Reliable Safeguards Verification Measurements Results and the International Target Values 2010

The International Target Values (ITVs) are reasonable uncertainty estimates that can be used in judging the reliability of measurement techniques applied to industrial nuclear and fissile materials subject to accountancy and/or safeguards verification. In the absence of relevant experimental estimates, ITVs can also be used to select measurement techniques and calculate sample population during the planning phase of verification activities. It is important to note that ITVs represent estimates of the “state-of-thepractice”, which should be achievable under routine measurement conditions affecting both facility operators and safeguards inspectors, not only in the field, but also in laboratory. Tabulated values cover measurement methods used for the determination of volume or mass of the nuclear material, for its elemental and isotopic assays, and for its sampling. The 2010 edition represents the sixth revision of the International Target Values (ITVs), issued by the International Atomic Energy Agency (IAEA) as a Safeguards Technical Report (STR-368). The first version was released as “Target Values” in 1979 by the Working Group on Techniques and Standards for Destructive Analysis (WGDA) of the European Safeguards Research and Development Association (ESARDA) and focused on destructive analytical methods. In the latest 2010 revision, international standards in estimating and expressing uncertainties have been considered while maintaining a format that allows comparison with the previous editions of the ITVs. Those standards have been usually applied in QC/QA programmes, as well as qualification of methods, techniques and instruments. Representatives of the Brazilian Nuclear Energy Commission (CNEN) and the Brazilian-Argentine Agency for Accounting and Control of Nuclear Materials (ABACC) participated in previous Consultants Group Meetings since the one convened to establish the first list of ITVs released in 1993 and in subsequent revisions, including the latest one in 2010. In this paper, the authors present the main changes introduced to the latest revision, in comparison to the previous one (2000), discuss possible impacts of these changes on evaluation programmes for production, quality control and safeguards of nuclear materials. In addition, actual safeguards measurement uncertainty estimates obtained by CNEN and ABACC as results of the application of national and regional safeguards, respectively, are presented and compared with the ITVs.