Micrometric particle's isotopics: An ultra-sensitive tool to detect nuclear plant discharge in the environment

CEA, Service Radioanalyses, Surveillance, Environnement, 91680 Bruyères-le-Châtel, France

Abstract

To monitor the impact of a nuclear plant on the environment, common analytical methods consist of measuring the entire sample giving an average value for the element or for the isotopic ratios of this element for the "bulk" sample content. For uranium and plutonium, quantification or isotopic ratio measurements are routinely performed in bulk analysis with mass spectrometry (ICPMS or TIMS), with sensitive limits of detection. To assess a better understanding of pollution sources and to get more precise information from environmental samples, new methods based on single particle measurements of U and Pu isotopics were developed. We discuss the clean-room based process that gives isotopic signatures for micron-scaled grains released in the environment by nuclear facilities. It decreases the total sample size needed to be measured in common analytical methods, and allows us to eliminate naturally occurring uranium.