Enhanced Guidance for the Preparation of Working Reference Materials for Nuclear Fuel Cycle Applications

Due to a several factors, availability of certified reference materials (CRM) for laboratory use to support accountancy, safeguards, and nuclear forensics applications is currently quite limited. Reference material providers globally are struggling due to issues with facilities, changes in the mix of materials needed, and the need to re-characterize older reference materials that are still in use throughout the nuclear laboratory community. Although efforts are under way to improve this situation, those efforts will take several years to bring about much improvement. In the interim, increased focus is being placed on the use of working reference materials (WRM), which can be prepared by individual laboratories, typically from CRM, for use in their own facilities. WRM can be tailored to the specific needs of a laboratory or method (for example, a specific matrix) but are still reference materials that need to be traceable to CRM or otherwise to the international system of measurement (SI). Thus, WRM adhere more to ISO 17034 than to ISO Guide 80, which describes quality control materials that are not metrologically traceable. The need for WRM, and for additional detailed guidance on the proper preparation of WRM, has been discussed in recent IAEA technical meetings. One of the recommendations from these meetings was to develop detailed guidance for WRM preparation by revising an existing standard, ASTM C1128, Standard Guide for Preparation of Working Reference Materials for Use in Analysis of Nuclear Fuel Cycle Materials. An international team has been working since summer 2016 to update and expand the information in C1128. The update should begin the balloting process later in 2017. This paper will provide background discussion on the differences between CRM, WRM, and quality control materials (as described in ISO Guide 80), the current status of the C1128 update, and an outline of the information to be provided in C1128. This will include discussion of up-front planning and project management, required studies, packaging and storage, ongoing monitoring, and some specific examples. The updated C1128 will facilitate the proper preparation and use of WRM, which will improve measurement quality and reduce the strain on the CRM supply.