High-temperature engineering test reactor

{{Short description|Research reactor in Ōarai, Ibaraki, Japan}}

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The high-temperature engineering test reactor (HTTR) is a graphite-moderated gas-cooled research reactor in Ōarai, Ibaraki, Japan operated by the Japan Atomic Energy Agency. It uses long hexagonal fuel assemblies, unlike the competing pebble bed reactor designs.

HTTR first reached its full design power of 30 MW (thermal) in 1999. Other tests have shown that the core can reach temperatures sufficient for hydrogen production via the sulfur-iodine cycle.{{cite news |last1=Hanawa |first1=Kazunari |title=Japan eyes hydrogen production using next-gen nuclear reactor |url=https://asia.nikkei.com/Business/Energy/Japan-eyes-hydrogen-production-using-next-gen-nuclear-reactor |access-date=4 April 2024 |work=Nikkei Asia |date=4 April 2024}}