TEPCO, the operator of the crippled Fukushima nuclear power plant, said on Tuesday that it dumped over 1,000 tons of radioactive water into the sea after typhoon Man-yi hit the plant.
The typhoon hit Japan on Monday. The heavy rain and wind caused flooding in some areas of Japan, including Kyoto.
Some of the tanks at Fukushima were found leaking toxic water after the heavy rain swamped the enclosure walls around clusters of water tanks.
“Workers measured the radioactive levels of the water collected in the enclosure walls, pumping it back into tanks when the levels were high,” said a TEPCO official.
“Once finding it was mostly rain water they released it from the enclosure, because there is a limit on how much water we can store.”
Around 1,130 tons of contaminated water have leaked into the ground. The level of radiation was low – below the 30 becquerels of strontium per litre safety limit imposed by Japanese authorities – according to TEPCO.
But toxic water with radiation levels beyond the safety limit has leaked from a different site as well, with workers not being able to pump the water quick enough due to the heavy rain and wind.
Separately, around 300 tons of mildly contaminated groundwater is entering the ocean every day having passed under the reactors, TEPCO says.
Strontium is a substance that can cause cancer if consumed.