What's the highest yeild that could be got from a nuke?

[data_link]

Would a sufficiently large mass of weapon-grade material reach critical mass on its own?

Yes. In the event that you are in posession of such a stockpile, you should endeavor to keep it as far away from any neutron sources as possible, as they may cause it to explode at any time.

Actually, it is more likely that it will just melt, rather than explode.

[Uraniun235]

Would a sufficiently large mass of weapon-grade material reach critical mass on its own?

Critical mass, quite possibly. Supercritical (the point at which it will explode violently), no, probably not.

Which is precisly why most modern nukes are several megatons tops.

Try a few hundred kilotons. The megatonners are rare beasts; the vast overwhelming majority of (American, at least) nukes are sub-megaton.

[The Duchess of Zeon]

Are you sure about that? Stuart noted that you could use a FFF warhead to get huge yields, but not that it was actually done. Various web sources indicate that even the 9MT B53 was "merely" a fission-fusion device.

Good point. Though I suspect the B53 was a bit inefficient.

What about the Sovs?

[BenRG]

I had a part-work called 'War Machine' dated from the 1980s. It said that there was a sub-type of the Soviet SS-18 ICBM that carried a single 50Mt warhead. I would suspect that was a sort of 'Sword of Damocles' threat as it is difficult to imagine a threat that such a weapon could tackle that smaller and more accurate MIRV weapons could not handle far more effectively.

Someone said that a sufficiently big nuke would be too heavy to move and would, therefore, be a very large and expensive paperweight. You forget the other use of such a device: The largest and most expensive suicide bomb known to human science.

[Zoink]

, as they may cause it to explode at any time.

Actually, it is more likely that it will just melt, rather than explode.

Its what I kinda thought. I was thinking this would place an upper limit on the size of the warhead.

[phongn]

Are you sure about that? Stuart noted that you could use a FFF warhead to get huge yields, but not that it was actually done. Various web sources indicate that even the 9MT B53 was "merely" a fission-fusion device.

Good point. Though I suspect the B53 was a bit inefficient.

Probably. It was a very old design (dating to 1962). Hrm, wait, the Nuke FAQ (not Stuart's, the other one) indicated that there were two varients, the B53-Y1 which was a FFF design and the latter B53-Y2 which was a FF design. It doesn't state if there are different yields, though I'd suspect the -Y1 would have a greater yield.

This site: http://www.johnstonsarchive.net/nuclear/wrjp159u.html has a listing as to US warhead designs, anything under TD represents fission-majority designs.

What about the Sovs?

Well, they had Tsar Bomba, but that wasn't really useful. That was a FFF design and tested as a FF weapon (thus ~halving the yield)

There was the SS-18 Mod 1 and SS-18 Mod 6 (R-36M, R-36M2, respectively) that had 18-20MT RVs, but I don't know if their warheads were FFF designs.

[phongn]

I had a part-work called 'War Machine' dated from the 1980s. It said that there was a sub-type of the Soviet SS-18 ICBM that carried a single 50Mt warhead. I would suspect that was a sort of 'Sword of Damocles' threat as it is difficult to imagine a threat that such a weapon could tackle that smaller and more accurate MIRV weapons could not handle far more effectively.

SS-18 Mod 1 & Mod 6 were 18-20MT designs, probably for killing hard targets.

Someone said that a sufficiently big nuke would be too heavy to move and would, therefore, be a very large and expensive paperweight. You forget the other use of such a device: The largest and most expensive suicide bomb known to human science.

No-one was going to build such a device.

[BenRG]

Someone said that a sufficiently big nuke would be too heavy to move and would, therefore, be a very large and expensive paperweight. You forget the other use of such a device: The largest and most expensive suicide bomb known to human science.

No-one was going to build such a device.

Don't bet the house on that one. Serioulsy, I would never want to underestimate what a sufficiently crazy, desperate or psychotic person would do. There is a thread on this forum about 'scorched Earth'. There are some groups who would rather see everything destroyed than their perceived 'enemies' emerge victorious.

[phongn]

Someone said that a sufficiently big nuke would be too heavy to move and would, therefore, be a very large and expensive paperweight. You forget the other use of such a device: The largest and most expensive suicide bomb known to human science.

No-one was going to build such a device.

Don't bet the house on that one. Serioulsy, I would never want to underestimate what a sufficiently crazy, desperate or psychotic person would do. There is a thread on this forum about 'scorched Earth'. There are some groups who would rather see everything destroyed than their perceived 'enemies' emerge victorious.

And who has the manpower, scientific knowledge and resources to implement such a warhead? Nation-states, and none exactly wanted to screw the world. The USSR certainly didn't, the PRC doesn't, the DPRK doesn't.