Tokyo Electric Power Company Holdings (Tepco) said Sunday that it has completed the fourth round of the fiscal 2024 release of treated water into the ocean from its disaster-crippled Fukushima No. 1 nuclear power plant in Fukushima Prefecture.
Since the discharge began on Aug. 24 last year, Tepco has released some 62,400 metric tons of the treated water — which contains small amounts of radioactive tritium — over a total of eight rounds.
In each round, about 7,800 metric tons of treated water was diluted with a large amount of seawater before being discharged offshore, at a point about 1 kilometer from the plant, through an undersea tunnel over a two-week period.
The government and Tepco have been monitoring tritium levels in nearby waters. The levels have been well below the government-set standard.
Tepco plans three more rounds of the discharge in the current fiscal year ending in March 2025.
The company hopes to begin in January next year at the earliest the work to dismantle the storage tanks at the crippled plant, the site of the March 2011 triple meltdown, that became empty after the water release. A total of 21 tanks are planned to be dismantled by the end of March 2026.