Two workers hospitalized for radiation exposure were wearing ordinary work shoes in liquid containing radioactivity 10,000 times the normal level of reactor-cooling water at the Fukushima No. 1 nuclear power plant, officials said on March 25.
Two workers hospitalized for radiation exposure were wearing ordinary work shoes in liquid containing radioactivity 10,000 times the normal level of reactor-cooling water at the Fukushima No. 1 nuclear power plant, officials said on March 25.
Officials of the Nuclear and Industrial Safety Agency (NISA) told a news conference it was highly likely that radiation in the liquid could have come from the reactor core.
Three workers were in the ankle-deep water on March 24 and were carrying dosemeters. But they ignored the high-radiation warnings of the devices and continue repair work in the soaked basement of the No. 3 reactor’s turbine building, officials of Tokyo Electric Power Co., the plant operator, said.
The water was about 15 centimeters deep, officials said.
“I thought (the dosemeter) was out of order,” one of the workers was quoted as saying. The radioactivity level had been low in the basement before.
TEPCO has come under fire for failing to properly ensure the safety of the workers trying to bring the nuclear crisis under control. The company has acknowledged that its safety measures were inadequate.
Two of the workers were rushed to a hospital in Fukushima city on March 24. They were taken on March 25 to the National Institute of Radiological Sciences in Chiba for examinations and treatment for possible beta ray radiation burns below their knees.
The workers were exposed to an estimated two to six sieverts of radiation, according to officials of the institute. They said skin transplant would not be necessary.
The third worker wearing long boots was unharmed.
TEPCO earlier said the water was likely contaminated with radioactive substances leaked from damaged nuclear fuel rods inside the reactor core or the cooling pool for spent fuel rods.
“Perhaps the fuel was damaged to a certain degree, and a certain amount may have been released,” Takeshi Takahashi, a TEPCO official, told a news conference.
The company was trying to determine where the water came from.
According to TEPCO and the NISA, the water was found with 3.9 million becquerels of radioactive substances per cubic centimeter, about 10,000 times the level of water used to cool reactor cores.
Cobalt-60, iodine-131, cesium-137 and other substances, which do not normally exist in cooling water, were detected, the officials said.
The workers’ dosemeters showed radiation amounts totaling 173 to 180 millisieverts, less than the maximum of 250 millisieverts per year allowed for an emergency situation.
But the level at the water’s surface was later found to be 400 millisieverts per hour.
The workers wore three layers of protective clothing, masks, helmets and gloves. But TEPCO gave them no instructions about their footwear because there were no deep water puddles the previous day.
The workers in ordinary work shoes were in the contaminated water for 40 to 50 minutes, and the tainted water had soaked through their clothes to their skin, according to officials.
Under an internal TEPCO rule, an official to gauge radioactivity levels is required to accompany workers and give instructions, but none did so for the three.
TEPCO officials admitted rules and guidelines were breached in some cases. NISA officials said they instructed the utility to correct its lax safety management.
Industry minister Banri Kaieda criticized TEPCO for the absence of the official in charge of measuring radiation levels.
“It was a mistake in the very basics of work,” he said.
Tadashi Narabayashi, a professor of nuclear reactor engineering at Hokkaido University, said the water may have come from the overflowing cooling pool for spent fuel rods or from the reactor’s containment vessel, which may have been deteriorated.