ASTM C781 : 08

Standard Practice for Testing Graphite and Boronated Graphite Materials for High-Temperature Gas-Cooled Nuclear Reactor Components

Standard Details

1.1 This practice covers the test methods for measuring the properties of graphite and boronated graphite materials. These properties may be used for the design and evaluation of high-temperature gas-cooled reactor components.

1.2 The test methods referenced herein are applicable to materials used for replaceable and permanent components as defined in Section 7 and Section 9, and includes fuel elements; removable reflector elements and blocks; permanent side reflector elements and blocks; core support pedestals and elements; control rod, reserve shutdown, and burnable poison compacts; and neutron shield material.

1.3 This practice includes test methods that have been selected from existing ASTM StandardDetails, ASTM StandardDetails that have been modified, and new ASTM StandardDetails that are specific to the testing of materials listed in 1.2. Comments on individual test methods for graphite and boronated graphite components are given in Sections 8 and 10, respectively. The test methods are summarized in Tables 1 and 2.

1.4 The values stated in SI units are to be regarded as standard. The values given in parentheses are for information only.

1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

TABLE 1 Summary of Test Methods for Graphite Components

Note—Designations under preparation will be added when approved.

	Fuel, Removable Reflector, and Core Support Elements; Pebble Bed Reflector, Key and Sleeves; and Dowel Pins	Permanent Side Reflector Elements and Dowel Pins	Core Support Pedestals and Dowels
Fabrication
As Manufactured Bulk Density	C838	C838	C838
Mechanical Properties
Compressive Strength	C695	C695	C695
Tensile Properties	C749^A	C749^A	C749^A
Poisson’s Ratio	E132^B	E132^B	E132^B
Flexural Strength	C651^A	C651^A	C651^A
Fracture Toughness	^B	^B	^B
Modulus of Elasticity	C747	C747	C747
Physical Properties
Bulk Density–Machined Specimens	C559	C559	C559
Surface Area (BET)	C1274	C1274	C1274
Permeability	C577^A^,^B	C577^A^,^B	C577^A^,^B
Apparent Porosity	C1039	C1039	C1039
Spectroscopic Analysis	^B	^B	^B
Electrical Resistivity	C611	C611	C611
Thermal Properties
Linear Thermal Expansion	E228^A
Thermal Conductivity	E1461^A	E1461^A	E1461^A
Chemical Properties
Oxidative Mass Loss	C1179^B	C1179^B	C1179^B
Sulfur Concentration	C816	C816	C816
Ash Content	C561^A	C561^A	C561^A
Equivalent Boron Content	C1233^A	C1233^A	^C

^A Modification of this test method is required. See Section 8 for details.

^B New test methods are required. See Section 8 for details.

^C There is no identified need for determining this property.

TABLE 2 Summary of Test Methods for Boronated Graphite Components

Note—Designations under preparation will be added when approved.

	Compacts			Neutron Shield Material
	Control Rod	Burnable Poison	Reserve Shutdown	Neutron Shield Material
Bulk Density	C838	C838	C838	D4292
Linear Thermal Expansion	^A	E228^A	E228^A	^B
Particle Size	^C	^C	^C	D2862
Mechanical Strength:
Compressive Strength	C695^A	C695^A	C695^A	^B
Impact Performance	^B	^B	^B	^C
Chemical Properties:
Sulfur Concentration	^C	^C	^C	^C
Hafnium Concentration	^C	^C	^C	^C
Relative Oxidation Rate	^C	^C	^C	^C
Boron Analysis:
Total Boron	^C	^C	^C	^C
Boron as Oxide	^C	^C	^C	^C
B₄C Particle Size	D2862^D	D2862^D	D2862^D	D2862^D

^A Modification of this test method is required. See Section 10 for details.

^B There is no identified need for determining this property.

^C New test methods are required. See Section 10 for details.

^D Additional test methods are required. See Section 10 for details.

General Information

Status : Historical

Standard Type: Main

Document No: ASTM C781 : 08

Document Year: 2008

Pages: 10

Section Volume:
05.05 Volume 05.05 Petroleum Products, Liquid Fuels, and Lubricants (V): D7756–latest; Combustion Characteristics; Manufactured Carbon and Graphite Products