Experimental validation of DEMAIN for predicting induced radioactivity in research testing reactor civil engineering

In the last decades, numerous nuclear reactors have been shut-down and have experienced decommissioning. This is also the case of CEA EOLE mock-up research reactor. Since its shut-down in 2017, some preliminary radiological characterizations have been launched. An integrated approach combining measurements and computations has been developed to study civil engineering activation and support radiological characterization campaign. In the computational study, we present the elementary bricks of the digital version of EOLE facility. The settings for an optimal computation scheme are detailed, and we try to walk readers through the halls of EOLE and along its experimental history. The computations were complemented by several sets of measurement, including radiochemistry, so that computations could be compared to an experimental figure. The satisfactory comparison of simulation results with experimental measurements allows the validation of developed models. Although this approach is similar to that conducted on other dismantling facilities worldwide, it suggests a new methodology to determine the most pertinent impurity composition and chemical samplings thanks to the inversion functionality of DARWIN package, which is quite innovative. This integrated method, thanks to its general principles, can be applied to several nuclear research reactors or facilities undergoing decommissioning, thus helping to reduce the characterization efforts and, possibly, the associated costs.