1.1 本指南为测试实验室评估和表达水和其他环境介质的放射化学测量不确定度提供了概念、术语、符号和建议。它适用于放射性核素活动的测量，包括总活动，无论它们是否涉及样品的化学制备。 1.2 本指南不提供测量不确定度的完整教程。感兴趣的读者应参考第节中列出的文件 2. 更多信息请参见参考文献。例如，参见GUM、QUAM、Taylor和Kuyatt ( 1. ) 2. 和MARLAP第19章 ( 2. ) . 1.3 未指定本指南的单位制。 本指南中的尺寸量仅作为计算方法的说明。这些示例对所处理的产品或测试方法没有约束力。 1.4 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。 1.5 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 本指南旨在帮助测试实验室以及这些实验室的方法和软件开发人员将测量不确定度的概念应用于放射化学分析。 5.2 实验室测量的结果永远不会完全等于被测量的真实值。两者之间的差异称为 错误 测量结果。对该误差可能大小的估计称为 不确定性 测量结果。虽然误差主要是一个理论概念，但由于其值从来都不知道，因此不确定性具有实际用途。测量值及其不确定度一起允许人们对被测对象的可能真实值设置界限。 5.3 可靠的基于测量的决策不仅需要测量值，还需要其不确定性的指示。传统上，使用不同成功程度的重要数字来暗示测量不确定性的数量级；然而，报告每个结果的显式不确定性估计更可靠，信息更丰富，被认为是行业标准的最佳实践。

1.1 This guide provides concepts, terminology, symbols, and recommendations for the evaluation and expression of the uncertainty of radiochemical measurements of water and other environmental media by testing laboratories. It applies to measurements of radionuclide activities, including gross activities, regardless of whether they involve chemical preparation of the samples. 1.2 This guide does not provide a complete tutorial on measurement uncertainty. Interested readers should refer to the documents listed in Section 2 and References for more information. See, for example, GUM, QUAM, Taylor and Kuyatt ( 1 ) 2 , and Chapter 19 of MARLAP ( 2 ) . 1.3 The system of units for this guide is not specified. Dimensional quantities in the guide are presented only as illustrations of calculation methods. The examples are not binding on products or test methods treated. 1.4 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. 1.5 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 This guide is intended to help testing laboratories and the developers of methods and software for those laboratories to apply the concepts of measurement uncertainty to radiochemical analyses. 5.2 The result of a laboratory measurement never exactly equals the true value of the measurand. The difference between the two is called the error of the measurement. An estimate of the possible magnitude of this error is called the uncertainty of the measurement. While the error is primarily a theoretical concept, since its value is never known, the uncertainty has practical uses. Together, the measured value and its uncertainty allow one to place bounds on the likely true value of the measurand. 5.3 Reliable measurement-based decision making requires not only measured values but also an indication of their uncertainty. Traditionally, significant figures have been used with varying degrees of success to indicate implicitly the order of magnitude of measurement uncertainties; however, reporting an explicit uncertainty estimate with each result is more reliable and informative, and is considered an industry-standard best practice.