Contribution des isotopes de l'uranium à l'expertise des sources de ce radioélément dans l'environnement

Abstract

This paper summarizes data recently acquired by IRSN and other published works as well, dealing with the use of uranium isotopes to evaluate the consequences in the environment of the releases of nuclear fuel production sites. Thus plants may show some anomalies of 235U/238U massic ratio compared with the ratio of natural uranium (235U/ 238U massic ratio = 0.72%). Furthermore, recent advances in mass spectrometry (ICP-MS) allow analyzing 236U, which is an artificial isotope of uranium and a reliable tracer for the release of uranium from spent fuel into the environment. The measurement of the 234U/ 238U activity ratio in aquatic environment, when secular equilibrium between isotopes occurs, is a tracer of the uranium releases from uranium milling or conversion. © EDP Sciences, 2011.