Nuclear powered heat pumps for near-term process heat applications

There is a substantial market for nuclear energy in non-electric applications such as hydrogen production or water desalination. Among the Generation IV reactor concepts, the very high temperature reactor (VHTR) with a reactor outlet temperature close to 1000 deg. C and a power conversion efficiency of approximately 50% is believed to be the most suitable concept for co-generation of process heat. Its high coolant exergy would enable centralized hydrogen production and other process heat applications. In this paper it is shown that a reactor with lower coolant outlet temperature or another near-term heat source can also meet the VHTR objectives which are high power conversion efficiency and capability to deliver high temperature process heat in the narrow temperature window required by thermochemical hydrogen production cycles. The approach was to separate the requirement for high temperature process heat production from the nuclear part of the plant, in other words the nuclear part of the power plant would run at acceptably low temperature while the high temperature heat production via a heat pump system would be limited to a conventional external circuit, thus avoiding nuclear constraints. The separation of these high temperature constraints from the reactor would avoid massive R and D requirements on materials, components and fuel with uncertain outcome thus unnecessarily delaying introduction of this otherwise very attractive reactor concept. We then show that the proposed technology is equally suitable for the generation of cold (e.g. for air conditioning) and for desalination of seawater