The drill was staged from February 10 to 12 in Miyagi Prefecture and elsewhere, with about 2,270 participants from 128 organizations representing the central government, local municipalities and nuclear operators. During the drill, the various parties taking part confirmed such matters as disaster-relief measures and cooperation among themselves.

Portions of the drill were in “blind form,” i.e., without predetermined scenarios. It proceeded from a hypothetical earthquake with an epicenter off Miyagi occurring on the first day, with water injection functions lost at the Onagawa-2 (BWR, 825 MWe) on the second day. Prime Minister Kishida issued a declaration of nuclear emergency, and ordered sheltering in place (known as “in-house evacuation”) to ensure safety.

Circumstances required coronavirus measures as well. Last year, the drill had been deferred due to COVID-19.