This publication presents the outputs of the INPRO collaborative project ROADMAPS. It introduces the concept of roadmapping for enhanced nuclear energy sustainability, which has been developed over the course of several collaborative projects within INPRO. The principal products of the ROADMAPS collaborative project are the roadmap template and the ROADMAPS-ET tool. ROADMAPS-ET is an analytical decision support tool for structuring, unifying and visualizing data on issues related to long term nuclear energy planning and nuclear energy system sustainability enhancement. It is supplemented by an approach for the bottom-up integration of national roadmaps. The publication includes case studies which are trial applications of the roadmap template. The studies address national or cooperative long term nuclear energy deployment scenarios with evolutionary as well as with innovative nuclear energy technologies. Examples of possible roadmap aggregation for analysis at regional and global levels are also provided.