FUKUSHIMA – The highest level yet of beta ray-emitting radioactive substances, including strontium, has been detected at one point in a drainage ditch at the crippled Fukushima No. 1 nuclear plant where measurements are regularly taken, Tokyo Electric Power Co. said Thursday.
According to Tepco, a water sample taken Wednesday at a point in the ditch some 300 meters from the ocean was found to contain 1,400 becquerels per liter of beta ray-emitting radioactive substances, the highest level ever detected at that location.
Tepco said water that passed through the ditch may have entered the sea.
A water sample taken Tuesday at the same point contained 19 becquerels of such radioactive substances.
The radiation level surged after heavy rain caused by Typhoon Wipha, which hit the Tohoku region, including Fukushima Prefecture, on Wednesday, Tepco said. It is thought the rain washed out radioactive substances that had been absorbed by the ground.
Radiation levels also hit record highs in water samples collected Wednesday at three upstream points in the drainage ditch, which passes close to the storage tank from which highly radioactive water spilled in August, with the amount of beta ray-emitting radioactive substances ranging from 2,000 to 2,300 becquerels per liter.
Tepco said it was unable to take seawater samples near the exit of the ditch because of bad weather.