Japan's Onagawa 2 reactor, shut down for 13 years, could resume operations in September

Japan is preparing to restart another nuclear unit that was shut down in 2011 after a devastating earthquake. Although the Onagawa nuclear power plant was closest to the earthquake’s epicenter, it was not irreparably damaged, unlike the Fukushima nuclear power plant, for example. According to its operator, operations could resume this September. Restarting shut-down power plants is significant for Japanese energy companies, as it helps them reduce imports of more expensive fossil fuels.

The accident at the Fukushima nuclear power plant, which occurred almost 13 years ago, had a major impact on Japan’s energy sector. In the aftermath, the country gradually shut down all 48 nuclear units, which had previously generated up to 300 TWh of electricity per year.

These included the three units at the Onagawa nuclear power plant. Although it was closest to the earthquake’s epicenter, the plant was not destroyed, and its units were shut down. According to World Nuclear News, the earthquake knocked out four transmission lines, although one remained operational. The one remaining line was therefore able to provide enough power to safely cool the reactors.

In December 2013, the plant’s operator, Tohoku Electric Power, asked Japan’s nuclear regulator to assess the safety of Unit 2. The regulator was to determine whether the newly implemented safety measures met the new standards. The regulator cleared the way for the restart of the 825 MW unit in February 2020, when it approved the final screening report. The operator must now complete the implementation of the new measures and obtain approval from local authorities.

Implementation of measures fell behind schedule

The operator had originally planned to restart the unit this May, but said in January that it expected a delay of several months. The delay was caused by hold-ups in providing fire protection for the cabling. Earlier this week, the company moved the planned start-up date to September this year, reflecting a four-month delay in implementing the measures.

“Following the completion of a thorough investigation, including securing the necessary materials, equipment and workers for construction, as well as assessing on-site feasibility, the deadline for completing work on safety measures at Unit 2 of the Onagawa nuclear power plant has been changed from the previous date of February 2024 to June 2024,” the operator said.