Publication Date: 12/1/74     Pages: 2     Date Entered: 2/23/84     Title: GENERAL METHODS FOR THE ANALYSIS OF URANYL NITRATE SOLUTIONS FOR ASSAY, ISOTOPIC DISTRIBUTION, AND IMPURITY DETERMINATIONS     December 1974     U.S. ATOMIC ENERGY COMMISSION     REGULATORY GUIDE     DIRECTORATE OF REGULATORY STANDARDS     REGULATORY GUIDE 5.39     GENERAL METHODS FOR THE ANALYSIS OF URANYL NITRATE SOLUTIONS     FOR ASSAY, ISOTOPIC DISTRIBUTION, AND IMPURITY DETERMINATIONS A. INTRODUCTION     Paragraph 70.22(b) of 10 CFR Part 70, "Special Nuclear Material,"     requires, among other things, that an applicant for a license to possess     certain quantities of special nuclear material in an unsealed form     describe his procedures for the control of and accounting for special     nuclear material. This guide identifies methods acceptable to the     Regulatory staff for chemical, isotopic, and impurity analyses which an     applicant may specify as part of his procedures for accounting for     special nuclear material. B. DISCUSSION     Committee C-26 on Fuel, Control, and Moderator Materials for     Nuclear Reactor Applications of the American Society for Testing and     Materials (ASTM) has developed a standard containing methods for the     chemical analysis of nuclear-grade uranyl nitrate solutions. This     standard is entitled "Standard Methods for Chemical, Mass Spectrometric,     Spectrochemical, Nuclear, and Radiochemical Analysis of Nuclear-Grade     Uranyl Nitrate Solutions."(*) As used in this standard, nuclear grade     material means material that is to be used exclusively for the     fabrication of nuclear fuel. Included in this standard are two methods     for the determination of uranium: 1. Ferrous Sulfate Reduction - Potassium Dichromate Titration. The     optimum quantities of uranium to be determined are 100 to 150 mg with a     stated precision of 0.1 percent relative standard deviation (RSD) at the     2 sigma level. 2. Ignition (Gravimetric) Method. The stated precision is 0.03     percent RSD at the 2 sigma level for 5 to 10g of U(3)O(8).     ----------     (*) Copies may be obtained from the American Society for Testing     and Materials, 1916 Race Street, Philadelphia, Pa. 19103.     ----------     This standard also includes a method for the determination of the     isotopic composition of UO(2)(NO(3))(2) solutions allowing for the use     of reference standards to determine bias. The stated precision of the     method for ratios at the 0.1 isotopic concentration level is 0.02% RSD;     at the 0.01 isotopic concentration level, 0.5% RSD; and at the 0.001     isotopic concentration level, 1.2% RSD, all at the 2 sigma level.     Various impurities such as chromium, molybdenum, thorium, phosphorus,     silicon, chloride, fluoride, bromide, iodide, nitrogen, carbon, sulfur,     boron, and volatile and nonvolatile impurities can be determined using     the methods that are included in the standard. Also described are     methods for the determination of specific gravity, free acid, impurities     by spark source mass spectrometry, U-232 by alpha spectrometry, total     alpha activity, and fission product activity. C. REGULATORY POSITION     The analytical methods for the measurement of nuclear-grade uranyl     nitrate solutions contained in the ASTM Standard C-799, "Standard     Methods for Chemical, Mass Spectrometric, Spectrochemical, Nuclear, and     Radiochemical Analysis of Nuclear-Grade Uranyl Nitrate Solutions"(*) are     acceptable and provide an adequate basis for the assay, isotopic     measurement, and impurity analysis of nuclear-grade uranyl nitrate     solutions subject to the following: 1. Precision and Accuracy Statements. The listed statements provide     guidance to the levels of performance which may be attained using the     described methods. The actual precision and accuracy of a method     applied within a selected laboratory can only be determined through a     well-planned measurement control program. 2. Calibration and Standardization. The standards should be prepared     in the same matrix as the samples, and the calibration points should     bracket the estimated range of the samples. 3. Safety. Procedures involving the use of perchloric acid should be     performed with caution because of the potential explosion and fire     hazard. D. IMPLEMENTATION     The purpose of this section is to provide information to     applicants and licensees regarding the Regulatory staff's plans for     utilizing this regulatory guide.     This guide reflects current regulatory practice. Therefore,     except in those cases in which an applicant or licensee proposes an     alternative method for complying with specified portions of the     Commission's regulations the method described herein will be used     immediately in the evaluation of applications for licenses to possess at     any one time special nuclear material in a quantity exceeding one     effective kilogram as described in Section 70.22(b) of 10 CFR Part 70     and in the evaluation of the performance of holders of such licenses..     39