Physicist Ted Taylor is widely credits for designing the smallest pure fission devices in the US arsenal, including the (in?)famous “Davy Crocket”, a 12" diamaeter, ~60 lb shell that could be fired from a howitzer. In George Dyson’s book Project Orion, which relates the details of the nuclear pulse-powered Orion rocket conceptual development (in which Taylor was the primary investigator for propulsion), Dyson, son of physicist Freeman Dyson, quotes Taylor as saying, “I was narrowing my focus, getting the quantities of plutonium that one could use to make nuclear explosions, down into less than a kilogram. Quite a bit less…I tried to find out what was the smallest bomb you could produce, and it was a lot smaller than Davy Crockett, but it was never built in those years. It certainly has been since then. It was a full implosion bomb that you could hold in one hand that was about six inches in diameter.”
So, according to Taylor (but not backed up by any unclassified documentation) one could conceivably fabricate fisson bombs down to the size of say, a grapefruit. Whether this would be of any utility as a weapon is another question; the heyday of the “battlefield nuke” was pretty short, as it was realized by the Sixties, and certainly after the Cuban Missile Crisis, that such weapons are not “tactical” in any political sense, and use of them in a battlefield environment would escalate to a strategic exchange. Project Orion was interested in them for reasons of economy and utility; smaller, minimum plutonium “pulse units” are more economical and allow you to build a smaller rocket (always a problem with Orion, as existing bomb designs predicated a low-end size of several thousand tons per vehicle).
Building such a device, on the other hand, would not be the work of a group of terrorists or a small developing nation. It would require significant testing in addition to computational and intellectual resources only available to a major power such as the US or USSR. These days the computation power is a nonissue, but the expertiese and experience in refining fission weapons is vastly diminished from the “salad days” of the Sixties. This isn’t to say that China or India could develop the capability on their own, but Iran or North Korea aren’t going to be building any atomic golf balls any time soon.
It is also conceivable that extremely compact fission devices could be constructed of transuranic elements such as californium. Again, the synthesis of the material (transuranic elements are not found in nature) and design of the weapon are beyond the means of all but the most advanced nations. Such weapons, by nature of the instability of their core material, aren’t especially useful as arsenal weapons and have the same tactical disadvantages described above and so are most likely not a part of the US arsenal.
So, yes, it’s possible to construct a nuclear device that could fit in a suitcase. Whether Albania[sup]*[/sup] could and would do such a thing is considerably more doubtful.
Stranger
[sup]*[/sup]From Wag The Dog:
Stanley Motss: Why Albania?
Conrad ‘Connie’ Brean: Why not?
Stanley Motss: What have they done to us?
Conrad ‘Connie’ Brean: What have they done FOR us? What do you know about them?
Stanley Motss: Nothing.
Conrad ‘Connie’ Brean: See? They keep to themselves. Shifty. Untrustable.