The NEA is organising a workshop on initial estimation of back-end costs for small modular reactors (SMRs) and Generation IV technologies. This topic has gained significant attention within both the Committee for Decommissioning and Legacy Management (CDLM) and Radioactive Waste Management Committee (RWMC), reflecting a growing interest from NEA Member Countries. The CDLM Expert Group on Costing for Decommissioning of Nuclear Installations and Legacy Management (EGCDL) is responsible for the organisation of the event.