Reply #10: Are you sure?

[BootinUp]

Not sure myself but I don't mind doing a little more googling...

http://www.nrdc.org/nuclear/furanium.asp

Had the 15-pound uranium cylinder been weapon-grade highly enriched uranium instead of depleted uranium (which is not suitable for nuclear weapons), the dose rate at the surface of the highly enriched uranium would have been more than 100 times higher. However, nearly all of this increase would be due to alpha radiation, which can be shielded with a sheet of paper. Meanwhile, the beta-ray dose rate would be about the same or lower and the gamma-ray dose would be ten or more times higher. At the surface of the shielded container the dose rate would be be about one to ten times higher. The dose rate of the highly enriched uranium cylinder could be easily reduced to that of the shielded depleted uranium container (i.e., 0.5 mrad/hr) by adding an additional 1/8 inch of lead (one-third of a centimeter) around the cylinder. This would add only about 6.6 pounds (3 kilograms) to the mass of the lead shielding.