ASTM C1429-99(2004)
(Test Method)Standard Test Method for Isotopic Analysis of Uranium Hexafluoride by Double-Standard Multi-Collector Gas Mass Spectrometer
Standard Test Method for Isotopic Analysis of Uranium Hexafluoride by Double-Standard Multi-Collector Gas Mass Spectrometer
SIGNIFICANCE AND USE
Uranium hexafluoride used to produce nuclear-reactor fuel must meet certain criteria for its isotopic composition. This test method may be used to help determine if sample materials meet the criteria described in Specifications C 787 and C 996.
SCOPE
1.1 This is a quantitative test method applicable to determine the mass percent of uranium isotopes in uranium hexafluoride (UF6) samples. This method as described is for concentrations of 235U between 0.1 and 10 mass percent, and 234U and 236U between 0.0001 to 0.1 mass percent.
1.2 This test method is for laboratory analysis by a gas mass spectrometer with a multi-collector.
1.3 This standard complements C 761, sections 35 through 40, the double-standard method for gas mass spectrometers using a single collector, by providing a method for spectrometers using a multi-collector.
1.4 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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Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation: C 1429 – 99 (Reapproved 2004)
Standard Test Method for
Isotopic Analysis of Uranium Hexafluoride by Double-
Standard Multi-Collector Gas Mass Spectrometer
This standard is issued under the fixed designation C1429; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber 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. Terminology
1.1 This test method covers a quantitative test method 3.1 Definitions of Terms Specific to This Standard:
applicabletodeterminingthemasspercentofuraniumisotopes 3.1.1 A standard, n—the low-value standard of a standard
in uranium hexafluoride (UF ) samples. This method as de- pair that brackets the sample.
scribed is for concentrations of U between 0.1 and 10 3.1.2 B standard, n—the high-value standard of a standard
234 236
mass%, and U and U between 0.0001 and 0.1 mass%. pair that brackets the sample.
1.2 Thistestmethodisforlaboratoryanalysisbyagasmass 3.1.3 determination, n—a single isotopic value, calculated
spectrometer with a multi-collector. from a sequence of ratios; the most basic isotopic value
1.3 This standard complements Test Methods C761, sec- calculated.
tions 35 through 40, the double-standard method for gas mass 3.1.4 Lagrange’s interpolation formula, n—a mathematical
spectrometers using a single collector, by providing a method equation designed to estimate values between two or more
for spectrometers using a multi-collector. known values.
1.4 This standard does not purport to address all of the 3.1.5 run, n—a completed, six-entry symmetrical sequence
safety concerns, if any, associated with its use. It is the consisting of A standard, sample, B standard, B standard,
responsibility of the user of this standard to establish appro- sample, and A standard from which a determination can be
priate safety and health practices and determine the applica- calculated for one or more isotopes.
bility of regulatory limitations prior to use. 3.1.6 standard spread, n—the difference between the high
and low standards; sometimes called standard range.
2. Referenced Documents
3.1.7 test result, n—a reported value; the mean of two or
2.1 ASTM Standards:
more determinations.
C761 Test Methods for Chemical, Mass Spectrometric,
4. Summary of Test Method
Spectrochemical, Nuclear, and RadiochemicalAnalysis of
Uranium Hexafluoride 4.1 Uranium hexafluoride gas is introduced into an ioniza-
C787 Specification for Uranium Hexafluoride for Enrich- tion source. The resulting ions are accelerated down the flight
ment tube into the magnetic field. The magnetic field separates the
C996 Specification for Uranium Hexafluoride Enriched to ions into ion beams in accordance with the m/e ratio. Four
235 234 + 235 + 236 +
Less Than 5% U collectors are stationed so the UF , UF , UF , and
5 5 5
238 +
C1215 Guide for Preparing and Interpreting Precision and UF ion beams strike individual collectors.
Bias Statements in Test Method Standards Used in the 4.2 Two standards are chosen whose values bracket the
Nuclear Industry desired isotope of the sample. The sample and two standards
are introduced in a six-entry, symmetrical sequence. Then,
measurements are taken that give the mole ratio of the desired
ThistestmethodisunderthejurisdictionofASTMCommitteeC26onNuclear
isotope to U.
Fuel Cycle and is the direct responsibility of Subcommittee C26.05 on Methods of
Test.
4.3 Through Lagrange’s interpolation formula, these mea-
CurrenteditionapprovedJune1,2004.PublishedJuly2004.Originallyapproved
surements are used to calculate the mass percent of the desired
in 1999. Last previous edition approved in 1999 as C1429-99.
2 isotope.Ifstandardsareavailablethatbracketallisotopes,then
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
234 235 236
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM the U, U, and U mass percents are calculated from the
Standards volume information, refer to the standard’s Document Summary page on
same six-entry run.
the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
C 1429 – 99 (2004)
4.4 The results of two six-entry, symmetrical-sequence runs 7.3.1 Adjust instrument parameters to focus ion beams in
238 238 +
areaveragedtofindtestresultsforeachisotope.The Umass proper collectors and maximize the UF current reading.
percent is obtained by subtraction. 7.3.2 Enter standard values and other information if needed
for calculations performed by computer.
5. Significance and Use 7.3.3 Program the spectrometer to run two of the following
six-entry, symmetrical sequences: low standard, sample, high
5.1 Uranium hexafluoride used to produce nuclear-reactor
standard, high standard, sample, low standard.
fuel must meet certain criteria for its isotopic composition.
7.4 Run the Analysis:
This test method may be used to help determine if sample
7.4.1 Obtain measurements from all four collectors during
materials meet the criteria described in Specifications C787
each entry.
and C996.
8. Calculation
6. Apparatus
8.1 Perform the following operations for each of the U,
6.1 Mass spectrometer with the following features and
235 236
U, and U isotopes:
capabilities:
+
8.1.1 For each entry, obtain a ratio by dividing the UF ion
6.1.1 Anionsourcewithanacceleratingvoltageofapproxi- 5
238 +
count of the desired isotope by the UF ion count.
mately 8 kV,
8.1.2 Find the mean of the two low standard ratios and
6.1.2 A resolving power of greater than or equal to 500,
designate this A.
6.1.3 A minimum of three points of attachment for stan-
8.1.3 Find the mean of the two sample ratios and designate
dards or samples,
this X.
6.1.4 An ion collection system consisting of four collector
234 + 235 + 236 +
8.1.4 Find the mean of the two high standard ratios and
cups stationed to collect UF , UF , UF , and
5 5 5
238 +
designate this B.
UF ions,
6.1.5 An ion-current amplifier for each collector cup,
NOTE 1—In a six-entry symmetrical run sequence,
6.1.6 A voltage-to-frequency (V-to-F) converter for each
~r 1 r !/2 5 A (1)
1 6
amplifier,
6.1.7 A counter for each V-to-F converter, and
~r 1 r !/2 5 X (2)
2 5
6.1.8 Computercontroloveropeningandclosingvalves,the
timing, and the integration of analytical sequences.
~r 1 r !/2 5 B (3)
3 4
7. Procedure
where:
th
7.1 Select standards: r = the ratio from the n entry.
n
7.1.1 Choose high and low standards that bracket the
8.1.5 Find the mass percent ratio of the low value standard
sample isotope(s) being evaluated. If the mass percent
(Astandard)bydividingthemasspercentofthedesiredisotope
234 235 236
of U, U, and U are all desired, then the two standards
by the mass percent U.
mustbracketeachofthethreeisotopestopermitcalculationof
234 238
E 5mass% U/mass% U (4)
all isotopes for every run.
A
7.1.2 If standards that bracket all isotopes are unavailable,
235 238
analyze the isotope(s) bracketed by the originally selected
H 5mass% U/mass% U (5)
A
standards, then select other standards to run the remaining
isotope(s).
236 238
Y 5mass% U/mass% U (6)
A
7.2 Prepare Sample and Standards:
8.1.6 Find the equivalent mass percent ratio for the high
7.2.1 Attach sample and standard containers to the spec-
value standard (B standard.) Label it either E , H ,or Y .
trometer. B B B
8.1.7 Find the difference (D) between the mass percent
7.2.2 Open and close the appropriate valves to evacuate the
ratios of the A and B standards.
air from the inlet system.
7.2.3 Open the sample and standard containers individually
NOTE 2— E − E = D , H − H = D , and Y − Y = D
B A E B A H B A Y
and vent the gas phase to the cold trap. This is to remove
8.1.8 Find the mass percent ratio (desired isotope/ U) of
impurities that may bias the results or interfere with the
the sample by calculating E , H ,or Y as follows:
X X X
ionization. If necessary, freeze the UF with ice water or a
mixture of crushed dry ice and isopropyl alcohol to permit E 5 X 2 A / B
...
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