Geostatistical analysis dedicated to radiological mapping: from measuring to characterization

The environmental remediation of an ancient nuclear facility requires a complete clean-up of the site. The first step of the process is to perform a radiological characterisation of the soil and buildings. CEA (French Alternative Energies and Atomic Energy Commission) has developed a method to optimize the number of measurements and sampling to do and to define the adequate soil depth to investigate in order to assess the amount of contaminated materials. This method is based on the feedback experience acquired during the dismantling and clean-up of all the nuclear installations present on the CEA center of Fontenay-aux-Roses (FR). The data processing uses a geostatistical method that was developed in the fifties for the characterisation of mine seams. According to that method more sampling are necessary in areas where variability and doubt are great rather than in areas where the level of radioactivity is the highest. (A.C.)