The Shimane plant (Image: Qurren/CreativeCommons)
The 789 MWe boiling water reactor (BWR) had been offline since January 2012.
In June 2021, Shimane 2 became the 17th Japanese reactor to pass the regulator's safety screenings and the fifth BWR - the same type as those at the Fukushima Daiichi plant - to receive regulatory approval to restart.
Following approvals by the cities of Matsue, Izumo, Yasugi and Unnan, in June 2022 the governor of Shimane prefecture approved the restart of Shimane 2. His approval marked the completion of the process to gain the consent of local communities for the unit to resume operation.
In early October, Chugoku released a revised schedule for the restart of the unit. It said the reactor was expected to restart in early December, with power generation scheduled to begin in late December. The reactor will resume commercial operation in early January 2025.
Chugoku began loading fuel into the core of Shimane 2 on 28 October. The process of loading the 560 fuel assemblies was completed on 3 November.
The company has now announced that the reactor was restarted at 3pm local time on 7 December, reaching criticality at 4.50pm.
Chugoku President and CEO Kengo Nakagawa said: "We believe that we have reached an important milestone in the restart process. We will continue to put safety first and work with even greater intensity as we steadily proceed with inspections and checks of equipment in preparation for paralleling (restarting) generators and resuming commercial operations one by one. We will do our best to ensure the restart process.
"Furthermore, we aim to be a power plant that provides peace of mind to the local community by striving to appropriately disclose information regarding the status and initiatives of the power plant, and providing detailed explanations at various opportunities."
The restart of Shimane 2 was welcomed by Kingo Hayashi, chairman of the Federation of Electric Power Companies of Japan. "We believe this is the result of the various efforts that Chugoku Electric Power and its partner companies have made to make safety their number one priority, as well as the careful explanation of those efforts to the local community. We would like to express our gratitude and respect to Chugoku Electric Power, the local government where the plant is located, and all those involved in the project.
"We recognise that this reactor startup marks an important milestone toward the restart of Shimane nuclear power plant unit 2. It is expected that the plant will be restarted under safe operations in the future, and in addition to this being from the perspectives of improving energy self-sufficiency, ensuring a stable supply of electricity, and achieving carbon neutrality, we believe this is extremely significant in that it will be the second restart of a BWR, which has not made as much progress in restarting as pressurised water reactors (PWRs), following the recent restart of Tohoku Electric Power's Onagawa nuclear power plant unit 2."
Onagawa 2 was restarted on 29 October, becoming the first BWR in Japan to be restarted.
