Using a deliberative approach, ECOSENS will analyse citizens’ views and risk perceptions, benefits and potentials of current and new nuclear technologies in the context of major societal challenges (climate crisis, sustainable energy policies, energy security). It will review through a socio-ethical lens the uptake of recommendations on stakeholder engagement and transdisciplinarity (notably integration of social sciences and humanities) in nuclear research and decision making, developing recommendations to overcome challenges. Societal stakeholders (authorities, industry, academia and civil society) are engaged to explore and co-construct possible energy futures and the role of nuclear energy therein. Sustainability assessment of current nuclear energy technologies will take into account the entire life of the nuclear investment including the nuclear fuel cycle. Integration of new technologies (Gen III+, IV, SMR) is then explored in the context of the future energy market and societal developments to identify the possible roles of nuclear energy in the climate neutral economy targeted for 2050. Multiple perspectives (nuclear experts, social scientist, stakeholder, society) are integrated and methodological recommendations for sustainability assessment are agreed. To address the weaknesses of existing economic models, ECOSENS develops a novel model based on the system of provision approach in order to create and calculate indicators relevant for a plethora of stakeholders (consumers, governments, suppliers). The model will include the “social discount rate” and considers the limits of our planet, as reflected in the “circular economy” system. A series of national case studies evaluates the model and provides relevant recommendations to stakeholders. ECOSENS activities and results will be largely communicated and disseminated through the network of stakeholders established to support innovative involvement, as well as through Open Access facilities.