For electricity and hydrogen production, the advanced reactor technology receiving the most international interest is a modular, passively-safe version of the high-temperature, helium-cooled reactor referred to in the United States as the modular helium reactor (MHR).

For electricity and hydrogen production, the advanced reactor technology receiving the most international interest is a modular, passively safe version of the high-temperature, helium-cooled reactor referred to in the USA as the Modular Helium Reactor (MHR). Because of its ability to produce high-temperature helium, the MHR is well suited for a number of process-heat applications, including hydrogen production. Two hydrogen-production technologies have emerged as leading candidates for coupling to the MHR: (1) thermochemical water splitting using the Sulphur–Iodine (SI) process and (2) High-Temperature Electrolysis (HTE). In this paper, we provide an update on conceptual designs being developed for coupling the MHR to the SI process and HTE. These concepts are referred to as the SI-based H2-MHR and the HTE-based H2-MHR, respectively.