Spent Fuel Rods

As previously mentioned and now written about directly in the Christian Science Monitor. No one is addressing the problem with our nuclear reactors. Spent fuel rods are packed far too densely at virtually all our nuclear power plants. The power companies would rather pack them more densely than build new pools to store the material. What would happen if the cooling system failed for one of these pools? Would the material would sink into the Earth, most likely to the core? And what would come up that hole? Devastation?

http://www.csmonitor.com/USA/2011/0330/Fukushima-warning-US-has-utterly-failed-to-address-risk-of-spent-fuel