Preliminary Analysis of ALFRED under seismic scenario

Generation IV reactors are at the forefront of advanced nuclear technology, aiming to address key challenges such as safety, sustainability, and proliferation resistance. Among the Gen IV reactor concepts, Lead Fast Reactors (LFRs) have acquired significant attention due to their inherent safety features and potential for high efficiency. One prominent example of an LFR is the Advanced Lead Fast Reactor European Demonstrator (ALFRED) designed by Ansaldo Nucleare. ALFRED represents a collaborative effort among European countries under the FALCON Consortium (Fostering ALfred CONstruction) in order to develop a demonstrator based on lead coolant technology, with a focus on achieving economic competitiveness and meeting strict safety standards. ALFRED aims to showcase the viability of LFR technology for commercial deployment, emphasizing its role in providing sustainable and reliable energy while minimizing the environmental impact. However, the use of liquid lead as a coolant introduces challenges e.g., high freezing temperature (i.e., 327 °C), opacity and corrosion. Thus, several R&D activities are needed. In this context, the European project ANSELMUS (Advanced Nuclear Safety Evaluation of Liquid Metal Using Systems) aims to address key challenges associated to LFR technology and seeks to design and demonstrate innovative solutions to enable the efficient and reliable operation of LFRs. This paper presents the results of ANSELMUS project regarding numerical evaluation of selected scenarios showing ALFRED behaviour in the event of an earthquake. The accidental transient was simulated by means of thermal hydraulic system code RELAP5/Mod3.3. The nodalization scheme is described in detail as well as transient boundary conditions and timing of events. This numerical activity showed that, despite the insertion of reactivity due to the core compaction caused by the earthquake, the temperature peaks of cladding and fuel are still below the safety limits and that the reactor reaches a new equilibrium point in a short time.