share: digg facebook twitter Police said falling radiation levels have allowed them to go inside a six-mile (10-kilometer) radius at the Fukushima Dai-ichi plant for the first time, as they search for thousands of victims still missing after the March 11 earthquake and tsunami. Japan acknowledged this week that overall leaked radioactivity already has catapulted the crisis into the highest severity on an international scale, on a par with Chernobyl, though still involving only a tenth of the radioactivity emitted in that 1986 disaster. Three of the plant's reactors also have about 20,000 metric tons of stagnant, radiation-contaminated water and it is proving difficult to reduce the amount spilling from the reactors, Nishiyama said. [...] cooling systems can be fully restored, flooding the reactors with water is the only way to help prevent them from overheating, but those many tons of water, tainted with radioactivity, pose a separate threat. The beleaguered plant operator, Tokyo Electric Power Co., or TEPCO, is seeking ways to eventually remove spent fuel rods from reactor storage pools as the plant is closed down for good.