Reliable and safe thermal coupling of generation-IV VHTR to a hydrogen fuel production complex

This paper presents a conceptual design of a hybrid, Heat Pipes-Thermosyphon Intermediate Heat Exchanger (HPTIHEX) for passive and reliable thermal coupling of the GEV-IV, helium-cooled and graphite moderated, Very High Temperature Reactor (VHTR) to a complex for the co-production hydrogen fuel. A VHTR could generate up to ∼600 MWth at an exit temperature of 900-1300 K. In addition to electricity generation at high thermal efficiency (>48%), these small-modular reactors provide high-temperature thermal energy for the co-production of hydrogen fuel using thermochemical processes. For safety considerations, however, the VHTR needs to be separated from the hydrogen production complex by 110-140 m. This relatively long distance is a challenge to thermally coupling the VHTR and the hydrogen complex, while reducing heat losses and the temperature drop. In addition, the thermal coupling needs to effectively suppress the propagation of a hypothetical explosion from the hydrogen complex to the VHTR. The proposed HPTIHEX design would facilitate a reliable and safe operation of the VHTR for electricity generation and the co-production of hydrogen and would effectively suppress the propagation of an explosion due to a self-ignition of hydrogen to the VHTR.