Measurement of activity in large packages of radioactive waste, taking into account heterogeneities in Mass and activity

The activity of a radwaste package is usually evaluated from gamma measurements associated with transfer functions. These functions are calculated assuming that both activity and mass distributions are homogeneous. But generally, activity and mass distributions are not homogeneous and potentially huge errors may arise from such evaluations. In this paper, we propose a method for creating a numeric model to simulate mass and activity distributions, which enables to both evaluate and reduce the level of uncertainty due to non homogeneous distributions. The model can be adjusted in order to be fully representative, and its representativeness can be justified. We show 2 examples of application of this method to acquisition data obtained from field experimentation.