Recent achievements for In-situ measurement: applications to an actual decommissioning project

Decommissioning a nuclear facility implies a policy of limiting the waste volume and its chemical - and especially radiological - toxicity. It is therefore important to determine the activity level contained in each component that will be dismantled. A variety of methods and analysis techniques are used for this purpose, ranging from simple dose rate measurements to γ spectrometry and γ imaging. The results of several measurement campaigns in a reactor currently in operation but for which decommissioning studies have now been undertaken are discussed. The measurements provide additional radiological data for the waste inventory, which is one of the first issues to be examined. This discussion focuses on the methods used (γ imaging, in situ γ spectrometry, etc.), the results obtained, and their implications for the project, as well as the technological and methodological innovations implemented during these campaigns. (authors)