The Nuclear Regulation Authority on Wednesday approved a draft safety screening report that concluded safety measures for the No. 1 and No. 2 reactors at Kyushu Electric Power Co.'s Sendai nuclear power plant meet new safety standards, paving the way for restart of the reactors as soon as autumn.
The NRA gave the endorsement to safety measures presented by Kyushu Electric, meaning the two reactors have effectively passed the safety screening by the NRA.
Passing safety screening under the new safety standards is a precondition for reactivation of reactors.
The two reactors are the first in the country to have effectively passed the NRA's screening under the new safety standards that entered into force a year ago.
The two reactors at the Sendai nuclear power plant in Kagoshima Prefecture are expected to be reactivated as early as autumn, after remaining screening procedures are completed and the consent for their restart is obtained from the local governments that host them.
The NRA, meanwhile, plans to accelerate screenings of 17 reactors at 11 nuclear power plants, including Kansai Electric Power Co.'s Takahama nuclear power plant in Fukui Prefecture, for which applications for safety screenings have been filed.
The 400-page draft safety screening report presented by the NRA concluded that Kyushu Electric's assumption for the maximum impact of an earthquake on the reactors and tsunami height, as well as its measures against serious accidents including hydrogen explosions, meet the new safety standards.
Compiling the draft safety screening report is part of a procedure relating to permission to modify establishments that incorporate nuclear reactors, which determines the basic policy for safety measures.
There will be a 30-day public consultation period during the screening process.
Also, detailed designs for devices installed at the Sendai nuclear power plant will be decided along with personnel distribution in the event of an accident.
Kyushu Electric will submit the necessary documents in August. The NRA will then inspect the devices at the plant.
Consent from local governments is expected, as few objections have been raised against the restart of the reactors.
The central government plans to reactivate the two reactors.
As several months are likely to be needed before all necessary procedures can be completed, the two reactors are expected to be reactivated in autumn at the earliest.
Kyushu Electric applied for safety screening of the No. 1 and No. 2 reactors at the Sendai nuclear power plant when the new safety standards entered into force in July last year.
Based on suggestions by the NRA, Kyushu Electric substantially raised its assumptions for the maximum impact of an earthquake on the reactors and tsunami height.
In March, the NRA designated the Sendai nuclear power plant as its priority by assigning more screening staff.
According to estimates by Kyushu Electric, the reactivation of the two reactors will significantly boost its supply capacity.
This summer, Kyushu Electric has surplus capacity of only 510,000 kilowatts-equivalent to the output capacity of one midsize thermal power plant-even if it procures a total of 1.49 million kilowatts from Tokyo Electric Power Co. and three other power companies.
Kyushu Electric will be able to substantially reduce the electricity it procures from other power companies if it reactivates the Sendai nuclear power plant's two reactors, which have a combined output capacity of 1.78 million kilowatts.
Kyushu Electric will not be able to increase the electricity output this summer, but the risk of electricity shortages will be low even at peak hours if the two reactors are reactivated.