Japan's Tohoku Electric has said it plans to restart unit 2 at its Onagawa nuclear station in Miyagi Prefecture around September after additional safety construction works have been completed. In January Tohoku gave notice that safety upgrades would not be completed in February as planned. The original target had been to restart commercial operation in May.

The Onagawa NPP was the closest to the epicentre of the earthquake and tsunami of 11 March 2011, but sustained relatively little damage. Although the earthquake destroyed four of the plant's five external power lines, the remaining line was able to power its three boiling water reactors (BWRs) enabling them to be brought to cold shutdown. Unit 1 suffered a small fire in the turbine building.

The fact that the plant is built on an elevated embankment more than 14 metres above sea level afforded protection from the tsunami, although but the basement floors of unit 2 were flooded. This is attributed to engineer Yanosuke Hirai, who in 1968 insisted on constructing defences against tsunamis higher than those recommended. Onagawa NPP was unaffected by the recent magnitude 7.6 earthquake, which killed more than 200 people in the Hokuriku region.

Meanwhile, a poll by Asahi Shimbun shows support rate for restarting idle NPPs in Japan is increasing. The poll found that 50% of respondents support resuming plant operation, while 35% want them to remain offline. Asahi said this is the second consecutive year that the majority were in favour. The survey has been conducted each year since 2013. In each of the polls, roughly 30% percent of respondents favoured restarting nuclear plants while 50-60% remained opposed. However, the February 2023 poll for the first time showed a

Before the March 2011 accident at the Fukushima Daiichi NPP, Japan had 54 reactors in operation providing around 30% of its electricity. However, within 14 months of the accident, all the plants were closed pending regulatory change in line with more stringent safety checks and regulations. Subsequently a number of nuclear units were closed permanently. To date, 12 of the remaining 33 operable reactors have cleared inspections confirming they meet the new regulatory safety standards and have resumed operation. Another 17 have applied to restart. The restarted plants are Sendai 1&2, Genkai 3&4, Ikata 3, Mihama 3, Ohi 3&4 and Takahama 1-4.

Image: Onagawa nuclear station in Miyagi Prefecture (courtesy of Tohoku Electric)