The gates of Canada's Chalk River atomic energy project, usually heavily guarded, were deliberately left deserted one recent evening. In lonely majesty a big road grader with a lead-shielded cab lumbered slowly out, towing a skid with a bulky, canvas-wrapped burden. As the skid scraped past, radiation detection devices went wildly off scale. Inside the canvas was a 2½-ton aluminum tank, probably the most troublesome radioactive object that man has ever handled.
Last December, Chalk River's nuclear reactor had to be shut down because of leakage of radioactive material. The aluminum jackets around several of its uranium "fuel" rods had corroded and...