Terminology C709.BDetermined in accordance with Practice C781.CDetermined in accordance with Test Method C559.DDetermined in accordance with Practice C1233.D7301 112with Practice C781 shall have a Specific Electrical Resistivity(SER) corresponding to a graphitization temperature of at least27
30、00C.5. Chemical Properties5.1 Each graphite production lot shall be sampled in accor-dance with Section 10. The chemical impurities to be 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
31、, Eu, Gd, and Sm.5.2 The boron equivalent shall be calculated in accordancewith Practice C1233. The acceptance limits for the boronequivalent 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 requirem
32、ents. Theimpurities are categorized as neutron absorbing impurities,oxidation promoting catalysts, activation relevant impurities,metallic corrosion relevant impurities, and fissile/fissionableelements.6. Physical and Mechanical Properties6.1 Each graphite production lot shall be sampled in accor-da
33、nce with Section 10 and shall conform to the requirementsfor physical properties prescribed in Table 2 and Table 4 for theappropriate nuclear 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 Meth
34、od C838.7. Other Requirements7.1 The graphitized billets shall be handled and stored suchthat they are protected from contaminants other than ambientair.7.2 Each graphite billet shall be marked with a unique billetidentification number. Each billet shall be traceable throughthese identifying numbers
35、 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 lot,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 perfor
36、med),7.2.11 Binder pitch,7.2.12 Impregnant pitch, and7.2.13 Additives used (if any).8. Dimensions8.1 Graphite billet dimensions are typically 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
37、 and Appearance9.1 Graphitized billets shall be brushed clean after removalfrom the graphitization furnace.10. Sampling and Cutting10.1 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 sample
38、d and thefrequency of sampling. The following minimum samplingfrequencies are recommended per production lot depending onthe number of billets per production lot.TABLE 3 Inspection Sampling and Testing of Filler CokesInspection Plan Sampling Procedure Tests and Test MethodsA representative sample of
39、 the cokeshall be taken prior to the mixing stepof manufactureSample in accordance with Practice D346 The procedure in Practice C781 shall be usedto prepare test specimens for the measurement of coke CTE1. A sufficient sample for preparation of CTE test specimens2. A sufficient sample will be taken
40、for additional testing.This sample shall be retained for a period specified bythe graphite purchaserMeasure the coke real density in accordance withTest Method D2638TABLE 4 Physical and Mechanical Properties for Nuclear GraphiteStrength,AWG, MPa, minClassBCoefficient of Thermal Expansion(25 to 500C)
41、, WG, C-1Thermal Conductivity at 25C, AGWm-1K-1(min)Tensile Flexural Compressive Dynamic Elastic Modulus, WGGPa (min)PracticeCC781 C781 C781 C781 C781 C781IAHP 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 10-6100 1
42、3 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 may be used
43、 by manufacturers based outside the United States.D7301 11310.1.1 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.10.1.3 For production lots exceeding 50 billets the addi-tion
44、al 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 analysis of the production data.Any revised sampling plan must be agreed upon between thesupplier and the purchaser.10.2 A cutting plan
45、shall be agreed upon by the purchaserand manufacturer. 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 5-7 of this specification. The cuttingplan shall reflect p
46、roperty gradients and anisotropy introducedby forming and processing. In addition the number of each typeof specimen defined by the cutting plan shall be sufficient toyield statistically significant data.11. Finished Inspection11.1 Graphite billets shall be visually inspected for externalflaws. The
47、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 is recommended that all graphite billets are non-destructively tested to screen for internal defects. The allow-able size, type,
48、 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 Rework12.1 Graphite billets failing on chemical purity (see Section5) may be purified/re-purified and subjected to retest.12.2 Gr
49、aphite 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 specification 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
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