29 Février 2012
Japan Struggles With Tainted Reactor Water
By PHRED DVORAK, The Wall Street Journal, FEBRUARY 29, 2012
OKUMA, Japan—Nearly a year after the March 11 earthquake and tsunami sparked triple meltdowns at reactors here, the taming of Fukushima Daiichi has become in large part a quest to control water.
Foreign journalists on a tour of the Fukushima Daiichi compound Tuesday saw fields of squat, gray water-storage tanks; miles of orange, black and gray hoses; an AstroTurf-covered barge full of contaminated water; and white-suited workers huddled in a field preparing space for a new water container.
Water is crucial to the continued safety and stability of the Fukushima Daiichi plant, even after reactor temperatures fell at the end of last year to a level at which little radioactivity is being emitted. Plant operator Tokyo Electric Power Co. is still injecting hundreds of thousands of gallons into the reactors every day to keep them from overheating again. Because that water and groundwater—now contaminated—is leaking out of the reactors at an estimated 10,000 tons a month, cleaning it up and storing the excess is a constant challenge.
When the temperature drops, as it is expected to do Tuesday night, there is the added problem that the water might freeze, bursting out of hoses, tanks and pipes.
Tepco says workers have been installing heaters near key equipment and wrapping pipes with insulation, starting with the most important ones that could cause the worst spills. Still, the company said frozen pipes likely caused 28 leaks in January and February. In one of the worst incidents, more than 8 tons of radioactive water leaked from a pipe in reactor No. 4 in early February. Tepco said the water had a low level of radiation, and drained into the basement without leaving the building.
"We've been taking steps to prevent freezing, starting with critical facilities like those for storing water from the reactors,'' Takeshi Takahashi, Fukushima Daiichi's new plant manager, told reporters Tuesday at the plant's command center. Like much of the staff there, Mr. Takahashi, a serious-looking man with dark circles under his eyes, was living at the center.
The water problem isn't one that will go away soon: Tepco has to keep bathing the nuclear reactors in cooling water until the fuel is removed. And until Tepco can plug the leaks and cracks in reactor piping and buildings, contaminated water will keep welling out. Officials estimate it will take six years to plug the leaks and 25 to remove the fuel.
The heart of Fukushima Daiichi's waterworks is atop a hill in the middle of the compound, in the back of a blue truck. There, three pumps send water coursing through thick, black, insulated hoses and into the three damaged reactors below. Next to that truck is a white one with three more pumps—emergency backup.
A third truck holds the emergency diesel generators that are supposed to power the pumps if the electricity goes down, as it did on March 11 of last year. At that time, the generators on the lower floors of the reactor buildings were destroyed by the tsunami. This time, they are set high enough on the hill so that they might remain dry if another big wave comes, said a Tepco official.
On the far side of the reactors, pumps suck contaminated liquid out of the reactor building basements and send it through a series of white, block buildings where oil, cesium and salt are removed.
One facility for removing cesium was created by Kurion Inc. of Irvine, Calif., featuring equipment so big it could only be transported by a special Russian aircraft, Tepco officials said. Another was made by France's Areva SA, which came up with an intricate system of pipes and valves that took 50 welders more than a month to put together, Tepco said. The Areva system isn't being used now.
A third cesium-removal facility was made by Toshiba Corp. Tepco says that one is the main decontamination system in use. Toshiba and support companies deploy 140 workers to operate and monitor the water-processing system, and another 20 to oversee pumping and circulation, through a 2.5-mile line of pressure-resistant hoses. Tepco has two sets of backup lines in place as well, in case the main line gets blocked and needs to be flushed out.
Some of this cleaned-up water goes back up to the truck at the top of the hill, to get rerouted through the reactors.
But much of it gets stored in the squat, gray tanks that have replaced the trees that once grew throughout the sprawling Fukushima Daiichi compound.The tanks store water that has a high saline content, which can damage equipment, explains one Tepco official. Water at other stages of processing are stored in containers of other shapes and colors. Tepco has the capacity to store 165,000 tons of contaminated water, said Katsuhiko Iwaki, deputy manager of the Fukushima Daiichi stabilization center. About 125,000 tons of water already is being stored. The company plans to expand capacity to about 205,000 tons, he said.
Fukushima Daiichi also has one floating container for contaminated water. "There's Megafloat,'' said Mr. Iwaki, pointing to a big, flat AstroTurf-covered barge quietly anchored in the sea by the side of reactor No. 1. The barge was originally created to be a floating fishing pier for the southwestern city of Shizuoka.