The nuclear safety body said Wednesday it has accepted the conclusion by geological experts that a fault below a reactor at Hokuriku Electric Power Co’s Shika nuclear plant in Ishikawa Prefecture may be active, a decision that could lead to the scrapping of the unit.
The experts on a panel under the Nuclear Regulation Authority concluded in March that the possibility cannot be ruled out that a fault directly below the idled No. 1 reactor at the Shika plant on the Sea of Japan coast is active.
Building nuclear reactors or other important facilities directly above active faults is prohibited in quake-prone Japan. The issue came under the spotlight after the 2011 Fukushima Daiichi meltdowns that resulted in all the country’s commercial reactors going offline.
Hokuriku Electric has denied the possibility of the fault being active and will do so again when it seeks permission for the restart of the Shika No. 1 reactor.
However, the NRA’s acceptance of the panel’s decision on the fault is expected to make it difficult for the utility to gain approval to put the reactor back online.
The panel said last year that the possibility cannot be denied that the S-1 fault just below the No. 1 reactor building had moved 120,000 to 130,000 years ago or since then.
Two other faults running beneath the turbine buildings of the Nos. 1 and 2 units at the Shika plant could also be active, the panel said.
Hokuriku Electric has already filed an application with the NRA to reboot the No. 2 reactor, and the nuclear watchdog will now resume discussions on whether to allow the No. 2 unit to restart.
Even if the reactor gains approval, the company may be required to make major safety upgrades.
NRA officials said at a meeting Wednesday more accurate surveys can be conducted by obtaining more data and that they are asking whether the power company has any more data available.
“The NRA will make a final decision with additional data,” Shunichi Tanaka, the head of the nuclear watchdog, said at the meeting.
The regulator’s decision received mixed reactions from local residents.
Matsusuke Nakatani, a 64-year old Shika town assemblyman, said the regulator had made “a landmark decision” that could prompt the company to close the unit.
But Hiroaki Hira, a 65 year-old worker who lives close to the nuclear plant, said it is hard to believe the decision was made on scientific grounds, given that NRA officials are demanding more data.