The operator of the leaking Fukushima nuclear plant said Tuesday that it dumped more than 1,000 tons of polluted water into the sea after a typhoon raked the facility.
Typhoon Man-yi smashed into Japan on Monday, bringing with it heavy rain that caused flooding in some parts of the country, including the ancient city of Kyoto.
The rain also lashed near the broken plant run by Tokyo Electric Power (TEPCO), swamping enclosure walls around clusters of water tanks containing toxic water that was used to cool broken reactors.
Some of the tanks were earlier found to be leaking contaminated water.
"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."
The utility said about 1,130 tons of water with low levels of radiation -- below the 30 becquerels of strontium per liter safety limit imposed by Japanese authorities -- were released into the ground.