ASTM C562-91(2000)
(Test Method)Standard Test Method for Moisture in a Graphite Sample
Standard Test Method for Moisture in a Graphite Sample
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1.1 This test method provides a practical determination for the percentage of moisture in a graphite sample.
1.2 This standard does not purport to address all of the safety problems, 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.
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An American National Standard
Designation:C 562–91(Reapproved 2000)
Standard Test Method for
Moisture in a Graphite Sample
This standard is issued under the fixed designation C 562; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the Department of Defense.
1. Scope 5.3 Drying Oven, air convection type, capable of being
controlled to 110 6 2°C (2306 4°F).
1.1 This test method provides a practical determination for
5.4 Desiccator, charged with indicating desiccant.
the percentage of moisture in a graphite sample.
1.2 This standard does not purport to address all of the
6. Sampling
safety concerns, if any, associated with its use. It is the
6.1 Samples may be solid or particulate. Solid bodies may
responsibility of the user of this standard to establish appro-
be sampled by removing one or more solid pieces from the
priate safety and health practices and determine the applica-
body by, for example, sawing, turning, milling, or fracturing.
bility of regulatory limitations prior to use.
Particulate samples may be generated from solid bodies by
2. Referenced Documents drilling, using a carbide drill to minimize contamination, or by
other crushing and grinding methods.
2.1 ASTM Standards:
C 561 Test Method for Ash in a Graphite Sample
7. Procedure
3. Significance and Use 7.1 Tare a dried sample holder using an analytical balance.
Weigh a 25 to 50-g sample into the tared sample holder and
3.1 This test method is feasible only for the volatile mois-
reweigh both. (Perform all weighings to a precision of 60.002
ture present on the graphite due to adsorption from the
g.)
atmosphere and is not intended to give representative moisture
7.2 Place the sample holder containing the sample in a
data for graphite that has been exposed to liquid water
drying oven maintained at 110 6 2°C (230 6 4°F) for 2 h.
contamination.
Remove from the oven and immediately place in the desicca-
4. Interferences tor. When the sample has reached room temperature, remove
from the desiccator and weigh immediately.
4.1 Final weights (and therefore percent moisture values)
7.3 Repeat the procedure prescribed in 7.2 until a constant
may be influenced by the following:
weight of 60.002 g is achieved.
4.1.1 Type and condition of desiccant.
7.4 The dried sample may be reserved for ash determina-
4.1.2 Ambient relative humidity at the time of the test.
tion. (See Test Method C 561.)
4.1.3 Timing and procedure for moving samples from des-
iccator to the balance.
8. Calculation
4.1.4 Adsorptivity of the graphite sample relative to the
8.1 Calculate the percentage of moisture as follows:
adsorptivity of the desiccant used.
4.1.5 Residency time in the desiccator.
Moisture, % 5 @~ B 2 C!/~B 2 A!# 3 100
5. Apparatus where:
A = weight of sample holder,
5.1 Alumina Ceramic
...
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FIG. 1 Block Diagram of Typical Test Apparatus
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1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
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1.1 This guide covers procedures for the impregnation of graphite with molten salt under a consistent pressure and temperature. Such procedures are necessary if the user wishes to prepare graphite specimens for testing that represent material that has been exposed to a molten salt environment in a molten salt nuclear reactor. The user will need to ensure that impregnation temperature and pressure conditions reflect those pertaining to the molten salt environment, noting that the properties of the material will change once it becomes irradiated.
Note 1: The term impregnation is used throughout this guide as this is the correct term for the described process. Other terms such as infiltration and intrusion may be encountered by the user in other texts and the term intrusion is commonly used to describe penetration of open porosity in graphite in a molten salt reactor environment.
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this guide.
1.3 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
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5.1 The Molten Salt Reactor is a nuclear reactor which uses graphite as reflector and structural material, and molten salt as coolant. The graphite components will be submerged in the molten salt during the lifetime of the reactor. The porous structure of graphite may lead to molten salt permeation, which can affect the thermal and mechanical properties of graphite. Consequently, it may be necessary to measure the various strengths of the manufactured graphite materials after impregnation with molten salt and before exposure to the reactor environment in a range of test configurations in order for designers or operators to assess their performance.
Note 1: Depending upon the salt selected for the reactor, there may be some chemical reaction between the salt and the graphite that could affect properties. The user should establish, prior to following this guide, that any interactions between the molten salt and graphite are understood and any implications for the validity of the strength tests have been assessed.
5.2 For gas-cooled reactors, the strength of a graphite specimen is usually measured at room temperature. However, for molten salt reactors, the operating temperature of the reactor must be higher than the melting temperature of the salt, and so the salt will be in solid state at room temperature. Consequently, room temperature measurements may not be representative of the performance of the material at its true operating conditions. It is therefore necessary to measure the strength at an elevated temperature where the salt is in liquid form.
Note 2: Users should be aware that a small increase in graphite strength is expected with increasing temperature. Testing at the plant operating temperature will eliminate this small uncertainty.
5.3 The purpose of this guide is to provide considerations, which should be included in testing graphite specimens impregnated with molten salt at elevated temperature.
5.4 For the test results to be meaningful, the...
SCOPE
1.1 This guide covers the best practice for strength measurements at elevated temperature of graphite impregnated with molten salt.
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.3 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
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4.1 Carbon and graphite can usually support higher loads in compression than in any other mode of stress. This test, therefore, provides a measure of the maximum load-bearing capability of carbon and graphite objects.
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1.1 This test method covers the determination of the compressive strength of carbon and graphite at room temperature.
1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.
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