Nuclear engineering and design nuclear heat supply system for a small district heating reactor

•A novel Heat Supply System for a Small District Heating Reactor is proposed.•Reactor modules are scalable between 2–120 MWs.•All reactor modules are transportable on standard roads, without special permits.•Reactor modules up to 36 MWth fit inside a standard sea container.•Concept offers an efficient and dispatchable means of decarbonizing the district heating sector. Small Modular Reactors (SMRs) are currently considered to be a potential solution for decarbonizing the district heating sector. The LUT Heat Experimental Reactor (LUTHER) is a concept for a small modular nuclear heating plant that is being designed to meet the demands of Nordic district heating networks while also incorporating high safety standards. This paper presents an extension of the work pursued by LUT University by proposing a reactor module that allows for easy scaling of unit sizes ranging from 2 MW to 120 MW. The pressure tube assembly geometry, which has been developed specifically for the LUTHER reactor module, was analyzed by modeling two significantly different-sized variants that utilize this unique structure. The modular design of LUTHER enables complete factory-assembly and the use of standard road transport for unit sizes up to 120 MW. This design prioritizes high inherent safety, targeting for siting near population centers. The proposed heating reactor concept offers a viable means of decarbonizing the district heating sector by replacing existing combustion-based production with emissions-free nuclear heat.