Safety assessments of two nuclear reactors at the Sendai plant in southwestern Japan showed progress Wednesday, as regulators basically approved the plant operator's estimate of the maximum seismic ground motion that could affect the site.
The move came as the Nuclear Regulation Authority seeks to narrow down reactors it will place priority on in the assessment. Units handpicked by the NRA are expected to see the review process finish earlier than others and move on to restart their operation.
After the day's safety screening meeting ended, an NRA official suggested that Kyushu Electric Power Co.'s estimate of the maximum possible seismic ground motion, set at maximum 620 gals in terms of speed of acceleration, was appropriate in principle. The figure is used for facilities' seismic design.
"I recognize the figure should be around that level," the official, who attended the meeting, said.
But he noted that discussions have not finished on some other important issues involving the plant located in Kagoshima Prefecture.
According to procedures agreed on in February, the NRA plans to specify which reactor or reactors have cleared the main agendas related to earthquake and tsunami hazards and have no other serious problems in proceeding with the review.
The NRA will then start crafting what it calls a "draft screening report" which will set the stage for issuing permission on the reactor's basic design.
Reactors also need to secure approvals for detailed designs and management rules, but permission regarding the basic design is seen to be most important in the overall safety review process.
So far, safety review applications for 17 units that belong to a total of 10 nuclear power plants nationwide have been submitted to the NRA after a set of new safety requirements were introduced last July.
Although concerns linger among the public about the use of nuclear power after the 2011 Fukushima Daiichi nuclear power plant disaster, Prime Minister Shinzo Abe's government has reiterated it will push for the resumption of reactors that have satisfied the new regulations.
All of Japan's 48 commercial reactors have been offline after two reactors at Kansai Electric Power Co.'s Oi nuclear complex in Fukui Prefecture shut down for mandatory regular checkups in September.