1.1 本规程适用于气态六氟化铀（UF）的取样 6. )利用氧化铝（Al）的吸附剂特性，从处理设施、同位素富集级联或储存筒中提取 2. O 3. ). 1.2 它基于“ABACC-Cristallini方法” ( 1. , 2. ) 2. 其目的是用于测定核材料保障以及其他应用所需的铀（U）同位素组成。 1.3 本规程的应用确保所得样品容器不含超滤 6. 氟化氢（HF）；因此，可以在不太严格的限制条件下对其进行处理和分类。 1.4 本规程的范围不包括防止危险性的规定。 1.5 单位- 以国际单位制表示的数值应视为标准。当提供非国际单位制时，它们仅供参考。 1.6 本标准并非旨在解决与其使用相关的所有安全问题（如有）。本标准的用户有责任在使用前制定适当的安全、健康和环境实践，并确定监管限制的适用性。 1.7 本国际标准是根据世界贸易组织技术性贸易壁垒（TBT）委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认标准化原则制定的。 ====意义和用途====== 5.1 设施操作员和安全检查人员定期接受UF检查 6. 来自处理线、同位素富集级联或储存筒的样品，以确定其U同位素组成，最重要的是 n ( 235 U）/ n ( 238 U） 同位素比率，用于计算裂变物质的量 235 样品中的U。当前版本的“核材料安全保障中测量不确定性的国际目标值” ( 3. ) 包含这些测量的建议指南。 5.2 常规采样实践收集UF 6. 样品在1-10g范围内，需要使用液氮在样品容器、金属瓶或P-10管中冷凝。然后必须将这些样品运送到外部分析实验室，以验证申报的数据，尤其是同位素比率。 除其他外，运输包括公共道路和洲际空运。由于超滤的危害 6. ，航空运输变得越来越困难，许多运输运营商和监管机构拒绝运输这些材料。 5.3 制定本抽样规程是为了满足以下要求: 5.3.1 适合用途:能够核查核材料申报数量。 5.3.2 简单性:确保简单快速的执行。 5.3.3 灵活性:适用于各种设施。 5.3.4 稳健性:确保即使操作参数稍有变化，也能对足够的材料进行采样。 5.3.5 可靠性:提供与使用传统抽样实践获得的结果一致的测量结果。 5.3.6 保密性:尊重设施的操作程序和数据的保密性。 5.3.7 安全:减少与放射性和危险材料的采样、处理和运输相关的风险。 5.4 这种抽样方法与传统抽样方法相比具有显著优势，因为它允许处理非- 反应性、非挥发性、固体UO 2. F 2. 而不是高度反应性和挥发性的超滤 6. . 5.5 较小的UO 2. F 2. 样品可以在较低的放射性水平下运输，并在发生事故时减少放射性问题。此外，不存在空气中铀颗粒和HF释放的风险。 5.6 UF中测量的U同位素比值 6. 通过常规采样和本采样实践进行采样，可提供在规定不确定度范围内良好一致的测量结果 ( 4. , 5. ) . 5.7 强烈建议丢弃使用过的P- 避免同位素交叉污染的可能性，主要是因为这种做法与处理极少量的铀有关。 5.8 如果使用回收的P-10管，必须采用非常有效和可靠的清洁程序，以确保U从P-10管内表面完全去除。 5.9 本规程为获取样品提供了指导，以确定材料核保障措施以及其他应用中的铀成分。此类样品不应用于确定是否符合规范 C787 和 C996 . 对于这些情况，实践的建议 C1052 或 C1703 必须遵守。 5.10 试验方法中介绍了描述六氟化铀二次采样、质谱、光谱化学、核和放射化学分析程序的试验方法 C761 . 其中大多数通常用于确定是否符合规范 C787 和 C996 .

1.1 This practice is applicable to sampling gaseous uranium hexafluoride (UF 6 ) from processing facilities, isotope enrichment cascades or storage cylinders, using the sorbent properties of aluminum oxide (Al 2 O 3 ). 1.2 It is based on the ‘ABACC-Cristallini Method’ ( 1 , 2 ) 2 and is intended to be used for the determination of uranium (U) isotopic composition required for nuclear material safeguards as well as other applications. 1.3 The application of this practice assures the resulting sample vessel contains no UF 6 and hydrogen fluoride (HF); therefore, it may be handled and categorized for transport under less stringent constraints. 1.4 The scope of this practice does not include provisions for preventing criticality. 1.5 Units— The values stated in SI units are to be regarded as the standard. When non-SI units are provided, they are for information only. 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, health, and environmental 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. ====== Significance And Use ====== 5.1 Facility operators and safeguards inspectors routinely take UF 6 samples from processing lines, isotopic enrichment cascades or storage cylinders to determine its U isotopic composition, most important the n ( 235 U)/ n ( 238 U) isotope ratio, needed to calculate the amount of the fissile 235 U in the sample. The current version of the “International Target Values for Measurement Uncertainties in Safeguarding Nuclear Materials” ( 3 ) contains recommended guidelines for these measurements. 5.2 The conventional sampling practice collects UF 6 samples in the range of 1-10 g and requires the use of liquid nitrogen to condense them in sample vessels, metallic bottles or P-10 tubes. These samples must then be transported to external analytical laboratories for verification of the declared data, especially the isotope ratios. Transport includes, among other things, public roads and intercontinental air shipment. Due to the hazards of UF 6 , air transport is becoming increasingly difficult, with many transport operators and regulators refusing to carry the material. 5.3 This sampling practice was developed to meet the following requirements: 5.3.1 Fit for Purpose: to enable the verification of the declarations of amounts of nuclear materials. 5.3.2 Simplicity: to ensure a simple and fast execution. 5.3.3 Flexibility: to be applied in a wide range of facilities. 5.3.4 Robustness: to ensure sufficient material is sampled even when operational parameters slightly change. 5.3.5 Reliability: to provide measurement results in agreement with those obtained using the conventional sampling practice. 5.3.6 Confidentiality: to respect the facility’s operational procedure and confidentiality of data. 5.3.7 Safety: to reduce the risks associated with the sampling, handling and transport of radioactive and hazardous materials. 5.4 This sampling practice offers significant advantages over the conventional sampling practice because it allows handling non-reactive, non-volatile, solid UO 2 F 2 instead of highly reactive and volatile UF 6 . 5.5 A smaller UO 2 F 2 sample can be transported with lower radioactivity level and reduced radiological problems in case of accident. Additionally, there is no risk of airborne uranium particle and HF release. 5.6 The U isotope ratios measured in UF 6 sampled by the conventional and this sampling practice provide measurement results which are in good agreement within the stated uncertainties ( 4 , 5 ) . 5.7 It is strongly recommended to discard used P-10 tubes to avoid the possibility of isotopic cross contamination, mainly because this practice is associated with the processing of very small amounts of U. 5.8 In case recycled P-10 tubes are used, a very efficient and reliable cleaning procedure must be employed to assure a complete removal of U from the P-10 tube inner surfaces. 5.9 This practice provides guidance to obtain samples for determining the U composition for material nuclear safeguards as well as other applications. Such samples should not be used for determining compliance with Specifications C787 and C996 . For these cases, the recommendations of Practices C1052 or C1703 must be followed. 5.10 The test methods describing procedures for subsampling, mass spectrometric, spectrochemical, nuclear, and radiochemical analysis of uranium hexafluoride are presented in Test Methods C761 . Most of them are routinely used to determine the compliance with Specifications C787 and C996 .