Japan’s nuclear watchdog will recalculate the projected maximum ground motion based on which an idled power plant in central Japan is to be reinforced. Two reactors at the Ohi nuclear plant in Fukui Prefecture are being screened to determine whether it is safe to restart them.
The Nuclear Regulation Authority’s decision was prompted by Kunihiko Shimazaki, who retired from the authority in 2014. Shimazaki last week told the head of the authority, Shunichi Tanaka, that the maximum jolt calculated using the current formula may be too small for some reactors, and requested a recalculation for the Ohi plant.
The authority had already agreed with the operator 2 years ago that the reactors must be able to withstand seismic motion of up to 856 gals.
But after discussing Shimazaki’s request, the authority members decided to recalculate using a different formula. They say they will consider whether to change the assumption after recalculation.
Tanaka says the authority’s assumptions on quakes have been fairly conservative, but it may have to revise the quake-resistance design for the Ohi plant if the recalculation indicates otherwise.