assuming the ICBM is a nuclear warhead…. Doesn’t the whole process behind a nuclear warhead involve an explosion that propels the nuclear “fuel” to start a chain reaction? i.e. exploding a warhead will essentially be the same as the explosion that causes the isotope to undergo fission?
ig the same can be said about conventional bombs as well but nuclear is more confusing.
In: Chemistry
Yes it’s an explosion, but not just ANY explosion.
The fissible material is arranged in a shape that it’s too far away from each other to trigger a chainreaction. Then a very specific shape of explosives is set off with a very precise timing around it to smash the fissible material into one single blob.
For example the “Implosion Design” uses a hollow sphere with a coat of explosives on the outside to make it collapse into a solid ball.
If you hit a nuke from the outside it’s extremely unlikely that a chainreaction is triggered, because the natural direction of explosions is “away in all directions” and not towards some centerpoint.
Conventional bombs can and do explode when intercepted. Usually it causes not a lot of harm if that happens high in the air though, and the largest problem is falling debris
Two reasons. First, the firing chain for a nuclear device is complex, and a single random explosion is unlikely to trigger it. Second, most interceptors don’t actually cause a detonation of the ICBM. They either have a proximity fuze that causes them to explode near the target and shower it with shrapnel, or they are a kinetic weapon that just hits the target to cause damage.
Nuclear warheads have to go off in a very specific way for the explosive lens to compress the plutonium enough to cause a reaction instead of just spreading radioactive materials everywhere. The way the lens works is that it uses a very specific arrangement of explosives to compress the nuclear material correctly, so if you blow it up, it won’t work.
To really dumb it down, nuclear fission in a warhead that has a very specific process to actually be successful and cause an explosion. If these events are disturbed, it causes the ICBM warhead to “fizzle” out which is basically a failure in one of the steps in the process.
Shooting the ICBM causes a disruption in this process, rendering the warhead useless. These steps are necessary because without them, the warheads can explode at any time, even in the silo.
Imagine you have an egg yolk on a plate surrounded by marbles, and your goal is to squish the entire yolk with all the marbles at the exact same time, in perfect sync, causing the yolk to geyser upwards in a perfect teardrop shape.
So you setup a system to propel all of those marbles with equal force directly into the yolk at exactly the same time. If one of those marbles hits the yolk even a little bit before the others, the yolk will still break but you won’t get that perfect splash.
Causing a nuclear detonation is kinda like that…If all the marbles in the warhead don’t hit in just the right way, the radioactive material will still get scattered but no boom. Destroying a warhead with another explosion all but guarantees to disrupt the timing.
To initiate the fission process in a nuclear weapon, it takes more than just some random explosion. There is a great deal of timing and precision involved to get the separate pieces of material brought together just right. The device has to be sort of fail safe so there are also safety interlocks and arming signals (kind of a good idea if you have lots of them stored relatively close to each other) The ICBM also has to survive the launch and reentry without going off prematurely.
To get a nuclear blast, you need to take a bunch of the right kind of radioactive material and compress it very, very hard. The only practical way to do that is with conventional explosives, and all the parts of your explosive have to go off with extremely precise timing. You have to ignite it from many different points simultaneously; if you just stick one fuse in the side and let it chain-react, then your core will get blown to powder before it can compress to critical mass.
At that point, you’ve got a big explosion that’s full of radioactive dust, which isn’t great for anyone nearby, but it’s still just a conventional explosion, many orders of magnitude smaller than a nuclear blast.
On top of that, I think the explosives used are less delicate and require e.g. an electrical charge to trigger. They’re not like dynamite or something that goes off if you put a match to it or hit it with a hammer. So it might not explode at all, not even with a conventional blast.
Apologies if I’m off on a few of the details, but that’s the general idea.
It depends! Some Anti-Ballistic Missiles (ABM) are actually nukes themselves. They’re designed to get “close enough” and make a (relatively) small nuclear explosion – but critically, well away from the strategic target they were intended to hit.
There is also more traditional methods – this requires significantly more precision, but the idea is the ABM sets off a conventional explosion a short distance from the target. Hopefully damaging the warhead and causing it to either fail to explode or “Fizzle” – exploding at a much lower yield than expected because parts of the detonation process failed.
There are multiple types of nukes, but most ICBM nukes are likely to be Implosion type or Fusion/Hydrogen Type. These start not just with an explosion, but rather several explosions that all have to happen all at once in order to compress the Fissile Material down and start the chain reaction. If an explosion causes that process to start on one part before another, the nuke will either fail to achieve the necessary compression and fail, or will fizzle, achieving enough of a compression to achieve a reaction, but lower than as designed. This results in a smaller explosion. In the case of Fusion Type warheads hopefully the fizzle prevents the fusion boost where the nuke derives most of its destructive power.
The explosives in a nuclear warhead need to be detonated simultaneously in order to compress the nuclear fuel. If those explosives are set off by an outside explosion, it starts from just one side, so you don’t get the nuclear chain reaction.
One thing I know is that a nuclear bomb that hits the ground and explodes is worse than one that explodes in the air. Hiroshima and Nagasaki had their bombs explode in the air above the city, and it’s why the city is habitable today. Had the bomb hit the ground then exploded the nuclear fallout would still be there and be a problem.
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