ASTM C1457-00
(Test Method)Standard Test Method for the Determination of Total Hydrogen Content of Uranium Oxide Powders and Pellets by Carrier Gas Extraction
Standard Test Method for the Determination of Total Hydrogen Content of Uranium Oxide Powders and Pellets by Carrier Gas Extraction
SCOPE
1.1 This test method applies to the determination of hydrogen in nuclear-grade uranium oxide powders and pellets to determine compliance with specifications. Gadolinium oxide (Gd2O3) and gadolinium oxide-uranium oxide powders and pellets may also be analyzed using this test method.
1.2 This standard describes a procedure for measuring the total hydrogen content of uranium oxides. The total hydrogen content results from absorbed water, water of crystallization, hydro-carbides and other hydrogenated compounds which may exist as fuel's impurities.
1.3 This test method covers the determination of 0.05 to 200 g of residual hydrogen.
1.4 This test method describes an electrode furnace carrier gas combustion system equipped with a thermal conductivity detector.
1.5 The preferred system of units is micrograms hydrogen per gram of sample (g/g sample) or micrograms hydrogen per gram of uranium (g/g U).
1.6 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.
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Designation:C1457–00
Standard Test Method for
Determination of Total Hydrogen Content of Uranium Oxide
Powders and Pellets by Carrier Gas Extraction
This standard is issued under the fixed designation C 1457; 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.
1. Scope 3. Summary of Test Method
1.1 This test method applies to the determination of hydro- 3.1 The total hydrogen content is determined using a hy-
gen in nuclear-grade uranium oxide powders and pellets to drogen analyzer. The hydrogen analyzer is based on the carrier
determine compliance with specifications. Gadolinium oxide gas method using argon or nitrogen as carrier gas. The actual
(Gd O ) and gadolinium oxide-uranium oxide powders and configuration of the system may vary with vendor and model.
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pellets may also be analyzed using this test method. 3.2 Thesamplestobeanalyzedaredroppedintoapreheated
1.2 This standard describes a procedure for measuring the graphite crucible, and then, heated up to a temperature of more
total hydrogen content of uranium oxides. The total hydrogen than 1700°C in a graphite crucible. At that temperature
content results from absorbed water, water of crystallization, hydrogen, oxygen, nitrogen, and carbon monoxide (oxygen is
hydro-carbides and other hydrogenated compounds which may converted to CO when it reacts with the crucible) are released.
exist as fuel’s impurities. The release gas is purified in the carrier gas stream by
1.3 Thistestmethodcoversthedeterminationof0.05to200 oxidation and absorption columns. The hydrogen is separated
µg of residual hydrogen. by chromatographic means and analyzed in a thermal conduc-
1.4 This test method describes an electrode furnace carrier tivity detector.
gas combustion system equipped with a thermal conductivity
4. Significance and Use
detector.
4.1 Uranium dioxide is used as a nuclear-reactor fuel.
1.5 The preferred system of units is micrograms hydrogen
per gram of sample (µg/g sample) or micrograms hydrogen per Gadolinium oxide is used as an additive to uranium dioxide. In
order to be suitable for this purpose, these materials must meet
gram of uranium (µg/g U).
certain criteria for impurity content. This test method is
1.6 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the designed to determine whether the hydrogen content meets
Specifications C 753, C 776, C 888, and C 922.
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica-
5. Interferences
bility of regulatory limitations prior to use.
5.1 Contamination of carrier gas, crucibles, or samples with
2. Referenced Documents
extraneous sources of hydrogen may cause a positive bias. A
blank correction will help to minimize the bias from carrier gas
2.1 ASTM Standards:
C 753 Specification for Nuclear-Grade, Sinterable Uranium and crucibles. Interference from adsorbed hydrogen on
samples may be eliminated by keeping the sample in an inert
Dioxide Powder
C 776 Specification for Sintered Uranium Dioxide Pellets atmosphere or vacuum.
5.2 The purification system typically associated with the
C 888 Specification for Nuclear-Grade Gadolinium Oxide
(Gd O ) Powder recommended combustion and detection equipment is de-
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signed to minimize other expected sources of interferences,
C 922 Specification for Sintered Gadolinium Oxide-
Uranium Dioxide Pellets suchassulfur,halogens,carbonmonoxide,carbondioxide,and
water.
5.2.1 The nitrogen and hydrogen peaks are close together
ThistestmethodisunderthejurisdictionofASTMCommitteeC-26onNuclear
and must be well-separated to prevent falsely high result from
Fuel Cycle and is the direct responsibility of Subcommittee C26.05 on Methods of
the nitrogen. The molecular sieve must be sufficiently long to
Test.
Current edition approved Feb. 10, 2000. Published March 2000.
Annual Book of ASTM Standards, Vol 12.01.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
C1457
separate the peaks and must be changed when the column 7.11 Aluminum Oxide (Al O ), to check furnace tempera-
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becomes loaded with contaminants that prevent proper peak ture.
separation. 7.12 Hydrogen Standard Materials—Calibrate the instru-
5.3 The temperature of >1700–1800°C must be reached. If ment using either high purity (99.9999 %) certified hydrogen
not, the decomposition of the released water to hydrogen and gas or NIST-traceable, or equivalent, metal standards. Steel
carbon monoxide may not be complete. The temperature will standards are the preferred metal standards because no flux is
depend upon the instrument and type of graphite crucible used. used, and this best matches the conditions used to analyze
Single wall crucibles will require a lower temperature (power) uranium oxide samples. Zr- or Ti-hydride standards may be
than double wall crucibles. used, but require the use of a flux metal.
5.4 Incomplete fusion may result in partial or a late release 7.13 Sodium Tartrate or Sodium Tungstate may be used as
of hydrogen resulting in low results. check standards for uranium powder analyses.
5.5 At temperatures of more than 2200°C uranium metal
8. Hazards and Precautions
may be formed, and carbon dioxide released because of
8.1 Take proper safety precautions to prevent inhalation or
reduction of UO by the graphite crucible.
ingestion of uranium dioxide powders or dust during grinding
5.5.1 Carbon dioxide will interfere with the thermal con-
or handling operations.
ductivity measurement. This is normally covered by use of
8.2 Operation of equipment presents electrical and thermal
chemical absorption, or a molecular sieve column, or both.
hazards. Follow the manufacturer’s recommendations for safe
5.5.2 Excess temperature, from too much power, or crucible
operation.
hot spots, from misaligned electrodes may cause analysis
8.3 This procedure uses hazardous chemicals. Use appro-
errors. Uranium samples should be evenly fused and should
priate precautions for handling corrosives, oxidizers, and
fall out freely of the crucibles and contain very little uranium
gases.
metal.
9. Preparation of Apparatus
6. Apparatus
9.1 Inspect and change instrument column packing and
6.1 Hydrogen Analyzer, consisting of an electrode furnace
reagents as recommended by manufacturer.
capable of operation at least up to 2200 to 2500°C, a thermal
9.2 Check to ensure that the furnace heats properly on a
conductivity detector for measuring, and auxiliary purification
periodic basis. A quarterly check is recommended. A properly
systems.
functioning furnace, set at normal operating parameters should
6.2 Balance, with precision of 6 1 mg.
fuse Al O (approximately 2050°C melting point, depending
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upon form).
7. Reagents and Materials
9.3 Set the operating controls of the instrument system
7.1 Purity of Reagents—Reagent grade chemicals shall be
according to the operating instructions for the specific equip-
used in all tests. Unless otherwise indicated, it is intended that
ment used.
all reagents shall conform to the specifications of the Commit-
9.4 Condition the apparatus by combustion of several
tee onAnalytical Reagents of theAmer
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