ASTM C799-19

Standard Test Methods for Chemical, Mass Spectrometric, Spectrochemical, Nuclear, and Radiochemical Analysis of Nuclear-Grade Uranyl Nitrate Solutions

SIGNIFICANCE AND USE
4.1 Uranyl nitrate solution is used as a feed material for conversion to the hexafluoride as well as for direct conversion to the oxide. In order to be suitable for this purpose, the material must meet certain criteria for uranium content, isotopic composition, acidity, radioactivity, and impurity content. These methods are designed to show whether a given material meets the specifications for these items described in Specification C788.  
4.1.1 An assay is performed to determine whether the material has the specified uranium content.  
4.1.2 Determination of the isotopic content of the uranium is made to establish whether the effective fissile content is in accordance with the purchaser’s specifications.  
4.1.3 Acidity, organic content, and alpha, beta, and gamma activity are measured to establish that they do not exceed their maximum limits.  
4.1.4 Impurity content is determined to ensure that the maximum concentration limit of certain impurity elements is not exceeded. Impurity concentrations are also required for calculation of the equivalent boron content (EBC), and the total equivalent boron content (TEBC).
SCOPE
1.1 These test methods cover procedures for the chemical, mass spectrometric, spectrochemical, nuclear, and radiochemical analysis of nuclear-grade uranyl nitrate solution to determine compliance with specifications.  
1.2 The analytical procedures appear in the following order:    
Sections  
Determination of Uranium  
8  
Specific Gravity by Pycnometry  
16 – 21  
Free Acid by Oxalate Complexation  
22 – 28  
Determination of Thorium  
29  
Determination of Chromium  
30  
Determination of Molybdenum  
31  
Halogens Separation by Steam Distillation  
32 – 36  
Fluoride by Specific Ion Electrode  
37 – 43  
Halogen Distillate Analysis: Chloride, Bromide, and Iodide by
Amperometric Microtitrimetry  
44  
Determination of Chloride and Bromide  
45  
Determination of Sulfur by X-Ray Fluorescence  
46  
Sulfate Sulfur by (Photometric) Turbidimetry  
47  
Phosphorus by the Molybdenum Blue (Photometric) Method  
55 – 62  
Silicon by the Molybdenum Blue (Photometric) Method  
63 – 70  
Carbon by Persulfate Oxidation-Acid Titrimetry  
71  
Conversion to U3O8  
72 – 75  
Boron by Emission Spectrography  
A  
Impurity Elements by Spark Source Mass Spectrography  
77  
Isotopic Composition by Thermal Ionization Mass Spectrometry  
78  
Uranium-232 by Alpha Spectrometry  
79 – 85  
Total Alpha Activity by Direct Alpha Counting  
86 – 92  
Fission Product Activity by Beta Counting  
93 – 99  
Entrained Organic Matter by Infrared Spectrophotometry  
100  
Fission Product Activity by Gamma Counting  
101  
Determination of Arsenic  
102  
Determination of Impurities for the EBC Calculation  
103  
Determination of Technetium 99  
104  
Determination of Plutonium and Neptunium  
105  
1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  Specific precautionary statements are given in Section 6.  
1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 30-Jun-2019
• ICS: 27.120.30 - Fissile materials and nuclear fuel technology
• Technical Committee: C26 - Nuclear Fuel Cycle
• Drafting Committee: C26.05 - Methods of Test

Relations

• Replaces: ASTM C799-12 - Standard Test Methods for Chemical, Mass Spectrometric, Spectrochemical, Nuclear, and Radiochemical Analysis of Nuclear-Grade Uranyl Nitrate Solutions
• Effective Date: 01-Jul-2019
• Refers: ASTM C1295-24 - Standard Test Method for Gamma Energy Emission from Fission and Decay Products in Uranium Hexafluoride and Uranyl Nitrate Solution
• Effective Date: 15-Jan-2024
• Refers: ASTM C859-24 - Standard Terminology Relating to Nuclear Materials
• Effective Date: 01-Jan-2024
• Refers: ASTM C696-19 - Standard Test Methods for Chemical, Mass Spectrometric, and Spectrochemical Analysis of Nuclear-Grade Uranium Dioxide Powders and Pellets
• Effective Date: 01-Nov-2019
• Refers: ASTM C1413-18 - Standard Test Method for Isotopic Analysis of Hydrolyzed Uranium Hexafluoride and Uranyl Nitrate Solutions by Thermal Ionization Mass Spectrometry
• Effective Date: 01-Nov-2018
• Refers: ASTM C1254-18 - Standard Test Method for Determination of Uranium in Mineral Acids by X-Ray Fluorescence
• Effective Date: 01-Oct-2018
• Refers: ASTM C1871-18 - Standard Test Method for Determination of Uranium Isotopic Composition by the Double Spike Method Using a Thermal Ionization Mass Spectrometer
• Effective Date: 01-Feb-2018
• Refers: ASTM C761-18 - Standard Test Methods for Chemical, Mass Spectrometric, Spectrochemical, Nuclear, and Radiochemical Analysis of Uranium Hexafluoride
• Effective Date: 01-Feb-2018
• Refers: ASTM C1287-18 - Standard Test Method for Determination of Impurities in Nuclear Grade Uranium Compounds by Inductively Coupled Plasma Mass Spectrometry
• Effective Date: 01-Jan-2018
• Refers: ASTM C1561-10(2016) - Standard Guide for Determination of Plutonium and Neptunium in Uranium Hexafluoride and U-Rich Matrix by Alpha Spectrometry
• Effective Date: 01-Jun-2016
• Refers: ASTM C1517-16 - Standard Test Method for Determination of Metallic Impurities in Uranium Metal or Compounds by DC-Arc Emission Spectroscopy
• Effective Date: 01-Apr-2016
• Refers: ASTM C1295-15 - Standard Test Method for Gamma Energy Emission from Fission and Decay Products in Uranium Hexafluoride and Uranyl Nitrate Solution
• Effective Date: 01-Jun-2015
• Refers: ASTM C859-14a - Standard Terminology Relating to Nuclear Materials
• Effective Date: 15-Jun-2014
• Refers: ASTM C1295-14 - Standard Test Method for Gamma Energy Emission from Fission and Decay Products in Uranium Hexafluoride and Uranyl Nitrate Solution
• Effective Date: 15-Jun-2014
• Refers: ASTM C859-14 - Standard Terminology Relating to Nuclear Materials
• Effective Date: 15-Jan-2014

Overview

ASTM C799-19, "Standard Test Methods for Chemical, Mass Spectrometric, Spectrochemical, Nuclear, and Radiochemical Analysis of Nuclear-Grade Uranyl Nitrate Solutions," is a widely recognized standard developed by ASTM International. This standard outlines comprehensive analytical procedures to determine the chemical composition and purity of nuclear-grade uranyl nitrate solutions, ensuring that these materials meet strict industry specifications for use as feed materials in nuclear fuel processing and reactor operations. Adherence ensures quality, safety, and regulatory compliance throughout the nuclear fuel cycle.

Key Topics

The standard covers a broad range of test methods critical for nuclear quality assurance and regulatory adherence, including:

• Uranium Content Determination: Accurate assay methods confirm the material has the required uranium concentration.
• Isotopic Analysis: Methods establish the uranium isotopic composition and effective fissile content, ensuring it meets specific requirements.
• Acidity and Organic Content: Procedures measure acidity and any organic impurities to verify they remain within allowable limits.
• Radioactivity Measurements: Alpha, beta, and gamma activities are quantified for compliance with prescribed safety thresholds.
• Contaminant and Impurity Evaluation: Tests determine maximum allowable levels of elements such as thorium, chromium, molybdenum, halogens, sulfur, phosphorus, silicon, arsenic, technetium, and more.
• Physical Properties Analysis: Includes specific gravity measurements and the assessment of the solution’s physical characteristics.
• Total Equivalent Boron Content (TEBC) Calculation: Impurity concentrations are analyzed for accurate boron equivalency calculations, critical in reactor material evaluation.
• Conversion to U3O8: Procedures for converting uranyl nitrate to uranium oxide for further analysis or processing.

Applications

Adherence to ASTM C799-19 is vital throughout the nuclear fuel cycle, including:

• Feedstock Qualification: Used by nuclear facilities and laboratories to validate uranyl nitrate solutions prior to conversion to uranium hexafluoride (UF6) or uranium oxides for downstream processing.
• Nuclear Fuel Fabrication: Guarantees that feed materials meet stringent parameters for uranium content, purity, and isotopic integrity.
• Quality Assurance & Compliance: Laboratories, manufacturers, and regulators rely on these methods for quality control, regulatory verification, international material transfers, and nuclear safeguards.
• Environmental and Safety Monitoring: Supports environmental, health, and safety protocols by quantifying radioactivity and limiting hazardous impurities or byproducts.

The comprehensive methods ensure that uranyl nitrate solutions not only meet the chemical, radiochemical, and isotopic specifications mandated by nuclear industry standards (such as ASTM C788), but also adhere to national and international safety and trade regulations.

Related Standards

Several other ASTM and international standards complement ASTM C799-19 by addressing similar or supporting methodologies and specifications, including:

• ASTM C788: Specification for Nuclear-Grade Uranyl Nitrate Solution or Crystals
• ASTM C761: Test Methods for Chemical and Spectrochemical Analysis of Uranium Hexafluoride
• ASTM C1287: Determination of Impurities in Nuclear Grade Uranium Compounds by ICP-MS
• ASTM C1254: Uranium in Mineral Acids by X-Ray Fluorescence
• ASTM C1295: Gamma Energy Emission from Fission and Decay Products
• ISO 7097: Determination of Uranium in Uranium Product Solutions by Cerium(IV) Oxidation Titrimetric Method

For organizations involved in nuclear materials processing, fuel fabrication, or regulation, following ASTM C799-19 and related standards is essential for technical reliability, regulatory compliance, and international acceptance.

By incorporating these test methods, nuclear professionals ensure accurate, repeatable, and compliant analysis of nuclear-grade uranyl nitrate solutions, facilitating safe operation and global collaboration in the nuclear industry.

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: C799 − 19
Standard Test Methods for
Chemical, Mass Spectrometric, Spectrochemical, Nuclear,
and Radiochemical Analysis of Nuclear-Grade Uranyl Nitrate
Solutions
This standard is issued under the fixed designation C799; 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 1.4 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
1.1 These test methods cover procedures for the chemical,
responsibility of the user of this standard to establish appro-
mass spectrometric, spectrochemical, nuclear, and radiochemi-
priate safety, health, and environmental practices and deter-
cal analysis of nuclear-grade uranyl nitrate solution to deter-
mine the applicability of regulatory limitations prior to use.
mine compliance with specifications.
Specific precautionary statements are given in Section 6.
1.2 Theanalyticalproceduresappearinthefollowingorder:
1.5 This international standard was developed in accor-
Sections
dance with internationally recognized principles on standard-
Determination of Uranium 8
ization established in the Decision on Principles for the
Specific Gravity by Pycnometry 16–21
Development of International Standards, Guides and Recom-
Free Acid by Oxalate Complexation 22–28
Determination of Thorium 29
mendations issued by the World Trade Organization Technical
Determination of Chromium 30
Barriers to Trade (TBT) Committee.
Determination of Molybdenum 31
Halogens Separation by Steam Distillation 32–36
2. Referenced Documents
Fluoride by Specific Ion Electrode 37–43
Halogen Distillate Analysis: Chloride, Bromide, and Iodide by 44
2.1 ASTM Standards:
Amperometric Microtitrimetry
Determination of Chloride and Bromide 45 C696Test Methods for Chemical, Mass Spectrometric, and
Determination of Sulfur by X-Ray Fluorescence 46
SpectrochemicalAnalysis of Nuclear-Grade Uranium Di-
Sulfate Sulfur by (Photometric) Turbidimetry 47
oxide Powders and Pellets
Phosphorus by the Molybdenum Blue (Photometric) Method 55–62
Silicon by the Molybdenum Blue (Photometric) Method 63–70
C761Test Methods for Chemical, Mass Spectrometric,
Carbon by Persulfate Oxidation-Acid Titrimetry 71
Spectrochemical,Nuclear,andRadiochemicalAnalysisof
Conversion to U O 72–75
3 8
A
Uranium Hexafluoride
Boron by Emission Spectrography
Impurity Elements by Spark Source Mass Spectrography 77
C788Specification for Nuclear-Grade Uranyl Nitrate Solu-
Isotopic Composition by Thermal Ionization Mass Spectrometry 78
tion or Crystals
Uranium-232 by Alpha Spectrometry 79–85
C859Terminology Relating to Nuclear Materials
Total Alpha Activity by Direct Alpha Counting 86–92
Fission Product Activity by Beta Counting 93–99 C1219Test Methods for Arsenic in Uranium Hexafluoride
Entrained Organic Matter by Infrared Spectrophotometry 100 3
(Withdrawn 2015)
Fission Product Activity by Gamma Counting 101
C1233Practice for Determining Equivalent Boron Contents
Determination of Arsenic 102
Determination of Impurities for the EBC Calculation 103
of Nuclear Materials
Determination of Technetium 99 104
C1254Test Method for Determination of Uranium in Min-
Determination of Plutonium and Neptunium 105
eral Acids by X-Ray Fluorescence
A
C1267Test Method for Uranium by Iron (II) Reduction in
Discontinued July 2019.
PhosphoricAcid Followed by Chromium (VI)Titration in
1.3 The values stated in SI units are to be regarded as
the Presence of Vanadium
standard. No other units of measurement are included in this
C1287Test Method for Determination of Impurities in
standard.
Nuclear Grade Uranium Compounds by Inductively
1 2
These test methods are under the jurisdiction of ASTM Committee C26 on For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Nuclear Fuel Cycle and are the direct responsibility of Subcommittee C26.05 on contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Methods of Test. Standards volume information, refer to the standard’s Document Summary page on
Current edition approved July 1, 2019. Published August 2019. Originally the ASTM website.
approved in 1975. Last previous edition approved in 2012 as C799–12. DOI: The last approved version of this historical standard is referenced on
10.1520/C0799-19. www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
C799 − 19
Coupled Plasma Mass Spectrometry 4.1.1 An assay is performed to determine whether the
C1295Test Method for Gamma Energy Emission from material has the specified uranium content.
Fission and Decay Products in Uranium Hexafluoride and 4.1.2 Determination of the isotopic content of the uranium
Uranyl Nitrate Solution is made to establish whether the effective fissile content is in
C1296Test Method for Determination of Sulfur in Uranium accordance with the purchaser’s specifications.
Oxides and Uranyl Nitrate Solutions by X-Ray Fluores- 4.1.3 Acidity, organic content, and alpha, beta, and gamma
cence (XRF) (Withdrawn 2007) activity are measured to establish that they do not exceed their
C1380Test Method for the Determination of Uranium Con- maximum limits.
tent and Isotopic Composition by Isotope Dilution Mass 4.1.4 Impurity content is determined to ensure that the
Spectrometry (Withdrawn 2018) maximum concentration limit of certain impurity elements is
C1413Test Method for Isotopic Analysis of Hydrolyzed not exceeded. Impurity concentrations are also required for
Uranium Hexafluoride and Uranyl Nitrate Solutions by calculationoftheequivalentboroncontent(EBC),andthetotal
Thermal Ionization Mass Spectrometry equivalent boron content (TEBC).
C1517TestMethodforDeterminationofMetallicImpurities
in Uranium Metal or Compounds by DC-Arc Emission 5. Reagents
Spectroscopy
5.1 Purity of Reagents—Reagent grade chemicals shall be
C1561Guide for Determination of Plutonium and Neptu-
used in all tests. Unless otherwise indicated, it is intended that
nium in Uranium Hexafluoride and U-Rich Matrix by
all reagents shall conform to the specifications of the Commit-
Alpha Spectrometry
tee onAnalytical Reagents of theAmerican Chemical Society,
C1871Test Method for Determination of Uranium Isotopic 4
where such specifications are available. Other grades may be
Composition by the Double Spike Method Using a Ther-
used, provided it is first ascertained that the reagent is of
mal Ionization Mass Spectrometer
sufficiently high purity to permit its use without lessening the
D1193Specification for Reagent Water
accuracy of the determination.
E12Terminology Relating to Density and Specific Gravity
5.2 Purity of Water—Unless otherwise indicated, references
of Solids, Liquids, and Gases (Withdrawn 1996)
towatershallbeunderstoodtomeanreagentwaterconforming
E60Practice for Analysis of Metals, Ores, and Related
to Specification D1193.
Materials by Spectrophotometry
E115Practice for Photographic Processing in Optical Emis-
5.3 Hydrofluoric acid (used in some of the procedures) is a
sion Spectrographic Analysis (Withdrawn 2002) highly corrosive acid that can severely burn skin, eyes, and
mucousmembranes.Hydrofluoricaciddiffersfromotheracids
2.2 American Chemical Society Specification:
because the fluoride ion readily penetrates the skin, causing
Reagent Chemicals
destruction of deep tissue layers. Unlike other acids that are
2.3 Other Documents:
rapidlyneutralized,hydrofluoricacidreactionswithtissuemay
ISO 7097Determination of Uranium in Uranium Product
continue for days if left untreated. Familiarization and compli-
Solutions and Solids with Cerium IV Oxidation Titrimet-
ance with the Safety Data Sheet is essential.
ric Method
6. Safety Precautions
3. Terminology
6.1 Use of this standard does not relieve the user of the
3.1 For definitions of terms used in this test method but not
obligation to be aware of and to conform to all health and
defined herein, refer to Terminology C859.
safety requirements.
6.2 The user should also be cognizant of and adhere to all
4. Significance and Use
federal,state,andlocalregulationsforprocessing,shipping,or
4.1 Uranyl nitrate solution is used as a feed material for
in any way using uranyl nitrate solutions.
conversion to the hexafluoride as well as for direct conversion
to the oxide. In order to be suitable for this purpose, the
7. Sampling
material must meet certain criteria for uranium content, isoto-
7.1 Criteria for sampling this material are given in Specifi-
pic composition, acidity, radioactivity, and impurity content.
cation C788.
These methods are designed to show whether a given material
meets the specifications for these items described in Specifi-
DETERMINATION OF URANIUM
cation C788.
8. Scope
4 8.1 Uraniumcanbedeterminedusingiron(II)reductionand
Reagent Chemicals, American Chemical Society Specifications, American
Chemical Society, Washington, DC. For suggestions on the testing of reagents not dichromate titration. Test Method C1267 can be used.
listed by the American Chemical Society, see Analar Standards for Laboratory
8.2 Uranium can also be determined using cerium (IV)
Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia
and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, oxidation titrimetry. ISO 7097 Test Method can be used.
MD.
8.3 UraniumcanalsobedeterminedbyX-RayFluorescence
Available fromAmerican National Standards Institute (ANSI), 25 W. 43rd St.,
4th Floor, New York, NY 10036, http://www.ansi.org. using Test Method C1254.
C799 − 19
8.4 Previous sections have been deleted. SPECIFIC GRAVITY BY PYCNOMETRY
URANIUM BY IGNITION GRAVIMETRY
16. Scope
16.1 This test method covers the determination of the
9. Scope
specific gravity of a solution of uranyl nitrate to 60.0004.
9.1 Thistestmethodcoversthedeterminationofuraniumin
nuclear-grade uranyl nitrate solution. Appropriate size sample
17. Summary of Test Method
aliquots are chosen to obtain 5 to 10 g of U O .
3 8
17.1 A known volume of the solution adjusted at a con-
10. Summary of Test Method
trolled temperature is weighed and compared to the weight of
water measured in the same container (Terminology E12).
10.1 The uranyl nitrate solution is evaporated to dryness,
ignited to U O , and weighed. Corrections are made for any
3 8
18. Apparatus
impurities present (1, 2).
18.1 Volumetric Flasks, 50-mL, Class A.
11. Interferences
18.2 Water Bath, temperature controlled to 60.1°C at a
11.1 The weight of U O is corrected for the nonvolatile
3 8
temperature slightly above normal room temperature, and
impurities present as determined by spectrographic analysis.
provided with clips for holding volumetric flasks.
11.2 Volatile anions that are difficult to decompose require
an extended ignition period.
19. Procedure
19.1 Weightheclean,dryvolumetricflaskanditsstopperto
12. Apparatus
the nearest 0.1 mg.
12.1 Heat Lamp, infrared.
19.2 Fillthevolumetricflaskwiththeuranylnitratesolution
12.2 Hot Plate.
to a point close to the volume mark, using a thin-stemmed
12.3 Muffle Furnace.
funnel and a glass dropper.
19.3 Place the stoppered volumetric flask in the water bath
13. Procedure
for 30 min.
13.1 Transfer a weighed portion of uranyl nitrate solution
19.4 Use a finely drawn glass dropper to adjust the liquid
containing 5 to 10 g of uranium into a preweighed platinum
volume to the mark.
dish and add 2 drops of HF (48%).
13.2 Positionthedishundertheheatlampandevaporatethe 19.5 Leave the flask in the water bath an additional 10 min
solution to dryness. to make sure that the bath temperature has been reached.
13.3 Placethedishonahotplatewithasurfacetemperature
19.6 Dry and weigh the flask to the nearest 0.1 mg.
of about 300°C and heat until most of the nitrate has decom-
19.7 Repeat 19.2 – 19.6 using boiled and cooled distilled
posed.
water instead of the uranyl nitrate solution.
13.4 Transfer the dish to a muffle furnace and ignite for 2 h
at 900°C.
20. Calculation
13.5 Remove the dish to a desiccator and allow to cool to
20.1 Very accurate determinations of specific gravity re-
room temperature.
quire that vacuo corrections be made, but if a median correc-
13.6 Weighthedish;thenrepeat13.4–13.6untilaconstant tion figure in terms of grams per grams of sample is applied to
weight is obtained. the solution weights in all cases the resulting error will not
exceed 0.05%.
14. Calculation
B 2 A10.0007 ~B 2 A!
Spgr 5 (2)
14.1 Calculate the uranium content as follows:
C 2 A10.0010 C 2 A
~ !
Uranium, g/g 5 B 2 C /A D (1)
~~ ! !
where:
where: B = sample plus flask in air, g,
A = flask in air, g,
A = sample, g,
C = water plus flask in air, g,
B =U O obtained, g,
3 8
0.0007 g/g = correctionfactorapplicablefordensitiesof1.3
C = impurity-element oxides, g, and
to 1.5, and
D = gravimetric factor, grams of uranium/grams of U O
3 8
0.0010 g/g = correction factor for water.
(varies according to uranium enrichment).
21. Precision
15. Precision
15.1 The limit of error at the 95% confidence level for a 21.1 The limit of error at the 95% level for a single
single determination is 60.03%. determination is 60.03%.
C799 − 19
NOTE 2—Negative values of free acid indicate an acid deficiency.
FREE ACID BY OXALATE COMPLEXATION
22. Scope
28. Precision
22.1 This test method covers the determination of the free
28.1 The limit of error at the 95% confidence level for a
acid content of uranyl nitrate solutions that may contain a ratio
single determination is 63%.
of up to 5 moles of acid to 1 mole of uranium.
DETERMINATION OF THORIUM
23. Summary of Test Method
29. Scope
23.1 Toadilutedsolutionofuranylnitrate,solid,pulverized
potassium oxalate is added until a pH of about 4.7 is reached.
29.1 The determination of thorium by the arsenazo (III)
The solution is then titrated with standard NaOH solution by
(photometric) method has been discontinued, (see C799-93).
the delta pH method to obtain the inflection point (3).
29.2 As an alternative, thorium can be determined using
Inductively Coupled Plasma Mass Spectrometry (ICP-MS).
24. Apparatus
See Test Method C1287.
24.1 pH Meter, with glass and calomel electrodes.
29.3 Previous sections have been deleted.
24.2 Buret, Class A, 50-mL.
DETERMINATION OF CHROMIUM
25. Reagents
25.1 Nitric Acid (2.0 N)—Dilute 130 mL of HNO (sp gr
3 30. Scope
1.42) to 1 L with water. Standardize with sodium hydroxide
30.1 The determination of chromium by the diphenyl car-
solution (see 25.4).
bazide method has been discontinued, (see C799-93).
25.2 Potassium Oxalate (K C O ·H O), crystals.
2 2 4 2
30.2 As an alternative, chromium can be determined using
25.3 Potassium Hydrogen Phthalate (C H KO ), acidimet-
8 5 4 inductively coupled plasma atomic emission spectrometry
ric standard grade.
(ICP-AES). Test Method C761 can be used providing a
transformation to U O so described hereafter in Sections 72 –
25.4 Sodium Hydroxide Solution (0.3 N)—Dissolve 12.0 g 3 8
75.Adirectconversiontotheamoniumfluorideplusnitricacid
ofNaOHin1Lofwater.Standardizewithpotassiumhydrogen
solution can also be used, (see C761).
phthalate.
30.3 As an alternative, chromium can be determined using
26. Procedure
atomic absorption spectroscopy. Test Method C761 can be
26.1 Transfer a 5-mLsample aliquot into a 250-mLbeaker.
used.
26.2 Add 100 mLof distilled water or such volume that the
30.4 As an alternative, chromium can be determined using
uranium concentration will be between 7 and 50 g/L.
ICP-MS. Test Method C1287 can be used.
26.3 Addaspikeofsufficient2.0NstandardHNO tomake
30.5 Previous sections have been deleted.
the sample definitely acid if the sample is neutral or acid
DETERMINATION OF MOLYBDENUM
deficient.
26.4 AddpulverizedK C O ·H Oslowlyandwithconstant
2 2 4 2
31. Scope
stirring until a pH of 4.7 to 4.9 is reached.
31.1 The determination of molybdenum by the thiocyanate
26.5 Immerse the titration beaker in an ice bath. (Titrations
(photometric) method has been discontinued, (See C799-93).
made at room temperature are possible but are less sharp.)
31.2 As an alternative, molybdenum can be determined
26.6 Titrate with 0.3 N NaOH using 0.20-mL increments
using ICP-MS. Test Method C1287 can be used.
and determine the inflection point by the delta pH or “analyti-
31.3 As an alternative, molybdenum can be determined
cal” method.
usingICP-AES.TestMethodC761,Sections251to271canbe
NOTE1—Thistestmethodoflocatingtheendpointdependsonthefact
used providing a tranformation to U O as described hereafter
2 2
3 8
that the second derivative ∆ pH/∆vol is zero at the point where the slope
in Sections 72–75. A direct conversion to the amonium
∆pH/∆vol is a maximum.
fluoride plus nitric acid solution can also be used, (see C761,
27. Calculation
Section 251).
27.1 Calculate the free acid normality, N, as follows:
31.4 Previous sections have been deleted.
N 5 A 3N 2 C 3N /5 (3)
~ !
B A
HALOGENS SEPARATION BY STEAM
where: DISTILLATION
A = NaOH solution used in the titration, mL
32. Scope
N = normality of the NaOH solution,
B
C = HNO solution used in the spike, mL, and
32.1 This test method covers the separation of the halogens
N = normality of HNO solution.
A 3
by means of a steam distillation.
C799 − 19
33. Summary of Test Method 36.2 Add 25 mLof the acid mixture to the distillation flask.
33.1 A sample aliquot is mixed with a solution containing 36.3 Transfer 5 mL of the KOH solution to a 100-mL
ferrousammoniumsulfate,sulfamicacid,phosphoricacid,and
graduated cylinder and position it under the condenser tip.
sulfuric acid. The halogens are then steam distilled at a
36.4 Heat the distillation flask until the thermometer in the
temperature of 140°C.
well reaches 140°C.
34. Apparatus
36.5 Pass steam through from the boiler, and maintain at a
temperature of 140°C until a volume of 90 mL is collected.
34.1 Steam Distillation Apparatus (see Fig. 1).
34.1.1 Distilling Flask, 200-mL with thermometer well.
36.6 Add2dropsofphenolphthaleinsolutionandadjustthe
34.1.2 Condenser.
pHofthedistillatewithKOHorHNO ,tothephenolphthalein
34.1.3 Heating Mantle.
end point. Make the volume to 100 mL.
34.1.4 Steam Boiler, 500-mL flask.
36.7 Repeatthedistillation,omittingtheuraniumsample,to
35. Reagents
use as the matrix for the fluoride standard curve.
35.1 Absorber Solution (4 M Potassium Hydroxide)—
36.8 Reserve the distillate for the fluoride and combined
Dissolve 22.4 g KOH pellets in water and dilute to 100 mL.
halide determinations.
35.2 Acid Mixture—Mix 0.2 M ferrous ammonium sulfate-
FLUORIDE BY SPECIFIC ION ELECTRODE
0.5 M sulfamic acid (see 35.3), phosphoric acid (85%), and
sulfuric acid (sp gr 1.84) in the ratio of1+2+5.
37. Scope
35.3 Ferrous Ammonium Sulfate Solution (0.2 M)-Sulfamic
37.1 This test method covers the determination of as low as
Acid (0.5 M) Solution—Dissolve 78.4 g Fe (NH ) (SO ) ·6
4 2 4 2
2 µg F/g U in distillate containing all the halogens.
H O and 48.6 g NH SOHinH SO (5+95) and dilute to 1 L
2 2 3 2 4
with H SO (5+95).
2 4
38. Summary of Test Method
35.4 Phenolphthalein Solution (10 g/L)—Dissolve1gof
38.1 An aliquot of the distillate representing1gof uranium
phenolphthalein in 50 mL of ethanol and add 50 mL of water.
is measured by specific ion electrode and compared to a
36. Procedure
standard curve prepared by spiking equivalent-size aliquots
taken from a blank distillation (4, 5).
36.1 Place a weighed portion of about 15 mL containing
approximately5gof uranium in the distillation flask.
39. Apparatus
39.1 pH Meter, expanded scale.
39.2 Ion-Selective Electrode, fluoride.
39.3 Reference Electrode, single-junction.
40. Reagents
40.1 BufferSolution(0.001N)—Dissolve0.1gofpotassium
acetate (KC H O ) in water. Add 0.050 mL of acetic acid (sp
2 3 2
gr 1.05) and dilute to 1 L.
40.2 Fluoride Standard Solution A (1 mL=1 mg F)—
Dissolve 0.220 g of dried sodium fluoride (NaF) in 25 mL of
water and dilute to 100 mL.
40.3 Fluoride Standard Solution B (1 mL=5 µg F)—Dilute
5 mLof the fluoride standard SolutionA(see 40.2) to 1 Lwith
water.
41. Procedure
41.1 Pipet a 20-mL aliquot of the sample distillate (repre-
senting about 1 g of uranium) into a 25-mL flask and make to
volume with the buffer solution.
41.2 Prepare a standard curve by pipetting 20-mL aliquots
−
from the blank distillate into 25-mL flasks and adding F
−
standard solution to make 0, 5, 10, and 20 µg F /25 mL.
41.3 Measure all of the solutions with the fluoride ion-
FIG. 1 Halogen Distillation Apparatus selective electrode.
C799 − 19
42. Calculation 49.2 Many variables, although not classed as interferants,
− effect the precision of this test method. Careful control of the
42.1 Calculate the F content as follows:
following parameters must be maintained to achieve the stated
F , µg/g 5 A/B (4)
precision: particle size of the barium chloride (BaCl ), particle
size of the BaSO formed, total ionic concentration of the final
where: 4
−
solution, degree of mixing of sample and reagents (number of
A =F found in the sample distillate aliquot, µg, and
times the flask is inverted), concentration of hydrogen ion in
B = uranium represented by the sample distillate aliquot, g.
the final solution, and the length of time of standing of the
supernatant before the absorbance is measured.
43. Precision
43.1 The limit of error at the 95% confidence level for a
50. Apparatus
single determination is 625%.
50.1 Spectrophotometer—See Practice E60.
HALOGEN DISTILLATE ANALYSIS: CHLORIDE,
51. Reagents
BROMIDE, AND IODIDE BY AMPEROMETRIC
MICROTITRIMETRY
51.1 BariumChloride(BaCl ),crystals.Siftthesaltanduse
only the portion that passes through a 28-mesh screen and is
44. Scope
retained on a 35-mesh screen.
44.1 The determination of chloride, bromide and iodide by
51.2 SodiumChloride-GlycerinSolution(16g/L)—Dissolve
microtitrimetric method has been discontinued, (see C799-93).
40 g of NaCl in 60 mL of HCl (sp gr 1.19). Add 833 mL of
44.2 Previous sections have been deleted. glycerin and dilute to 2.5 L with water.
−
51.3 Sulfate Standard Solution (1 mL=1000 µg SO )—
DETERMINATION OF CHLORIDE AND BROMIDE
Dissolve 1.1813 g of K SO , dried at 110°C for 1 h, and dilute
2 4
45. Scope to 1 L with water.
51.4 TributylPhosphateSolution(3+7)—Dilute300mLof
45.1 Determination of bromide by the fluorescein (photo-
TBPwith700mLofkeroseneandequilibratewith8MHNO .
metric) method has been discontinued, (see C799-93).
45.2 As an alternative, bromide and chloride can be deter-
52. Procedure
mined by X-Ray Fluorescence. Halogens are precipitated by
52.1 Transfer a weighed aliquot of sample that contains
silver nitrate and filtrated. The precipitate is washed and
approximately1gof uranium to a 60-mL separatory funnel.
counted by X-Ray Fluorescence.
Adjustthenitricacidconcentrationto4to5 Mandthevolume
45.3 Previous sections have been deleted.
to 5 mL.
DETERMINATION OF SULFUR BY X-RAY 52.2 Add 10 mL of TBP solution (see 51.4) and equilibrate
FLUORESCENCE
the solutions.
52.3 Allow the layers to separate and transfer the aqueous
46. Scope
layer to 50-mL volumetric flask containing 30 mL of distilled
46.1 Sulfur can be determined using X-Ray Fluorescence.
water. Use a minimum volume of 1 N HNO wash solution to
See Test Method C1296.
ensure quantitative transfer of the aqueous layer to the 50-mL
flask.
SULFATE SULFUR BY (PHOTOMETRIC)
52.4 Pipet 10 mLof NaCl-glycerin solution into the 50-mL
TURBIDIMETRY
flask and dilute to volume with water.
47. Scope
52.5 Add 0.50 g of BaCl (see 51.1), stopper the flask, and
47.1 Thistestmethodcoversthedeterminationofthesulfur
invert the solution 20 times to dissolve the BaCl . This step
concentration, which exists as sulfate in uranyl nitrate
must be performed in the same manner for standards and for
solutions, in the range from 100 to 1000 µg S/g of uranium.
samples.
52.6 Allowthesolutiontostand60 65min.Thisstepmust
48. Summary of Test Method
be performed in the same manner for standards and for
48.1 The uranium in the sample is removed by extraction
samples.
with tributyl phosphate (TBP). The sulfate is then precipitated
52.7 Measure the absorbance at 450 nm in 5-cm cells with
as barium sulfate (BaSO ) in the presence of excess salt and
a blank containing all of the reagents except sample as the
acid and is held in suspension in a glycerin matrix. Sulfate is
reference.
determined turbidimetrically using a spectrophotometer (6, 7).
52.8 Prepare a calibration curve by transferring 0.200,
49. Interferences
0.500, 1.000, 1.500, and 2.000-mL aliquots of the standard
49.1 Any anions that form insoluble precipitates with sulfate solution into 60-mL separatory funnels that contain 5
barium, such as phosphate, oxalate, and chromate, will inter- mLof4to5 M nitric acid and process in accordance with 52.2
fere. – 52.6.
C799 − 19
53. Calculation dilute to 1 L with water. Store in a polyethylene bottle
containing 1 to2goftin metal pellets or granules.
53.1 Calculatethesulfurcontentinmicrogramspergramof
uranium as follows:
60. Procedure
Sulfur, µg/g 5 A 3B /C (5)
~ !
60.1 Transferaweighedportionofsamplesolutioncontain-
where:
ing 0.1 g of uranium or an appropriate dilution to a 150-mL
beaker.
A =SO =found in the sample solution, µg,
B = 0.334, the gravimetric factor converting SO =to S,
60.2 Add 3 mL of HClO (72%) or H SO (sp gr 1.84) to
4 2 4
and
the beaker and heat to strong fumes.
C = uranium in the sample solution aliquot, g.
60.3 Add 40 mL of water and 5 mL of Na MoO ·2 H O
2 4 2
54. Precision
solution and let stand 5 min.
54.1 The limit of error at the 95% confidence level for a
60.4 Transfer to a 125-mL separatory funnel.
single determination is 63%.
60.5 Add 40 mL of isobutanol and extract for 1 min.
PHOSPHORUS BY THE MOLYBDENUM BLUE
60.6 Discard the aqueous layer.
(PHOTOMETRIC) METHOD
60.7 Wash the organic layer with two 25-mL portions of
water and discard the aqueous layers.
55. Scope
60.8 Add 25 mL of SnCl solution and shake for 15 s.
55.1 This test method covers determination of phosphorus
in nuclear-grade uranyl nitrate solutions. Appropriate dilution
60.9 Discard the aqueous layer.
may be made to facilitate obtaining samples containing 0 to 60
60.10 Draintheorganiclayerintoa50-mLvolumetricflask.
µg P.
Wash the funnel with isobutanol and add the washings to the
flask.
56. Summary of Test Method
60.11 Make to volume with isobutanol and read at 725 nm
56.1 Phosphorus is determined by the formation of het-
in 1-cm cells with isobutanol as the reference.
eropoly molybdophosphoric acid and its subsequent reduction
to molybdenum blue. Sodium molybdate is used to complex
60.12 Prepare a standard curve by carrying 0 to 60 µg P
the P in an acid solution containing the sample. The yellow
through the procedure (60.2 – 60.11).
complex is then extracted into isobutanol. After the excess
molybdate is washed out with water, the organic phase is 61. Calculation
contacted with an ac
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: C799 − 12 C799 − 19
Standard Test Methods for
Chemical, Mass Spectrometric, Spectrochemical, Nuclear,
and Radiochemical Analysis of Nuclear-Grade Uranyl Nitrate
Solutions
This standard is issued under the fixed designation C799; 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
1.1 These test methods cover procedures for the chemical, mass spectrometric, spectrochemical, nuclear, and radiochemical
analysis of nuclear-grade uranyl nitrate solution to determine compliance with specifications.
1.2 The analytical procedures appear in the following order:
Sections
Determination of Uranium 7
Determination of Uranium 8
Specific Gravity by Pycnometry 15 – 20
Specific Gravity by Pycnometry 16 – 21
Free Acid by Oxalate Complexation 21 – 27
Free Acid by Oxalate Complexation 22 – 28
Determination of Thorium 28
Determination of Thorium 29
Determination of Chromium 29
Determination of Chromium 30
Determination of Molybdenum 30
Determination of Molybdenum 31
Halogens Separation by Steam Distillation 31 – 35
Halogens Separation by Steam Distillation 32 – 36
Fluoride by Specific Ion Electrode 36 – 42
Fluoride by Specific Ion Electrode 37 – 43
Halogen Distillate Analysis: Chloride, Bromide, and Iodide by 43
Amperometric Microtitrimetry
Halogen Distillate Analysis: Chloride, Bromide, and Iodide by 44
Amperometric Microtitrimetry
Determination of Chloride and Bromide 44
Determination of Chloride and Bromide 45
Determination of Sulfur by X-Ray Fluorescence 45
Determination of Sulfur by X-Ray Fluorescence 46
Sulfate Sulfur by (Photometric) Turbidimetry 46
Sulfate Sulfur by (Photometric) Turbidimetry 47
Phosphorus by the Molybdenum Blue (Photometric) Method 54 – 61
Phosphorus by the Molybdenum Blue (Photometric) Method 55 – 62
Silicon by the Molybdenum Blue (Photometric) Method 62 – 69
Silicon by the Molybdenum Blue (Photometric) Method 63 – 70
Carbon by Persulfate Oxidation-Acid Titrimetry 70
Carbon by Persulfate Oxidation-Acid Titrimetry 71
Conversion to U O 71 – 74
3 8
Conversion to U O 72 – 75
3 8
Boron by Emission Spectrography 75 – 81
A
Boron by Emission Spectrography
Impurity Elements by Spark Source Mass Spectrography 82
Impurity Elements by Spark Source Mass Spectrography 77
Isotopic Composition by Thermal Ionization Mass Spectrometry 83
Isotopic Composition by Thermal Ionization Mass Spectrometry 78
Uranium-232 by Alpha Spectrometry 84 – 90
Uranium-232 by Alpha Spectrometry 79 – 85
These test methods are under the jurisdiction of ASTM Committee C26 on Nuclear Fuel Cycle and are the direct responsibility of Subcommittee C26.05 on Methods
of Test.
Current edition approved Jan. 1, 2012July 1, 2019. Published February 2012August 2019. Originally approved in 1975. Last previous edition approved in 20052012 as
C799 – 99C799 – 12.(2005). DOI: 10.1520/C0799-12.10.1520/C0799-19.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
C799 − 19
Total Alpha Activity by Direct Alpha Counting 91 – 97
Total Alpha Activity by Direct Alpha Counting 86 – 92
Fission Product Activity by Beta Counting 98 – 104
Fission Product Activity by Beta Counting 93 – 99
Entrained Organic Matter by Infrared Spectrophotometry 105
Entrained Organic Matter by Infrared Spectrophotometry 100
Fission Product Activity by Gamma Counting 106
Fission Product Activity by Gamma Counting 101
Determination of Arsenic 107
Determination of Arsenic 102
Determination of Impurities for the EBC Calculation 108
Determination of Impurities for the EBC Calculation 103
Determination of Technetium 99 109
Determination of Technetium 99 104
Determination of Plutonium and Neptunium 110
Determination of Plutonium and Neptunium 105
A
Discontinued July 2019.
1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
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 safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use. Specific precautionary statements are given in Section 56.
1.5 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
C696 Test Methods for Chemical, Mass Spectrometric, and Spectrochemical Analysis of Nuclear-Grade Uranium Dioxide
Powders and Pellets
C761 Test Methods for Chemical, Mass Spectrometric, Spectrochemical, Nuclear, and Radiochemical Analysis of Uranium
Hexafluoride
C788 Specification for Nuclear-Grade Uranyl Nitrate Solution or Crystals
C859 Terminology Relating to Nuclear Materials
C1219 Test Methods for Arsenic in Uranium Hexafluoride (Withdrawn 2015)
C1233 Practice for Determining Equivalent Boron Contents of Nuclear Materials
C1254 Test Method for Determination of Uranium in Mineral Acids by X-Ray Fluorescence
C1267 Test Method for Uranium by Iron (II) Reduction in Phosphoric Acid Followed by Chromium (VI) Titration in the
Presence of Vanadium
C1287 Test Method for Determination of Impurities in Nuclear Grade Uranium Compounds by Inductively Coupled Plasma
Mass Spectrometry
C1295 Test Method for Gamma Energy Emission from Fission and Decay Products in Uranium Hexafluoride and Uranyl Nitrate
Solution
C1296 Test Method for Determination of Sulfur in Uranium Oxides and Uranyl Nitrate Solutions by X-Ray Fluorescence (XRF)
(Withdrawn 2007)
C1380 Test Method for the Determination of Uranium Content and Isotopic Composition by Isotope Dilution Mass
Spectrometry (Withdrawn 2018)
C1413 Test Method for Isotopic Analysis of Hydrolyzed Uranium Hexafluoride and Uranyl Nitrate Solutions by Thermal
Ionization Mass Spectrometry
C1517 Test Method for Determination of Metallic Impurities in Uranium Metal or Compounds by DC-Arc Emission
Spectroscopy
C1561 Guide for Determination of Plutonium and Neptunium in Uranium Hexafluoride and U-Rich Matrix by Alpha
Spectrometry
C1871 Test Method for Determination of Uranium Isotopic Composition by the Double Spike Method Using a Thermal
Ionization Mass Spectrometer
D1193 Specification for Reagent Water
E12 Terminology Relating to Density and Specific Gravity of Solids, Liquids, and Gases (Withdrawn 1996)
E60 Practice for Analysis of Metals, Ores, and Related Materials by Spectrophotometry
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
The last approved version of this historical standard is referenced on www.astm.org.
C799 − 19
E115 Practice for Photographic Processing in Optical Emission Spectrographic Analysis (Withdrawn 2002)
2.2 American Chemical Society Specification:
Reagent Chemicals
2.3 Other Documents:
ISO 7097 Determination of Uranium in Uranium Product Solutions and Solids with Cerium IV Oxidation Titrimetric Method
3. Terminology
3.1 For definitions of terms used in this test method but not defined herein, refer to Terminology C859.
4. Significance and Use
4.1 Uranyl nitrate solution is used as a feed material for conversion to the hexafluoride as well as for direct conversion to the
oxide. In order to be suitable for this purpose, the material must meet certain criteria for uranium content, isotopic composition,
acidity, radioactivity, and impurity content. These methods are designed to show whether a given material meets the specifications
for these items described in Specification C788.
4.1.1 An assay is performed to determine whether the material has the specified uranium content.
4.1.2 Determination of the isotopic content of the uranium is made to establish whether the effective fissile content is in
accordance with the purchaser’s specifications.
4.1.3 Acidity, organic content, and alpha, beta, and gamma activity are measured to establish that they do not exceed their
maximum limits.
4.1.4 Impurity content is determined to ensure that the maximum concentration limit of certain impurity elements is not
exceeded. Impurity concentrations are also required for calculation of the equivalent boron content (EBC), and the total equivalent
boron content (TEBC).
5. Reagents
5.1 Purity of Reagents—Reagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that all
reagents shall conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society, where
such specifications are available. Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high
purity to permit its use without lessening the accuracy of the determination.
5.2 Purity of Water—Unless otherwise indicated, references to water shall be understood to mean reagent water conforming to
Specification D1193.
5.3 Hydrofluoric acid (used in some of the procedures) is a highly corrosive acid that can severely burn skin, eyes, and mucous
membranes. Hydrofluoric acid differs from other acids because the fluoride ion readily penetrates the skin, causing destruction of
deep tissue layers. Unlike other acids that are rapidly neutralized, hydrofluoric acid reactions with tissue may continue for days
if left untreated. Familiarization and compliance with the Safety Data Sheet is essential.
6. Safety Precautions
6.1 Use of this standard does not relieve the user of the obligation to be aware of and to conform to all health and safety
requirements.
6.2 The user should also be cognizant of and adhere to all federal, state, and local regulations for processing, shipping, or in
any way using uranyl nitrate solutions.
7. Sampling
7.1 Criteria for sampling this material are given in Specification C788.
DETERMINATION OF URANIUM
7. Scope
7.1 Uranium can be determined using iron (II) reduction and dichromate titration. Test Method C1267 can be used.
7.2 Uranium can also be determined using cerium (IV) oxidation titrimetry. ISO 7097 Test Method can be used.
7.3 Uranium can also be determined by X-Ray Fluorescence using Test Method C1254.
7.4 Previous sections have been deleted.
Reagent Chemicals, American Chemical Society Specifications, American Chemical Society, Washington, DC. For suggestions on the testing of reagents not listed by
the American Chemical Society, see Analar Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and National
Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, MD.
Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036, http://www.ansi.org.
C799 − 19
8. Scope
8.1 Uranium can be determined using iron (II) reduction and dichromate titration. Test Method C1267 can be used.
8.2 Uranium can also be determined using cerium (IV) oxidation titrimetry. ISO 7097 Test Method can be used.
8.3 Uranium can also be determined by X-Ray Fluorescence using Test Method C1254.
8.4 Previous sections have been deleted.
URANIUM BY IGNITION GRAVIMETRY
8. Scope
8.1 This test method covers the determination of uranium in nuclear-grade uranyl nitrate solution. Appropriate size sample
aliquots are chosen to obtain 5 to 10 g of U O .
3 8
9. Scope
9.1 This test method covers the determination of uranium in nuclear-grade uranyl nitrate solution. Appropriate size sample
aliquots are chosen to obtain 5 to 10 g of U O .
3 8
10. Summary of Test Method
10.1 The uranyl nitrate solution is evaporated to dryness, ignited to U O , and weighed. Corrections are made for any impurities
3 8
present (1, 2).
11. Interferences
11.1 The weight of U O is corrected for the nonvolatile impurities present as determined by spectrographic analysis.
3 8
11.2 Volatile anions that are difficult to decompose require an extended ignition period.
12. Apparatus
12.1 Heat Lamp, infrared.
12.2 Hot Plate.
12.3 Muffle Furnace.
13. Procedure
13.1 Transfer a weighed portion of uranyl nitrate solution containing 5 to 10 g of uranium into a preweighed platinum dish and
add 2 drops of HF (48 %).
13.2 Position the dish under the heat lamp and evaporate the solution to dryness.
13.3 Place the dish on a hot plate with a surface temperature of about 300°C and heat until most of the nitrate has decomposed.
13.4 Transfer the dish to a muffle furnace and ignite for 2 h at 900°C.
13.5 Remove the dish to a desiccator and allow to cool to room temperature.
13.6 Weigh the dish; then repeat 12.413.4 – 12.613.6 until a constant weight is obtained.
14. Calculation
14.1 Calculate the uranium content as follows:
Uranium, g/g5 ~~B 2 C!/A! D (1)
where:
A = sample, g,
B = U O obtained, g,
3 8
C = impurity-element oxides, g, and
D = gravimetric factor, grams of uranium/grams of U O (varies according to uranium enrichment).
3 8
15. Precision
15.1 The limit of error at the 95 % confidence level for a single determination is 60.03 %.
SPECIFIC GRAVITY BY PYCNOMETRY
15. Scope
15.1 This test method covers the determination of the specific gravity of a solution of uranyl nitrate to 60.0004.
C799 − 19
16. Scope
16.1 This test method covers the determination of the specific gravity of a solution of uranyl nitrate to 60.0004.
17. Summary of Test Method
17.1 A known volume of the solution adjusted at a controlled temperature is weighed and compared to the weight of water
measured in the same container (Terminology E12).
18. Apparatus
18.1 Volumetric Flasks, 50-mL, Class A.
18.2 Water Bath, temperature controlled to 60.1°C at a temperature slightly above normal room temperature, and provided with
clips for holding volumetric flasks.
19. Procedure
19.1 Weigh the clean, dry volumetric flask and its stopper to the nearest 0.1 mg.
19.2 Fill the volumetric flask with the uranyl nitrate solution to a point close to the volume mark, using a thinstemmedthin-
stemmed funnel and a glass dropper.
19.3 Place the stoppered volumetric flask in the water bath for 30 min.
19.4 Use a finely drawn glass dropper to adjust the liquid volume to the mark.
19.5 Leave the flask in the water bath an additional 10 min to make sure that the bath temperature has been reached.
19.6 Dry and weigh the flask to the nearest 0.1 mg.
19.7 Repeat 18.219.2 – 18.619.6 using boiled and cooled distilled water instead of the uranyl nitrate solution.
20. Calculation
20.1 Very accurate determinations of specific gravity require that vacuo corrections be made, but if a median correction figure
in terms of grams per grams of sample is applied to the solution weights in all cases the resulting error will not exceed 0.05 %.
B 2 A10.0007 B 2 A
~ !
Sp gr 5 (2)
C 2 A10.0010 ~C 2 A!
where:
B = sample plus flask in air, g,
A = flask in air, g,
C = water plus flask in air, g,
0.0007g/g = correction factor applicable for densities of 1.3 to 1.5, and
0.0010 g/g = correction factor for water.
21. Precision
21.1 The limit of error at the 95 % level for a single determination is 60.03 %.
FREE ACID BY OXALATE COMPLEXATION
21. Scope
21.1 This test method covers the determination of the free acid content of uranyl nitrate solutions that may contain a ratio of
up to 5 moles of acid to 1 mole of uranium.
22. Scope
22.1 This test method covers the determination of the free acid content of uranyl nitrate solutions that may contain a ratio of
up to 5 moles of acid to 1 mole of uranium.
23. Summary of Test Method
23.1 To a diluted solution of uranyl nitrate, solid, pulverized potassium oxalate is added until a pH of about 4.7 is reached. The
solution is then titrated with standard NaOH solution by the delta pH method to obtain the inflection point (3).
24. Apparatus
24.1 pH Meter, with glass and calomel electrodes.
24.2 Buret, Class A, 50-mL.
C799 − 19
25. Reagents
25.1 Nitric Acid (2.0 N)—Dilute 130 mL of HNO (sp gr 1.42) to 1 L with water. Standardize with sodium hydroxide solution
(see 24.325.4).
25.2 Potassium Oxalate (K C O ·H O), crystals.
2 2 4 2
25.3 Potassium Hydrogen Phthalate (C H KO ), acidimetric standard grade.
8 5 4
25.4 Sodium Hydroxide Solution (0.3 N)—Dissolve 12.0 g of NaOH in 1 L of water. Standardize with acid potassium hydrogen
phthalate.
26. Procedure
26.1 Transfer a 5-mL sample aliquot into a 250-mL beaker.
26.2 Add 100 mL of distilled water or such volume that the uranium concentration will be between 7 and 50 g/L.
26.3 Add a spike of sufficient 2.0 N standard HNO to make the sample definitely acid if the sample is neutral or acid deficient.
26.4 Add pulverized K C O ·H O slowly and with constant stirring until a pH of 4.7 to 4.9 is reached.
2 2 4 2
26.5 Immerse the titration beaker in an ice bath. (Titrations made at room temperature are possible but are less sharp.)
26.6 Titrate with 0.3 N NaOH using 0.20-mL increments and determine the inflection point by the delta pH or “analytical”
method.
2 2
NOTE 1—This test method of locating the end point depends on the fact that the second derivative Δ pH/Δvol is zero at the point where the slope
ΔpH/Δvol is a maximum.
27. Calculation
27.1 Calculate the free acid normality, N, as follows:
N 5 A 3N 2 C 3N /5 (3)
~ !
B A
where:
A = NaOH solution used in the titration, mL
N = normality of the NaOH solution,
B
C = HNO solution used in the spike, mL, and
N = normality of HNO solution.
A 3
NOTE 2—Negative values of free acid indicate an acid deficiency.
28. Precision
28.1 The limit of error at the 95 % confidence level for a single determination is 63 %.
DETERMINATION OF THORIUM
28. Scope
28.1 The determination of thorium by the arsenazo (III) (photometric) method has been discontinued, (see C799-93).
28.2 As an alternative, thorium can be determined using Inductively Coupled Plasma Mass Spectrometry (ICP-MS). See Test
Method C1287.
28.3 Previous sections have been deleted.
29. Scope
29.1 The determination of thorium by the arsenazo (III) (photometric) method has been discontinued, (see C799-93).
29.2 As an alternative, thorium can be determined using Inductively Coupled Plasma Mass Spectrometry (ICP-MS). See Test
Method C1287.
29.3 Previous sections have been deleted.
DETERMINATION OF CHROMIUM
29. Scope
29.1 The determination of chromium by the diphenyl carbazide method has been discontinued, (see C799-93).
29.2 As an alternative, chromium can be determined using inductively coupled plasma atomic emission spectrometry
(ICP-AES). Test Method C761 can be used providing a transformation to U O so described hereafter in sections 117–120. A direct
3 8
conversion to the amonium fluoride plus nitric acid solution can also be used, (see C761).
C799 − 19
29.3 As an alternative, chromium can be determined using atomic absorption spectroscopy. Test Method C761 can be used.
29.4 As an alternative, chromium can be determined using ICP-MS. Test Method C1287 can be used.
29.5 Previous sections have been deleted.
30. Scope
30.1 The determination of chromium by the diphenyl carbazide method has been discontinued, (see C799-93).
30.2 As an alternative, chromium can be determined using inductively coupled plasma atomic emission spectrometry
(ICP-AES). Test Method C761 can be used providing a transformation to U O so described hereafter in Sections 72 – 75. A direct
3 8
conversion to the amonium fluoride plus nitric acid solution can also be used, (see C761).
30.3 As an alternative, chromium can be determined using atomic absorption spectroscopy. Test Method C761 can be used.
30.4 As an alternative, chromium can be determined using ICP-MS. Test Method C1287 can be used.
30.5 Previous sections have been deleted.
DETERMINATION OF MOLYBDENUM
30. Scope
30.1 The determination of molybdenum by the thiocyanate (photometric) method has been discontinued, (See C799-93).
30.2 As an alternative, molybdenum can be determined using ICP-MS. Test Method C1287 can be used.
30.3 As an alternative, molybdenum can be determined using ICP-AES. Test Method C761, sections 251 to 271 can be used
providing a tranformation to U O as described hereafter in sections 71 – 74. A direct conversion to the amonium fluoride plus
3 8
nitric acid solution can also be used, (see C761, section 251).
30.4 Previous sections have been deleted.
31. Scope
31.1 The determination of molybdenum by the thiocyanate (photometric) method has been discontinued, (See C799-93).
31.2 As an alternative, molybdenum can be determined using ICP-MS. Test Method C1287 can be used.
31.3 As an alternative, molybdenum can be determined using ICP-AES. Test Method C761, Sections 251 to 271 can be used
providing a tranformation to U O as described hereafter in Sections 72 – 75. A direct conversion to the amonium fluoride plus
3 8
nitric acid solution can also be used, (see C761, Section 251).
31.4 Previous sections have been deleted.
HALOGENS SEPARATION BY STEAM DISTILLATION
31. Scope
31.1 This test method covers the separation of the halogens by means of a steam distillation.
32. Scope
32.1 This test method covers the separation of the halogens by means of a steam distillation.
33. Summary of Test Method
33.1 A sample aliquot is mixed with a solution containing ferrous ammonium sulfate, sulfamic acid, phosphoric acid, and
sulfuric acid. The halogens are then steam distilled at a temperature of 140°C.
34. Apparatus
34.1 Steam Distillation Apparatus (see Fig. 1).
34.1.1 Distilling Flask, 200-mL with thermometer well.
34.1.2 Condenser.
34.1.3 Heating Mantle.
34.1.4 Steam Boiler, 500-mL flask.
35. Reagents
35.1 Absorber Solution (4 M Potassium Hydroxide)—Dissolve 22.4 g KOH pellets in water and dilute to 100 mL.
35.2 Acid Mixture—Mix 0.2 M ferrous ammonium sul-fate-0.5sulfate-0.5 M sulfamic acid (see 34.335.3), phosphoric acid
(85 %), and sulfuric acid (sp gr 1.84) in the ratio of 1 + 2 + 5.
C799 − 19
FIG. 1 Halogen Distillation Apparatus
35.3 Ferrous Ammonium Sulfate Solution (0.2 M)-Sulfamic Acid (0.5 M) Solution—Dissolve 78.4 g Fe (NH ) (SO ) ·6 H O
4 2 4 2 2
and 48.6 g NH SO H in H SO (5 + 95) and dilute to 1 L with H SO (5 + 95).
2 3 2 4 2 4
35.4 Phenolphthalein Solution (10 g/L)—Dissolve 1 g of phenolphthalein in 50 mL of ethanol and add 50 mL of water.
36. Procedure
36.1 Place a weighed portion of about 15 mL containing approximately 5 g of uranium in the distillation flask.
36.2 Add 25 mL of the acid mixture to the distillation flask.
36.3 Transfer 5 mL of the KOH solution to a 100-mL graduated cylinder and position it under the condenser tip.
36.4 Heat the distillation flask until the thermometer in the well reaches 140°C.
36.5 Pass steam through from the boiler, and maintain at a temperature of 140°C until a volume of 90 mL is collected.
36.6 Add 2 drops of phenolphthalein solution and adjust the pH of the distillate with KOH or HNO , to the phenolphthalein
end point. Make the volume to 100 mL.
36.7 Repeat the distillation, omitting the uranium sample, to use as the matrix for the fluoride standard curve.
36.8 Reserve the distillate for the fluoride and combined halide determinations.
FLUORIDE BY SPECIFIC ION ELECTRODE
36. Scope
36.1 This test method covers the determination of as low as 2 μg F/g U in distillate containing all the halogens.
37. Scope
37.1 This test method covers the determination of as low as 2 μg F/g U in distillate containing all the halogens.
38. Summary of Test Method
38.1 An aliquot of the distillate representing 1 g of uranium is measured by specific ion electrode and compared to a standard
curve prepared by spiking equivalent-size aliquots taken from a blank distillation (4, 5).
C799 − 19
39. Apparatus
39.1 pH Meter, expanded scale.
39.2 Ion-Selective Electrode, fluoride.
39.3 Reference Electrode, single-junction.
40. Reagents
40.1 Buffer Solution (0.001 N)—Dissolve 0.1 g of potassium acetate (KC H O ) in water. Add 0.050 mL of acetic acid (sp gr
2 3 2
1.05) and dilute to 1 L.
40.2 Fluoride Standard Solution A (1 mL = 1 mg F)—Dissolve 0.220 g of dried sodium fluoride (NaF) in 25 mL of water and
dilute to 100 mL.
40.3 Fluoride Standard Solution B (1 mL = 5 μg F)—Dilute 5 mL of the fluoride standard Solution A (see 39.240.2) to 1 L with
water.
41. Procedure
41.1 Pipet a 20-mL aliquot of the sample distillate (representing about 1 g of uranium) into a 25-mL flask and make to volume
with the buffer solution.
−
41.2 Prepare a standard curve by pipetting 20-mL aliquots from the blank distillate into 25-mL flasks and adding F standard
−
solution to make 0, 5, 10, and 20 μg F /25 mL.
41.3 Measure all of the solutions with the fluoride ion-selective electrode.
42. Calculation
−
42.1 Calculate the F content as follows:
F , µg/g5 A/B (4)
where:
−
A = F found in the sample distillate aliquot, μg, and
B = uranium represented by the sample distillate aliquot, g.
43. Precision
43.1 The limit of error at the 95 % confidence level for a single determination is 625 %.
HALOGEN DISTILLATE ANALYSIS: CHLORIDE, BROMIDE, AND IODIDE BY AMPEROMETRIC
MICROTITRIMETRY
43. Scope
43.1 The determination of chloride, bromide and iodide by microtitrimetric method has been discontinued, (see C799-93).
43.2 Previous sections have been deleted.
44. Scope
44.1 The determination of chloride, bromide and iodide by microtitrimetric method has been discontinued, (see C799-93).
44.2 Previous sections have been deleted.
DETERMINATION OF CHLORIDE AND BROMIDE
44. Scope
44.1 Determination of bromide by the fluorescein (photometric) method has been discontinued, (see C799-93).
44.2 As an alternative, bromide and chloride can be determined by X-Ray Fluorescence. Halogens are precipitated by silver
nitrate and filtrated. The precipitate is washed and counted by X-Ray Fluorescence.
44.3 Previous sections have been deleted.
45. Scope
45.1 Determination of bromide by the fluorescein (photometric) method has been discontinued, (see C799-93).
45.2 As an alternative, bromide and chloride can be determined by X-Ray Fluorescence. Halogens are precipitated by silver
nitrate and filtrated. The precipitate is washed and counted by X-Ray Fluorescence.
C799 − 19
45.3 Previous sections have been deleted.
DETERMINATION OF SULFUR BY X-RAY FLUORESCENCE
45. Scope
45.1 Sulfur can be determined using X-Ray Fluorescence. See Test Method C1296.
46. Scope
46.1 Sulfur can be determined using X-Ray Fluorescence. See Test Method C1296.
SULFATE SULFUR BY (PHOTOMETRIC) TURBIDIMETRY
46. Scope
46.1 This test method covers the determination of the sulfur concentration, which exists as sulfate in uranyl nitrate solutions,
in the range from 100 to 1000 μg S/g of uranium.
47. Scope
47.1 This test method covers the determination of the sulfur concentration, which exists as sulfate in uranyl nitrate solutions,
in the range from 100 to 1000 μg S/g of uranium.
48. Summary of Test Method
48.1 The uranium in the sample is removed by extraction with tributyl phosphate (TBP). The sulfate is then precipitated as
barium sulfate (BaSO ) in the presence of excess salt and acid and is held in suspension in a glycerin matrix. Sulfate is determined
turbidimetrically using a spectrophotometer (6, 7).
49. Interferences
49.1 Any anions that form insoluble precipitates with barium, such as phosphate, oxalate, and chromate, will interfere.
49.2 Many variables, although not classed as interferants, effect the precision of this test method. Careful control of the
following parameters must be maintained to achieve the stated precision: particle size of the barium chloride (BaCl ), particle size
of the BaSO formed, total ionic concentration of the final solution, degree of mixing of sample and reagents (number of times
the flask is inverted), concentration of hydrogen ion in the final solution, and the length of time of standing of the supernatant
before the absorbance is measured.
50. Apparatus
50.1 Spectrophotometer—See Practice E60.
51. Reagents
51.1 Barium Chloride (BaCl ), crystals. Sift the salt and use only the portion that passes through a 28-mesh screen and is
retained on a 35-mesh screen.
51.2 Sodium Chloride-Glycerin Solution (16 g/L)—Dissolve 40 g of NaCl in 60 mL of HCl (sp gr 1.19). Add 833 mL of glycerin
and dilute to 2.5 L with water.
−
51.3 Sulfate Standard Solution (1 mL = 1000 μg SO )—Dissolve 1.1813 g of K SO , dried at 110°C for 1 h, and dilute to 1
4 2 4
L with water.
51.4 Tributyl Phosphate Solution (3 + 7)—Dilute 300 mL of TBP with 700 mL of kerosinekerosene and equilibrate with 8 M
HNO .
52. Procedure
52.1 Transfer a weighed aliquot of sample that contains approximately 1 g of uranium to a 60-mL separatory funnel. Adjust the
nitric acid concentration to 4 to 5 M and the volume to 5 mL.
52.2 Add 10 mL of TBP solution (see 50.451.4) and equilibrate the solutions.
52.3 Allow the layers to separate and transfer the aqueous layer to 50-mL volumetric flask containing 30 mL of distilled water.
Use a minimum volume of 1 N HNO wash solution to ensure quantitative transfer of the aqueous layer to the 50-mL flask.
52.4 Pipet 10 mL of NaCl-glycerin solution into the 50-mL flask and dilute to volume with water.
52.5 Add 0.50 g of BaCl (see 50.151.1), stopper the flask, and invert the solution 20 times to dissolve the BaCl . This step must
2 2
be performed in the same manner for standards and for samples.
C799 − 19
NOTE 3—The conditions of mixing and the time of standing prior to measuring the absorbance must be the same for sample and standards.
52.6 Allow the solution to stand 60 6 5 min. This step must be performed in the same manner for standards and for samples.
52.7 Allow the solution to stand 60 6 5 min; then measure the Measure the absorbance at 450 nm in 5-cm cells with a blank
containing all of the reagents except sample as the reference.
52.8 Prepare a calibration curve by transferring 0.200, 0.500, 1.000, 1.500, and 2.000-mL aliquots of the standard sulfate
solution into 60-mL separatory funnels that contain 5 mL of 4 to 5 M nitric acid and process in accordance with 51.252.2 –
51.652.6.
53. Calculation
53.1 Calculate the sulfur content in micrograms per gram of uranium as follows:
Sulfur, µg/g5 A 3B /C (5)
~ !
where:
A = SO = found in the sample solution,μ g,
A = SO = found in the sample solution, μg,
B = 0.334, the gravimetric factor converting SO = to S, and
C = uranium in the sample solution aliquot, g.
54. Precision
54.1 The limit of error at the 95 % confidence level for a single determination is 63 %.
PHOSPHORUS BY THE MOLYBDENUM BLUE (PHOTOMETRIC) METHOD
54. Scope
54.1 This test method covers determination of phosphorus in nuclear-grade uranyl nitrate solutions. Appropriate dilution may
be made to facilitate obtaining samples containing 0 to 60 μg P.
55. Scope
55.1 This test method covers determination of phosphorus in nuclear-grade uranyl nitrate solutions. Appropriate dilution may
be made to facilitate obtaining samples containing 0 to 60 μg P.
56. Summary of Test Method
56.1 Phosphorus is determined by the formation of heteropoly molybdophosphoric acid and its subsequent reduction to
molybdenum blue. Sodium molybdate is used to complex the P in an acid solution containing the sample. The yellow complex
is then extracted into isobutanol. After the excess molybdate is washed out with water, the organic phase is contacted with an acid
solution of stannous chloride to reduce the complex. The resulting molybdenum blue is read at 725 nm using a spectrophotometer
(8).
57. Interferences
57.1 The molybdenum blue reaction is not specific for phosphorus; however, adjustment of the acidity to above 0.9 N avoids
the formation of molybdosilicic acid.
57.2 Fluoride and chloride must be fumed off before the heteropoly acid is formed.
58. Apparatus
58.1 Spectrophotometer—See Practice E60.
59. Reagents
59.1 Isobutanol.
59.2 Phosphorus Standard Solution A (1 mL = 100 μg P)—Dissolve 0.4393 g of KH PO , which has been dried at 110°C for
2 4
1 h, in 1 L of water.
59.3 Phosphorus Standard Solution B (1 mL = 10 μg P)—Dilute 10.0 mL of Solution A to 100 mL with water.
59.4 Sodium Molybdate Solution (10 g/L)—Dissolve 25 g of Na MoO ·2 H O in 250 mL of water. Filter if turbid and store in
2 4 2
a polyethylene bottle.
59.5 Stannous Chloride Solution (2 N in HCl)—Dissolve 2.38 g of SnCl ·2 H O in 170 mL of HCl (sp gr 1.19), and dilute to
2 2
1 L with water. Store in a polyethylene bottle containing 1 to 2 g of tin metal pellets or granules.
C799 − 19
60. Procedure
60.1 Transfer a weighed portion of sample solution containing 0.1 g of uranium or an appropriate dilution to a 150-mL beaker.
60.2 Add 3 mL of HClO (72 %) or H SO (sp gr 1.84) to the beaker and heat to strong fumes.
4 2 4
60.3 Add 40 mL of water and 5 mL of Na MoO ·2 H O solution and let stand 5 min.
2 4 2
60.4 Transfer to a 125-mL separatory funnel.
60.5 Add 40 mL of isobutanol and extract for 1 min.
60.6 Discard the aqueous layer.
60.7 Wash the organic layer with two 25-mL portions of water and discard the aqueous layers.
60.8 Add 25 mL of SnCl solution and shake for 15 s.
60.9 Discard the aqueous layer.
60.10 Drain the organic layer into a 50-mL volumetric flask. Wash the funnel with isobutanol and add the washings to the flask.
60.11 Make to volume with isobutanol and read at 725 nm in 1-cm cells with isobutanol as the reference.
60.12 Prepare a standard curve by carrying 0 to 60 μg P through the procedure (59.260.2 – 59.1160.11).
61. Calculation
61.1 Calculate the phosphorus content as follows:
Phosphorus, µg/g5 A/B (6)
where:
A = phosphorus found in the sample solution, μg, and
B = uranium contained in the sample solution, g.
62. Precision
62.1 The limit of error at the 95 % confidence level for a single determination is 63 %.
SILICON BY THE MOLYBDENUM BLUE (PHOTOMETRIC) METHOD
62. Scope
62.1 This test method covers the determination of up to 20 μg Si (2 to 200 μg Si/g U) in uranyl nitrate solutions.
63. Scope
63.1 This test method covers the determination of up to 20 μg Si (2 to 200 μg Si/g U) in uranyl nitrate solutions.
64. Summary of Test Method
64.1 Silicon is determined by the formation of B-silicomolybdic acid and subsequent reduction to molybdenum blue.
Ammonium molybdate is used to complex the silicon in an acid solution of the sample. Oxalic acid and sodium sulfite are added
to prevent phosphorus interference and to stabilize the complex. Reduction to molybdenum blue is carried out with stannous
chloride. Measurement is made at 820 nm using a spectrophotometer (9, 10, 11).
65. Interferences
65.1 Phosphorus also forms a heteropoly acid with molybdate; however, oxalic acid is used to decompose it.
66. Apparatus
66.1 Plastic Beakers.
66.2 Polyethylene Pipets.
66.3 Spectrophotometer—See Practice E60.
67. Reagents
67.1 Ammonium Molybdate Solution (65 g/L)—Dissolve 65 g of (NH ) Mo O ·4 H O in water, dilute to 1 L, and store in a
4 6 7 24 2
plastic bottle.
67.2 Hydrochloric Acid (1 + 9)—Mix 100 mL of HCl (sp gr 1.19) with 900 mL water and store in a plastic bottle.
67.3 Oxalic Acid Solution (100 g/L)—Dissolve 25 g of HO CCO H in 250 mL of water and store in a plastic bottle.
2 2
C799 − 19
67.4 Silicon, Standard Solution A (1 mL = 100 μg Si)—Fuse 0.0214 g of silicon dioxide (SiO ) with 1 g of Na CO until a clear
2 2 3
melt is obtained. Dissolve the cooled melt in water and dilute to volume in a 100-mL polyethylene volumetric flask.
67.5 Silicon, Standard Solution B (1 mL = 2 μg Si)—Dilute 2 mL of standard silicon Solution A (see 66.467.4) to 100 mL in
a polyethylene volumetric flask.
67.6 Sodium Carbonate (Na CO ), anhydrous powder.
2 3
67.7 Sodium Sulfite Solution (150 g/L)—Dissolve 30 g of Na SO in 200 mL of water and store in a plastic bottle.
2 3
67.8 Stannous Chloride Solution A (100 g/L)—Dissolve 50 g of SnCl ·2 H O in 100 mL of HCl (sp gr 1.19) and 50 mL of water.
2 2
Heat, if necessary, to dissolve. Dilute to 500 mL with water and store in a plastic bottle containing 1 g of metallic tin (Sn).
67.9 Stannous Chloride Solution B—Dilute 10 mL of stannous chloride Solution A (see 66.867.8) to 100 mL with water. Make
fresh daily.
67.10 Sulfuric Acid (1 + 3)—Add 125 mL of H SO (sp gr 1.84) slowly to 375 mL of water. Cool and store in a plastic bottle.
2 4
68. Procedure
68.1 Pipet 5 mL of (NH ) Mo O ·4 H O solution and 4 mL of HCl (1 + 9) into a 100-mL plastic beaker.
4 6 7 24 2
68.2 Transfer a weighed portion of sample solution containing 2 to 3 drops of HF (48 %) or an appropriate dilution into the
beaker and swirl to mix.
68.3 Dilute to 35 mL with water and let stand 15 to 30 min.
68.4 Add, in order and swirling after each addition, 2 mL of oxalic acid solution, 2 mL of sodium sulfite solution, and 5 mL
of sulfuric acid (1 + 3), and let stand 3 min.
68.5 Add 1 mL of stannous chloride Solution B, dilute to 100-mL volume with water, and let stand 5 min.
68.6 Read at 820 nm in 5-cm cells with water as a reference.
68.7 Prepare a standard curve by carrying 0 to 20 μg Si through the procedure (67.168.1 – 67.668.6).
NOTE 3—Uranium does not contribute to a blank when present in 100-mg amounts or less.
69. Calculation
69.1 Calculate the silicon content as follows:
Silicon, µg/g5 A/B (7)
where:
A = silicon found in the sample solution, μg, and
B = uranium contained in the sample solution, g.
70. Precision
70.1 The limit of error at the 95 % confidence level for a single determination is 65 %.
CARBON BY PERSULFATE OXIDATION-ACID TITRIMETRY
70. Scope
70.1 Determination of carbon by the persulfate oxidation titrimetry method has been discontinued, (see C799-93).
70.2 Previous sections have been deleted.
71. Scope
71.1 Determination of carbon by the persulfate oxidation titrimetry method has been discontinued, (see C799-93).
71.2 Previous sections have been deleted.
CONVERSION TO U O
3 8
71. Scope
71.1 This test method is specifically designed for the conversion of uranyl nitrate to U O .
3 8
72. Scope
72.1 This test method is specifically designed for the conversion of uranyl nitrate to U O .
3 8
C799 − 19
73. Summary of Test Method
73.1 Uranyl nitrate is evaporated to dryness and baked on a hot plate to yield uranium trioxide (UO ). The UO is transferred
3 3
to a platinum crucible and ignited at 900°C for 2 h to obtain U O which is used for the spectrographic analysis.
3 8
74. Apparatus
74.1 Beaker, TFE-fluorocarbon, 100-mL.
74.2 Crucible, platinum, 50-mL capacity.
74.3 Heat Lamp, infrared.
74.4 Hot Plate.
74.5 Muffle Furnace.
74.6 Plastic Balls, poly(methyl methacrylate), 9.52 mm ( ⁄8 in.) in diameter.
74.7 Plastic Vial, 19.05 by 50.8 mm ( ⁄4 by 2 in.).
74.8 Shaker, heavy-duty.
74.9 Spatula, long-handle, platinum or tantalum.
75. Procedure
75.1 Transfer 5 g of uranyl nitrate solution to a clean 100-mL TFE-fluorocarbon beaker.
75.2 Evaporate the solution to crystallization under an infrared lamp.
75.3 Transfer the beaker and contents to a hot plate having a surface temperature of approximately 300°C. (At this temperature,
the uranyl nitrate crystals convert to a mixture of UO and nitrates.)
75.4 Remove the beaker from the hot plate and cool when the uranium mixture is an orange-colored solid.
75.5 Transfer the orange UO to a clean 50-mL platinum crucible using a platinum or tantalum spatula. (All of the samples must
be removed from the beaker for impurity analysis.)
75.6 Place the platinum crucible in the muffle furnace and ignite at 900°C for 2 h.
75.7 Remove the sample of U O from the furnace and cool.
3 8
3 3
75.8 Transfer the sample to a 19.05 by 50.8-mm ( ⁄4 by 2- in.) plastic vial containing one 9.52-mm ( ⁄8-in.) plastic ball.
75.9 Close the plastic vial and seal the lid with masking tape.
75.10 Place the vial and its contents in the heavy-duty shaker and lock it into its holder.
75.11 Set the shaker timer for 2 min and start.
75.12 Examine the blend for uniformity of particles after the shaker has stopped. If it is lumpy, or different in texture from the
standards, blend for an additional 2 min.
75.13 If the blend is uniform in size then the sample is ready for spectrochemical impurity analysis as described in Test Methods
C696 or Test Methods C761.
BORON BY EMISSION SPECTROGRAPHY
75. Scope
75.1 This test method covers the determination of 0.05 to 33 μg B/g of uranium.
76. Scope
76.1 This test method was discontinued in 2019 and is replaced by Test Method C1517. As an alternative, boron can also be
determined by ICP-MS using Test Method C1287.
76. Summary of Test Method
76.1 Boron is separated from uranium in dilute nitric acid by cation exchange. Mannitol complexing is used to prevent boron
losses during evaporation of the effluent to dryness prior to the spectrographic determination (12).
77. Apparatus
77.1 Ion-Exchange Column, 1.0 cm by 14 cm.
77.2 Beaker, TFE-fluorocarbon.
C799 − 19
78. Reagents
78.1 Boron Standard Solution (1 mL = 100 μg B)—Dissolve 0.5724 g of boric acid (H BO ) in 0.2 N HNO and dilute to 1
3 3 3
L with 0.2 N HNO .
78.2 Boron Working Standard Solutions— Pipet 1, 2, 5, 10, 50, and 100-mL aliquots of the boron standard solution (see 78.1)
into 100-mL flasks and dilute to volume with 0.2 N HNO .
10 +
78.3 Cation Exchange Resin, H form (200–400 mesh)—Wash the resin free of “fines,” residual color, and any boron
contamination, and prepare a resin bed 80 mm in length. Wash the bed with 50 mL of 1 N HNO , then 150 mL of 0.2 N HNO
3 3
immediately prior to use.
NOTE 5—The resin column can only be used once.
78.4 Electrodes, ASTM C-1 cathode and ASTM S-1 pedestal with anode cap. Seal the caps with two applications of 5 drops
each of 2 % polychlorotrifluorethylene grease in carbon tetrachloride (CCl ). Evaporate the solvent completely after each
application.
78.5 Indium Oxide (In O ), boron-free.
2 3
78.6 Mannitol, powder, reagent grade.
78.7 Zinc Internal Standard Solution (1 mL = 4 mg Zn)—Dissolve 1.2448 g of high-purity ZnO (99.99 + %) in 0.2 N HNO
and dilute to 250 mL with 0.2 N HNO .
79. Procedure
79.1 Determine a blank on each prepared ion-exchange column by adding 10 mL of 0.2 N HNO .
79.2 Adjust the flow rate at about 0.3 to 0.5 mL/min and collect the effluent in a TFE-fluorocarbon dish.
79.3 Wash the column with 50 mL of 0.2 N HNO when the level of solution reaches the top of the resin bed.
79.4 Add 25 mg of mannitol to the effluent in the dish.
79.5 Dissolve the mannitol and slowly evaporate the solution to dryness under heat lamps but do not bake.
79.6 Cool the dish and dissolve the residue in 500 μL of the zinc internal standard solution.
79.7 Pipet 100-μL aliquots of this solution onto each of four sealed electrodes containing 2.5 mg of In O as spectrographic
2 3
matrix and dry under heat lamps.
79.8 Pipet 5 mL of the sample solution into a platinum dish and evaporate to near dryness on a steam bath.
79.9 Add 10 mL of 0.2 N HNO and transfer to a column. Continue with 79.2 – 79.7.
79.10 Make exposures of each sample under the following excitation conditions:
Exposure: 10 s
Current: 25 d-c A
Gap: 4 mm
Entrance Slit: 25 μm
Spectral Range: 2300 to 2900 Å
A
Photographic Plates:
A
Eastman SA-1.
79.11 Measure the boron 2497.73 Å and zinc 2756.45Å analytical lines on the processed photographic plates with a
microphotometer.
79.12 Prepare an analytical working curve by pipetting 100-μL aliquots of the standard boron solutions onto sealed graphite
electrodes containing 5 mg of mannitol and 2.5 mg of In O . Dry the electrodes and add 100 μL of the zinc internal standard
2 3
solution to each, dry again, and excite the electrode following the above procedure.
80. Calculation
...