1、Designation: C 781 02An American National StandardStandard Practice forTesting Graphite and Boronated Graphite Components forHigh-Temperature Gas-Cooled Nuclear Reactors1This standard is issued under the fixed designation C 781; the number immediately following the designation indicates the year ofo
2、riginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice covers the test methods for measuringthose pr
3、operties of graphite and boronated graphite materialsthat may be used for the design and evaluation of high-temperature gas-cooled reactors.1.2 The test methods referenced herein are applicable tomaterials used for replaceable and permanent components asdefined in Section 7 and include fuel elements
4、; removablereflector elements and blocks; permanent side reflector ele-ments and blocks; core support pedestals and elements; controlrod, reserve shutdown, and burnable poison compacts; andneutron shield material.1.3 This practice includes test methods that have beenselected from existing ASTM stand
5、ards, 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. The test methodsare summarized in Table 1 and
6、 Table 2.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility 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. Ref
7、erenced Documents2.1 ASTM Standards:C 559 Test Method for Bulk Density by Physical Measure-ments of Manufactured Carbon and Graphite Articles2C 560 Test Methods for Chemical Analysis of Graphite2C 561 Test Method for Ash in a Graphite Sample2C 577 Test Method for Permeability of Refractories3C 625 P
8、ractice for Reporting Irradiation Results on Graph-ite2C 626 Methods for Estimating the Thermal Neutron Ab-sorption Cross Section of Nuclear Graphite4C 651 Test Method for Flexural Strength of ManufacturedCarbon and Graphite Articles Using Four-Point Loading atRoom Temperature2C 695 Test Method for
9、Compressive Strength of Carbonand Graphite2C 709 Terminology Relating to Manufactured Carbon andGraphite2C 747 Test Method for Moduli of Elasticity and Fundamen-tal Frequencies of Carbon and Graphite Materials by SonicResonance2C 749 Test Method for Tensile Stress-Strain of Carbon andGraphite2C 816
10、Test Method for Sulfur in Graphite by Combustion-Iodometric Titration Method2C 838 Test Method for Bulk Density of As-ManufacturedCarbon and Graphite Shapes2C 1179 Test Method for Oxidative Mass Loss of Manufac-tured Carbon and Graphite Materials in Air2C 1251 Test Method for Determination of Specif
11、ic SurfaceAreas of Advanced Ceramic Materials by Gas Adsorption2D 2854 Test Method for Apparent Density of ActivatedCarbon2D 2862 Test Method for Particle Size Distribution ofGranular Activated Carbon2D 4292 Test Method for Vibrated Bulk Density of CalcinedPetroleum Coke5E 132 Test Method for Poisso
12、ns Ratio at Room Tempera-ture6E 228 Test Method for Linear Thermal Expansion of SolidMaterials with a Vitreous Silica Dilatometer7E 261 Practice for Determining Neutron Fluence Rate, Flu-ence, and Spectra by Radioactivation Techniques8E 1461 Test Method for Thermal Diffusivity of Solids bythe Flash
13、Method73. Terminology3.1 Definition:1This practice is under the jurisdiction 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 Dec. 10, 2002. Published April 2003. Ori
14、ginallyapproved in 1977. Last previous edition approved in 1996 as C 78196.2Annual Book of ASTM Standards, Vol 05.05.3Annual Book of ASTM Standards, Vol 15.01.4Discontinued; see 1985 Annual Book of ASTM Standards, Vol 15.01.5Annual Book of ASTM Standards, Vol 05.02.6Annual Book of ASTM Standards, Vo
15、l 03.01.7Annual Book of ASTM Standards, Vol 14.02.8Annual Book of ASTM Standards, Vol 12.02.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.1.1 Terminology C 709 shall be considered as applying tothe terms used in this practice.4.
16、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 temperature gas-cooled reactors.4.2 The test meth
17、ods are applicable primarily to specimensin the unirradiated and unoxidized 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 to consider the instructionsgiven in the test met
18、hods.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 intendedapplication.6. Test Reports6.1 Test re
19、sults should be reported in accordance with thereporting requirements included in the applicable test method.Where relevant, information on grade designation, lot number,TABLE 1 Summary of Test Methods for Graphite ComponentsNOTEDesignations under preparation will be added as editorial changes when
20、approved.Fuel, Removable Re-flector, and Core Sup-port Elements; PBMRReflector, Keys andSleeves; and DowelPinsPermanent Side Re-flector Elements andDowel PinsCore Support Pedes-tals and Dowel PinsBulk Density:As-Manufactured ShapesMachined SpecimensC 838C 559C 838C 559C 838C 559Thermal Properties:Li
21、near Thermal ExpansionThermal ConductivityE 228AE 1461AE 228AE 1461AE 228AE 1461AMechanical Properties:Compressive Strength C 695 C 695 C 695Tensile Properties C 749AC 749AC 749APoissons Ratio E 132AE 132AE 132AFlexural Strength C 651AC 651AC 651AFracture ToughnessBBBModulus of Elasticity C 747 C 74
22、7 C 747Oxidation Related Proper-ties:Relative Oxidation Rate C 1179BC 1179BC 1179BSurface Area C 1251 C 1251 C 1251Permeability C 577ABC 577ABC 577ABCatalytic Impurities C 560BC 560BC 560BSulfur Concentration C 816 C 816 C 816PorosityBBBNeutronic Impurities:Ash C 561AC 561AC 561ASpectroscopic Analys
23、isThermal Absorption Cross C 626AC 626ACSectionAModification 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 GraphiteComponent
24、sNOTEDesignations under preparation will be added as editorialchanges when approved.CompactsNeutron ShieldMaterialControlRodBurnablePoisonReserveShutdownBulk Density C 838 C 838 C 838 D 4292Linear Thermal ExpansionAE 228AE 228ABParticle SizeCCCD 2862Mechanical Strength:Compressive StrengthImpact Per
25、formanceC 695ABC 695ABC 695ABBCChemical Properties:Catalytic ImpuritiesCCC CSulfur ConcentrationHafnium ConcentrationCCC CRelative Oxidation RateBoron Analysis:Total BoronCCC CBoron as OxideB4C Particle Size D 2862DD 2862DD 2862DD 2862DAModification of this test method is required. See Section 10 fo
26、r details.BThere is no identified need for determining this property.CNew test methods are required. See Section 10 for details.DAdditional test methods are required. See Section10 for details.C781022billet number, orientation, and location (position of sample inthe original billet) shall be provide
27、d.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 is a removable grap
28、hite element thatcontains channels for the passage of coolant gas, the fuelmaterial, the alignment dowel pins, and the insertion of ahandling machine pickup head. A fuel element may alsocontain channels for reactivity control material (control rods),reserve shutdown compacts, and burnable poison com
29、pacts,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 the fuel, reactivity control materials, and nuclearinstrumentation within
30、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 andcontainment of fuel material, reactivity control materials, andnuclear instrumentat
31、ion.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 channels for thepassage of coolant gas, reactivity control materials (controlro
32、ds), 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 elements) is to provide for moderation of fastneutrons escaping from and refle
33、ction 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 Reflector Elements:7.2.1 A permanent side reflector element is a graphite blo
34、ckthat 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 neutron fluxcontrol materials (boronated steel pins) and nuclear instru
35、men-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 permanent side reflector elements encircle theactive (fuel) elements and passive (removable re
36、flector) 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 fuel, removable reflector, and coresupport elements, (3) moderation of f
37、ast 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 reducing the neutron flux to metallic structuresoutside the permanent s
38、ide 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 core supportpedestal has a central reduced cross-section (dog bone sha
39、pe)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 metallicstructure that supports the graphite core support assembly. A
40、core 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, neutronflux control materials, and nuclear instrumentation.7.3.2 The primar
41、y 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 mechanicalsupport for adjacent core support pedestals and permanent sidereflector el
42、ements 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. Inaddition, core support elements provide for lateral mechanicalsupport for
43、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 Pebble Bed Modular Reactor (PBMR) Reflector Blocks:7.4.1 The PBMR core s
44、tructure consists of a graphitereflector supported and surrounded by a metallic core barrel.The graphite reflector is comprised of a large number ofgraphite blocks arranged in circular rings of separate columns.The graphite reflector can be sub divided into three sub-systems, namely, the bottom, sid
45、e, and top reflector. The sidereflector is split into an inner 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.7.4.2 The primary function of the reflector
46、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.7.4.3 Replaceable reflector blocks contain vertical channelsfor the reactivity control rod
47、s and reserve shutdown system.These channels contain graphite sleeves to eliminate cross flowof reactor coolant gas.8. Test Methods8.1 Bulk Density:8.1.1 Determine bulk density on as-manufactured or ma-chined specimens in accordance with Test Methods C 838 andC781023C 559, respectively. Test Method
48、C 838 includes shaped ar-ticles other than right circular cylinders and rectangular paral-lelepipeds. Test Method C 559 is used when a higher degree ofaccuracy is required. The procedures of Test Method C 559 aremodified in Annex A1 to provide for the measurement of bulkdensity of nonuniform specime
49、ns.8.2 Thermal Properties:8.2.1 Determine linear thermal expansion in general accor-dance with Test Method E 228. Modifications to Test MethodE 228, which are in preparation and will be presented as anannex, are required to ensure the reliability of measurementsfor coarse-grained graphite and to permit more convenientsizes for irradiation test specimens and manufacturing control.8.2.2 Calculate the thermal conductivity from the thermaldiffusivity as determined by Test Method E 1461. The requiredcalculation is described in Annex Annex A2.8.3 Mechanical Properties:8.3.1 Determine comp