Значение и использование

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 C 788.

3.1.1 An assay is performed to determine whether the material has the specified uranium content.

3.1.2 Determination of the isotopic content of the uranium is made to establish whether the effective fissile content is in accordance with the purchaser’specifications.

3.1.3 Acidity, organic content, and alpha, beta, and gamma activity are measured to establish that they do not exceed their maximum limits.

3.1.4 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).

Область применения

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 Specific Gravity by Pycnometry 15-20 Free Acid by Oxalate Complexation 21-27 Determination of Thorium28 Determination of Chromium29 Determination of Molybdenum30 Halogens Separation by Steam Distillation 31-35 Fluoride by Specific Ion Electrode 36-42 Halogen Distillate Analysis: Chloride, Bromide, and Iodide by
Amperometric Microtitrimetry43 Determination of Chloride and Bromide44 Determination of Sulfur by X-Ray Fluorescence45 Sulfate Sulfur by (Photometric) Turbidimetry46 Phosphorus by the Molybdenum Blue (Photometric) Method 54-61 Silicon by the Molybdenum Blue (Photometric) Method62-69 Carbon by Persulfate Oxidation-Acid Titrimetry70 Conversion to U₃O₈71-74 Boron by Emission Spectrography75-81 Impurity Elements by Spark Source Mass Spectrography82 Isotopic Composition by Thermal Ionization Mass Spectrometry83 Uranium-232 by Alpha Spectrometry84-90 Total Alpha Activity by Direct Alpha Counting91-97 Fission Product Activity by Beta Counting98-104 Entrained Organic Matter by Infrared Spectrophotometry105 Fission Product Activity by Gamma Counting106 Determination of Arsenic107 Determination of Impurities for the EBC Calculation108 Determination of Technetium 99109 Determination of Plutonium and Neptunium110

1.3 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. Specific precautionary statements are given in Section 5.

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.

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 U₃O₈.

15.1 This test method covers the determination of the specific gravity of a solution of uranyl nitrate to ±0.0004.

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.

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.

29.1 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 U₃O₈ so described hereafter in sections 117–120 A direct conversion to the amonium fluoride plus nitric acid solution can also be used, (see C761).

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.

30.1 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 U₃O₈ as described hereafter in sections 71-74. A direct conversion to the amonium fluoride plus nitric acid solution can also be used, (see C761, section 251).

30.4 Previous sections have been deleted.

31.1 This test method covers the separation of the halogens by means of a steam distillation.

36.1 This test method covers the determination of as low as 2 μg F/g U in distillate containing all the halogens.

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.

44.1 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.

45.1 Sulfur can be determined using X-Ray Fluorescence. See Test Method C1296.

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.

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.

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.

70.1 Determination of carbon by the persulfate oxidation titrimetry method has been discontinued, (see C799-93).

70.2 Previous sections have been deleted.

71.1 This test method is specifically designed for the conversion of uranyl nitrate to U₃O₈.

75.1 This test method covers the determination of 0.05 to 33 μg B/g of uranium.

82.1 The determination of impurities by spark source mass spectrography method has been discontinued, (see C799-93).

82.2 Previous section have been deleted.

83.1 The determination of isotopic composition using a single collector thermal ionisation mass spectrometer has been discontinued, (see C799-93 and C696).

83.2 As an alternative, the isotopic composition can be measured using a multi- collector thermal ionisation spectrometer. Test Method C1413 can be used.

83.3 As an alternative, the isotopic composition can be measured using isotope dilution mass spectormetry. Test Method C1380 can be used.

83.4 Previous section have been deleted.

84.1 This test method covers the determination of uranium-232 in nuclear-grade uranyl nitrate solutions, in concentrations as low as 0.05 ng ²³²U/ ²³⁵U.

91.1 This test method covers the determination of the sum of all alpha-emitting nuclides in uranyl nitrate solutions.

98.1 This test method covers the measurement of the beta emitters fission product activity of nuclear-grade uranyl nitrate solutions.

105.1 The determination of entrained organic matter by infrared spectrophotometry method has been discontinued, (see C799-93).

106.1 The determination of gamma emiters fission products can be done with Test Method C1295.

107.1 The determination of arsenic can be done with atomic absorption. Test Method C1219 can be used.

107.2 As an alternative, arsenic can be determined using ICP-MS. Test Method C1287 can be used.

108.1 The determination of impurities for the Equivalent Boron Content can be done with ICP-MS. Test Method C1287 can be used. The EBC table described in C1233 can be used.

109.1 The determination of Technetium 99 can be done using ICP-MS. Test Method C1287 can be used.

109.2 As an alternative, Technetium can be determined after solvent extraction by beta counting. Test Method C761 can be used.

110.1 Plutonium can be determined by alpha counting after ion exchange. Test Method C761 can be used.

110.2 As an alternative, plutonium can be determined by alpha counting after solvent extraction. Test Method C761 can be used.

110.3 Neptunium can be determined by alpha counting after solvent extraction. Test Method C761 can be used.

110.4 Previous sections have been deleted.