Kansai Electric Power Co. estimates that around ¥200 billion will be required to protect its nuclear plants in Fukui Prefecture from major natural disasters.

The estimate, up from an initially projected ¥70 billion, is included in an additional set of safety measures presented to the Fukui Prefectural Government, officials of the utility said Monday.

Under the measures, Kansai Electric plans to surround its nuclear plants in the towns of Mihama and Takahama with sea walls of up to 11.5 meters by the end of fiscal 2015.