Two years ago, on July 8, 2013, and immediately after new regulatory standards came into effect, the power company initially filed its applications with the NRA for three related items: (a) permission to change reactor installations, (b) approval of the construction plan for the Sendai-1 and -2 NPPs, and (c) approval of changes to operational safety programs for the two units.

The NRA designated both units as priority NPPs, after which it carried out the required examinations. It finally approved the applications for permission to change reactor installations (basic design) in September 2014.

The construction plans, as required under the new regulatory standards, contain descriptions of such equipment as pumps, available power sources and numbers of units, as part of measures to respond to severe accidents. The NRA and Kyushu Electric Power had been working on partial revisions and adjustments to the descriptions.