Tokyo Electric Power Co. has warned its stricken Fukushima No. 1 nuclear plant could be hit by tsunami as high as 26.3 meters.
The deluge would likely cause seawater to mingle with the radiation-tainted water accumulating in the basements of the reactor buildings at the six-unit plant, allowing 100 trillion becquerels of cesium to escape, according to an estimate that Tepco revealed Friday at a meeting of the Nuclear Regulation Authority.
Tepco said a tsunami of that size occurs once every 10,000 to 100,000 years.
The Fukushima No. 1 plant, more than 40 years old, was crippled by the March 2011 earthquake and tsunami after waves as high as 15.5 meters inundated the facility, knocking out all power and disabling the vital backup cooling systems for reactors 1 to 4, triggering three core meltdowns.
Tepco also said the nearby Fukushima No. 2 nuclear plant, which is nearly as old as Fukushima No. 1, could be hit by tsunami of up to 27.5 meters, but that its idled reactors and fuel pools would not be damaged by such an event.