>> If one nuclear weapon gets into the hands of someone willing to lose it, millions of people will die.
That's just not true. There are a host of technologies designed to prevent a captured bomb ever being used, and I presume an entire department at the DoE dedicated to them. The very structure of a modern bomb makes use by thieves impractical. (Misuse by US forces is a different matter.)
(1) Bombs do not have hollywood-style timers. You cannot just cross a few wires. Getting a modern fusion device to properly explode requires the participation of a great many systems. For example, a warhead meant for a missile has safety triggers looking for flight path and altitude. Faking something like 200 seconds of zero-G flight while in vacuum isn't easy. Bypassing the sensors isn't easy. Detonating the explosives yourself, bypassing the electronics altogether, will not create a nuclear explosion. You have to know how to time everything very precisely. Doing that without the bomb's willing participation is practically impossible. The necessary equipment to launch the device in a manner that will result in a nuclear explosion doesn't travel with the bomb anywhere except while deployed.
(2) There isn't much nuclear material in a modern fusion bomb. This isn't a blob of enriched uranium like seen in WWII bombs. This is a very thin and hollow sphere of uranium packed with hydrogen and other harmless elements. You could grind up that sphere to make a "dirty" bomb but even then there is very little material. You won't be killing millions. For the effort, a terror group could do far more damage with weapons bought legally at any wallmart.
(3) Bombs in transit (ie off-base) are packed in tech meant to prevent misuse. Just cracking open the crate will probably trigger a device to blank the circuitry’s internal memory, making proper detonation impossible. (I've read about such system on non-nuclear missile systems and presume they are also used with nukes).
I agree that you can't simply capture a bomb then detonate it; there are many ways to prevent that from happening.
I assume the threat model people are worried about is the plot of Tom Clancy's 'The Sum of All Fears' [1] wherein a damaged nuclear bomb is captured by terrorists who can't enrich uranium themselves, but can replace the firing mechanisms once they have the fissile material.
And of course, a group that might be able to replace the firing mechanism would be able to engage in nuclear blackmail even if their replacement didn't work so long as nobody called their bluff.
But even in tom clancy's senario it took the efforts of russian weapons experts. And they were working with an oldschool core. Modern weapons use hollow/layered cores and so require better timing to achieve critical mass than those of the past.
"The bomb weighs approximately 1,100 kilograms (2,400 lb)"
"the greater part of the total mass is contained in the nuclear explosive. It has a variable yield: the destructive power is adjustable from somewhere in the low kiloton range up to a maximum of 1.2 megatons"
1.2 MT is 60 times stronger yield than the Nagasaki bomb which had only "6.19 kilograms (13.6 lb) of plutonium."
> packed with hydrogen and other harmless elements
They are never "hydrogen and other harmless elements."
It's radioactive, produced only in the nuclear reactors, and specifically for the colloquially called H-bomb part of the current designs.
It's the computerized part that controls the desired yield and we know that
a) the computers can't be made to be bug free and 100% secure
b) the mechanical parts controlled by the computer have all the necessary material for the full yield.
The argument "but it's more secure because the built-in computer controls it" should be laughable for the HN readers. Hiding behind the "it's complex that's why it's safer" works better only for those without the technical background.
The people who know how that stuff works are typically the most worried. There are enough worries when countries acquire even enough raw material which can be used to produce the bomb, here we talk about the fully built bombs with enough material for the full yield.
You conflate terms. Explosive warhead includes conventional explosives and the "physics package" with nuclear material. Modern bombs have proportionally more explosive and less fission material than historic weapons. By weight they are mostly all conventional explosives. And tritium is harmless. ... too many similar issues to address here on mobile.
> There isn't much nuclear material in a modern fusion bomb. This isn't a blob of enriched uranium like seen in WWII bombs. This is a very thin and hollow sphere of uranium packed with hydrogen and other harmless elements.
Primary and secondary in todays devices arent as different as they once were in "spark plug" configs. These are boosted weapons. A hollow sphere of fission material is collapsed into a point. Hydrogen is inside to add fusion reactions, increasing the efficiency of the fission reaction without the need of a formal secondary.
That's just not true. There are a host of technologies designed to prevent a captured bomb ever being used, and I presume an entire department at the DoE dedicated to them. The very structure of a modern bomb makes use by thieves impractical. (Misuse by US forces is a different matter.)
(1) Bombs do not have hollywood-style timers. You cannot just cross a few wires. Getting a modern fusion device to properly explode requires the participation of a great many systems. For example, a warhead meant for a missile has safety triggers looking for flight path and altitude. Faking something like 200 seconds of zero-G flight while in vacuum isn't easy. Bypassing the sensors isn't easy. Detonating the explosives yourself, bypassing the electronics altogether, will not create a nuclear explosion. You have to know how to time everything very precisely. Doing that without the bomb's willing participation is practically impossible. The necessary equipment to launch the device in a manner that will result in a nuclear explosion doesn't travel with the bomb anywhere except while deployed.
(2) There isn't much nuclear material in a modern fusion bomb. This isn't a blob of enriched uranium like seen in WWII bombs. This is a very thin and hollow sphere of uranium packed with hydrogen and other harmless elements. You could grind up that sphere to make a "dirty" bomb but even then there is very little material. You won't be killing millions. For the effort, a terror group could do far more damage with weapons bought legally at any wallmart.
(3) Bombs in transit (ie off-base) are packed in tech meant to prevent misuse. Just cracking open the crate will probably trigger a device to blank the circuitry’s internal memory, making proper detonation impossible. (I've read about such system on non-nuclear missile systems and presume they are also used with nukes).