This paper presents the evolution of atmospheric and ground
activity simulated at local scale (within 80 km of FNPP1). Simulations
are made with pX, IRSN’s Gaussian puff model. The pX
model is part of the operational platform C3X, which is used by
IRSN’s Emergency Response Center in case of an accidental radioactive
release. The aim of this study is to better understand the
formation processes of the contaminated areas, but also to give
new insights on the pertinence and limitations of model evaluation
tools and indicators in accidental situations. Indeed, usual
Gaussian model evaluations are made on simple, well-known
dispersion experiments. The Fukushima accident provides an unprecedented
case to evaluate atmospheric dispersion models
devoted to radionuclides, with many environmental measurements.
We try to highlight advantages and shortcomings of each
kind of measurements and of statistical indicators used to evaluate
a model’s performance.