When American Airlines Flight 11 flew at low altitude down the Hudson River valley on the morning of Sept. 11, 2001, its target was the north tower of the World Trade Center. But its impact is still being felt at a cluster of buildings it passed about five minutes before it reached lower Manhattan, at a nuclear-reactor complex called Indian Point in Buchanan, NY. Adjacent to the site's two operating reactors are two buildings packed with highly radioactive spent-fuel rods, in pools of water 12 meters deep and tinged Ty-D-Bol blue by boron added to tamp down nuclear chain reactions. The soothing hum of the pumps that circulate the building's warm, moist air -- and, critically, keep the water cool -- lends an atmosphere of industrial tranquility.

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