Workers at Japan’s Fukushima Daiichi nuclear power plant discovered a radioactive hot spot far more lethal than anything previously recorded at the facility, the plant's owner told CNN on Tuesday.
The highest level reported in the days following the disaster was 400 millisieverts. But the reading at the base of a ventilation tower between the No. 1 and No. 2 reactors Monday afternoon was 10,000 millisieverts per hour. According to Tokyo Electric Power Company, 10,000 millisieverts per hour is high enough that exposure to the radiation for 60 minutes could kill a man or woman within weeks, CNN reports.
A U.S. expert explained to CNN that radioactive particles most likely concentrated in that area in the first days of the disaster, as plant operators tried to vent the damaged reactors.
Gary Was, a nuclear engineering professor at the University of Michigan, told CNN that the location of the hot spot suggests that radioactive material was filtered from air and steam released to relieve pressure inside the reactors during the meltdowns.
"As they were venting, either intentionally or unintentionally, the building air was being sent through filters," Was said. Those filters may have been concentrating radioactive particles "into one spot," he said.
In response to the discovery, Tokyo Electric immediately cordoned off the area and is investigating the cause of the radiation and how it will affect the recovery work, company spokesman Naoki Tsunoda told CNN.
None of the workers who made the discovery have been injured, the company said.
According to CNN, Tokyo Electric says it expects to fully wind down the crisis at the plant sometime between October and January.
