Nuclear Cogeneration of High Temperature Process Heat and Electricity with Heat Pump Driven Superheating

The Generation IV VHTR reactor concept aims at approx. 50% power conversion efficiency and, according to the prevailing opinion, a temperature close to 1000'C would be required to enable massive centralized hydrogen production. These high temperature constraints on materials, components and fuel imply massive R&D requirements with uncertain outcome thus unnecessarily delaying introduction of this otherwise very attractive reactor concept. The objective of this paper is to outline methods to both reach the VHTR power conversion efficiency target and the capability to deliver high temperature process heat with a reactor based on HTR technology or other near-term heat sources. 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. This paper describes several power conversion cycle options for heat sources < 850'C such as a classical HTR. After description of selected cycles, their feasibility, efficiency and safety aspects are presented as well as other possibilities for the described heat pump technology underlining the enormous flexibility of this concept.JRC.F.3-High Flux and Future Reactor