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To: Sea Otter who wrote (226945)11/5/2007 12:10:11 AM
From: Nadine Carroll  Read Replies (1) | Respond to of 793914
 
According to this, there are some designs that use a reflector that need as little as 16 kilos of U-235:

(a) Uranium-235 needed to make a bomb:

- 15 kilograms: Weight of a solid sphere of 100 percent uranium-235 just large enough to achieve a critical mass with a beryllium reflector. Diameter of such a sphere: 4.48 in (11.4 cm). Diameter of a regulation softball: 3.82 in (9.7 cm).
- 16 kilograms: Amount needed for an Iraqi bomb design found by UN inspectors.
- 50 kilograms: Weight of a solid sphere of 100 percent uranium-235 just large enough to achieve a critical mass without a reflector. Diameter of such a sphere: 6.74 in (17.2 cm), comparable to an average honeydew melon.
- 60 kilograms: Reported amount used in Hiroshima bomb "Little Boy."

http://www.wisconsinproject.org/pubs/articles/2001/bomb%20facts.htm



To: Sea Otter who wrote (226945)11/5/2007 10:36:25 AM
From: D. Long  Respond to of 793914
 
I think we have a "metric problem" here. 110 pounds is roughly 50 kilos, so he probably just tacked on the wrong unit. And as Nadine points out, there are designs using much less than 50 kilos of uranium. 16 kilos would fit into his range of 20-50.