cacosapo, those parts aren't necessary. The only component need is a nuclear reactor. These component everyone speaks of are for air delivery of the payload involving avionics etc. You wouldn't want the bomb to go off on the launch pad or airplane so componenty are needed to arm and detonate the bomb. All that is really needed are:

1. Some decent *nium (uraniam etc) or some other matter of potential fissionable magnitude
2. A detonator
3. A target

Ok so how does one make a nuclear detonator? All you have to do is keep two pieces of fissionable material below critical mass and then bring them together very fast. It's popular to use a gun chanber to do this. Another way is the "soccer ball" principle using implossion for detonation. That was used in a movie back in the 80 or early 90s called the Manhattan project or something. The bombs dropped on Hiroshima and Nagasaka were very simple. No "advanced" components were needed, in fact they weren't even tested before deployment. Just two clumps of Uranium and a gun barrel type detonator.

Our saving factor so far has been the ability to handle weapons safely. This has been the limiting factor so far. There are other advanced methods of detonation which provides for the massive weaponry we stockpile but all that is needed for mass destruction is about 16 kg of uraniam at 88 percent mass and a detonator you can make at a hardware store.

//EDIT Here I drew one up based on the design of FatMan and LittleBoy, the bombs used in WW2 (in the name of science) assuming it get's uploaded.