Six more workers involved in efforts to contain the nuclear crisis at the crippled Fukushima No. 1 power plant are feared to have been exposed to radiation above the emergency limit, Tokyo Electric Power Co. said Monday.
The announcement follows a finding that two Tepco employees suffered more than twice the maximum limit of 250 millisieverts that has been set exclusively for workers dealing with the crisis at the complex.
The eight are among some 3,700 workers who were involved in emergency work when the crisis began in March, the nuclear safety agency said.
Nuclear and Industrial Safety Agency spokesman Hidehiko Nishiyama said Tepco has submitted provisional assessments of the external and internal radiation exposure levels for 2,400 of the workers to the government, indicating that the number who received the maximum dose is likely to climb even further.
To deal with the country’s worst nuclear crisis, the government raised the limit on the amount of radiation each worker can be exposed to from 100 millisieverts to 250 millisieverts. Even among those who have not maxed out, six have been exposed to more than 200 millisieverts and 88 have surpassed the old 100-millisievert line, although their doses are still below 200 millisieverts.
Meanwhile, Tepco started full-scale operation Monday of a system to clean seawater in the complex that has been contaminated with radioactive fuel from the plant.
The contaminated seawater is contained in areas that are separated from the ocean by “silt fence” barriers.
The system pumps out the polluted water, removes radioactive cesium and dumps “purified water into the sea. Tepco had initially planned to test the system starting June 1 and start running it around June 5, but a problem in a power panel delayed the schedule.
If the test run goes well, the utility wants to fully start the equipment to decontaminate radioactive water by the end of this week — two to three days behind the originally scheduled date of Wednesday, Tepco said.
On Sunday, the utility said its preparations for a test-run of a new piece of equipment that absorbs cesium hit a snag again as the piping in the equipment developed by Kurion Inc. of the United States likely clogged.