Experience of HTTR licensing for Japan's New Nuclear Regulation

Ishitsuka, Etsuo   

On June 3rd, 2020, JAEA obtained the permission of reactor installation change for restarting the High Temperature Engineering Test Reactor (HTTR, 30 MW) from the Nuclear Regulation Authority (NRA) of Japan. This is the first restart permission for a gas-cooled reactor in Japan under the New Regulatory Requirements. By employing a high-temperature-resistant and large-heat-capacity graphite core, HTTR enables inherent safety characteristic of slow and limited temperature transient without fuel damage even in a loss of coolant accident. The safety review by NRA against the New Regulatory Requirements has confirmed that no fuel damage would occur even in the event of a beyond design basis accident such as multiple losses of reactor shutdown functions. With the aim of early restarting, the refurbishment to the HTTR as mandated by the permission of changes to reactor installation is steadily carrying out, including installation of countermeasure systems against internal and external fires and so on. In this Webinar, an experience of HTTR licensing for Japan's New Nuclear Regulation will be introduced.