【国外标准】 Standard Test Methods for Arsenic in Uranium Hexafluoride (Withdrawn 2015)

Arsenic compounds are suspected to cause corrosion in some materials used in UF6 handling equipment. Arsenic originates as a contaminant in fluorspar (CaF2) used to produce anhydrous hydrogen fluoride which is used subsequently in the production of UF 6.These test methods are used to measure the arsenic content in UO2F2 solutions prepared from the hydrolysis of UF6 for determination of conformance to Specification C 787.1.1 These test methods are applicable to the determination of total arsenic in uranium hexafluoride (UF6) by atomic absorption spectrometry. Two test methods are given: Test Method A—Arsine Generation-Atomic Absorption (Sections 5-10), and Test Method B—Graphite Furnace Atomic Absorption (Appendix X1).1.2 The test methods are equivalent. The limit of detection for each test method is 0.1 μg As/g U when using a sample containing 0.5 to 1.0 g U. Test Method B does not have the complete collection details for precision and bias data thus the method appears as an appendix.1.3 Test Method A covers the measurement of arsenic in uranyl fluoride (UO2F2) solutions by converting arsenic to arsine and measuring the arsine vapor by flame atomic absorption spectrometry.1.4 Test Method B utilizes a solvent extraction to remove the uranium from the UO2F2 solution prior to measurement of the arsenic by graphite furnace atomic absorption spectrometry.1.5 Both insoluble and soluble arsenic are measured when UF6 is prepared according to Test Method C 761.1.6 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.7 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.