In what could be a major step forward at Japan's Fukushima Daiichi nuclear plant, Tokyo Electric Power Co. has started using treated water from plant basements for core cooling.
For more than a week, engineers have struggled to overcome leaks and higher-than-expected radiation accumulation in a water filtration system installed at the plant. Designed by Areva, Veolia and Kurion, the system was built to remove radioactive contaminants from 105,000 metric tons of water accumulating at the plant and threatening to overflow. On Monday afternoon, Japan Time, TEPCO announced it began using water treated by the system to cool units 1 though 3.
Since the crisis started following the March 11 earthquake and tsunami, operators have resorted to a makeshift core cooling system that pumps water into reactors from outside but does not remove it. Flooding from the tsunami combined with leaks in reactor pressure vessels have filled the units' lower levels with irradiated water that has prevented repair work.
"We've taken a large step in efforts to restore the crisis-hit plant," Goshi Hosono, a special adviser to the Japanese prime minister, was quoted by Asian news services as saying at a news conference announcing the start of water recirculation.
The next stage in TEPCO's plans is to inject 16 tons of mostly recycled water per hour into the reactors and to continue removing and treating accumulated water. Test runs of the filtration system have treated roughly 1,850 tons of water. Once fully operational, the system is designed to treat 1,200 tons of contaminated water per day.