Pre-conceptual hydrogen production modular helium reactor designs

Hydrogen and electricity are expected to dominate the world energy system in the long term. The world currently consumes about 50 million metric tons of hydrogen per year, with the bulk of it being consumed by the chemical and refining industries. The demand for hydrogen is expected to increase, especially if the U.S. and other countries shift their energy usage towards a hydrogen economy, with hydrogen consumed as an energy commodity by the transportation, residential, and commercial sectors. There is strong motivation to not use fossil fuels in the future, as a feedstock for hydrogen production, in part because the greenhouse gas carbon dioxide is a byproduct. An advanced reactor technology receiving considerable international interest for both electricity and hydrogen production is the Modular Helium Reactor (MHR), which is a passively safe concept that has evolved from earlier high-temperature gas-cooled reactor designs. For hydrogen production, this concept is referred to as the H2-MHR. Two different hydrogen production technologies are being investigated for the H2-MHR; an advanced sulfur-iodine (SI) thermochemical water splitting process and high-temperature electrolysis (HTE.) This paper describes pre-conceptual designs and economic evaluations for full-scale, nth-of-a-kind SI-Based and HTE-Based H2-MHR plants. Full-scale plants include four MHR modules. Preliminary economic evaluations show both concepts are capable of producing hydrogen at a cost of approximately $2/kg. (author)