--- title: "Onagawa NPP Unit 2 Shut Down Due to Radioactive Water Leak" description: "Tohoku Electric Power has shut down Unit 2 of the Onagawa NPP for 10 days due to a radioactive water leak through a faulty valve. No contamination has been recorded outside the plant." date: 2026-10-18T08:00:52.132Z lang: en url: https://xab.info/en/posts/onagawa-npp-unit-2-shut-down tags: [japan, nuclear-power, onagawa, tohoku-electric, safety-incident] author: "Roman V." publisher: "XAB.info" --- # Onagawa NPP Unit 2 Shut Down Due to Radioactive Water Leak ![Onagawa Nuclear Power Plant on the sea coast in Japan](https://xab.info/media/2026/10/18/onagawa-aes-utechka-radioaktivnoy-vody/onagawa-aes-utechka-radioaktivnoy-vody-1.webp) ## Key Points - Onagawa NPP Unit 2 shut down for ~10 days due to a radioactive water leak from a faulty valve - Leakage volume reached about 0.2 tons per hour; no radioactive contamination detected outside the plant - This is the second incident at the plant in 2026 following a May radioactive steam leak - Unit 2 was the first reactor in eastern Japan to resume operations after 2011 (October 2024) Unit 2 of the Onagawa Nuclear Power Plant in Miyagi Prefecture has been temporarily shut down due to a radioactive water leak. Tohoku Electric Power Company, the plant's operator, announced this on October 17, 2026. The reactor will be taken offline for approximately 10 days to inspect and replace malfunctioning components. ### Cause of the Incident and Volume of Leakage According to the operator, the leak was caused by a faulty valve. The estimated volume of leaked water was approximately 0.2 tons per hour. The company noted that the water level in the wastewater collection pit began rising as early as July, allowing station personnel to identify the leak and take containment measures. ### Environmental Safety Tohoku Electric Power Company stated that all leaked water was contained within the station's perimeter. The operator confirmed that no radioactive substances leaked outside the power plant's territory, and no abnormal radiation levels were detected in the environment. The incident has been classified as posing no threat to the environment. ### Not the First Incident in 2026 This is not the only radioactive material incident at the Onagawa NPP this year. Earlier, in May 2026, the station had to be temporarily shut down due to a minor radioactive steam leak. The recurrent incident has once again drawn attention to equipment operation issues at Japanese nuclear facilities and compliance with safety standards. ### Context: First Reactor in Eastern Japan Since 2011 Onagawa Unit 2 was restarted in October 2024, becoming the first reactor in eastern Japan to resume operations following the 2011 earthquake and tsunami. The plant was shut down after the Fukushima Daiichi accident that same year and remained inactive for more than two years prior to its restart. ### Japan's Nuclear Program: Current Status The 2011 Fukushima Daiichi accident forced the Japanese government to shut down all 54 nuclear power plants nationwide, seriously impacting energy supplies. Before the disaster, nuclear reactors provided about a third of Japan's total electricity consumption. Since then, the country has been gradually restarting its nuclear power plants in accordance with new, stricter safety standards. Currently, 14 reactors are in operation, and this number continues to grow. The Japanese government, led by Prime Minister Sanae Takaichi, supports the resumption of operations at halted reactors and is actively negotiating with local authorities on the matter. ## Fact-Check & Sources - [Япония остановила работу ядерного реактора после утечки радиоактивной воды.](https://www.vietnam.vn/ru/nhat-ban-dung-lo-phan-ung-hat-nhan-sau-su-co-ro-ri-nuoc-nhiem-phong-xa) - Contains Tohoku Electric Power Company's statement on shutting down Unit 2, the cause (faulty valve), leakage volume (0.2 t/h), absence of external contamination, as well as context regarding the May incident and the unit's restart in October 2024. ## FAQ ### What happened at the Onagawa NPP on October 17, 2026? Tohoku Electric Power Company announced the temporary shutdown of Unit 2 for approximately 10 days to inspect and replace malfunctioning components due to a radioactive water leak. ### What is the cause of the leak? According to the operator, the cause was a faulty valve. The water level in the wastewater collection pit had been rising since July, allowing the leak to be discovered. ### Is there a threat to the environment? No. The company confirmed that leaked water was contained within the station's perimeter, no radioactive substances leaked outside, and no abnormal radiation levels were detected in the environment. ### Is this the first incident at the plant in 2026? No. In May 2026, the Onagawa NPP was already temporarily shut down due to a minor radioactive steam leak. ### What is the significance of Onagawa Unit 2 for Japan? In October 2024, it became the first reactor in eastern Japan to resume operations following the 2011 earthquake, tsunami, and Fukushima accident.