The operator of the damaged Fukushima nuclear power plant has begun testing a complex system to decontaminate highly radioactive wastewater. Tokyo Electric Power Company, or TEPCO, began the test run early on Thursday ahead of full-fledged operation on Friday, Japanese NHK reported. More than 110,000 tons of the toxic wastewater has accumulated at the plant after months of using water to cool overheating nuclear fuel. The water is hampering work to bring the facility under control. TEPCO is struggling to find storage space for the water, which is accumulating at a rate of 500 tons daily. The treatment system combines 4 devices, including those made by French and US makers. The French-made device uses a special chemical agent to treat the contaminated water. The US-made device is designed to remove radioactive cesium. Tuesday\'s testing showed it reduced the amount of cesium in the water to one-3,000th of the previous amount. TEPCO plans to reduce the level of radioactive substances to one-10,000th before moving decontaminated water to temporary tanks. Technical problems delayed the test by 4 days.