US Warns of Fresh Threats at Fukushima But radioactive water leak is finally plugged at crippled nuke plant By Rob Quinn, Newser Staff Posted Apr 6, 2011 1:19 AM CDT Updated Apr 6, 2011 7:53 AM CDT 2 comments Comments Damaged reactors at Fukushima. (AP Photo/Japan Defense Ministry) (Newser) – The Fukushima nuclear plant is facing fresh threats that could persist indefinitely, according to a report prepared by American experts and obtained by the New York Times. The engineers warn that steps being taken to stabilize the plant are presenting threats of their own, including the risk that containment structures being filled with radioactive cooling water could rupture during aftershocks that continue to rattle the nuclear complex. The report, which provides more detailed technical information than Japanese authorities have released, questions whether pouring water on nuclear fuel in the absence of cooling systems can be sustained indefinitely. "I thought they were, not out of the woods, but at least at the edge of the woods,” said a nuclear engineer at the Union of Concerned Scientists. “This paints a very different picture, and suggests that things are a lot worse. They could still have more damage in a big way if some of these things don’t work out." There is finally some good news at the plant, however. The utility that runs the plant says the leak of radioactive water from a cracked concrete pit has now been plugged, the Wall Street Journal reports. Workers poured 1,560 gallons of "water glass"—a sodium silicate compound—into cracks to stop the leakage.