In recent days, Japanese government authorities have voiced similar concerns and complained about what they say is Tepco’s lack of transparency. On Monday, Tepco released its first detailed map of water leakage at the plant, with diagrams of nine separate areas, including the turbine buildings for each of the plant’s six reactors.
In some places, according to the maps, contaminated water is ankle-high. In other areas, it’s nearly seven feet deep. The unit 4 turbine building is almost entirely underwater. Some of Tepco’s data are more than a month old, and accurate readings are hard to obtain from the most dangerous areas. Still, Tepco’s readings indicated that in some areas airborne radiation levels were once at 1,000 millisieverts per hour. A worker could stay in such an area for 15 minutes before reaching his or her annual dosage limit.
Graphic
Watch how the crisis at the Fukushima Daiichi power plant unfolded.
Tepco is having difficulty securing areas to store the radioactive water — more than 100,000 metric tons of it, according to the latest estimates. Last month, workers installed tanks capable of holding 6,400 and 6,200 metric tons. A seaborne storage tank hauled away about 10,000 metric tons in the middle of the month. Engineers are also trying to use zeolite, a mineral, to absorb radiation from the water.
The onset of Japan’s rainy season this month has prompted concerns that contaminated water levels could rise, with overflow spilling into the environment. Experts have also said there is a risk that water seeps through potential cracks in the floors of the Fukushima facility, contaminating the soil.
Under normal circumstances, Areva’s system can decontaminate 50 tons of water per hour. But experts acknowledge that it is hard to predict how efficiently the system will handle water that contains not only radioactivity but also debris, oil and salt. Water might need to be treated numerous times, not just once, before it can be dumped into the ocean.
“Normally, the processing is done at small volumes and you have carefully controlled chemistry,” Barrett said. “Here you have massive volumes and a very heterogeneous chemistry.”
“Honestly, it’s hard to say how it will work,” said Patricia Marie, an Areva spokeswoman. “We hope everything will be fine.”
Special correspondent Akiko Yamamoto contributed to this report.
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