Tsar Bomba and the Limits of Thermonuclear Warhead Power

[GoSlash27]

As a matter of fact, the Tsar bomba was a scientific experiment to prove exactly that - that there is no limit to its yield.

Important distinction here:

The largest known hydrogen bombs were not practical warheads, but rather overgrown science experiments for the purposes of either developing practical nuclear warheads or cold war saber-rattling.

There may or may not be a practical upper limit for how big you can make the yield of an experimental thermonuclear device (I wouldn't know), but there is *definitely* an upper limit to how big you can make a practical thermonuclear warhead. And honestly... there's an upper limit to how much yield you'd actually want anyway.

Best,

-Slashy

[Xannari Ferrows]

Theoretically there is no limit to the amount of power you can get from these weapons. I mean, sure there's a limit somewhere, but it's difficult to say because of our limited capabilities, will, and the chemistry of the material itself.

I'm not promoting Nuclear weapons or anything, those should go away and die. But, if it was further looked into, I'm sure something would happen that destroys the world eventually.

[magnemoe]

Important distinction here:

The largest known hydrogen bombs were not practical warheads, but rather overgrown science experiments for the purposes of either developing practical nuclear warheads or cold war saber-rattling.

There may or may not be a practical upper limit for how big you can make the yield of an experimental thermonuclear device (I wouldn't know), but there is *definitely* an upper limit to how big you can make a practical thermonuclear warhead. And honestly... there's an upper limit to how much yield you'd actually want anyway.

Best,

-Slashy

This, warhead size went down during the cold war, multiple smaller ones was more effective against point targets. Main reason for the multi megaton ones was poor accuracy.

Soviet kept some of the huge ones to take out deep underground strategic bunkers.

[jwenting]

As a matter of fact, the Tsar bomba was a scientific experiment to prove exactly that - that there is no limit to its yield. Technically speaking, our Sun is also a thermonuclear blast but it has so much fuel (hydrogen) that it's been 'exploding' for already ~4 billion years. Actually, they worried not about environmental impact (nobody cared all that much back then) they worried about ocean water being involved in fusion reaction as well. I'm not in a position to say if it is really possible to 'ignite' our oceans and what it takes to do that, but at that time this theoretic possibility was considered seriously. That was the reason the bomb yield was reduced by 50%.

That's how it worked out. But the Soviets did intent to deploy a number of them on N-1 rockets on strategic alert to take out high priority hardened targets in the USA. Places like Cheyenne Mountain (which may not have existed yet at the time, but that's the kind of thing they intended the thing for).

The N-1 proved too unreliable (to put it mildly) and was cancelled, leaving the big bomb without a viable deployment mechanism so it never entered production.

They'd of course never have had many of them, but they'd not have needed many.

Its role was taken instead by the SS-18 Mod 1 and later the SS-18 Mod 3, armed with 25MT warheads.

[DerekL1963]

And honestly... there's an upper limit to how much yield you'd actually want anyway.

Yep. And interestingly enough, the 'sweet spot' between deliverability, yield, and usefulness for the West seems to be down in the 300-400 kiloton range (though some are smaller still). (The Russians seem to prefer weapons more in the 700kt-1mt range.) Though the US built and deployed a number of multi-megaton horrors during the 50's, the average yield of strategic weapons dropped sharply in the 60's and 70's.

Between these lower yields and the possibilities of boosted fission, and because Teller-Ulam can drive a lightweight and extraordinarily efficient pure fission* or boosted fission secondary as easily as it does a fusion secondary... there's a school of thought that questions whether the US actually has any "true" (Teller-Ulam, fission-fusion-fission) thermonuclear weapons in it's inventory.

* What eventually became Teller-Ulam in fact started as a method of using a fission primary to drive the implosion of fission secondary.

[cicatrix]

That's how it worked out. But the Soviets did intent to deploy a number of them on N-1 rockets on strategic alert to take out high priority hardened targets in the USA. Places like Cheyenne Mountain (which may not have existed yet at the time, but that's the kind of thing they intended the thing for).

The N-1 proved too unreliable (to put it mildly) and was cancelled, leaving the big bomb without a viable deployment mechanism so it never entered production.

They'd of course never have had many of them, but they'd not have needed many.

Its role was taken instead by the SS-18 Mod 1 and later the SS-18 Mod 3, armed with 25MT warheads.

Actually, nuclear weapons are too much overrated. They have limited military potential. It's a political weapon. In pure military terms you simply don't have this many military targets (if we agree not to bomb cities, of course). But even when it comes to bombing civilians you want your target cities to be nice and circular. You don't want them being prolonged or assymetric. Even in this case for uniform destruction one would require ~5-6 x 500 Kt bombs rather than 1x100 Mt.

Tactical small yield nukes are actually more useful when we talk about military use (not a senseless slaughter).

And finally, even if a global nuclear exchange happens it wouldn't be the end of the world as they tell us in movies. USA and Russia are the only two countries who have barely enough warheads to severely cripple economies of each other. Cripple but not destroy. The total amount of casualties in a global nuclear conflict at the current level of stockpiles is estimated to be around 600-800 millions (including those who would die out of hunger, radiation poisoning, etc - the total amount). Granted, it will be a new 'world record' after WW2 but still it is 'only' ~11% of the world's population. There will be areas like in southern hemisphere that would be totally unaffected by it.

[Jouni]

Actually, they worried not about environmental impact (nobody cared all that much back then) they worried about ocean water being involved in fusion reaction as well. I'm not in a position to say if it is really possible to 'ignite' our oceans and what it takes to do that, but at that time this theoretic possibility was considered seriously. That was the reason the bomb yield was reduced by 50%.

Some Americans were worried about the runaway fusion reaction in seawater much earlier, before the first thermonuclear tests. The reasons why the yield of Tsar Bomba was reduced were moral and economic. The fallout from the test would have ended up on Soviet territory, quite possibly in populated regions. There were also concerns that the plane dropping the bomb would not have been able to escape from a full 100-megaton explosion.

[Coga19000]

And finally, even if a global nuclear exchange happens it wouldn't be the end of the world as they tell us in movies. USA and Russia are the only two countries who have barely enough warheads to severely cripple economies of each other. Cripple but not destroy. The total amount of casualties in a global nuclear conflict at the current level of stockpiles is estimated to be around 600-800 millions (including those who would die out of hunger, radiation poisoning, etc - the total amount). Granted, it will be a new 'world record' after WW2 but still it is 'only' ~11% of the world's population. There will be areas like in southern hemisphere that would be totally unaffected by it.

Firstly, 11% if the population is more than enough to make humanity no longer the same. Secondly, other countries have a sizable amount of nukes, which are not enough to cripple humanity by themselves ,but will add to the total tally. Thirdly, people will still have to contend with the results of vast areas irradiated. And finally, nuclear winter.

Americans were worried about the runaway fusion reaction in seawater much earlier, before the first thermonuclear tests. The reasons why the yield of Tsar Bomba was reduced were moral and economic. The fallout from the test would have ended up on Soviet territory, quite possibly in populated regions. There were also concerns that the plane dropping the bomb would not have been able to escape from a full 100-megaton explosion.

Just the ocean? People were worried about nukes igniting the goddamn atmosphere during the development of the Gadget.

[jwenting]

Actually, nuclear weapons are too much overrated. They have limited military potential. It's a political weapon. In pure military terms you simply don't have this many military targets (if we agree not to bomb cities, of course). But even when it comes to bombing civilians you want your target cities to be nice and circular. You don't want them being prolonged or assymetric. Even in this case for uniform destruction one would require ~5-6 x 500 Kt bombs rather than 1x100 Mt.

Tactical small yield nukes are actually more useful when we talk about military use (not a senseless slaughter).

Partially true, but not completely. Many nuclear weapons ended up targeted at each other. And of course military installations can be quite sprawling facilities. Think airfields and naval bases.

The 100MT bomb was intended to be political in part, but also had a real military target, superhardened bunkers. Cheyenne Mountain for example would be an ideal target for something like it.

And you'd need several to guarantee (or as close to as you'll ever get) destruction. Not only was there a real threat of anti-missile weapons becoming a reality at the time (though the technical difficulties were greatly underestimated by all sides), but the rockets and wrheads were far from 100% reliable.

The Soviets were going on 30-50% never achieving launch, and 50% or so of those that did launch never hitting the target, let alone detonating.

So they were planning to launch 4-5 missiles against each target, hoping one would work, and that was before multiplying those numbers to account for losses due to US missile interceptors like Sprint.

And remember that with the relatively large CEP of those missiles in the 1960s they needed larger warheads to ensure even a near hit would have the desired effect than were needed by the US weapons which always were more accurate than their Soviet counterparts (until the US abandoned ICBM and SLBM development in the 1980s, the Soviets have surpassed them now but it took them decades).

[DerekL1963]

(until the US abandoned ICBM and SLBM development in the 1980s

I can't speak to the Chair Farce, but the guys who've developed (IIRC) three generations of guidance systems for the Trident II (the most recent started deployment in 2014) will be very surprised to learn this.