6 more nuclear plant workers exposed to radiation above limit

TOKYO (Kyodo) - Six more workers involved in efforts to contain the nuclear crisis at the Fukushima Daiichi power plant are feared to have been exposed to radiation above the prescribed limit, Tokyo Electric Power Co. said Monday, bringing the total number of such workers to eight.
Tokyo Electric said that the preliminary radiation doses of the six employees were between 264.7 and 497.6 millisieverts, compared with the maximum allowable limit of 250 millisieverts, which has been set exclusively for workers dealing with the Fukushima crisis.
The six, who worked in reactor control rooms, checked radiation levels or restored measuring devices, have not reported any health problems, according to the plant operator known as TEPCO.
The latest announcement was made as TEPCO is checking the external and internal radiation exposure of a total of 3,726 workers who were involved in the emergency work in March, after the megaquake and ensuing tsunami crippled the plant on March 11.
So far, TEPCO has come up with provisional assessments for 2,367 workers and reported the outcome to the Health, Labor and Welfare Ministry and the government's nuclear safety agency.
TEPCO failed to complete all of the assessments by Monday as ordered by the health ministry, leading the ministry to criticize the delay as ''extremely deplorable'' and call on the company to finish the work by June 20.
The Nuclear and Industrial Safety Agency, which also received the report, warned the company Friday to work out measures to prevent a recurrence of similar cases when two TEPCO employees were confirmed to have suffered radiation doses more than twice the maximum limit.
Now that six more workers are feared to have been exposed to high levels of radiation, agency spokesman Hidehiko Nishiyama said that he expects TEPCO to swiftly report the final figures on their exposure and conduct a ''thorough'' investigation to look into the cause.
To deal with the country's worst nuclear crisis, the government has raised the maximum allowable limit on the amount of radiation to which each worker can be exposed from 100 millisieverts to 250 millisieverts. Workers leave the Fukushima plant once they are exposed to radiation in excess of 200 millisieverts.
Even among workers who have not exceeded the maximum limit, six have been exposed to more than 200 millisieverts, and 88 have surpassed the 100-millisievert line, although their doses are still 200 millisieverts or less, according to the report by TEPCO.
Experts say that exposure of 250 millisieverts could raise the risk of cancer throughout a person's life by around 1 percent.
While the utility's radiation management has often been questioned, it also said Monday that a worker in his 60s may have suffered internal exposure because he forgot to attach a charcoal filter, which absorbs radioactive substances, to his full face mask.
It was found that radioactive substances have not entered his body, but the nuclear safety agency said that it would like the company to take measures to prevent similar cases.
Meanwhile, TEPCO started full-scale operation on Monday of a system to clean seawater near the Fukushima Daiichi plant that has been contaminated with radioactive substances leaked from the plant.
The contaminated seawater is basically enclosed in areas near the plant, including by ''silt fence'' curtain barriers installed in the sea. The system pumps out the polluted water, removes radioactive cesium and returns the cleaned water back into the sea.
TEPCO had initially planned to test run the system from June 1 and fully operate it around June 5, but a problem with a power panel delayed the schedule.