HOWTO Build a Nuclear Device

[Steve Schear]

At 12:24 AM 11/17/2001 -0800, Tim May wrote:
>On Friday, November 16, 2001, at 08:20 PM, !Dr. Joe Baptista wrote:
>
>Anyone on this planet can build a nuclear device.  So the only issue in
>>building the device is the will to die for a cause.  And the only thing I
>>find unfortunate in all of this is that there are so many causes that
>>people are willing to die for.  And war will not make those reasons go
>>away - it will only encourage them.
>
>It's really _not_ this easy. It took China and India a while before they 
>successfully tested an A-bomb (many years after they had the raw materials 
>from their reactor programs). It may have taken the South Africans and 
>Israelis a few years after getting materials, too. So, why didn't they 
>just hammer U-235 into stainless steel mixing bowls and do it the way 
>"anyone on this planet can build a nuclear device," one wonders.
>
>I'd guess that the "tall pipe" version is the most buildable of the 
>basement nukes. (In a nutshell: a tall drainpipe, perhaps 40 feet tall. 
>Set up in an apartment building, warehouse, etc. At the base the pipe is 
>reinforced with copious amounts of concrete. The subcritical masses are at 
>opposite ends of the pipe. The mass on top is piled on with several 
>hundred pounds of ballast, to "tamp" the early critical mass action. To 
>explode the bomb, drop the mass from the top of the pipe. The critical 
>mass is briefly contained by the concrete collar around the pipe and the 
>inertial mass above. Is it enough to produce a real chain reaction? Well, 
>it's all relative. Still, not very efficient.)

Interestingly enough, the United States government conducted a controlled 
experiment called the Nth Country Experiment to see how much effort was 
actually required to develop a viable fission weapon design starting from 
nothing. In this experiment, which ended on 10 April 1967, three newly 
graduated physics students were given the task of developing a detailed 
weapon design using only public domain information. The project reached a 
successful conclusion, that is, they did develop a viable design (detailed 
in the classified report UCRL-50248) after expending only three man-years 
of effort over two and a half calendar years. In the years since, much more 
information has entered the public domain so that the level of effort 
required has obviously dropped further.

This experiment established an upper limit on the required level of effort 
that is so low that the hope that lack of information may provide even a 
small degree of protection from proliferation is clearly a futile one.

http://www.fas.org/nuke/hew/Nwfaq/Nfaq4.html

steve