Japan’s Shikoku Electric Power Company announced on 27 March that unit 2 of the Ikata nuclear plant in Ehime prefecture is to be decommissioned. Ikata 2, a 538MWe pressurised water reactor (PWR) began operation in March 1982. It was taken offline in January 2012 for routine inspections. Shikoku said the cost and scale of modifications needed to upgrade the unit to meet revised safety standards made it uneconomical to restart the reactor. It is the ninth operable Japanese reactor to be declared for decommissioning since the 2011 Fukushima Daiichi accident.

In March 2016 Shikoku decided to decommission Ikata 1, a similar 538MWe PWR, which had been in operation since September 1977 and was closed for routine inspection in September 2011. The cost of upgrading the unit to operate beyond the statutory 40 years was put at more than JPY170bn ($1.6bn).

Ikata 3, an 846MWe PWR, which was taken offline for periodic inspection in April 2011, was permitted by the Nuclear Regulatory Authority to restart in April 2016. The unit resumed commercial operation in September 2016, but in December 2017, a Japanese high court ordered its closure. The injunction is effective until the end of September 2018.

In mid-March 2015, the Ministry of Economy, Trade and Industry's Agency for Natural Resources and Energy revised the accounting procedures for the calculation of decommissioning costs to encourage the decommissioning of older and smaller units. As a result,  five smaller operable nuclear power reactors are to be decommissioned – Kansai Electric Power Company's Mihama 1&2; Japan Atomic Power Company's Tsuruga 1, Kyushu Electric Power Company's Genkai 1, and Chugoku Electric Power Company's Shimane 1. In December 2017, Kansai announced that it would not seek permission to restart Ohi 1&2 in Fukui Prefecture (both 1,175MWe PWRs).