1.1 本指南涵盖实验室生产的用于核燃料循环材料分析的工作参考材料（WRM）的制备和表征。为正确规划、准备、包装和储存提供指导；表征要求；均匀性和稳定性考虑；以及价值分配。当WRM需要SI的可追溯性时，将通过定义的、统计上可靠的表征过程来实现，该过程可追溯到认证参考材料上的认证值。虽然所提供的指南是针对核燃料循环材料的通用指南，但附录中提供了一些材料的详细示例。 1.2 本指南不适用于认证参考材料（CRM）的生产和表征。参考ISO 17034和ISO指南35，了解参考材料生产、表征、认证、销售和分销要求的指南。 1.3 本指南提供的信息可在以下章节中找到: 部分 执行WRM规划 6. 准备和处理材料 7. 材料的包装和储存 8. 进行同质性研究 9 进行稳定性研究 10 表征材料 11 执行不确定性分析 12 制作文档 13 执行WRM利用和监测 14 1.4 以国际单位制表示的值应视为标准值。 摩尔的非SI单位， M 和正常， N ，也被视为标准。括号中显示的任何非国际单位制计量单位仅供参考。 1.5 本标准并不旨在解决与其使用相关的所有安全问题（如有）。本标准的使用者有责任在使用前建立适当的安全、健康和环境实践，并确定监管限制的适用性。 1.6 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《国际标准、指南和建议制定原则决定》中确立的国际公认标准化原则制定的。 =====意义和用途====== 5.1 由核材料制备的认证参考材料（CRM）具有良好的特性、可追溯性，并且对于其预期用途具有足够的均匀性和稳定性。通常，他们使用最无偏见和最精确的测量方法进行认证，通常在国家或国际层面上使用多个实验室。CRM位于参考材料计量等级的顶端。典型国家核测量系统的图形表示如 图3 . 图3 典型国家核测量系统 5.2 工作参考材料（WRM）需要具有与CRM相似的质量特征，尽管用于实现这些特征的严格性通常不如CRM严格。 同样，WRM的生产应符合ISO 17034的适用要求。在可能的情况下，CRM通常用于校准用于建立分配给WRM的参考值的方法，从而按照ISO/IEC 17025的要求提供CRM的可追溯性。WRM通常是为特定应用准备的。 5.3 由于拥有来自核材料分析的高度可靠的测量数据的重要性，特别是出于材料控制和问责目的，CRM在可用时用于校准。然而，由核材料制备的CRM并不总是可用于特定应用。 因此，可能需要一个实验室来制备核材料WRM以满足特定需求；以例如匹配过程样本中的矩阵。在这种情况下，可定制WRM以满足工艺或实验室的特定需求。此外，CRM供应可能太有限，无法满足长期常规使用所需的数量。如果准备得当，WRM将与CRM一样适用于大多数应用，使用WRM将有助于保持CRM的供应。 5.4 由于核材料的化学和物理财产，在用核材料制备RM时可能会遇到困难。化学不稳定性、确保化学计量的问题、均匀性和放射性是需要考虑的因素之一，所有三个因素都与某些材料有关。 用核材料制备WRM的人员需要了解这些因素可能如何影响制备，并了解控制制备可靠WRM的其他标准。 5.5 虽然WRM的使用为实验室带来了好处，但重要的是要注意WRM与CRM之间的区别，WRM由实验室（或在某些情况下，实验室服务的附属卫星实验室或生产设施）制备，供该实验室使用，CRM提供分析证书（根据ISO指南31），并可供出售。

1.1 This guide covers the preparation and characterization of working reference materials (WRM) that are produced by a laboratory for its own use in the analysis of nuclear fuel cycle materials. Guidance is provided for proper planning, preparation, packaging, and storage; requirements for characterization; homogeneity and stability considerations; and value assignment. When traceability to SI is desired for a WRM, it will be achieved by a defined, statistically sound characterization process that is traceable to a certified value on a certified reference materials. While the guidance provided is generic for nuclear fuel cycle materials, detailed examples for some materials are provided in the appendixes. 1.2 This guide does not apply to the production and characterization of certified reference materials (CRM). Refer to ISO 17034 and ISO Guide 35 for guidance on reference material production, characterization, certification, sale, and distribution requirements. 1.3 The information provided by this guide is found in the following sections: Section Perform WRM Planning 6 Prepare and Process Materials 7 Packaging and Storage of Materials 8 Perform Homogeneity Study 9 Perform Stability Studies 10 Characterize Materials 11 Perform Uncertainty Analysis 12 Produce Documentation 13 Carry Out WRM Utilization and Monitoring 14 1.4 The values stated in SI units are to be regarded as standard. The non-SI units of molar, M , and normal, N , are also regarded as standard. Any non-SI units of measurement shown in parentheses are for information only. 1.5 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. 1.6 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 Certified reference materials (CRMs) prepared from nuclear materials are well characterized, traceable, and sufficiently homogenous and stable for their intended use. Usually they are certified using the most unbiased and precise measurement methods available, often with more than one laboratory being used on a national or international level. CRMs are at the top of the metrological hierarchy of reference materials. A graphical representation of a typical national nuclear measurement system is shown in Fig. 3 . FIG. 3 Typical National Nuclear Measurement System 5.2 Working reference materials (WRMs) need to have quality characteristics that are similar to CRMs, although the rigor used to achieve those characteristics is not usually as stringent as for CRMs. Similarly, production of WRMs should be in accordance with applicable requirements of ISO 17034. Where possible, CRMs are typically used to calibrate the methods used for establishing reference values assigned to WRMs, thus providing traceability to CRMs as required by ISO/IEC 17025. A WRM is normally prepared for a specific application. 5.3 Because of the importance of having highly reliable measurement data from nuclear material analysis, particularly for material control and accountability purposes, CRMs are used for calibration when available. However, CRMs prepared from nuclear materials are not always available for specific applications. Thus, there may be a need for a laboratory to prepare nuclear material WRMs to meet specific needs; for example, to match the matrix in process samples. In such cases, a WRM can be tailored to meet specific needs of a process or laboratory. Also, CRM supply may be too limited for use in the quantities needed for long-term, routine use. When properly prepared, WRMs will serve equally well as CRMs for most applications, and using WRMs will help preserve supplies of CRMs. 5.4 Difficulties may be encountered in the preparation of RMs from nuclear materials because of the chemical and physical properties of the materials. Chemical instabilities, problems in ensuring stoichiometry, homogeneity, and radioactivity are among the factors to be considered, with all three factors being involved with some materials. Those preparing WRMs from nuclear materials need to be aware of how these factors may affect preparation, as well as being aware of the other criteria governing the preparation of reliable WRMs. 5.5 While use of WRMs provides benefits for the laboratory, it is important to observe the distinction between WRMs, which are prepared by a laboratory for use by that laboratory (or, in some cases, an affiliated satellite laboratory or production facility served by the laboratory), and CRMs which provide certificates of analysis (in accordance with ISO Guide 31) and can be offered for sale.