The Arms race: Constructing a Nuclear Bomb

[Brand X]

I would assume (and you know what they say about assumptions :)) that most of the following is in the ballpark: (if not, please fight my ignorance)

The science to build a nuclear device, whilst obviously a challenging and complex field, is sufficiently public to allow any competent specialist to follow it and understand the necessary mechanisms of the process.
The mechanical necessities and complex circuitry required for control devices would not be any more challenging or difficult to create than those for other legitimate uses.
This leaves the collection / purchase / theft / creation of weapons grade plutonium (or uranium) for the device, which I presume is generally the main sticking point.

So, given the finances and inclination, is the main complexity and difficulty in obtaining a nuclear weapon solely down to acquiring the right core material for use?

I trust a disclaimer is not required to the fact I am not planning on building such a device. :D

[Aro]

I don't know much about it (but I'm sure someone will soon), but here's a link (http://www.terrorismanswers.org/weapons/making_print.html) that seems to know:

Looks to be a lot more complicated, even the science, than you give it credit for.High-level expertise in a broad range of subjects, including the physical, chemical, and metallurgical properties of the materials to be used; engineering; nuclear physics; the nuclear and biological effects of radiation; the technology of high explosives and chemical propellants; hydrodynamics; and highly precise electrical circuitry. As many as a dozen highly skilled scientists and engineers would probably be necessary, experts say.Bolding mine

[refusal]

Extracting the correct uranium isotope, U-235, from uranium ore is very tricky, requiring complex techniques (gaseous diffusion (http://www.nrc.gov/materials/fuel-cycle-fac/ur-enrichment.html) or centrifuging), a lot of time, and a considerable degree of danger.

If you have a sufficiently large mass of enriched uranium it's easy to produce a simple bomb like Little Boy, the one used on Hiroshima, which used conventional explosives to fire one mass of U-235 into another, creating a critical mass. To produce a smaller, more efficient bomb (e.g. a suitcase bomb) requires higher technology, as does producing a missile to deliver it, or making a hydrogen bomb.

So to answer the OP, if you can get enriched uranium, you're most of the way to a simple bomb.

I wonder if the CIA monitor people doing Google searches for this kind of thing.

[engineer_comp_geek]

Didn't a high school (or maybe a college) student once build a complete bomb, complete with everything except the uranium? I seem to recall the experts thinking that it probably would have exploded. The incident also inspired some low budget movies as I recall.

I hope the CIA or someone is monitoring searches on this kind of thing. The US government managed to make some pretty spiffy bombs using WWII era technology, which is painfully crude by today's standards.

[Bosda Di'Chi of Tricor]

However, if you had a complete set of plans and tech notes of an existing model of bomb, very few people, and very little effort, would be needed.