Several hundred tons of radioactive water that leaked from a storage tank at Tokyo Electric Power Co.’s crippled Fukushima No. 1 nuclear plant may have flowed to the sea, Tepco admitted Wednesday, adding that it is “hurriedly checking” to learn if 350 similar tanks are also leaking.
Tepco is desperately trying to seal the tank, which has leaked about 300 tons of radioactive water. The tank, considered temporary, is made of steel plates bolted together with sealed seams. Tepco is also using more durable welded tanks to store the highly radioactive water, which is accumulating daily.
The water was used to cool the three melted reactors, then stored for later possible decontamination. So far, Tepco has built more than 1,000 tanks on site.
Spokesman Tsuyoshi Numajiri said traces of radioactivity were detected in a drainage stream.
“There is a possibility that earth and sand contaminated with the leaked water flowed into the drainage. We cannot rule out the possibility that part of the contaminated water flowed into the sea,” he said.
“We intend to make detailed examinations.”
A Tepco official said earlier Wednesday the tank was believed to still be leaking but the utility has yet to pinpoint where the hole is. The water is apparently being absorbed into the ground and possibly mixing with the groundwater that flows under the stricken plant.
Tepco was also desperately trying to determine if 350 similar temporary tanks at the plant were also leaking.
Numajiri said workers are removing soil contaminated by the leaked water, and pumping the remaining water from the leaky tank.
He said there were no significant changes in radiation levels outside the plant.
An earthquake-generated tsunami knocked out reactor cooling systems and sparked the three meltdowns at the plant in March 2011, in the worst nuclear plant calamity since Chernobyl in 1986.