Thermal Energy Storage integration with Nuclear Power: Material challenges and Innovation pathways towards Flexible Low-Carbon Systems

Recent accelerated shift towards deep decarbonisation demands nuclear power to evolve from baseload generation into flexible one with multi services. The integration of thermal energy storage (TES) with nuclear reactors provides a promising pathway to decouple heat and power functions, enabling steady-state reactor operation while allowing the delivery of dispatchable electricity and industrial process heat. This perspective paper outlines the material, component, and system-level challenges constraining TES deployment under the nuclear contexts - particularly corrosion, thermal fatigue, and irradiation effects under high-temperature molten salt and phase-change environments. Advances in alloy design, redox-controlled salt chemistry, modular TES architectures, and predictive control strategies are identified as critical innovation levers. Drawing on lessons from concentrated solar power and small modular reactor development, the paper proposes a roadmap for cross-sector collaboration and standardised materials qualification. Overcoming these barriers could reposition nuclear power plants as flexible, carbon-neutral energy hubs, bridging clean energy generation with heat and power applications across future integrated energy systems.