1、Designation:D721908(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 case o
2、f 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 graphite bil
3、lets 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 s
4、ignificant 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 theresponsibili
5、ty 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 Carbon and Graphite Arti
6、clesC709 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 Practice for Determining E
7、quivalent 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 System of Units(SI):T
8、he 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-baking chargenumber of bil
9、lets 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,recyclegraphite,a
10、nd 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 sufficient to meet the design-e
11、rs 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 a graphitizing fu
12、rnace 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 Committee D02 onPetroleum Produc
13、ts,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 08.DOI:10.1520/D7219-08R14.2For refere
14、nced 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 Mechanical Engineers(ASME),ASMEInternatio
15、nal 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 States1 3.2.11 impregnation chargenumber of billets in an auto-clave cycle.3.2.12 isotropic nuclear graphitegraphite in which theisotropy rati
16、o 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 filler 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
