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 preparation, packaging, and storage; requirements for characterization; homogeneity and stability considerations; and establishing traceability of WRMs to certified reference materials by a defined, statistically sound characterization process. 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 preparation and characterization of certified reference materials (CRM). Refer to ISO 17034 and Guide 35 for those requirements.

1.3 The information provided by this guide is found in the following sections:

1.4 The values stated in SI units are to be 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.