The operator of the crippled Fukushima Daiichi nuclear power plant says the average daily increase of contaminated water in the year through March was the lowest since the 2011 accident.



Tokyo Electric Power Company, or TEPCO, says about 70 tons of polluted water was generated per day in fiscal 2024, or around one-seventh of the level of the peak year of fiscal 2015.



Contaminated water has been accumulating at the plant since it suffered a triple meltdown following a massive earthquake and tsunami in March 2011.



Water used to cool molten nuclear fuel mixes with rain and groundwater that flow into damaged reactor buildings, creating the contaminated water.



The utility treats the water to remove most radioactive substances before storing it in tanks. The treated water, which still contains tritium, is stored in more than 1,000 tanks at the plant compound.



The operator has taken various measures to reduce the inflow of groundwater into reactor buildings. One is to create a frozen soil wall around the buildings. The ground around them has also been covered with concrete and other materials.



TEPCO says the water inflow also decreased because annual rainfall in the last fiscal year was around two-thirds of the usual figure.



The utility has set a target of reducing the daily level of contaminated water generation to between 50 tons and 70 tons by fiscal 2028.