ASTM C1429-99(2009)
(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 test method covers a quantitative test method applicable to determining 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 %, and 234U and 236U between 0.0001 and 0.1 mass %.
1.2 This test method is for laboratory analysis by a gas mass spectrometer with a multi-collector.
1.3 This standard complements Test Methods 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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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation: C 1429 – 99 (Reapproved 2009)
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 (´) indicates an editorial change since the last revision or reapproval.
1. Scope C1215 Guide for Preparing and Interpreting Precision and
Bias Statements in Test Method Standards Used in the
1.1 This test method covers a quantitative test method
Nuclear Industry
applicabletodeterminingthemasspercentofuraniumisotopes
in uranium hexafluoride (UF ) samples. This method as de-
3. Terminology
scribed is for concentrations of U between 0.1 and 10
234 236
3.1 Definitions of Terms Specific to This Standard:
mass%, and U and U between 0.0001 and 0.1 mass%.
3.1.1 A standard, n—the low-value standard of a standard
1.2 Thistestmethodisforlaboratoryanalysisbyagasmass
pair that brackets the sample.
spectrometer with a multi-collector.
3.1.2 B standard, n—the high-value standard of a standard
1.3 This standard complements Test Methods C761, sec-
pair that brackets the sample.
tions 35 through 40, the double-standard method for gas mass
3.1.3 determination, n—a single isotopic value, calculated
spectrometers using a single collector, by providing a method
from a sequence of ratios; the most basic isotopic value
for spectrometers using a multi-collector.
calculated.
1.4 This standard does not purport to address all of the
3.1.4 Lagrange’s interpolation formula, n—a mathematical
safety concerns, if any, associated with its use. It is the
equation designed to estimate values between two or more
responsibility of the user of this standard to establish appro-
known values.
priate safety and health practices and determine the applica-
3.1.5 run, n—a completed, six-entry symmetrical sequence
bility of regulatory limitations prior to use.
consisting of A standard, sample, B standard, B standard,
2. Referenced Documents sample, and A standard from which a determination can be
calculated for one or more isotopes.
2.1 ASTM Standards:
3.1.6 standard spread, n—the difference between the high
C761 Test Methods for Chemical, Mass Spectrometric,
and low standards; sometimes called standard range.
Spectrochemical, Nuclear, and RadiochemicalAnalysis of
3.1.7 test result, n—a reported value; the mean of two or
Uranium Hexafluoride
more determinations.
C787 Specification for Uranium Hexafluoride for Enrich-
ment
4. Summary of Test Method
C996 Specification for Uranium Hexafluoride Enriched to
235 4.1 Uranium hexafluoride gas is introduced into an ioniza-
Less Than 5 % U
tion source. The resulting ions are accelerated down the flight
tube into the magnetic field. The magnetic field separates the
ions into ion beams in accordance with the m/e ratio. Four
234 + 235 + 236 +
This test method is under the jurisdiction ofASTM CommitteeC26 on Nuclear
collectors are stationed so the UF , UF , UF , and
5 5 5
Fuel Cycle and is the direct responsibility of Subcommittee C26.05 on Methods of
+
238UF ion beams strike individual collectors.
Test.
4.2 Two standards are chosen whose values bracket the
CurrenteditionapprovedJune1,2009.PublishedJuly2009.Originallyapproved
in 1999. Last previous edition approved in 2004 as C1429–99 (2004).
desired isotope of the sample. The sample and two standards
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
are introduced in a six-entry, symmetrical sequence. Then,
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
measurements are taken that give the mole ratio of the desired
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. isotope to U.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
C 1429 – 99 (2009)
4.3 Through Lagrange’s interpolation formula, these mea- pressure, or exhausting through the cold trap and observing
surements are used to calculate the mass percent of the desired pressure on the other side, or any other suitable means.
isotope.Ifstandardsareavailablethatbracketallisotopes,then 7.2.6 Ifnecessary,repeat7.2.3-7.2.5untilsamplesareclean.
234 235 236
the U, U, and U mass percents are calculated from the 7.3 Prepare Instrument:
same six-entry run. 7.3.1 Adjust instrument parameters to focus ion beams in
238 +
4.4 The results of two six-entry, symmetrical-sequence runs proper collectors and maximize the UF current reading.
areaveragedtofindtestresultsforeachisotope.The Umass 7.3.2 Enter standard values and other information if needed
percent is obtained by subtraction. for calculations performed by computer.
7.3.3 Program the spectrometer to run two of the following
5. Significance and Use
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
235U, and U isotopes:
capabilities: +
8.1.1 For each entry, obtain a ratio by dividing the UF ion
6.1.1 Anionsourcewithanacceleratingvoltageofapproxi-
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
8.1.4 Find the mean of the two high standard ratios and
234 + 235 + 236 +
cups stationed to collect UF , UF , UF , and
5 5 5
designate this B.
+
238UF ions,
NOTE 1—In a six-entry symmetrical run sequence,
6.1.5 An ion-current amplifier for each collector cup,
6.1.6 A voltage-to-frequency (V-to-F) converter for each
~r 1 r !/2 5 A (1)
1 6
amplifier,
r 1 r !/2 5 X (2)
~
2 5
6.1.7 A counter for each V-to-F converter, and
~r 1 r !/2 5 B (3)
3 4
6.1.8 Computercontroloveropeningandclosingvalves,the
timing, and the integration of analytical sequences.
where:
th
r = the ratio from the n entry.
n
7. Procedure
8.1.5 Find the mass percent ratio of the low value standard
7.1 Select standards:
(Astandard)bydividingthemasspercentofthedesiredisotope
7.1.1 Choose high and low standards that bracket the
by the mass percent U.
sample isotope(s) being evaluated. If the mass percent
234 235 236 234 238
E 5mass% U/mass% U (4)
of U, U, and U are all desired, then the two standards
A
mustbracketeachofthethreeisotopestopermitcalculationof 235 238
H 5mass% U/mass% U (5)
A
all isotopes for every run.
236 238
Y 5mass% U/mass% U (6)
A
7.1.2 If standards that bracket all isotopes are unavailable,
analyze the isotope(s) bracketed by the originally selected 8.1.6 Find the equivalent mass percent ratio for the high
standards, then select other standards to run the remaining value standard (B standard.) Label it either E , H ,or Y .
B B B
isotope(s). 8.1.7 Find the difference (D) between the mass percent
7.2 Prepare Sample and Standards: ratios of the A and B standards.
7.2.1 Attach sample and standard containers to the spec-
NOTE 2—E − E = D , H − H = D , and Y − Y = D
B A E B A H B A Y
trometer.
8.1.8 Find the mass percent ratio (desired isotope/ U) of
7.2.2 Open and close the appropriate valves to evacuate the
the sample by calculating E , H ,or Y as follows:
air from the inlet system. X X X
7.2.3 Open the sample and standard containers individually
E 5~~X 2 A!/ ~B 2 A!!· D 1 E (7)
X E A
and ve
...
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