Nuclear hydrogen demonstration project using the HTTR – Demarcation of nuclear-industrial laws and design standards

A high temperature gas cooled reactor has inherent safety features and potential to produce competitive and large amounts of carbon-free hydrogen. Japan Atomic Energy Agency has initiated the high temperature engineering test reactor (HTTR) Heat Application Test Project to establish coupling technologies for a nuclear hydrogen production system that connects a nuclear reactor plant and a hydrogen production plant. In order to ensure the public safety, appropriate laws and design standards should be applied to the hydrogen production plant because it handles combustible and toxic gases. The present study proposed a relative evaluation methodology using six metrics to characterize the superiority of candidates for the demarcation of applicable laws and design standards for a for the nuclear hydrogen production system. The proposed methodology was applied to the HTTR Heat Application Test Facility to select the most superior demarcation of applicable laws and design standards from six candidates for the HTTR Heat Application Test Facility. Candidates, applying nuclear law to all facilities, showed least superiority due to the higher cost of commercialized hydrogen production and the difficulty in entry for non-nuclear vendors to the business. The candidates, applying the High Pressure Gas Safety Act for the steam reformer and the Heat Application Test Facility (hydrogen production plant), showed least superiority in the feasibility of the system or the demonstration of the key equipment and technologies for commercialization depending on the installation of the secondary intermediate heat exchanger. On the other hand, a candidate applying the High Pressure Gas Safety Act to the Heat Application Test Facility (hydrogen production plant) and design standards established under the High Pressure Gas Safety Act to the steam reformer did not show the lowest category in any of the metrics, and was proposed as the most superior candidate for the demarcation of applicable laws and design standards the HTTR Heat Application Test Facility.