The Euratom Tailored Safeguards Approach for the Melox MOX Fuel Fabrication Plant – Quantitative Effects on Interim Verifications

The Melox MOX fabrication plant is a modern, large-scale plant that features a high level of automation. For safeguards purposes Euratom is using branching on the operator’s equipment to get measurement data that are compared with the declared operating data on a daily basis. Therefore, the inspection scheme has been specially designed to increase the level of knowledge about the nuclear material flowing through the process by using the operator’s on-line measurements. A statistical approach was developed to quantify the benefit of the information obtained by the branching over the overall inspection effort. The probability of nondetection, the frequency of the verification activities and the demanded timeliness are the parameters that determine the sample size to be selected for gross and partial defect. A comparison between the efforts demanded by a conventional and a tailored inspection scheme are here highlighted.