(From left) Units 3, 2, and 1 of Shikoku Electric Power Co.’s Ikata Nuclear Power Plant in Ikata Town, Ehime Prefecture, Japan, December 14, 2021; photo by Takao Kitamura from a Honsha helicopter.


Shikoku Electric Power Co. and Ehime Prefecture announced on April 18 that the concentration of radioactive iodine in the primary cooling water passing through the reactor at the No. 3 reactor of the Ikata Nuclear Power Plant (Ikata-cho, Ehime Prefecture) had risen to about three times the normal level. There is no external radiation impact, and the plant will continue to operate under enhanced monitoring. There is a possibility that a small hole has been made in the fuel rods and radioactive material is leaking out.

 According to the prefectural government, at around 5:45 p.m. on the 18th, the iodine concentration rose to 0.25 becquerels per cubic centimeter, up from the normal level of 0.09 becquerels per cubic centimeter. This is less than 1/120,000 of the operational limit (32,000 becquerels per cubic centimeter). Shikoku Electric Power Co. has increased the number of inspections from three times a week to once every three to four hours and will continue to monitor the situation.