ASTM C1429-99(2009)e1
(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, 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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Designation:C1429 −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.
´ NOTE—Section 1.3 was updated editorially in July 2009.
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
calculated.
1.3 This standard complements Test Methods C761, the
double-standard method for gas mass spectrometers using a
3.1.4 Lagrange’s interpolation formula, n—amathematical
singlecollector,byprovidingamethodforspectrometersusing
equation designed to estimate values between two or more
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.
C761Test Methods for Chemical, Mass Spectrometric,
Spectrochemical,Nuclear,andRadiochemicalAnalysisof
4. Summary of Test Method
Uranium Hexafluoride
4.1 Uranium hexafluoride gas is introduced into an ioniza-
C787Specification for Uranium Hexafluoride for Enrich-
ment tion source. The resulting ions are accelerated down the flight
tube into the magnetic field. The magnetic field separates the
C996Specification for Uranium Hexafluoride Enriched to
Less Than 5 % U ions into ion beams in accordance with the m/e ratio. Four
234 + 235 + 236 +
collectors are stationed so the UF , UF , UF ,
C1215Guide for Preparing and Interpreting Precision and
5 5 5
238 +
Bias Statements in Test Method Standards Used in the and UF ion beams strike individual collectors.
Nuclear Industry
4.2 Two standards are chosen whose values bracket the
desired isotope of the sample. The sample and two standards
are introduced in a six-entry, symmetrical sequence. Then,
This test method is under the jurisdiction ofASTM CommitteeC26 on Nuclear
measurements are taken that give the mole ratio of the desired
Fuel Cycle and is the direct responsibility of Subcommittee C26.05 on Methods of
Test.
isotope to U.
CurrenteditionapprovedJune1,2009.PublishedJuly2009.Originallyapproved
4.3 Through Lagrange’s interpolation formula, these mea-
in 1999. Last previous edition approved in 2004 as C1429–99 (2004). DOI:
10.1520/C1429-99R09E01.
surements are used to calculate the mass percent of the desired
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
isotope.Ifstandardsareavailablethatbracketallisotopes,then
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
234 235 236
the U, U, and U mass percents are calculated from the
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. same six-entry run.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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C1429−99 (2009)
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
5.1 Uranium hexafluoride used to produce nuclear-reactor six-entry, symmetrical sequences: low standard, sample, high
standard, high standard, sample, low standard.
fuel must meet certain criteria for its isotopic composition.
This test method may be used to help determine if sample
7.4 Run the Analysis:
materials meet the criteria described in Specifications C787
7.4.1 Obtain measurements from all four collectors during
and C996.
each entry.
6. Apparatus
8. Calculation
6.1 Mass spectrometer with the following features and
8.1 Perform the following operations for each of the U,
capabilities:
235 236
U, and U isotopes:
6.1.1 Anionsourcewithanacceleratingvoltageofapproxi-
+
8.1.1 For each entry, obtain a ratio by dividing the UF ion
mately 8 kV,
238 +
count of the desired isotope by the UF ion count.
6.1.2 A resolving power of greater than or equal to 500,
8.1.2 Find the mean of the two low standard ratios and
6.1.3 A minimum of three points of attachment for stan-
designate this A.
dards or samples,
8.1.3 Find the mean of the two sample ratios and designate
6.1.4 An ion collection system consisting of four collector
234 + 235 + 236 + this X.
cups stationed to collect UF , UF , UF , and
5 5 5
+
8.1.4 Find the mean of the two high standard ratios and
238UF ions,
designate this B.
6.1.5 An ion-current amplifier for each collector cup,
6.1.6 A voltage-to-frequency (V-to-F) converter for each
NOTE 1—In a six-entry symmetrical run sequence,
amplifier,
~r 1r !/2 5 A (1)
1 6
6.1.7 A counter for each V-to-F converter, and
~r 1r !/2 5 X (2)
6.1.8 Computercontroloveropeningandclosingvalves,the 2 5
timing, and the integration of analytical sequences.
r 1r /2 5 B (3)
~ !
3 4
where:
7. Procedure
th
r = the ratio from the n entry.
n
7.1 Select standards:
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)
A
all isotopes for every run.
235 238
H 5mass% U/mass% U (5)
A
7.1.2 If standards that bracket all isotopes are unavailable,
236 238
Y 5mass% U/mass% U (6)
analyze the isotope(s) bracketed by the originally selected
A
standards, then select other standards to run the remaining
8.1.6 Find the equivalent mass percent ratio for the high
isotope(s).
value standard (B standard.) Label it either E , H ,or Y .
B B B
7.2 Prepare Sample and Standards:
8.1.7 Find the difference (D) between the mass percent
7.2.1 Attach sample and standard containers to the spec-
ratios of the A and B standards.
trometer.
NOTE 2—E − E = D , H − H = D , and Y − Y = D
B A E B A H B A Y
7.2.2 Open and close the appropriate valves to evacuate the
8.1.8 Find the mass percent ratio (desired isotope/ U) of
air from the inlet system.
the sample by calculating E , H ,or Y as follows:
7.2.3 Open the sample and standard containers individually
X X X
and vent the gas phase to the cold trap. This is to remove
E 5~~X 2 A!/~B 2 A!!·D 1E (7)
X E A
impurities that may bias the results or interfere with the
ionization. If necessary, freeze the UF with ice water or a
H 5~~X 2 A!/~B 2 A!!·D 1H (8)
X H A
mixture of crushed dry ice
...
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