1、Designation: C781 08 (Reapproved 2014) An American National StandardStandard Practice forTesting Graphite and Boronated Graphite Materials for High-Temperature Gas-Cooled Nuclear Reactor Components1This standard is issued under the fixed designation C781; the number immediately following the designa
2、tion indicates the year 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 practice covers the test met
3、hods for measuring theproperties of graphite and boronated graphite materials. Theseproperties may be used for the design and evaluation ofhigh-temperature gas-cooled reactor components.1.2 The test methods referenced herein are applicable tomaterials used for replaceable and permanent components as
4、defined in Section 7 and Section 9, and includes fuel elements;removable reflector elements and blocks; permanent sidereflector elements and blocks; core support pedestals andelements; control rod, reserve shutdown, and burnable poisoncompacts; and neutron shield material.1.3 This practice includes
5、test methods that have beenselected from existing ASTM standards, ASTM standards thathave been modified, and new ASTM standards that are specificto the testing of materials listed in 1.2. Comments on individualtest methods for graphite and boronated graphite componentsare given in Sections 8 and 10,
6、 respectively. The test methodsare summarized in Tables 1 and 2.1.4 The values stated in SI units are to be regarded asstandard. The values given in parentheses are for informationonly.1.5 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is the
7、responsibility 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
8、Graphite ArticlesC561 Test Method for Ash in a Graphite SampleC577 Test Method for Permeability of RefractoriesC611 Test Method for Electrical Resistivity of ManufacturedCarbon and Graphite Articles at Room TemperatureC625 Practice for Reporting Irradiation Results on GraphiteC651 Test Method for Fl
9、exural Strength of ManufacturedCarbon and GraphiteArticles Using Four-Point Loading atRoom TemperatureC695 Test Method for Compressive Strength of Carbon andGraphiteC709 Terminology Relating to Manufactured Carbon andGraphiteC747 Test Method for Moduli of Elasticity and FundamentalFrequencies of Car
10、bon and Graphite Materials by SonicResonanceC749 Test Method for Tensile Stress-Strain of Carbon andGraphiteC769 Test Method for Sonic Velocity in ManufacturedCarbon and Graphite Materials for Use in ObtainingYoungs ModulusC816 Test Method for Sulfur in Graphite by Combustion-Iodometric Titration Me
11、thodC838 Test Method for Bulk Density of As-ManufacturedCarbon and Graphite ShapesC1039 Test Methods for Apparent Porosity, Apparent Spe-cific Gravity, and Bulk Density of Graphite ElectrodesC1179 Test Method for Oxidation Mass Loss of Manufac-tured Carbon and Graphite Materials in AirC1233 Practice
12、 for Determining Equivalent Boron Contentsof Nuclear MaterialsC1274 Test Method for Advanced Ceramic Specific SurfaceArea by Physical AdsorptionD346 Practice for Collection and Preparation of CokeSamples for Laboratory AnalysisD1193 Specification for Reagent WaterD2854 Test Method for Apparent Densi
13、ty of ActivatedCarbonD2862 Test Method for Particle Size Distribution of Granu-lar Activated CarbonD3104 Test Method for Softening Point of Pitches (MettlerSoftening Point Method)1This practice is under the jurisdiction of ASTM Committee D02 on PetroleumProducts, Liquid Fuels, and Lubricants and is
14、the direct responsibility of Subcom-mittee D02.F0 on Manufactured Carbon and Graphite Products.Current edition approved May 1, 2014. Published July 2014. Originally approvedin 1977. Last previous edition approved in 2008 as C781 08. DOI: 10.1520/C0781-08R14.2For referenced ASTM standards, visit the
15、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.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. Uni
16、ted States1D4292 Test Method for Determination of Vibrated BulkDensity of Calcined Petroleum CokeD5600 Test Method for Trace Metals in Petroleum Coke byInductively Coupled Plasma Atomic Emission Spectrom-etry (ICP-AES)D7219 Specification for Isotropic and Near-isotropicNuclear GraphitesE11 Specifica
17、tion for Woven Wire Test Sieve Cloth and TestSievesE132 Test Method for Poissons Ratio at Room TemperatureE228 Test Method for Linear Thermal Expansion of SolidMaterials With a Push-Rod DilatometerE261 Practice for Determining Neutron Fluence, FluenceRate, and Spectra by Radioactivation TechniquesE6
18、39 Test Method for Measuring Total-Radiance Tempera-ture of Heated Surfaces Using a Radiation Pyrometer(Withdrawn 2011)3E1461 Test Method for Thermal Diffusivity by the FlashMethod3. Terminology3.1 DefinitionsTerminology C709 shall be considered asapplying to the terms used in this practice.4. Signi
19、ficance and Use4.1 Property data obtained with the recommended testmethods identified herein may be used for research anddevelopment, design, manufacturing control, specifications,performance evaluation, and regulatory statutes pertaining tohigh temperature gas-cooled reactors.4.2 The test methods a
20、re applicable primarily to specimensin the non-irradiated and non-oxidized state. Many are alsoapplicable to specimens in the irradiated or oxidized state, or3The last approved version of this historical standard is referenced onwww.astm.org.TABLE 1 Summary of Test Methods for Graphite ComponentsNOT
21、E 1Designations under preparation will be added when approved.Fuel, Removable Reflector,and Core Support Elements;Pebble Bed Reflector,Key and Sleeves;and Dowel PinsPermanent SideReflector Elementsand Dowel PinsCore Support Pedestalsand DowelsFabricationAs Manufactured Bulk Density C838 C838 C838Mec
22、hanical PropertiesCompressive Strength C695 C695 C695Tensile Properties C749AC749AC749APoissons Ratio E132BE132BE132BFlexural Strength C651AC651AC651AFracture ToughnessBBModulus of Elasticity C747 C747 C747Physical PropertiesBulk DensityMachined Specimens C559 C559 C559Surface Area (BET) C1274 C1274
23、 C1274Permeability C577A,BC577A,BC577A,BApparent Porosity C1039 C1039 C1039Spectroscopic AnalysisBBElectrical Resistivity C611 C611 C611Thermal PropertiesLinear Thermal Expansion E228AThermal Conductivity E1461AE1461AE1461AChemical PropertiesOxidative Mass Loss C1179BC1179BC1179BSulfur Concentration
24、 C816 C816 C816Ash Content C561AC561AC561AEquivalent Boron Content C1233AC1233ACAModification of this test method is required. See Section 8 for details.BNew test methods are required. See Section 8 for details.CThere is no identified need for determining this property.TABLE 2 Summary of Test Method
25、s for Boronated GraphiteComponentsNOTE 1Designations under preparation will be added when approved.CompactsNeutronShieldMaterialControlRodBurnablePoisonReserveShutdownBulk Density C838 C838 C838 D4292Linear Thermal ExpansionAE228AE228ABParticle SizeCC CD2862Mechanical Strength:Compressive Strength C
26、695AC695AC695ABImpact PerformanceBB B CChemical Properties:Sulfur ConcentrationCC C CHafnium ConcentrationRelative Oxidation RateCC C CBoron Analysis:Total BoronCC C CBoron as OxideB4C Particle Size D2862DD2862DD2862DD2862DAModification of this test method is required. See Section 10 for details.BTh
27、ere is no identified need for determining this property.CNew test methods are required. See Section 10 for details.DAdditional test methods are required. See Section 10 for details.C781 08 (2014)2both, provided the specimens meet all requirements of the testmethod. The user is cautioned to consider
28、the instructionsgiven in the test methods.4.3 Additional test methods are in preparation and will beincorporated. The user is cautioned to employ the latestrevision.5. Sample Selection5.1 All test specimens should be selected from materialsthat are representative of those to be used in the intendeda
29、pplication.6. Test Reports6.1 Test results should be reported in accordance with thereporting requirements included in the applicable test method.Where relevant, information on grade designation, lot number,billet number, orientation, and location (position of sample inthe original billet) shall be
30、provided.6.2 Information on specimen irradiation conditions shall bereported in accordance with Practices C625 and E261 orreferenced to source information of equivalent content.GRAPHITE COMPONENTS7. Description and Function7.1 Fuel and Removable Reflector Elements:7.1.1 A fuel element is a removable
31、 graphite element thatcontains channels for the passage of coolant gas, the fuelmaterial (typically in the form of a compact containing coatedparticle fuel), the alignment dowel pins, and the insertion of ahandling machine pickup head. A fuel element may alsocontain channels for reactivity control m
32、aterial (control rods),reserve shutdown compacts, and burnable poison compacts,and nuclear instrumentation.7.1.2 The fuel elements serve multiple functions, including(1) vertical and lateral mechanical support for the fuel elementsand removable reflector elements above and adjacent to them,and for t
33、he fuel, reactivity control materials, and nuclearinstrumentation within them, (2) moderation of fast neutronswithin the core region, (3) a thermal reservoir and conductorfor nuclear heat generated in the fuel, (4) a physical constraintfor the flow of coolant gases, and (5) a guide for andcontainmen
34、t of fuel material, reactivity control materials, andnuclear instrumentation.7.1.3 A removable reflector element is a removable graphiteelement that contains channels for the alignment dowel pinsand the insertion of a handling machine pickup head. Aremovable reflector element may also contain channe
35、ls for thepassage of coolant gas, reactivity control materials (controlrods), neutron flux control materials (neutron shield materials),and nuclear instrumentation.7.1.4 The primary function of the removable reflector ele-ments that are located at the boundaries of the active reactorcore (fuel eleme
36、nts) is to provide for moderation of fastneutrons escaping from and reflection of thermal neutrons backinto the active core region.7.1.5 Except for support, guide, and containment of fuelmaterial, removable reflector elements may also serve any ofthe functions listed in 7.1.2.7.2 Permanent Side Refl
37、ector Element:7.2.1 A permanent side reflector element is a graphite blockthat is designed to remain permanently in the core but may beremoved for inspection and replacement, if necessary. Apermanent side reflector element contains channels for align-ment dowel pins. It may also contain channels for
38、 neutron fluxcontrol materials (boronated steel pins) and nuclearinstrumentation, and recessed areas along its length on its outerperiphery to provide channels for the passage of coolant gasbetween the element and the metallic lateral restraint for thereactor core.7.2.2 The permanent side reflector
39、elements encircle theactive (fuel) elements and passive (removable reflector) ele-ments of the reactor core and serve multiple functions, includ-ing (1) vertical and lateral mechanical support for the perma-nent side reflector elements above and beside them, (2) lateralmechanical support for the fue
40、l, removable reflector, and coresupport elements, (3) moderation of fast neutrons within thereflector region, (4) reflection of thermal neutrons back into thecore region, and (5) support, guide, and containment of nuclearinstrumentation and neutron flux control materials (boronatedsteel pins) for re
41、ducing the neutron flux to metallic structuresoutside the permanent side reflector boundary.7.3 Core Support Pedestals and Elements:7.3.1 A core support pedestal is a graphite column that isdesigned to remain permanently in the core but can be removedfor inspection and replacement, if necessary. A c
42、ore supportpedestal has a central reduced cross-section (dog bone shape)that at its upper end contains channels for the passage ofcoolant gas, alignment dowel pins, and the insertion of ahandling machine pickup head, and at its lower end contains arecessed region for locating it with respect to the
43、metallicstructure that supports the graphite core support assembly. Acore support element is a graphite element that containschannels for alignment dowel pins and the insertion of ahandling machine pickup head. The core support elements mayalso contain channels for the passage of coolant gas, neutro
44、nflux control materials, and nuclear instrumentation.7.3.2 The primary function of the core support pedestals isto provide for vertical mechanical support for core supportelements and permanent side reflector elements above them. Inaddition, core support pedestals provide for lateral mechanicalsuppo
45、rt for adjacent core support pedestals and permanent sidereflector elements and physical constraint for the flow ofcoolant gases. The primary function of the core supportelements is to provide for vertical mechanical support for coresupport, fuel, and removable reflector elements above them. Inaddit
46、ion, core support elements provide for lateral mechanicalsupport for adjacent core support and permanent side reflectorelements and may provide for the physical constraint of coolantgases and for the support, guide, and containment of neutronflux control materials and nuclear instrumentation.7.4 Peb
47、ble Bed Modular Reactor Reflector Blocks:C781 08 (2014)37.4.1 The fuel form of a pebble bed reactor is typically a60 mm diameter sphere (pebble) containing graphite-carbonmatrix and coated particle fuel.7.4.2 The Pebble Bed reactor core structure consists of agraphite reflector supported and surroun
48、ded by a metallic corebarrel. The graphite reflector is comprised of a large number ofgraphite blocks arranged in circular rings of separate columns.The graphite reflector can be subdivided into three subsystems,namely, the bottom, side, and top reflector. The side reflectormay be split into an inne
49、r replaceable reflector and an outerpermanent reflector. The graphite reflector blocks are inter-linked within each circular ring by graphite keys set inmachined channels in the reflector blocks. Certain Pebble Bedreactors designs have annular fuelled cores, and thus thereactor contains a central graphite column.7.4.3 The primary function of the reflector blocks that arelocated at the boundary of the active reactor core (fuelledregion) is to provide for moderation of fast neutrons escapingfrom, and reflection of thermal neutrons back into, the activecore region.7.4.4 Replac
