1、Designation: C 781 08An 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 C 781; the number immediately following the designation indicates th
2、e 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. Scope*1.1 This practice covers the test methods for measuri
3、ng 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 asdefined in Secti
4、on 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 test methods tha
5、t 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, respectively. T
6、he 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 theresponsibility o
7、f 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:2C 559 Test Method for Bulk Density by Physical Measure-ments of Manufactured Carbon and Graphite Articl
8、esC 561 Test Method for Ash in a Graphite SampleC 577 Test Method for Permeability of RefractoriesC611 Test Method for Electrical Resistivity of Manufac-tured Carbon and Graphite Articles at Room TemperatureC 625 Practice for Reporting Irradiation Results on Graph-iteC 651 Test Method for Flexural S
9、trength of ManufacturedCarbon and Graphite Articles Using Four-Point Loading atRoom TemperatureC 695 Test Method for Compressive Strength of Carbonand GraphiteC 709 Terminology Relating to Manufactured Carbon andGraphiteC 747 Test Method for Moduli of Elasticity and Fundamen-tal Frequencies of Carbo
10、n and Graphite Materials by SonicResonanceC 749 Test Method for Tensile Stress-Strain of Carbon andGraphiteC 769 Test Method for Sonic Velocity in ManufacturedCarbon and Graphite Materials for Use in Obtaining anApproximate Youngs ModulusC 816 Test Method for Sulfur in Graphite by Combustion-Iodomet
11、ric Titration MethodC 838 Test Method for Bulk Density of As-ManufacturedCarbon and Graphite ShapesC 1039 Test Methods for Apparent Porosity, Apparent Spe-cific Gravity, and Bulk Density of Graphite ElectrodesC 1179 Test Method for Oxidation Mass Loss of Manufac-tured Carbon and Graphite Materials i
12、n AirC 1233 Practice for Determining Equivalent Boron Con-tents of Nuclear MaterialsC 1274 Test Method for Advanced Ceramic Specific Sur-face Area by Physical AdsorptionD 346 Practice for Collection and Preparation of CokeSamples for Laboratory AnalysisD 1193 Specification for Reagent WaterD 2854 Te
13、st Method for Apparent Density of ActivatedCarbonD 2862 Test Method for Particle Size Distribution ofGranular Activated CarbonD 3104 Test Method for Softening Point of Pitches (MettlerSoftening Point Method)D 4292 Test Method for Determination of Vibrated Bulk1This practice is under the jurisdiction
14、 of ASTM Committee D02 on PetroleumProducts and Lubricants and is the direct responsibility of Subcommittee D02.F0 onManufactured Carbon and Graphite Products.Current edition approved Sept. 1, 2008. Published October 2008. Originallyapproved in 1977. Last previous edition approved in 2002 as C 78102
15、.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.1*A Summary of Changes section appears at the end of this st
16、andard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.Density of Calcined Petroleum CokeD 5600 Test Method for Trace Metals in Petroleum Coke byInductively Coupled Plasma Atomic Emission Spectrom-etry (ICP-AES)D 7219 Specification fo
17、r Isotropic and Near-isotropicNuclear GraphitesE11 Specification for Wire Cloth and Sieves for TestingPurposesE 132 Test Method for Poissons Ratio at Room Tempera-tureE 228 Test Method for Linear Thermal Expansion of SolidMaterials With a Push-Rod DilatometerE 261 Practice for Determining Neutron Fl
18、uence, FluenceRate, and Spectra by Radioactivation TechniquesE 639 Test Method for Measuring Total-Radiance Tempera-ture of Heated Surfaces Using a Radiation PyrometerE 1461 Test Method for Thermal Diffusivity by the FlashMethod3. Terminology3.1 DefinitionsTerminology C 709 shall be considered asapp
19、lying to the terms used in this practice.4. Significance 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 tempe
20、rature gas-cooled reactors.4.2 The test methods are applicable primarily to specimensin the non-irradiated and non-oxidized state. Many are alsoapplicable to specimens in the irradiated or oxidized state, orboth, provided the specimens meet all requirements of the testmethod. The user is cautioned t
21、o consider 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.TABLE 1 Summary of Test Methods for Graphite ComponentsNOTEDesignations under preparation will be added when approved.Fuel,
22、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 C 838 C 838 C 838Mechanical PropertiesCompressive Strength C 695 C 695 C 695Tensile P
23、roperties C 749AC 749AC 749APoissons Ratio E 132BE 132BE 132BFlexural Strength C 651AC 651AC 651AFracture ToughnessBBModulus of Elasticity C 747 C 747 C 747Physical PropertiesBulk DensityMachined Specimens C 559 C 559 C 559Surface Area (BET) C 1274 C 1274 C 1274Permeability C 577A,BC 577A,BC 577A,BA
24、pparent Porosity C 1039 C 1039 C 1039Spectroscopic AnalysisBBElectrical Resistivity C611 C611 C611Thermal PropertiesLinear Thermal Expansion E 228AThermal Conductivity E 1461AE 1461AE 1461AChemical PropertiesOxidative Mass Loss C 1179BC 1179BC 1179BSulfur Concentration C 816 C 816 C 816Ash Content C
25、 561AC 561AC 561AEquivalent Boron Content C 1233AC 1233ACAModification 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 Methods for Boronated Graphit
26、eComponentsNOTEDesignations under preparation will be added when approved.CompactsNeutronShieldMaterialControlRodBurnablePoisonReserveShutdownBulk Density C 838 C 838 C 838 D 4292Linear Thermal ExpansionAE 228AE 228ABParticle SizeCC CD 2862Mechanical Strength:Compressive Strength C 695AC 695AC 695AB
27、Impact PerformanceBB B CChemical Properties:Sulfur ConcentrationCC C CHafnium ConcentrationRelative Oxidation RateCC C CBoron Analysis:Total BoronCC C CBoron as OxideB4C Particle Size D 2862DD 2862DD 2862DD 2862DAModification of this test method is required. See Section 10 for details.BThere is no i
28、dentified 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.C7810825. Sample Selection5.1 All test specimens should be selected from materialsthat are representative of those to be used in t
29、he intendedapplication.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 bille
30、t) shall be provided.6.2 Information on specimen irradiation conditions shall bereported in accordance with Practices C 625 and E 261 orreferenced to source information of equivalent content.GRAPHITE COMPONENTS7. Description and Function7.1 Fuel and Removable Reflector Elements:7.1.1 A fuel element
31、is a removable 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 reacti
32、vity control material (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
33、them,and for the 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
34、 andcontainment 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
35、contain channels 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 reactorco
36、re (fuel elements) 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 Perma
37、nent Side Reflector 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 contai
38、n channels for neutron fluxcontrol materials (boronated steel pins) and nuclear instrumen-tation, and recessed areas along its length on its outer peripheryto provide channels for the passage of coolant gas between theelement and the metallic lateral restraint for the reactor core.7.2.2 The permanen
39、t side reflector 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 su
40、pport for the fuel, 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 (boronateds
41、teel pins) for reducing 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,
42、if necessary. A core 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 wit
43、h respect to the 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 co
44、olant gas, neutronflux 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 latera
45、l mechanicalsupport 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 ab
46、ove them. Inaddition, 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 instru
47、mentation.7.4 Pebble Bed Modular Reactor Reflector Blocks:7.4.1 The fuel form of a pebble bed reactor is typically a 60mm diameter sphere (pebble) containing graphite-carbon ma-trix and coated particle fuel.7.4.2 The Pebble Bed reactor core structure consists of agraphite reflector supported and sur
48、rounded 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
49、inner replaceable reflector and an outerpermanent reflector. The graphite reflector blocks are inter-linked within each circular ring by graphite keys set inC781083machined 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.
