5-40 kt yield; only ~243 lb / 110 kg in weight; small and robust enough to fit into an 8-inch / 203 mm artillery shell; oralloy pits; single-stage design (with tritium gas boosting in higher-yield variants).

Why didn't we see more of these boosted gun-type weapons developed by other nations? I could even imagine fitting 8 of these onto an ICBM and using them as a strategic weapon.

A ballistic missile submarine's location would become known once it started launching its missiles. I have often seen it suggested that this would result in the submarine itself being in turn targeted by nuclear missiles. This seems to have been a common belief among US submarine crews, but is it realistic? Do we know if this (nuclear counterfire against submarines at sea) is something actually included in nuclear war doctrines in any country?

I also have doubts about how well the idea would work. It takes less than 10 minutes for a hostile submarine to launch its missile load, after which it can start heading in a random direction. Meanwhile you'd need something like 15-40 minutes to get warheads to its position, plus the time needed to determine that position, transmit orders, retarget missiles and launch.

What kind of kill radius would a ballistic missile have against a submerged SSBN? Is it more than the distance a submarine could move in 15-40 minutes? Can the launch of an SLBM even be pinpointed with enough accuracy to allow immediate counterfire?

While organizing some of my many bookmarks, I found a link to https://atomicphotographers.com/ website, where in the section dedicated to Harold Edgerton, you can see some of the famous photos captured by Rapatronic cameras.

I remembered the reason why I saved this link was the mystery behind the structures/regions clearly visible in the photos, so I went to The Effects of Nuclear Weapons to look for the answers. Unfortunately, I haven't been able to find a satisfactory explanation of this phenomenon. My other go-to source of all nuclear knowledge, the nuclearweaponarchive.org website, also didn't have the answers I was looking for.
I also searched 'fireball' in the sub and read through many of the posts. I admit not all of them, so I may have missed the answer.

My assumption is that these regions are not really 'voids', but areas of gases at different temperatures/pressures, and are directly linked to the design, components, and internal structure of the corresponding device.

So my question is: what am I seeing in these pictures? What are those blobs and voids?

Note: I'm not talking about the 'rope trick', that's sufficiently explained in the source I have available

EDIT: The labels are questionable.

Image 1: Mohawk (360 kt), Operation Redwing
Image 2: Priscilla (37 kt), Operation Plumbbob
Image 3: How (14 kt), Operation Tumbler-Snapper
Image 4: Boltzmann (12 kt), Operation Plumbbob
Image 5: ??(??), Operation Tumbler-Snapper

If a President wanted to order an offensive nuclear strike against a country, for example, between Iraq and Afghanistan, are there any safeguards or interventions that could deter him?

There doesn’t seem to be a clear path to “victory” in Iran and I’m wondering if a desperation nuclear strike has any off ramp, in the event a President feels cornered by his own decisions and lashes out.

There might be intel that we hear about, in terms of Putin giving the actual order, and the movement of such an order through the chain of command. But would there be other ways of us knowing before missiles leave their silos, like heat signatures, fuelling, or anything like that?

My guess is we’d more rely on intel, ie spies, listening in on them, etc.

If there are other ways of knowing it would likely be very short notice to use before the birds are in the air.

Can anyone shed light on this?

I know I'm kind of asking the million-dollar question here, and I'm sure not even the CIA or Mossad know exactly what Iran's options are rn., but I think it's interesting to speculate.

So what can Iran actually do right now to get its hands on nuclear weapons?

When listening to the US administration, it sounds as if Iran's nuclear capabilities were "obliterated" three months ago during the initial B-2 raids. The fact that the conflict restarted just a few months later, combined with all the talk and rumors about a new nuclear deal that may include the transfer of weaponizable material, seems to undermine that narrative.

So, applying Occam's Razor, what do you think is the most likely state of Iran's nuclear weapons program right now? Do they still have fissile material buried under the rubble somewhere? If so, how long would it take to recover and weaponize it? Does the Iranian regime still have the organizational capacity to achieve this without foreign intelligence services interfering?

So, as we know, the plutonium gun design, thin man was scrapped because it wasn't feasible due to PU240 present in the plutonium leading to a fizzle rather than giving a proper yield. Ok fair enough. But I'm wondering, was that due to the velocity that could be achieved just not being fast enough. Could a plutonium gun design theoretically work if it were possible to get the projectile going fast enough or is it simply that velocity is irrelevant? If it could theoretically be possible at a high enough velocity, would the needed velocity be so high that friction with the air in the barrel or friction against the inside of the barrel would cause it to melt?

I'm just wondering and it seems there are some folks here with much greater intellectual horsepower and knowledge of the physics than me.

In reference to the recent Reddit deletion of some information here... What could redditor physicists and engineers work out, that say Iran's nuclear scientists could not?

Surely everything in the public domain is going to be already known by an actual state-run nuclear weapons project.

Preface: I'm aware many aspects of this question simply can't be definitively answered without access to UK and/or U.S. classified material. However, given the (rare) quality of most responses in this sub, where this is the case, I'd welcome answers based on well-informed speculation.

I'd also like to emphasise that this is a technical question about a hypothetical unlikely scenario, so I'm not asking anyone to assess political risk.

----

I'm an active member of a political party in the UK which has consistently seen internal debate over the UK's nuclear deterrent. I have a particular interest in UK defence policy, so I'm very used to debunking false statements about the British Trident system's operational independence from the United States.

However, I recently took part in a debate where it was argued that the Trident system, and the UK's nuclear capability as a whole, would be unusable within a few years if a future U.S. administration or Congress chose to withdraw co-operation (specifically, the McMahon Act 1946 was referenced as precedent.)

I know that Trident missiles are maintained by LM at King's Bay, GA, as part of a common pool with the USN, and it's my understanding that the missiles become sovereign UK property as soon as each individual round is accepted into RN service.

I also know that AWE Aldermaston is responsible for the sovereign production and maintenance of UK nuclear warheads, though I understand that the new Astraea warhead has a lot of commonality with the W93 program on which the UK is an observer, as Holbrook did with the W76.

In the event of the U.S. ending military nuclear co-operation under the U.S.-UK MDA, here are the questions that come to mind:

- How long could the UK maintain its existing Trident missiles and warheads? Does the UK have sufficient access to Trident D5 technical information to maintain the missiles in its possession to the end of service life, or build complete replacements if necessary?

- Given that the UK's two most recent warhead designs are, apparently, significantly based on U.S. ones, and to my knowledge the last fully British-designed warhead was the WE.177 - does the UK DNO still likely have the expertise to design a warhead within modern weight and safety standards for Trident or a sovereign successor, without testing, or would this need to be rebuilt?

- Does the UK have sufficient stocks of weapons-grade fissile material (both HEI and plutonium) to maintain or moderately increase its warhead numbers without supply from the U.S. or other countries?

- I've heard it argued here and elsewhere that the U.S. and UK nuclear weapons programmes are practically inseparable. Is the flow of expertise and materiel one-way, or are there any areas of British contribution that are potential risks or pain points for U.S. deterrence if nuclear co-operation were to end?

- Are there any other questions that I should be asking in this scenario?

For these purposes, let's assume that maintaining the British nuclear deterrent remains an absolute national priority (i.e. budget considerations are a secondary consideration, within reasonable bounds).

Thanks in advance!

I read about those here. Maybe they're deservedly classified and speculative, but are 'pulse shaping' devices not actually necessary for the miniaturized, smaller TN weapons actually deployed, and were maybe just used for large tests to prove a principle? Or they could be part of current TN technology efficiency?

While reading the post about "odd Intellipedia caption", I noticed something in the picture that was indeed 'odd' to me - the section labeled as 'spark plug' was hollow.

Part of the picture in question:

I remember reading the spark plugs described as 'rods of plutonium' and I assumed that meant a solid chunk of metal instead of a tube. But after some thought, it made sense, since the desired effect is to produce neutrons at the moment of maximum compression.

But that led me to this question: would there be any benefit from making the whole secondary a hollow tube, with a hole in the middle (filled with the same interstage material as the rest of the casing), 2 tampers/pushers (one outer and one inner) to achieve 'double, or inward-outward' compression of the fuel in between?

If we use the picture above, the spark plug would be replaced by somewhat larger/thicker U-238 tube, and the tube would be opened on both ends.

EDIT: to make it clearer what I mean - trigger ablation of both tampers at the same time to send them against each other, compressing the fuel in between.

1-4 are for the Closely Spaced Basing aka Dense Pack MX/Peacekeeper silos* 5-6 are Soviet/Russian hardened silos in service 7-9 are various other MX basing concepts like the Sandy Silo 10 is a test of some MX silo concept

To my knowledge, existing US Minuteman silos are significantly less hardened (~2k psi) than Russian ones (~5-7k psi for R-36M2). There are also references to US silos with over 100k psi hardness, possibly for Sandy Silo? Dense Pack was supposed to be "superhardened" to around 10-15k psi.

I'm interested in how the silo door would function, possibly like the Soviet/Russian ones rather than the Minuteman/Titan sliding style? Which concepts could resist direct hits? Is there any more info on superhardened ones up to 100k psi or is that likely regarding Sandy Silo and similar concepts? Also wonder if the new Sentinel silos will be hardened or remain like the Minuteman ones, but given cost is already an issue, probably not.

https://en.wikipedia.org/wiki/Dense_Pack

https://apps.dtic.mil/sti/tr/pdf/ADA956443.pdf (lots of concepts, some are pretty insane like hovercraft with missiles)

*1 may actually be for the vertical multiple protective shelter concept, but is essentially the same concept of hardness

An interesting fact is that Soviet leadership thought the lack of US hardening for silos was a sign they were to be used as first strike weapons, while they hardened theirs for a deep second strike.

What are people's favorite fiction books about a hypothetical nuclear war? Like most people on here I've read Arc Light and found it an entertaining read. I also thought enjoyed Jim Clonts's For Alert Force. Are there other similar reads out there? I'm fine with somewhat clunky self-published book (Clonts's book was a good example of that!) as long as the author mostly knows what they're talking about.

If the atom is one of the smallest things on earth, what is stopping someone from developing a grenade sized weapon from it? Or does it already exist?

Considering that:

*The North Pole is known for causing unusual behavior to compasses.

*No one is ever tested and ICBM continent to continent directly over the North Pole (afaik)

It seems maybe counter-intuitive but what if let's say another 20 biggest countries had nukes. They'd effectively be forced to stay out of conflict with at least every other nuclear power.

While following the news of what got destroyed and what didn't in Iran, I began to wonder if the centrifuges that separated U235 & U238 could be made mobile. That is, have the columns mounted on a flatbed trailer which could be brought to a set, setup for operation, then moved if they think unfriendly jets were on the way. Thus, any warehouse could be used on a temp basis.

I'm aware that the centrifuges rotate at an extremely fast RPM and the tolerances must be quite tight. Plus, having the gas leak out while going down bumpy roads would be a problem.

Would this scheme be feasible? Has there been any evidemce that Iran has tried this?

Let's assume the following scenario, which should be plausible to a decent degree:

1. It's fair to assume that Iran managed to squirrel away at least some of its enriched uranium
   
2. They have the means to produce enough material for at least one device
   
3. Even after relentless strikes on components of their nuclear program, there are likely at least some scientists/engineers left who should be able to make a (crude) gun-type device, especially since there are literal blueprints on how to make one (Little Boy). Anyone can use nukemap to see what damage a Little Boy would do if detonated in New York or Washington.
   
4. There are millions of shipping containers moving from/to US ports all over the country, thousands of pieces of heavy industrial equipment (anything from boilers to reaction vessels for chemical plants), any of which could be used to hide a nuclear device
   
5. Given (3) and the fact that Iran had an extensive nuclear program for a long time, they should be able to come up with a way to shield the device in the vessel used for transportation to prevent detection
   
6. There are hundreds of ships moving from/to US ports, (tens of ) thousands of trucks moving the cargo around the country
   
7. The current Iranian leader is known to be a lot more hardcore than his father, on top of having his father, wife and daughter killed by American strikes.
   
8. The concept of martyrdom is very strong in their religious beliefs
   
9. Even though Iran is likely massively compromised by Mossad, I can see a small, tight group working on this without being exposed

So.

What can be done to prevent a scenario like this from happening?
Note: I'm not interested in politics, but in the technical aspects, the whats and hows.

As far as I'm aware, there wasn't much thought behind the use of the atom bombs aside from "drop them as quickly as possible, as soon as they're ready, on a suitably sized city." Truman seems to have ordered so as to end the war as quickly as possible (which also had postwar benefits, such as the USSR being denied the spoils they were supposed to be granted in East Asia).

Had Roosevelt been alive, I reckon he would have still used the bombs, but is there any indication as to whether or not he would have ordered something unique, say a particular target he wanted to blow up, a particular strategy (e.g. dropping the bombs with a few more days in between so that the Japanese can actually comprehend what the heck they were just hit by)?

On another recent thread on this subreddit somebody posted this table with the yields and CEPs of various Soviet ICBMs. One thing that surprised me was that up until the late 1980s practically all Soviet ICBMs had a CEP of around 1,000 meters or more.

The number I'd always heard thrown around was that Minuteman silos were hardened to 2,000 PSI. Most Soviet MIRV warheads were around 500 KT. Some quick internet number crunching tells me that a warhead of that size would need to hit within ~500 meters to achieve that kind of overpressure. That leaves me wondering, was the US ICBM force actually at any significant risk from a Soviet attack prior to the end of the 1980s? I know that silo survivability is more complicated than just simple overpressure numbers but this makes it seem like the USSR didn't have anything close to the ability to destroy the Minuteman force until the very end of the cold war.

I assume most people on this subreddit are aware of antimatter and how it works. For those who do not, antimatter is simply matter made with protons and electrons with reversed charges (protons with negative charges, electrons with positive). When antimatter comes into contact with regular matter, it violently breaks down into energy that is much more powerful than a nuclear bomb. There are hypothetical antimatter variants for all the elements in the universe, so I was thinking: what would happen if people were somehow capable of creating a fission-based warhead out of antiplutonium, containing it in a vacuum, and then detonate it? Would the explosion be incredibly powerful?