ASTM C1703-08(2013)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation:C1703 −08 (Reapproved 2013)
Standard Practice for
Sampling of Gaseous Uranium Hexafluoride
This standard is issued under the fixed designation C1703; 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 priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use.
1.1 This practice covers methods for withdrawing represen-
tative sample(s) of uranium hexafluoride (UF ) during a
2. Referenced Documents
transfer occurring in the gas phase. Such transfer in the gas
2.1 ASTM Standards:
phase can take place from a mother cylinder, for example in an
autoclave to a receiving cylinder. It can also occur during the C761 Test Methods for Chemical, Mass Spectrometric,
Spectrochemical, Nuclear, and RadiochemicalAnalysis of
filling in the gas phase of a cylinder during a continuous
production process, for example centrifuge enrichment facility Uranium Hexafluoride
C787 Specification for Uranium Hexafluoride for Enrich-
or the distillation column in a conversion facility. Such
ment
sample(s) may be used for determining compliance with the
C996 Specification for Uranium Hexafluoride Enriched to
applicable commercial specification, for example Specification
Less Than 5 % U
C996 or Specification C787.
C1052 Practice for Bulk Sampling of Liquid Uranium
1.2 Since UF sampling is taken during the filling process,
Hexafluoride
this practice does not address any special additional arrange-
2.2 Other Document:
ments that may be agreed upon between the buyer and the
ISO/DIS 7195 Packaging of Uranium Hexafluoride (UF )
seller when the sampled bulk material is being added to 6
for Transport
residues already present in a container (“heels recycle”). Such
arrangements will be based on QA procedures such as trace-
3. Terminology
abilityofcylinderorigin(topreventforexamplecontamination
with irradiated material).
3.1 Definitions of Terms Specific to This Standard:
3.1.1 container—a vessel either holding or receiving by
1.3 If the receiving cylinder is purged after filling and
transfer, the UF to be sampled; it may consist of, for example,
sampling, special verifications must be performed by the user
a fixed vessel in a UF handling plant or a cylinder to be used
to verify the representativity of the sample(s). It is then 6
for the transport of UF .
expected that the results found on volatile impurities with gas
phase sampling may be conservative. 3.1.2 sample vessel—the small vessel into which the sample
of UF is withdrawn for analysis in the laboratory for charac-
1.4 This practice is only applicable when the transfer occurs
terization. It can be a 1S or 2S bottle or a PCTFE
in the gas phase. When the transfer is performed in the liquid
(polydifluorodichloroethylene)/ PTFE (polytetrafluoroethyl-
phase, Practice C1052 should apply. This practice does not
ene) pot or tube or any other type of cylinder compatible with
apply to gas sampling after the cylinder has been filled since
UF .
the sample taken will not be representative of the cylinder.
1.5 The scope of this practice does not include provisions
4. Summary of Practices
for preventing criticality incidents.
4.1 Two methods of withdrawing gas UF for sampling are
1.6 This standard does not purport to address all of the
possible, namely: (1) continuous withdrawal using for example
safety concerns, if any, associated with its use. It is the
a capillary and producing only one sample, or (2) sequential
responsibility of the user of this standard to establish appro-
withdrawals producing a composite sample. Depending on the
1 2
This practice is under the jurisdiction of ASTM Committee C26 on Nuclear For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Fuel Cycle and is the direct responsibility of Subcommittee C26.02 on Fuel and contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Fertile Material Specifications. Standards volume information, refer to the standard’s Document Summary page on
Current edition approved Jan. 1, 2013. Published January 2013. Originally the ASTM website.
approved in 2008. Last previous edition approved in 2008 as C1703 – 08. DOI: Available fromAmerican National Standards Institute (ANSI), 25 W. 43rd St.,
10.1520/C1703-08R13. 4th Floor, New York, NY 10036, http://www.ansi.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
C1703−08 (2013)
pressure and temperature conditions during the transfer, the 7.1.1 It is recommended to validate the gas sampling using
sampled UF is either liquefied or solidified in the sample a comparison on several cylinders with liquid sampling after
vessel. filling. Statistically significant sampling basis and requirement
should be established. Adequacy shall be demonstrated by
4.2 An example of (1) is the sampling of UF coming from
quality assurance procedures.
a distillation column. In such case, the sampled gas UF can be
7.1.2 In case of the presence of volatile impurities close to
condensed in the liquid phase in the sampling vessel. The
the specification (for example within 80 % of the
representative sample is then homogenized before analysis at
specification), a confirmation using liquid sampling may be
the laboratory. It is assumed that the flow rate from the
necessary.
distillation is either constant (for example using a mass flow
controller) or that the capillary will take its variation in 7.2 Uranium hexafluoride is very reactive and corrosive. It
account. reactsreadilywithwater,atmosphericmoisture,certainmetals,
and many organic materials. For reasons of safety and to avoid
4.3 Examples of (2) are the sampling of UF from an
contamination,precautionsmustbetakentoavoidcontactwith
autoclave or from the cascades of an enrichment facility. This
such materials.The sampling equipment is therefore fabricated
would apply only to a stable process. In such case, the
to appropriate high standards of vacuum and high temperature
sequential withdrawals must take into account the potential
integrity, and components in direct contact with UF are made
variation of flow rate which must be continuously monitored
from nickel, high-nickel alloys, or materials having equivalent
during the transfer. A composite sample is prepared and is
resistance to UF corrosion. The formation of an inert fluoride
compared to an average calculation using on line analysis.
layer is often an important feature of UF corrosion resistance,
4.4 For both methods of sampling, the presence of residues
and hence, internal surfaces are generally conditioned with a
may have significant implications for the quality of the UF .
suitable fluorinating agent, sometimes UF itself.
For safety and quality reasons, cylinders and bottles shall be
7.3 Cross-contamination may occur between subsequent
clean, dry, and empty before filling.
samples taken using the same equipment, and appropriate
precautions must be taken to prevent this. It is therefore
5. Significance and Use
recommended that, before taking definitive samples, the equip-
5.1 Uraniumhexafluorideisnormallyproducedandhandled
ment is flushed through with an aliquot of the material to be
in large (typically 1 to 14-ton) quantities and must, therefore,
sampled. This is normally accomplished by taking an initial
be characterized by reference to representative samples (see
volume which is then rejected and not used for definitive
ISO/DIS 7195).The samples are used to determine compliance
analysis. Alternative procedures to prevent cross-
with the applicable commercial specifications C996 and C787.
contamination are possible and should be validated individu-
The quantities involved, physical properties, chemical
ally.
reactivity, and hazardous nature of UF are such that for
representative sampling, specially designed equipment must be
8. Procedure for Continuous Sampling During Filling of
used and operated in accordance with the most carefully
a Transport Cylinder
controlled and stringent procedures. This practice can be used
8.1 Sample Preparation:
by UF converters, enrichers, and fuel fabricators to review the
8.1.1 The equipment consists of a continuous sampling
effectiveness of existing procedures or as a guide to the design
vessel that has the ability to collect a desired weight/volume of
of equipment and procedures for future use.
UF during the filling of a UF transport cylinder,andasample
6 6
5.2 The intention of this practice is to avoid liquid UF
manifold used for obtaining the aliquot of UF from the
sampling once the cylinder has been filled. For safety reasons,
continuous sampling vessel. The sampling manifold can be a
manipulation of large quantities of liquid UF should be
permanent (fixed) manifold, and can be the same manifold
avoided when possible.
used for sampling straight from a product cylinder. The
5.3 Itisemphasizedthatthispracticeisnotmeanttoaddress
continuous sampling vessel should be fed gaseous UF from a
conventional or nuclear criticality safety issues. slip stream at the exit of the supplying source (for example, a
distillation column) that is supplying UF to a transport
6. Hazards
cylinder.
6.1 Because of its chemical, radiochemical, and toxic 8.1.2 The continuous sampling vessel should be maintained
properties, UF is a hazardous material. at a temperature and pressure adequate for condensing and
mainta
...