The 40-year operating lifetime limit of the unit could have been extended by up to 20 years with the approval of the Nuclear Regulation Authority (NRA), but the power company calculated that, with Ikata-1’s relatively small output, the return would be financially insufficient to justify the high expected costs of the necessary safety measures.
Given that the 40-year operating limit on the Ikata-1 was to legally expire in September 2017, the company had been required to file an application with the NRA for permission to extend it. Shikoku Electric Power considered the matter, and finally determined to decommission the unit on the basis of cost-effectiveness. The unit has generated 132.6TWh total during its operation.
The decision seems also to have been affected by the formulation in March 2015 of an accounting system for facilitating decommissioning efforts, after which five aging NPPs around the country, all operated since the 1970’s, and all with small outputs, were slated to be decommissioned.
Specifically, the five units are: Mihama-1 and -2 (Kansai Electric Power Co.), Genkai-1 (Kyushu Electric Power Co.), Tsuruga-1 (Japan Atomic Power Co.) and Shimane-1 (Chugoku Electric Power Co.).
Meanwhile, Shikoku Electric Power plans to restart the Ikata-3 (PWR, 890MWe) this coming summer.
