Engineering Design Elements of a Two-Phase Thermosyphon to Trannsfer NGNP Nuclear Thermal Energy to a Hydrogen Plant

Abstract

Three hydrogen production processes, powered by a Next Generation Nuclear Plant (NGNP), are currently under investigation at Idaho National Laboratory. The first is high-temperature steam electrolysis, which uses both heat and electricity; the second is thermo-chemical production through the sulfur iodine process primarily using heat; the third is a hybrid sulfur process (not part of this study) which incorporates sulfur acid decomposition and sulfur dioxide depolarized electrolysis, all processes require a high temperature (>850°C) for enhanced efficiency; temperatures indicative of the NGNP. Safety and licensing mandates prudently dictate that the NGNP and the hydrogen production facility be physically isolated, perhaps requiring separation of over 100 m. This research presents useful insights into making decisions regarding the thermosyphon heat transfer system between the nuclear reactor and chemical plant. Developing very high-temperature reactor technologies for producing electricity, hydrogen, and other energy products is a high priority for a successful national energy future.