Due to energetic choices and the nuclear plants end of design life economic considerations and political decisions, an increasing number of nuclear installations and power reactors is to be dismantled in the coming decades. The nuclear market is a matter of country-specific legal regulations and requirements. More than 300 NPPs are estimated to be shut down between now and 2047, as estimated by a study conducted by the PLEIADES consortium. Within the European Union alone, estimations indicate that 80 NPPs will be shut down until 2047. France shutting down 40 NPPs and Ukraine 13 NPPs, will be the most affected countries, to the current knowledge. This large number of dismantling sites in the next decades combined with the mandatory reliability and safety requirements impose to make the dismantling operations becoming more efficient, safer and more cost-effective. PLEIADES (PLatform based on Emerging and Interoperable Applications for enhanced Decommissioning processES), an international project that receives funding from the Euratom research and training programme 2014-2018 under grant agreement No 899990, aims at making the decommissioning of nuclear facilities more efficient, through demonstrating an innovative digital decommissioning approach inspired by the BIM (Building Information Modelling) concept. BIM provides a digital twin and enables all the information related to a building to be managed through a central 3D model, enhancing information exchanges between different jobs and enabling scenario simulations for work on the building. PLEIADES applies this concept to the dismantling domain and will demonstrate how a BIM-like models (containing data required for decommissioning planning) can be used for scenario simulations improving safety, minimising radiation exposure, optimising costs and schedules. To achieve this, PLEIADES has: • Developed a platform including a set of innovative modules, developed by most of the partners, based on simulation technologies, • Developed a common ontology for nuclear decommissioning, aligned with results from international organisations, ensuring a basic compatibility to international knowledge resources such as the combined IAEA, EU and OECD taxonomy for decommissioning. • Conducted a market study on the plants to be decommissioned as a basis for developing the business case. PLEIADES will now implement this platform on three real cases of nuclear facilities: • a research reactor (Halden Research Reactor in Norway), • a nuclear power plant (Santa Maria de Garona in Spain), • a maintenance facility (Base Chaude Opérationnelle de Tricastin in France). The implementation on these different kinds of facilities will enable to highlight strengths and weaknesses of such a digital twin and simulation approach.