ASTM C1689-21

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Designation: C1689 − 08a (Reapproved 2014) C1689 − 21
Standard Practice for
Subsampling of Uranium Hexafluoride
This standard is issued under the fixed designation C1689; 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 is applicable to subsampling uranium hexafluoride (UF ), using heat liquefaction techniques, from bulk
containers, obtained in conformance with Practices C1052, C1703, and C1883, into smaller sample containers, which are required
for laboratory analyses.
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 It is assumed that the liquid UF being sampled comprises a single quality and quantity of material. This practice does not
address any special additional arrangement that might be required for taking proportional or composite samples.
1.4 The number of samples to be taken, their nominal sample weight, and their disposition shall be agreed upon between the
parties.
1.5 The scope of this practice does not include provisions for preventing criticality incidents.
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.
1.7 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
C761C1052 Test Methods for Chemical, Mass Spectrometric, Spectrochemical, Nuclear, and Radiochemical Analysis of
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, 2021. Published February 2014March 2021. Originally approved in 2008. Last previous edition approved in 20082014 as
C1689 – 08a.C1689 – 08a (2014). DOI: 10.1520/C1689-08aR14.10.1520/C1689-21.
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.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
C1689 − 21
Practice for Bulk Sampling of Liquid Uranium Hexafluoride
C1052C1703 Practice for Bulk Sampling of LiquidGaseous Uranium Hexafluoride for Enrichment
C1883 Practice for Sampling of Gaseous Enriched Uranium Hexafluoride
2.2 Other Documents:
ANSI N14.1 Uranium Hexafluoride: Packaging for Transport
ISO/DISISO 7195 Packaging of Uranium Hexafluoride (UF ) for Transport
USEC-651 The UF Manual: Good Handling Practices for Uranium Hexafluoride, latest revision
3. Terminology
3.1 Definitions:
3.1.1 Terms shall be defined in accordance with Terminology C859 except for the following:Terms shall be defined in accordance
with Terminology C859 except for the following:
3.1.2 sample bottle—the vessel (typically a 1S or 2S bottle) into which the sample of UF is withdrawn from the container for
transfer to the laboratory, analysis or dispatch to the customer.
3.1.3 subsample tube—the small vessel (for example, a P10 tubetube)) into which a subsample of UF is withdrawn from the
sample bottle for analysis of UF quality or dispatch to the customer.
3.1.3.1 Discussion—
Polychlorotrifluoroethylene P10 tubes are widely accepted by the industry for subsample collection and subsequent UF quality
analyses or dispatch to the customer. Other types of subsample tubes, for example P-20, P-80, or P100 , can be used for internal
subsample collection and processing. Dispatch of these subsample tubes may be agreed upon by buyer and seller and subject to
(local) transport regulations.
3.1.4 subsample rig—the equipment to perform the transfer of liquid UF from the sample bottle into the subsample tube, typically
a vacuum manifold equipped with heating and a liquid nitrogen trap.
4. Summary of Practice
4.1 Two methods of withdrawing a subsample of UF are described which differ based on safety requirements namely: (1)
homogenizing of liquefied UF by agitation before liquid transfer, and (2) homogenizing of liquefied UF by convection before
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liquid transfer. The first method involves homogenization of liquifiedliquefied UF in a sample bottle by vigorous shaking.
Subsequently the sample bottle is inverted and connected to the top of a heated vacuum-manifold system, and the subsample tube
is attached to the appropriate port of the system. The system is evacuated and the liquid UF allowed to flow by gravity into the
subsample tube. In the second method the sample bottle containing solid UF is connected to the top of a manifold system, and
a subsample tube is attached to the appropriate port of the system. The whole system is enclosed in secondary containment that
can be heated (hot-box). After evacuation the complete system is heated for specific period (typically > 1.5 hr) >1.5 h) to allow
for complete homogenization of the liquid UF by convection. Subsequently the liquid UF is allowed to flow by gravity either
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directly or via graduated volume into the subsample tube.
4.2 For both methods of sampling, the presence of residues may have significant implications for the quality of UF . For safety
and quality reasons, sample bottles and subsample tubes shall be clean, dry, and empty before filling.
4.3 Various types of sample bottles and tubes are in use and are described in detail in the applicable national and international
standards, for example, ANSI N14.1 and ISO/DISISO 7195. For a given type of sample bottle, the detailed configuration, for
example valve orientation, terminal fittings and the like, may vary. Hence the type and configuration of bottles used for the
withdrawal of samples shall be agreed upon between the parties.
5. Significance and Use
5.1 Uranium hexafluoride is normally produced and handled in large (typically 1- to 14-ton) quantities and must, therefore be
Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036, http://www.ansi.org.
Available from International Organization for Standardization (ISO), 1, ch. de la Voie-Creuse, Case postale 56, CH-1211, Geneva 20, Switzerland, http://www.iso.ch.ISO
Central Secretariat, Chemin de Blandonnet 8, CP 401, 1214 Vernier, Geneva, Switzerland, https://www.iso.org.
Available from United States Enrichment Corp., 6903 Rockledge Dr., Bethesda, MD 20817, http://www.usec.com.Centrus Energy Corporation, 6901 Rockledge Drive,
Bethesda, MD 20817.
C1689 − 21
characterized by reference to representative samples. The samples are used to determine compliance with the applicable
commercial Specifications C996 and C787 by means of the appropriate test method (for example, Test Method C761 and
references therein). The quantities involved, physical properties, chemical reactivity, and hazardous nature of UF are such that for
representative sampling, specially designated equipment must be used and operated in accordance with the most carefully
controlled and stringent procedures. This practice indicates appropriate principles, equipment and procedures currently in use for
subsampling of liquid UF . It is used by UF converters, enrichers and fuel fabricators to review the effectiveness of existing
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procedures or to design equipment and procedures for future use. Other subsampling procedures such as UF vapor sampling are
not directly representative of the chemical quality of liquid UF .
5.2 It is emphasized that this test guide is not meant to address conventional or nuclear criticality safety issues.issues, nor does
it address the conditioning of subsample tubes to make them suitable for transport.
6. Apparatus
6.1 Hot Water Bath.
6.2 Subsample Rig—For ProcedureProcedures 1 see Fig. 1and Procedure 2 see Fig. 2Figs. 1 and 2. , respectively. Materials of
construction in direct contact with liquid UF are made from nickel, high nickel alloys, or materials having comparable resistance
to UF corrosion.
6.3 Gaseous Isotopic Abundance Sample Tube (Fig. 3).
6.4 Polychlorotrifluoroethylene Subsample Tube and Closing Disc (Fig. 4)—)—The tube must be of uniform density, free from
cracks or occlusions and able to withstand temperatures from –195°C–195 °C to +150°C. +150 °C. Materials of construction in
direct contact with liquid UF are made from polychlorotrifluoroethylene, PTFE/TFE (gaskets), or materials having comparable
resistance to UF corrosion.
6.5 Flare Nut and Plug—Flare nuts and plugs for subsample tube closure, storage and transport can be constructed from Monel,
nickel, high nickel alloys or 316 SS.
NOTE 1—All lines are ⁄8 in. (9.5 mm) Monel tubing.
NOTE 2—All valves are Monel diaphragm type valves.
NOTE 3—The valves and lines are wrapped with heating tape to maintain a system temperature of about 80°C.80 °C.
NOTE 4—Valve 2 is a 3-way valve modified to make it a 4-way valve. When the valve is closed, the polychlorotrifluoroethylene tube is isolated from
the system, but the lines from valve 1 to valve 3 and to the bulk container are open.
FIG. 1 Subsample Rig Used for Procedure 1
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NOTE 1—All lines in direct contact with liquid UF are ⁄8 in. (9.5 mm) 9.5 mm Monel tubing.
NOTE 2—All other lines are ⅜ in. (9.5 mm) 9.5 mm 316 SS tubing.
NOTE 3—Valves 1–3 are Monel below sealed valves that can be operated from outside the hotbox.
NOTE 4—Valves 4–8 are 316 SS below sealed valves.
NOTE 5—Flange connections are equipped with helicoflex (high pressure) gaskets. gaskets resistant to liquid UF , viton and helicoflex have been found
to be acceptable for this application
FIG. 2 Subsample Rig Used for Procedure 2
6.6 Polychlorotrifluoroethylene Knockout Cylinder (Fig. 5),closed with a Cajon M-16 VCR-1 female nut and an M-16 VCR-4
male nut or equivalent.
NOTE 1—Brand names mentioned in this practice are intended to be typical, not limiting. Another brand with comparable characteristics could perform
equally well.
6.7 Nickel Filter Disc, porous, 2μm, free of chromium (Fig. 6).
NOTE 2—The filterdisc filter disc should weigh approximately 1 g. It should be made of nickel powder produced from carbonyl nickel and formed by
the no pressure sintering method in graphite or ceramic molds.
6.8 Gas Sample Cylinder.
6.9 Heat Sources—Heat gun (or an equivalent) and heat lamps.
6.10 Dewar Flask, for liquid nitrogen, stainless steel.
7. Hazards
7.1 Uranium hexafluoride (UF ) is radioactive, toxic, and highly reactive especially in the presence of with reducing substances
and moisture. Safe techniques mustAppropriate laboratory facilities, materials of construction, and techniques shall be utilized
when handling UF . Suitable handling procedures are described in USEC-651. (see for example USEC-651).
C1689 − 21
FIG. 3 Isotopic Abundance Sample Tube.Tube
FIG. 4 Example of a Polychlorotrifluoroethylene Subsample Tube
C1689 − 21
FIG. 5 Example of a Polychlorotrifluoroethylene Knock-out Tube
FIG. 6 Filter Disc Unit for Determination of Soluble and Insoluble Chromium
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7.2 Follow all safety procedures for handling uranium and UF as provided by your facility.the facility. Review the Safety Data
Sheet (SDS) for UF6 prior to performing the procedure.
7.3 Review Material Safety Data Sheets for UF and all chemicals associated with this method prior to performance.
7.3 Perform subsampling operations in a fume hood that has been verified operable and has undergone regular inspections to
ensure proper airflow.laboratory hood. Hoods should be regularly inspected for proper air flow
7.4 When released to atmosphere, gaseous UF reacts with moisture to produce HF gas and toxic UO F particulates (a white
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amorphous solid) and becomes readily visible as a white cloud. The corrosive nature of HF and UFparticulates. Use sufficient
ventilation can result in skin burns and lung impairment. Medical evaluation is mandatory after contact with HF or UFor
respiratory . When water-soluble UO protection to avoid F is inhaled or ingested in large quantities it can be toxic to the
6 2 2
kidneys.breathing fumes. Use appropriate personal protective equipment such as gloves, eye, and face protection.
7.5 Hydrofluoric acid is a highly corrosive acid that can severely burn skin, eyes, and mucous membranes. Hydrofluoric acid
differs from other acids because the fluoride ion readily penetrates the skin, causing destruction of deep tissue layers. Unlike other
acids that are rapidly neutralized, hydrofluoric acid reactions with tissue may continue for days if left untreated. Familiarization
and compliance with the Safety Data Sheet is essential
7.5.1 Use gloves designed for use with cryogenic substances, and wear goggles or a face shield when handling bulk quantities of
liquid nitrogen.
8. Principles
8.1 The essential purpose of the sample is to be representative of the bulk material for the purpose of determining compliance with
the applicable material specification. To ensure that the sample is representative for this purpose, certain principles, as described
below, must be observed.
8.2 Special attention must be given to ensuring that the bulk material, from which the sample is withdrawn, is homogeneous. In
practice, the low viscosity, and hence easy mobility of liquid UF facilitates the process of homogenization by the action of
convection currents within the bulk upon heating. It is necessary to determine and establish for each set of subsampling equipment
the physical conditions, normally a combination of the minimum time and temperature for which liquefied uranium hexafluoride
is held, which guaranty homogeneity of the bulk UF .
8.3 Uranium
...