The EURATOM work programme project INSIDER (Improved Nuclear Site Characterization for Waste minimization in Decommissioning under Constrained Environment) was launched June 2017. This 4 year project has 18 partners. It aims at improving the management of contaminated materials arising from Decommissioning and Dismantling (DetD) operations by proposing an integrated methodology for radiological characterization. This methodology is based on advanced statistical processing and modelling, coupled with adapted and innovative analytical and measurement methods, with respect to sustainability and economic objectives. In order to achieve these objectives, the approaches will be then applied to common case studies in the form of Inter-laboratory comparisons on matrix representative reference samples and benchmarking. Assessment of the outcomes will be used for providing recommendations and guidance resulting in pre-standardization texts.