Safety of operating nuclear power plants and research reactors is sponsored by European Commission — Horizon Europe. Expected Outcome: The project’s results are expected to contribute to some of the following expected outcomes. Continuing safety assessment and long-term operation compliance that address technical challenges, regulatory expectations and economic competitiveness goals. Licence-holders and regulators will ensure the successful implementation of the requirements of the Nuclear Safety Directive [1] , Basic Safety Standards Directive [2] , Radioactive Waste Management Directive [3] and topical peer reviews [4] for current and planned nuclear power plants and research reactors. Safety assessment of ageing management programmes and optimisation of safety solutions; as well as the development and validation of advanced tools for ageing management and evaluation of reactors’ safety margins. The aim is to prevent and mitigate risks (including those associated with severe accidents) by using innovative cross-cutting technologies (applicable to multiple reactor technologies), digital upgrades, digital twins, AI/ML-assisted defect detection, advanced multi-physics (including fluid structure interaction) and/or multiscale modelling and simulation, as well as PSA updates for extended operations. Safety assessment of internal and external hazards in order to evaluate nuclear installations’ safety (applicable to multiple reactor technologies and nuclear fuel cycle facilities), prevent and mitigate accidental situations, and improve and validate advanced modelling tools (including AI-based approaches). Further development and validation of advanced materials testing as well as of component and structural integrity assessment methods to quantify material degradation (including concrete structures, metal fatigue, corrosion, irradiation embrittlement, defect tolerance, advanced NDE techniques and safety margins in aged and potentially degraded plants). Reactor Long-Term Operation (LTO) fuel and core safety management, to evaluate ‑‑high burnup fuel and cladding integrity; and assessment of alternative fuels, core physics and neutron flux redistribution effects, and impacts of LTO on spent fuel inventory and interim storage. Ensuring the highest nuclear safety standards for the deployment of alternative nuclear fuel in Soviet-designed research reactors in EU Member States and Ukraine. This could encourage consistent approaches to the licensing and deployment of this alternative fuel. Drawing up best practice guidance for developed assessment methods, identifying knowledge gaps in safety margins, disseminating project outputs and providing appropriate training in the use of developed assessment methods. The sharing of examples of LTO strategies to facilitate learning and exchange. Support for the establishment of international collaboration benchmarks; the sharing of consistent and harmonised approaches between regulators to safety assessments of different nuclear technologies (for example, through regular exchanges between licensees and regulatory bodies and/or their technical support organisations); further improving safety across the Community, EU Member States and Associated Countries. Such action should ensure complementarities with the recently launched grant scheme in support of competent national regulatory authorities in coordinated approaches to new regulatory challenges in nuclear safety. [5] Development of competences and ensuring continuity in short-term to long-term research. This will support the energy and climate strategies of interested Member States, highlighting LTO’s role in making their energy production more climate-neutral (in accordance with and respecting the EU’s technology neutrality principle), thereby increasing the energy security of both the EU and Member States. Scope: Euratom research will be driven by the increasing importance of long-term operation (LTO) and by the fact that the current and planned innovative fleet will consist mainly of light water-cooled reactors. Proposals should address challenges related to

Programme areas: Energy Systems and Grids, Climate, Energy and Mobility, Global Challenges and European Industrial Competitiveness