ASTM C1346-19

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Designation: C1346 − 08 (Reapproved 2014) C1346 − 19
Standard Practice for
1,2
Dissolution of UF from P-10 Tubes
This standard is issued under the fixed designation C1346; 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 (´) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 This practice covers the dissolution of UF from a P-10 tube to provide solutions for analysis.
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 safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use. For specific safeguard and safety precaution statements, see Section 89.
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.
2. Referenced Documents
2.1 ASTM Standards:
C761 Test Methods for Chemical, Mass Spectrometric, Spectrochemical, Nuclear, and Radiochemical Analysis of Uranium
Hexafluoride
C787 Specification for Uranium Hexafluoride for Enrichment
C859 Terminology Relating to Nuclear Materials
C996 Specification for Uranium Hexafluoride Enriched to Less Than 5 % U
D1193 Specification for Reagent Water
3. Terminology
3.1 Definitions:
3.1.1 For definitions of terms relating to the nuclear fuel cycle, refer to Terminology C859.
4. Summary of Practice
4.1 UF samples intended for analysis are packaged in P-10 tubes to prevent sublimation and reaction with moisture in the air.
The P-10 tube assembly (Fig. 1) consists of a Polychlorotrifluoroethylene (PCTFE) tube containing the UF , a PCTFE gasket to
cover the tube’s opening, and a nut and plug (Monel or SS) to seal the gasket to the tube.
4.2 The UF tube is weighed, cooled in liquid nitrogen, and quickly opened and immersed in water for dissolution. The pieces
of the tube’s assembly are removed from the resulting solution, rinsed, dried, reassembled, and weighed. The solution is dried for
gravimetric conversion to U O , or diluted to an appropriate concentration for dispensing into aliquots for subsequent analysis.
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5. Significance and Use
5.1 Uranium hexafluoride is a basic material used to prepare nuclear reactor fuel. To be suitable for this purpose the material
must meet criteria for uranium content, isotopic composition and metallic impurities in Specification C787 and C996. This practice
results in the complete dissolution of the sample for uranium and impurities analysis, and determination of isotopic distribution
by mass spectrometry as described in, for example, Test Methods C761.
This practice is under the jurisdiction of ASTM Committee C26 on Nuclear Fuel Cycle and is the direct responsibility of Subcommittee C26.05 on Methods of Test.
Current edition approved Jan. 1, 2014Feb. 1, 2019. Published February 2014February 2019. Originally approved in 1996. Last previous edition approved in 20082014
as C1346 – 08.C1346 – 08 (2014). DOI: 10.1520/C1346-08R14.10.1520/C1346-19.
Polychlorotrifluoroethylene P-10 tubes are widely accepted by the industry for subsample collection and subsequent UF quality analyses or dispatch to the customer.
The procedure for subsample collection and dissolution can also be used for other types of subsample tubes, for example, P-20, P-80 or P-100 , P-100, in that case the amount
of water has to be adjusted to ensure complete hydrolisation of UF and avoid excessive heat evolution.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
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C1346 − 19
FIG. 1 Example of a P-10 Sample Tube
6. Apparatus
6.1 Steam bath, in a hood, if optional step 9.2.1310.2.13 is used.
6.2 Vacuum oven, if option 2 of 9.2.1410.2.14 is used. The oven should be adjustable to 80°C at an absolute pressure of 3 ×10
Pa.
6.3 Dewar flask, wide-mouth.
6.4 Vise, small lab-bench model or similar type of holder.
6.5 Wrench, ⁄16 in.
6.6 Plastic clamping forceps, 12 to 13 cm long, with a claw-like bent tip, to securely hold the cylindrical PCTFE tube.
NOTE 1—These forceps are not commercially available. Bend the ends of a straight-tip forceps by heating over a moderate flame, shaping, and
maintaining the shape until cool.
6.7 TFE-fluorocarbon-coated spatula, 0.5- to 1-cm wide at its flat end, optional.
6.8 Platinum or PCTFE rod, optional.
6.9 Platinum dishes or plastic beakers with compatible HF resistance (typically PolyEthylene; PE), large enough to contain a
completely submerged P-10 tube.
6.10 Copper wires, optional. The wires should be flexible and looped at one end to loosely fit around the PCTFE tube without
allowing the flare nut to pass through.
6.11 Desiccator, optional.
6.12 Balance, ≥100-g capacity, readable to at least 0.1 mg, preferably 0.01 mg.
NOTE 2—Use of a balance with lower sensitivity will negatively impact on sampling error.
7. Interferences
7.1 The weight of the PCTFE tube is affected by atmospheric humidity. Keep the P-10 tube assembly in a desiccator between
weighings until constant weight is attained.
7.2 The capacity of the UF tube (a maximum of approximately 13.0 g UF ) limits the number and size of the aliquots that can
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be obtained from each tube. See analytical procedures for their requirements.
8. Reagents
8.1 Purity of Reagents—Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all
reagents conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society where such
specifications are available. Other grades of reagents may be used, provided it is first ascertained that the reagent is of sufficiently
high purity to permit its use without lessening the accuracy of the determination.
8.2 Liquid nitrogen.
8.3 Deionized distilled water in accordance with Specification D1193, approximately 50–100 50 to 100 cm per sample.
Reagent Chemicals, American Chemical Society Specifications, American Chemical Society, Washington, DC. For suggestions on the testing of reagents not listed by
the American Chemical Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and National
Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, MD.
C1346 − 19
8.4 Ethanol or other suitable, volatile organic solvent.
9. Hazards
9.1 Since UFUranium hexafluoride materials(UF are) is radioactive, toxic, and highly reactive,reactive especially with
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reducing substances and moisture, adequate laboratory facilities and fume hoods along with safe techniques must be used in
handling samples containing these materials. A detailed discussion of all necessary precautions is beyond the scope of this practice.
However, personnel who handle radioactive materials should be familiar with the safe handling practices moisture. Appropriate
laboratory facilities, materials of construction, and techniques shall be utilized when handling UF of the facility.
9.2 Follow all safety procedures for handling uranium and UF provided by the facility. Review the Material Safety Data Sheet
(MSDS)(SDS) for UF prior to performing the procedure.
9.3 Perform dissolutions in a laboratory hood. Hoods should be regularly inspected for proper air flow.
9.4 Gaseous UFWhen released , when released to the atmosphere, to the atmosphere, gaseous UF reacts with moisture to
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formproduce HF gas and toxic UO F particulate (a white amorphous solid that settles on all surfaces). Release of UFparticulates.
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Use sufficient ventilation to the atmosphere is readily visible as a white cloud
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