The Japan Atomic Energy Agency (JAEA) plans to produce clean hydrogen using heat from a high-temperature gas-cooled nuclear reactor at the Oarai Nuclear Engineering Institute in Ibaraki prefecture, northeast of Tokyo.
JAEA has applied to Japan’s Nuclear Regulation Authority to connect a hydrogen production facility to its high-temperature test reactor, as part of a broader effort to decarbonise hard-to-abate sectors such as steelmaking and the chemical industry.
If approved, the project could position high-temperature gas-cooled reactor technology as a viable production method for low-carbon hydrogen. According to the agency, it would mark the world’s first use of a high-temperature gas reactor for hydrogen production at this scale.
The process will use heat (up to 950°C) generated by the test reactor to split water into hydrogen and oxygen. This method, known as thermochemical water splitting, enables hydrogen production without carbon dioxide emissions.
JAEA aims to begin hydrogen production by 2030, subject to regulatory approval, using the pilot system to validate the technology ahead of plans for a full-scale demonstration reactor.
Although the agency has not disclosed projected hydrogen output volumes, high temperature gas-cooled reactors are seen as promising due to their ability to generate higher outlet temperatures than conventional light-water reactors, allowing for larger amounts of hydrogen to be produced.
JAEA officials said the facility will be installed next to the test reactor, allowing high-temperature heat to be transferred via underground piping.
While the thermochemical process itself is emissions-free, JAEA is also exploring hydrogen production methods that avoid CO2 emissions from auxiliary systems such as power generation and materials handling.
A full-scale demonstration of the gas-cooled reactor is expected to begin operations in the second half of the 2030s.
