ASTM E318-91

Test Method for Uranium in Aqueous Solutions by Colorimetry (Withdrawn 1996)

SCOPE
1.1 This test method  covers the quantitative determination of uranium in known volumes of aqueous solutions that contain radioactive nuclides. These solutions arise from the processing of irradiated nuclear fuel and from laboratory studies on irradiated uranium.  
1.2 The applicability of the test method is limited to solutions that contain a minimum of 30 [mu]g of uranium per sample. It will detect as little as 0.5 [mu]g but with lower precision. Highest precision is obtained when 50 to 75 [mu]g of uranium is in the test sample. At concentrations above 750 [mu]g/mL dilutions must be made. The test method as described is limited to sample volumes of 1 mL or less, but reagent volumes can be scaled to accommodate larger sample aliquots or the sample can be concentrated by evaporation. The only known metal ion interferences are thorium and cerium(IV) when present at molar concentrations equal to or greater than the concentration of uranium. Thorium and cerium(IV) have tolerance limits greater than 1000 if the special extraction and scrub solutions are employed. Cerium(IV) present as a fission product does not interfere because its molar concentration is very low compared to uranium. The tolerance limit (no interference at the 95% confidence limit), expressed as the weight ratio of impurity to uranium, is greater than 1000 for silver, bismuth, calcium, cadmium, cobalt, chromium, copper, iron, mercury, lanthanum, manganese, sodium, nickel, lead, strontium, and zinc. The tolerance limit is greater than 100 for barium, beryllium, potassium, magnesium, and zirconium. Plutonium does not interfere when the weight ratio of plutonium to uranium is less than two. The test method is not designed for solutions containing plutonium in the presence of large amounts of thorium or cerium(IV). The tolerance limit is greater than 100 for the following anions: acetate, borate, bromate, chloride, fluoride, ferricyanide, molybdate, oxalate, phosphate, sulfate, persulfate, thiosulfate, and vanadate. The following anions interfere and have tolerance limits as follows: ferrocyanide 2, thiocyanate 58, and tungstate 12. The tolerance limit for free acid is 16 milliequivalents in the sample aliquot.  
1.3 The values stated in SI units are to be regarded as the standard.  
1.4 This standard does not purport to address all of the safety problems, 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. For a specific precaution statement, see Note 1.

General Information

• Status: Withdrawn
• Publication Date: 31-Dec-1990
• Withdrawal Date: 09-Jul-1996
• ICS: 27.120.30 - Fissile materials and nuclear fuel technology
• Technical Committee: C26 - Nuclear Fuel Cycle
• Drafting Committee: C26.05 - Methods of Test

Standards Content (Sample)

'ASTM E318 91 m 0759530 0080144 b m
AMERICAN SOCIETY FûR TESTING AND MATERIALS
Designation: E 318 - 91
1916 Race St Philadelphia, Pa 19103
Reprinted from the hua1 Book of ASTM Standards. Copyright ASTM
4Tb
if not ïffited in the current combined index, will appear in the nexi edtion.
Standard Test Method for
Uranium in Aqueous Solutions by Colorimetry'
This standard is issued under the fixed designation E 318; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope
safety problems, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
1.1 This test method2 covers the quantitative determina-
priate safety and health practices and determine the applica-
tion of uranium in known volumes of aqueous solutions that
bility of regulatory limitations prior to use. For a specific
contain radioactive nuclides. These solutions arise from the
precaution statement, see Note i.
processing of irradiated nuclear fuel and from laboratory
studies on irradiated uranium.
2. Referenced Documents
1.2 The applicability of the test method is limited to
2.1 ASTM Standards:
solutions that contain a minimum of 30 pg of uranium per
D 1193 Specification for Reagent Wate3
sample. It will detect as little as 0.5 pg but with lower
E 60 Practice for Photometric and Spectrophotometric
precision. Highest precision is obtained when 50 to 75 pg of
Methods for Chemical Analysis of Metals4
uranium is in the test sample. At concentrations above 750
E 180 Practice for Determining the Precision of ASTM
pg/mL dilutions must be made. The test method as de-
Methods for Analysis and Testing of Industrial Chem-
scribed is limited to sample volumes of l mL or less, but
ical~~
reagent volumes can be scaled to accommodate larger
E 267 Test Method for Uranium and Plutonium Concen-
sample aliquots or the sample can be concentrated by
trations and Isotopic Abundance&
evaporation. The only known metal ion interferences are
thorium and cerium(1V) when present at molar concentra-
3. Summary of Test Method
tions equal to or greater than the concentration of uranium.
3.1 The test method is based upon the measurement of
Thorium and cerium(1V) have tolerance limits greater than
the absorbance of the uranium-dibenzoylmethane complex
1000 if the special extraction and scrub solutions are
at 415 nm. All the uranium in the measured volume of
employed. Cerium(1V) present as a fission product does not
sample is first oxidized to uranium(V1) by potassium
interfere because its molar concentration is very low com-
permanganate. An acid-deficient solution of aluminum ni-
pared to uranium. The tolerance limit (no interference at the
trate and tetrapropylammonium nitrate serves as a salting
95 % confidence limit), expressed as the weight ratio of
solution to obtain quantitative extraction of uranium into a
impurity to uranium, is greater than 1000 for silver, bismuth,
hexone solvent. Scrubbing the organic extract with an
calcium, cadmium, cobalt, chromium, copper, iron, mer-
acid-deficient solution of aluminum nitrate containing
cury, lanthanum, manganese, sodium, nickel, lead, stron-
(ethylenedinitri1o)tetraacetic acid, and fer-
tartrate, oxalate,
tium, and zinc. The tolerance limit is greater than 100 for
rous sulfamate removes most interfering ions. Color develop-
barium, beryllium, potassium, magnesium, and zirconium.
ment is made in the hexone phase with the addition of
Plutonium does not interfere when the weight ratio of
dibenzoylmethane in an ethyl alcohol-pyridine mixture. A
plutonium to uranium is less than two. The test method is
portion of the solution is placed in a clean 5-cm absorption
not designed for solutions containing plutonium in the
cell and its absorbance measured. The concentration of
presence of large amounts of thorium or cerium(1V). The
uranium in the sample is determined from two comparison
tolerance limit is greater than i00 for the following anions:
standards bracketing the unknown and run concurrently, or
acetate, borate, bromate, chloride, fluoride, ferricyanide,
from a standard curve.
molybdate, oxalate, phosphate, sulfate, persulfate, thio-
3.2 If large amounts of thorium or cerium(1V) are present,
sulfate, and vanadate. The following anions interfere and
of aluminum nitrate without
an acid-deficient solution
have tolerance limits as follows: ferrocyanide 2, thiocyanate
tetrapropylammonium nitrate serves as the salting solution,
58, and tungstate 12. The tolerance limit for free acid is 16
and then the hexone phase is scrubbed with a solution of
milliequivalents in the sample aliquot.
ammonium acetate and sodium diethyldithiocarbamate. A
1.3 The value
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