The plant’s operator and the utility responsible for the clean-up Tokyo Electric Power Company (TEPCO) detected record radiation levels on a duct which connects reactor buildings and the 120 meter tall ventilation pipe located outside on Friday.
TEPCO measured radiation at eight locations around the pipe with the highest estimated at two locations - 25 Sieverts per hour and about 15 Sieverts per hour, the company said.
This is the highest level ever detected outside the reactor buildings, according to local broadcaster NHK. Earlier TEPCO said radiation levels of at least 10 Sieverts per hour were found on the pipe.
The ventilation pipe used to conduct radioactive gasses after the nuclear disaster may still contain radioactive substances, TEPCO added.
The earthquake in March 2011 triggered a tsunami that hit Japan’s coast, damaging the Fukushima Daiichi plant and causing the meltdown of three nuclear reactors. The crippled reactors burnt through the concrete basement while the water used to cool them has been leaking into the soil and contaminating the ground water on the premises of the nuclear facility. The radioactive water stored at the site has been seeping into the Pacific Ocean.
The water leakage has raised health concerns among Japan’s neighbors. For instance, South Korea has been testing fish caught off the country's coast, according to the country’s fisheries ministry.
Currently 400 tons of contaminated water is being produced at the site on a daily basis. In an attempt to solve the storage problem the International Atomic Energy Agency (IAEA) proposed on Wednesday to consider dumping toxic water into the ocean after lowering the level of radioactive materials.
"Regarding the growing amounts of contaminated water at the site, TEPCO should... examine all options for its further management, including the possibility of resuming controlled discharges (into the sea) in compliance with authorized limits," the IAEA said in a statement.
TEPCO has been testing a high-tech water processing machine called ALPS, which can remove all radioactive materials from the water except tritium. However, the low-energy isotope is considered to be less dangerous than other radioactive isotopes such as caesium and strontium, also contained in the tainted water.
SHI/SHI