1、Designation: D7301 11 (Reapproved 2015) An 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 y
2、ear oforiginal adoption 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, process
3、ing,and properties 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 neu
4、tron irradia-tion 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 irradiati
5、on dose. Nuclear graphitesmeeting 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 AS
6、TM Standards:2C559 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 Compon
7、entsC838 Test Method 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 PetroleumCok
8、e by Helium PycnometerD7219 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. Term
9、inology3.1 DefinitionsDefinitions 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.
10、2 baking/re-baking 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,
11、 nmass of coke, recycle 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-moldedgra
12、phite artifact with dimensions sufficient to meet the design-ers requirements for reactor components.1This specification is under the jurisdiction of ASTM Committee D02 onPetroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility ofSubcommittee D02.F0 on Manufactured Carbon an
13、d Graphite Products.Current edition approved June 1, 2015. Published July 2015. Originally approvedin 2008. Last previous edition approved in 2011 as D7301 11. DOI: 10.1520/D7301-11R15.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceast
14、m.org. For Annual 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, http:/www.asme.org.Copyright ASTM Int
15、ernational, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.2.8 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.3.2.9 graphitizing fur
16、nace run, ntotal number of billetsgraphitized 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
17、impregnation charge, nnumber of billets in anautoclave cycle.3.2.13 low purity nuclear graphite, nnuclear graphite withan Equivalent Boron Content greater than 2 ppm but less than10 ppm.3.2.14 mix formulation, npercentages of each specificallysized filler used to manufacture a graphite grade.3.2.15
18、molding forming lot, nnumber of billets 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 lo
19、t.3.2.17 nuclear graphite class, ndesignation 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 pu
20、rification charge, nnumber of billets in a purifi-cation 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:
21、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 accordance with PracticeC781 and measured over the temperature range 25 C to500 C, less than 5.5 10-6C-1.4.2.1.3 The coke shall
22、 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 ofSections 57may be used as recycle material in the mixformulation.4.2.1.5 Recycle green mix manufactured from raw materialsin complia
23、nce 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 shall consist of coal tar pitch of thesame grade from the same manufacturer. The specific binder(s)used shall be identified to the p
24、urchaser 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. The specific impregnant(s) used shall be identi-fied to the purchaser and be traceable through the impregnationsteps.4.5 Manufact
25、uring or Processing AdditivesAdditives (forexample, extrusion aids) may be used to improve theprocessing, quality and properties of the product, but only withthe consent and approval of the purchaser, and they must betraceable through the forming lot.4.6 Manufacture:TABLE 1 ASTM Graphite Grain Size
26、Definitions from TerminologyC709GraphiteDesignationDefinition 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 1.7 EALPMolded, anisotropic
27、-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 C709.BDetermined in accordance with Practice C781.CDetermined in accordance with Test Method C559.DDetermined in accordance with Practice C1233.D7301
28、11 (2015)24.6.1 FormulationThe mix formulation (as defined in3.2.14) and recycle 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 byextrusion, molding (including vibration
29、ally molding), or iso-molding.4.6.3 Graphitization TemperatureThe graphitization tem-perature shall be determined on each billet using the proceduredescribed in Practice C781. Each billet tested in accordancewith Practice C781 shall have a Specific Electrical Resistivity(SER) corresponding to a grap
30、hitization 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 measuredshall be agreed upon between the supplier and the purchaser.The minimum list of elements to be measured and used for t
31、heEBC calculation shall be B, Cd, Dy, 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 me
32、asured 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.6. Physical and Mechanical Properties6.1 Each graphite product
33、ion 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 nuclear graphite class, and to the additional re-quirements of the purchaser.6.2 The bulk density of each graphite billet shall be
34、 mea-sured as described in Test Method 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 tracea
35、ble 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 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
36、,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 typically 0.4 m to 0.6 min diameter (extruded) or thickness (molded/extruded) of 0.6 mby 0.6 m cross-section (iso-molded) and 0.75 m
37、 to 3.0 m inlength.TABLE 3 Inspection Sampling and Testing of Filler CokesInspection Plan Sampling Procedure Tests and Test MethodsA representative sample of the cokeshall be taken prior to the mixing stepof manufactureSample in accordance with Practice D346 The procedure in Practice C781 shall be u
38、sedto prepare test specimens for the measurement of coke CTE1. A sufficient sample for preparation of CTE test 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
39、 withTest Method D2638TABLE 4 Physical and Mechanical Properties for Nuclear GraphiteStrength,AWG, MPa, minClassBCoefficient of Thermal Expansion(25 C to 500 C), WG, C-1Thermal Conductivity at 25 C, AGWm-1K-1(min)Tensile Flexural Compressive Dynamic Elastic Modulus, WGGPa (min)PracticeCC781 C781 C78
40、1 C781 C781 C781IAHP Less than 5.5 10-680 20 30 55 8IALP Less than 5.5 10-680 20 30 55 8EAHP Less than 5.5 10-6100 13 20 43 8EALP Less than 5.5 10-6100 13 20 43 8MAHP Less than 5.5 10-690 8 11 24 4MALP Less than 5.5 10-690 8 11 24 4AAt least one of the three strength measurements should be selected
41、for production lot acceptance in agreement with the supplier and the purchaser.BWG = With Grain; AG = Against Grain.CEquivalent practices may be used by manufacturers based outside the United States.D7301 11 (2015)39. Workmanship, Finish, and Appearance9.1 Graphitized billets shall be brushed clean
42、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 sampled and thefrequency of sampling. The following minimum sampling
43、frequencies are recommended per production lot depending onthe number of 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.10.1.3 For productio
44、n 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 analysis of the production data.Any revised sampling plan must be agreed upon between thesuppli
45、er 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 archive specimens needed for property determinationsas set forth in Sections 57of this specifi
46、cation. 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 toyield statistically significant data.11. Finished Inspection11.1 Graphite billets shall be vis
47、ually 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 is recommended that all graphite billets are non-destructively tested to screen for inter
48、nal 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 Rework12.1 Graphite billets failing on chemical purity (see Section5) may be purified/re-p
49、urified 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 57of 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 th
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