[AgThorn]

Yes, but, batteries and conventional explosives can be replaced ... if they could get their hands on a suitcase bomb that has a bad battery and needs it's fuse updated, that is still a scary scenario.

The stuff that doesn't last 3 years is not that hard to replace .. the stuff that last longer is.

[Southack]

The atomic isotope used for nuclear triggers has a typical half-life of 90 days or less. The useful life for the booster isotope (normally tritium) is typically 8 years or so. The core lasts longer, of course, but you've got to have it all for it to do something more than simply fizzle into lethal short-range bursts of radiation and heat.

And even replacing the electronics and conventional explosives is more than meets the eye. You've got to avoid letting much air touch any of your heavy metals (forms rust rapidly), you can't let any vibrations shattle your fragile heavy metals (they are among the most brittle of all metals), and you can't move your core too close to your "bullet". Nor do you want to induce any electrical currents into your circuitry while you are doing your maintenance.

[Southack]

Polonium is a chemical element in the periodic table that has the symbol Po and atomic number 84. A rare radioactive metalloid, polonium is chemically similar to tellurium and bismuth and occurs in uranium ores. Polonium had been studied for possible use in heating spacecraft.

Notable Characteristics

This radioactive substance dissolves readily in dilute acids, but is only slightly soluble in alkalis. It is closely related chemically to bismuth and tellurium.

Polonium-210 is a volatile metal with 50% being vaporized in air after 45 hours at 328 K. This isotope is an alpha emitter that has a half-life of 138.39 days. A milligram of this metalloid emits as many alpha particles as 5 grams of radium.

A great deal of energy is released by its decay with a half a gram quickly reaching a temperature above 750 K. A few curies of polonium emit a blue glow which is caused by excitation of surrounding air.

Applications

When it is mixed or alloyed with beryllium, polonium can be a neutron source.

[Don Joe]

Yes, but, batteries and conventional explosives can be replaced ... if they could get their hands on a suitcase bomb that has a bad battery and needs it's fuse updated, that is still a scary scenario.

The stuff that doesn't last 3 years is not that hard to replace .. the stuff that last longer is.

Yup. We're for some odd reason afflicted with seminar posters who are intent on spouting a line that has no basis in fact, using a variety of logical fallacies, such as explaining the complextity of modern American nuclear munitions, and using that as a "proof" of the impossibility of any crude "go boom" devices.

It's like taking down a modern M16 and explaining all the metallurgy, machining, engineering, and hand-tooling and fitting that goes into its manufacture, and using that as "proof" that we have no reason to fear that a bunch of people with rags on their heads could ever come up with something as daunting as "the rifle."

Of course, we've all seen the news footage of the barefoot armorers of Afghanistan, sitting in their dirt-floored stalls, making fully operational machineguns out of scrap auto parts over a charcoal forge maintained by a kid with a bellows.

Here's my reply from the other thread, to one poster's repeatedly spammed "see post 95" non-replies. (Amazingly, they refuse to address any of these facts, preferring to spam the same appeal to authority (their own!) over and over again):

And lots of solid information, such as Are Suitcase Bombs Possible? and Fission Weapon Designs serve well to debunk reams of feel-good whistlling-past-the-graveyard happytalk.

All is not well, and recognition of this reality is not restricted to "chicken little"/"the sky is falling!" types.

You seem deeply vested in the idea that it is impossible for crude nuclear weapons to be constructed and sucessfully deployed.

I don't know why. I do find it disconcerting, however, and I hope that people don't accept your say-so as gospel. There is plenty of solid information available that puts the lie to the "don't worry, be happy" comfortspeak.

For those who still persist in the belief that it's only the uninformed and ignorant who would even consider the possiblity of nuclear-armed terrorists, I leave you with this excerpt from Christopher Hitchens' too-quickly forgotten article, "The night of the weak knees":

The night of the weak knees

Christopher Hitchens
Wednesday December 5, 2001
The Guardian

Four weekends ago, I really did receive two Friday-night telephone calls from well-positioned Washingtonians. "Leave now," they told me. "There's a tactical nuke on the loose, and it's headed for DC." One of these callers was in a position to know, and the other was in a position where he was actually paid to know. Calls were being placed to an immediate circle of friends to which, in theory, I was flattered to belong. Those who were calling were also leaving - while not informing the rest of the citizens. Why, then, did I resolve to stay? It wasn't just British pluck, strong as that naturally is. I thought, first, that it was unlikely that al-Qaida, if it had the bomb, would have conducted a petty dress rehearsal with United Airlines. I thought, second, that the detonation of a "use it or lose it" freelance nuke could not be predicted for any given weekend. And I thought, third, that I would feel a colossal cretin if I fled and then came slithering back on Monday morning (especially if the nuclear holocaust was timed for Monday's rush hour after all). In the end, I did take the family on a pre-arranged trip to Gettysburg, leaving late and returning early.

Officially, nobody now remembers this night of the weak knees. It rated a brief and embarrassed mention in Hugh Sidey's Time column, and that was it. But I shall not forget how some of those in supposed authority decided that the end had come, and made it a point to keep it to themselves and their immediate friends, perhaps to stop the crowding of the roads. That's how it will be on the day of Armageddon, and that's why the citizen should always plan to outlive the state, rather than the other way round.