Japan’s Reactor Restarts Slow Amid New Regulatory Requirements

The Yomiuri Shimbun

17:27 JST, July 16, 2023

The restart of nuclear power plants in Japan has been slow in the decade since new regulatory requirements came into effect.

Electric power companies have so far applied to the Nuclear Regulation Authority (NRA) for safety screenings of 27 reactors at 16 power plants, but only 10 reactors at six plants have been allowed to restart. In particular, the three reactors at the Tomari nuclear power plant in Hokkaido have yet to pass their screenings even 10 years after applying.

The new regulatory requirements came into force on July 8, 2013. They were based on the lessons learned from the 2011 accident at the Fukushima No. 1 nuclear power plant following the Great East Japan Earthquake. Tokyo Electric Power Company Holdings, Inc. is currently decommissioning the plant.

One major feature of the new requirements is for significantly stricter measures against natural disasters such as earthquakes, tsunami, volcanic eruptions and tornadoes. They also include measures to prevent the diffusion of radioactive materials and damage to the reactor core in the event of a severe accident, which had previously been left to the autonomy of each power company.

The day when the new regulatory requirements went into effect, Kansai Electric Power Co., Shikoku Electric Power Co., Kyushu Electric Power Co. and Tomari operator Hokkaido Electric Power Co. applied to the NRA for safety screening. Of these screenings, the Tomari plant is the only one that has yet to have any of its reactors cleared to restart operations.

Just last month during a screening meeting on June 9, Hokkaido Electric finally cleared a major hurdle with the setting of “design basis earthquake ground motions” used as standards for earthquake resistance calculations. One reason for the significant delay in its screenings is the lack of human resources at the utility. During the meeting, company staff often got bogged down answering questions from the nuclear watchdog’s experts.

At the time of application, the utility had about 60 staff handling the screening procedures. Although the utility has gradually increased the number since then, it has not appeared to be sufficient.

“Lack of staff who can respond to specialized discussions on earthquakes and tsunami has critically affected the screening process,” then NRA chief Toyoshi Fuketa said in April 2022.

According to Hokkaido Electric, as of May, it had secured 220 staff for the screening procedures in addition to support staff from nuclear power plant manufacturers and other electric power companies that are further along in their screenings.

“We are now able to produce data with sufficient quality needed for screenings,” said company President Susumu Saito.

Despite the recent breakthrough, the Tomari plant has yet to be screened on measures against other natural disasters such as volcanic eruptions and tsunami, as well as on facility design. The utility’s goal is for the plant to restart in December 2026, but it is unclear whether it will achieve is target. The delay in restarting the reactors has continued to result in higher electricity prices for Hokkaido Electric’s customers.

‘Maximum use’

In addition, Hokuriku Electric Power Co. and Chubu Electric Power Co. have failed to pass the screening for the nuclear power plants they want to restart.

In March, the NRA finally agreed with Hokuriku Electric’s assessment that none of the 10 faults at the site of the No. 2 reactor at the Shika plant in Ishikawa Prefecture, including those directly under the reactor building, are active faults.

Chubu Electric is dragging its feet on issues of tsunami countermeasures for the Nos. 3 and 4 reactors at the Hamaoka plant in Shizuoka Prefecture in the possible event of a massive Nankai Trough earthquake. Although the utility has obtained the NRA’s general understanding by raising its tsunami assumptions to 22.7 meters, there are still some issues to be considered, such as the effects of undersea volcanic activity.

The central government intends to make active use of nuclear power in a bid to ensure stable electricity supplies while realizing a carbon-free society. The basic plan for green transformation adopted in February mentions “maximum use” of nuclear power.

The government plan also stipulates that nuclear power plants that have been decided to be decommissioned will be rebuilt and next-generation reactors will be constructed on the same site with enhanced safety features.

In addition, a related law was enacted this year to effectively allow nuclear power plants to operate for more than 60 years, by excluding from their total operation terms the offline periods for safety inspections by the NRA and other circumstances.