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Take a look at post #203 and #207, since they aren't from me they may carry more credibility with you.

You made a comment above such that using "excess material" (presumably meaning excess U-235 or Plutonium would make up for poor manufacturing).

That's incorrect.

Placing "excess" fissionable matter in close proximity will result in a merely a radioactive "fizzle".

Moreover, the reason that an initiator/trigger is used is because the critical spherical shape doesn't last very long during the conventional explosive phase. There is a critical moment where the mass is still in the correct configuration, and at that moment the initiator does its deed, but both the gun-type as well as the implosion-type designs fail to maintain their perfect shape for very long during the detonation of whatever conventional explosives are used for the first phase.

Thus, without the preciseness of the initiator, you'll probably just get the above-mentioned fizzle.

Further, it is unquestionable that the material used in the trigger/initiator deteriorates. Radioactive decay is precisely what the trigger requires, but such decay limits the half-life of the isotope.

These triggers have a precise size, shape, and chemical purity that must usually be tailored to a precise core/pit configuration. Thus, replacing a trigger is a non-trivial exercise. Even using a more modern neutron tube trigger requires precise electrical circuits tailored for the type of conventional explosives used, tailored again for the size/shape of the pit/core used (and that is further based upon the chemical purity and size/shape of the fissionable components involved), et al.

The electronics involved also need some very specialized maintenance, as the radiation degrades the circuitry over time.

In short, even if a fully functional weapon (and its arming codes) were GIVEN to Joe Jihadist, he's got a very limited time in which he could detonate it. The longer he waits, the less chance he has that the device will still function.

To repeat: It is possible to build a fission bomb WITHOUT a "trigger" of any kind. Such a weapon would have a shelf life of several years without maintenance. It would NEVER need the radioactive material replaced (at least in our lifetimes). It would need the electronics replaced at predictable intervals.

You can CERTAINLY add extra fissionable material, and almost every bomb ever made does. The minimum needed to sustain a chain reaction is dependent on the specifics of the bomb design, but the amount used is always more than the theoretical minimum. A stupid designer might design the bomb with the fissionable material too close together for the shielding used, but I doubt we are that lucky. We are talking about Russia, not Iraq or Al Qaida, here.

Basically, there is flat out no question that it can be done. You might debate whether or not it actually WAS done (the Russians say it was), but not the fact that it CAN be done.

You are completely right about the fail safe mechanisms. I am personally quite familiar with the way a U.S. nuke is protected, and I can assure you they are completely impossible to set off without the proper codes. Details about Russia's weapons are unknown to me, but my hope is that they ALL have similar protections. Unfortunately, the claim is that the suitcase nukes were built with less protection. Let's hope that claim is false.

Bottom line: There is absolutely no doubt that a nuke can be built without a trigger. Such a weapon would need periodic electronic maintenance, but not replacement of the fissionable material. It could go for years without being touched. The Russians say they built some. Some Russian leaders say some are missing, some say they are not.

Let's hope none are missing. Or if they are, they are protected and the bad guys do not know the code.

But let's NOT bury our heads in the sand and say they can't be set off because they need to be refreshed every 60 days. That is flat out untrue. Likewise, let's not say the smallest they could be is the size of a steamer trunk. That is also flat out untrue. While we're at it, let's not think we can track these things by satellite. Another flat out untruth.

There is a lot of wishful thinking out there. The facts are that we face a potentially major threat, and not just from nukes either. Biological weapons could be even more deadly.

BTW: The bang from a suitcase nuke is estimated to destroy everything within a 3 block radius. Published reports indicate a yield considerably smaller than what we dropped on Japan, possibly as low as 1 kiloton. It would be bad, but not what most people expect from a nuke.

BTW2: The U.S. never built a suitcase bomb, but we DID build nuclear underwater mines. They were designed to be attached magnetically by scuba divers. I do not know the details of these weapons, but I have seen pictures. They were not very large. Likewise, the nukes designed to be fired from artillery were small.

BTW3: I AM familiar with the warheads used on aircraft bombs and missiles, and with the warheads used on ICBMs. They are fusion weapons and much more complex than a suitcase nuke would be, but they are MUCH smaller than you would expect. They make a much bigger bang than a suitcase nuke would, too.