[sirchtruth]

Set aside the issue of maintenance needed.

I don't get it. What maintenance is needed? And if you know, how would you know?

[blackdog]

In order to attain a nuclear chain reaction, the explosives timing needs to be precisely controlled so that all 360 degrees of the core is compressed by the explosion uniformly to within thousands of microseconds. That kind of accuracy requires maintenance or replacement of resistor networks, capacitors, software, firmware, clock oscillators, and the conventional explosives that compress the fissile material.

This is precisely why nuclear testing bans were so scary. A country could have plenty of bombs, but it's uncertain if they still work without testing and the deterioration tables that can be extrapalated from such testing. The replacement components are easy to track too. Resistors and capacitors manufactured to within plus or minus .0002% are not exactly easy to come by. Commercial stuff is plus or minus 5%, and military spec stuff is plus or minus 2%. They perform differently based on outside air temperature, barometric pressure, and age.

Ever try to use a 900MHZ cordless phone or monitor in a below zero environment? If it's commercial, it's worthless in two minutes.

[blackdog]

Thousands should be thousandths......Sorry.

[dallasgop]

The explosive initiators have to be replaced about once every 10 years. The radiation from the "physics" package deteriorate the explosives and certain metal parts. You cannot build a nuke and store it for 20 years and expect it to work.

[Ichneumon]

I don't get it. What maintenance is needed? And if you know, how would you know?

Nuclear weapons small enough to be called "suitcase nukes" contain subcritical amounts of fissile material, and require a "booster" made of tritium or some other short-lived isotope as a neutron source. Over the course of a few years the tritium decays and is no longer able to boost the reaction to criticality unless it is replaced. And replacement is a high-tech operation, beyond the technical capabilities of anyone who isn't capable enough to build their own nuclear weapons from scratch in the first place.

At least one of the US nuclear tests in the 50's failed because the tritium booster wasn't up to snuff.

So the good news is that portable nuclear weapons have a limited "shelf life".

[Publius6961]

That approach is so mature, I suggest that you use it at your first oportunity when a surgeon is about to do a number on you.

[Stultis]

I don't get it. What maintenance is needed?

I'm no expert, but from what I'm given to understand lots of maintenance is required, both frequent (along the lines of every few years) and of a highly technical nature (on the order of that required to build the bomb in the first place).

First, precisely because this is a super miniaturized bomb, it's not going to have a critical mass of fissile material. It therefore has to be "doped" with elements like Tritium that feed the reaction with neutrons. The suitable elements are all short lived and very difficult to obtain (more difficult even than plutonium) because they are produced in very small quantities and tightly controlled.

Secondly the radiation from the bomb deteriorates both metal and electrical components over time. The bomb must, in large measure, be "rebuilt" every x years. (I get the impression "x" is on the order of 5 to 10 years.) Again, the necessary components (e.g. super high-speed switches -- necceessary to ensure the precise timing of the conventional explosions that initiate the nuclear reaction) are not mass market items and are tightly controlled.

Basically, you have to be a major nation state with an advanced nuclear industry and an established expertise in nuclear weapons technology to maintain these things.