Section: New Results
Source reconstruction of an accidental radionuclide release at European scale
Source retrieval is one of the problems that are currently being addressed within a framework of data assimilation for dispersion of radionuclides. Firstly, a series of hypothetical releases have been designed. The accidents have been imagined to take place at one of the European nuclear facilities at a time. The aim of a retrieval is to tell the position of the source and the shape of its temporal profile. The solution is given by a procedure based on the maximum of entropy principle. A couple of new, problem-adapted cost functions have been put forward and their performance tested. The tests have been undertaken with perfect and noisy synthetic measurements, and have been assessed with an objective indicator. In perfect measurement configurations, perfect reconstructions have been obtained for a number of measurements significantly lower than the number of unknowns. Secondly, temporal profile of an accidental release of caesium-137 in Algeciras steel mill has been inverted. The total reconstructed activity falls within an interval given by the official estimations. The profile is narrow which remains in accordance with the information disclosed after the release but is slightly shifted towards the earlier times.