【国外标准】 Standard Practice for Subsampling of Uranium Hexafluoride

5.1 Uranium hexafluoride is normally produced and handled in large (typically 1- to 14-ton) quantities and must, therefore be characterized by reference to representative samples. The samples are used to determine compliance with the applicable commercial Specifications C996 and C787 by means of the appropriate test method (for example, Test Method C761 and references therein). The quantities involved, physical properties, chemical reactivity, and hazardous nature of UF6 are such that for representative sampling, specially designated equipment must be used and operated in accordance with the most carefully controlled and stringent procedures. This practice indicates appropriate principles, equipment and procedures currently in use for subsampling of liquid UF6. It is used by UF6 converters, enrichers and fuel fabricators to review the effectiveness of existing procedures or to design equipment and procedures for future use. Other subsampling procedures such as UF6 vapor sampling are not directly representative of the chemical quality of liquid UF6.5.2 It is emphasized that this test guide is not meant to address conventional or nuclear criticality safety issues, nor does it address the conditioning of subsample tubes to make them suitable for transport.1.1 This practice is applicable to subsampling uranium hexafluoride (UF6), using heat liquefaction techniques, from bulk containers, obtained in conformance with Practices C1052, C1703, and C1883, into smaller sample containers, which are required for laboratory analyses.1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.3 It is assumed that the liquid UF6 being sampled comprises a single quality and quantity of material. This practice does not address any special additional arrangement that might be required for taking proportional or composite samples.1.4 The number of samples to be taken, their nominal sample weight, and their disposition shall be agreed upon between the parties.1.5 The scope of this practice does not include provisions for preventing criticality incidents.1.6 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.1.7 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.