How many nuclear weapons do we need?

[zen]

This really has to stay theoretical.

And really, not just another stale debate on should we have them or not.

But more crucially, how many of what sort?

This likely comes down to two factors.
1. The scale and difficulty of targets
2. The threshold at which a political leadership respects the threat of a certain capacity of certain capability.

Surely the central question is what does it take to Deterr?

Some claim only mutually assured destruction (MAD) will do.
Others suggest significant degradation/weakening is enough.

 

[Orionblamblam]

You need enough to destroy the enemies ability to destroy *you.*

Let's say that means you need to nuke 100 targets. That doesn't mean you need 100 nukes. That's the *minimum.*

Let's say 1/2 of your nukes will detonate correctly. Now you need 200.
Let's say half of your nukes will actually make it through enemy defenses. Now you need 400.
Let's say half your launch/bomber systems will fail on startup. Now you need 800.
Let's say the enemy will catch half your nukes on the ground in a surprise attack. Now you need 1,600.
Let's say half your nukes are down for maintenance or refurb at any one time. Now you needs 3,200.
Let's say you're unsure just how many targets actually need to be nuked. Say you double your estimate; now you need 6,400.

 

[zen]

So obviously hardened silos, mobile and submarine systems are difficult to take out. Of the mobile sort aircraft are the hardest to keep ready.
However the targeting problem includes accuracy. Hence why Polaris went to 3 RVs to straddle the target.
The reliability of missiles is certainly a question. But a 50% failure rate seems questionable.
As for reliability of the devices themselves.....possibly finger breaking territory.

 

[uk 75]

As far as the UK is concerned the expert is Prof Peter Hennessy.
Until 1991 it was clear cut for the UK as the Moscow criteria determined both Polaris and Trident.
With the withdrawal of the WE177 tactical nukes in the 90s Trident was supposed to take on a sub-strategic role.
Have not seen much mention of this. The Russian Iskander depots in Kaliningrad might qualify.
I can't really see circumstances where the UK would use its one patrolling SSBN against targets in China.
That said, Douglas Hurd did mention using Polaris in his 1971 novel

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[Orionblamblam]

So obviously hardened silos, mobile and submarine systems are difficult to take out. Of the mobile sort aircraft are the hardest to keep ready.
However the targeting problem includes accuracy. Hence why Polaris went to 3 RVs to straddle the target.
The reliability of missiles is certainly a question. But a 50% failure rate seems questionable.
As for reliability of the devices themselves.....possibly finger breaking territory.

The US hasn't set off a nuke in thirty years. Would *any* of our (US, UK, Russia, France, Israel, etc.) current stock even go off? We simply don't know. We can assume; there are certainly simulations and such... but we don't *know.* Similarly, it's not like *anybody* is regularly launching representative ICBMs and SLBMs. The lack of testing leads to a lack of faith in reliability, thus leading to a need to have *more* nukes.

If people want there to be fewer nukes, the US and Russia need to resume nuclear testing and weekly test launches of ballistic missiles.

 

[uk 75]

More ominously the reduction in the variety of nuclear weapons since 1991 has removed the lower rungs of the ladder of deterrence.
In the absence of battlefield and theatre nuclear weapons in the NATO inventory the only allied response to a nuclear strike by Russian Iskander missiles would be the remaining US B61 freefall bombs still held at some European bases. After that it's an RN or USN SLBM or even a Minuteman.

 

[zen]

The problem with tactical weapons is the temptation to use them to resolve a deteriorating situation. But the risk is they are misread as strategic use, the prelude to strategic use, and that only the threat of strategic use will prevent their use.

 

[Deleted member 2278]

For the UK, as many as we have launch tubes for plus maybe a boat-worth of spares. That much probably isn't going to make it down-range should the occasion call for it so any more would be academic at best.

The Big Three's strategic positions are different (and better described by others). I would hope though that we could all cap force levels at more or less their current numbers. That's rainbows and unicorns enough for me.

The decline of tactical nuclear devices is fine by me. They are if anything more dangerous than strategic weapons (temptation). Nukes though, were always an all or nothing proposition. I don't believe tactical nuclear use would work out well for anyone.

 

[uk 75]

The tactical nuclear weapon was very much a product of the fifties when any weapon could be given a nuclear warhead.
By the end of the Cold War the more dangerous ones like the Genie air to air missile had been replaced by conventional alternatives.
The remaining NATO options like Lance battlefield missiles, artillery rounds and atomic demolition munitions in West Germany were increasingly seen as a last rather than initial response to overwhelming Soviet armoured forces.
The Soviets seemed to plan enormous volleys of nuclear weapons as part of their attack on Germany and Denmark. But by the late 80s they appeared to move away from their early use.
The threat posed to NATO by Russia now is more subtle. The Baltic States are vulnerable to a range of conventional attacks and a NATO nuclear response seems irrelevant.
However, if a conflict with Russia escalated to include Poland and the use of large armoured forces by Russia and NAT0 then the nuclear response might again become necessary.
Conflict with China is likely to be limited to naval and air action. Apart from Vietnam there is no potential opportunity for massed PLA armour to be brought to bear. Amphibious assaults on Taiwan or other neighbours can be defeated by conventional torpedos and missiles launched from subs.
Only India and Pakistan find themselves in a situation similar to Cold War Europe. Their range of weapons is tactical through to strategic. So far they have detered the angry neighbours from using their large conventional forces to settle their differences.

 

[Dilandu]

So obviously hardened silos, mobile and submarine systems are difficult to take out. Of the mobile sort aircraft are the hardest to keep ready.
However the targeting problem includes accuracy. Hence why Polaris went to 3 RVs to straddle the target.
The reliability of missiles is certainly a question. But a 50% failure rate seems questionable.
As for reliability of the devices themselves.....possibly finger breaking territory.

The rule of thumb is that you need three RV's per hardened target, because A - nuclear warheads aren't 100% reliable, and B - CEP determine the area in which 50% of warheads would statistically fall, the other 50% would fall outside.

 

[Dilandu]

The decline of tactical nuclear devices is fine by me. They are if anything more dangerous than strategic weapons (temptation). Nukes though, were always an all or nothing proposition. I don't believe tactical nuclear use would work out well for anyone.

Well, I consider the decision to retire nuclear SAM's and AAM's a mistake.

 

[uk 75]

The decline of tactical nuclear devices is fine by me. They are if anything more dangerous than strategic weapons (temptation). Nukes though, were always an all or nothing proposition. I don't believe tactical nuclear use would work out well for anyone.

Well, I consider the decision to retire nuclear SAM's and AAM's a mistake.

I am intrigued by this comment since the reason given for their removal is that there are no longer suitable targets as bombers no longer fly in formations. In the anti-missile role Galosh and Spartan/Sprint ABMs needed nuclear heads..Is that the sort of thing you meaan?

 

[Archibald]

The decline of tactical nuclear devices is fine by me. They are if anything more dangerous than strategic weapons (temptation). Nukes though, were always an all or nothing proposition. I don't believe tactical nuclear use would work out well for anyone.

Well, I consider the decision to retire nuclear SAM's and AAM's a mistake.

I do not... https://en.wikipedia.org/wiki/BOMARC_missile_accident_site

Wonder if the Soviets got any incident with nuke SA-2 and SA-5 ?

 

[Nik]

There was an old joke that RN had most of its sub-nukes aimed at NATO hit list in Russia, but kept one for contingencies, and one for Washington (DC) to ensure treaty commitments would be kept in extremis...

 

[Dilandu]

I am intrigued by this comment since the reason given for their removal is that there are no longer suitable targets as bombers no longer fly in formations. In the anti-missile role Galosh and Spartan/Sprint ABMs needed nuclear heads..Is that the sort of thing you meaan?

Mainly I consider nuclea-tipped SAM a viable method of dealing with hypersonic missiles.

 

[uk 75]

I am intrigued by this comment since the reason given for their removal is that there are no longer suitable targets as bombers no longer fly in formations. In the anti-missile role Galosh and Spartan/Sprint ABMs needed nuclear heads..Is that the sort of thing you meaan?

Mainly I consider nuclea-tipped SAM a viable method of dealing with hypersonic missiles.

Even more interesting. How would this work? A Sprint style pop up high velocity missile?

 

[Orionblamblam]

Mainly I consider nuclea-tipped SAM a viable method of dealing with hypersonic missiles.

Might rather depend on that hypersonic missile. If it's a ballistic warhead, or a hypersonic boost-glide vehicle at high altitude... sure, go ahead and nuke it. If it's bopping along at Mach 5 and treetop level, opening up a can of artificial sunshine right next to it might annoy the local landlords.

If you have something like Sprint or HIBEX with modern precision guidance and you're going after hypersonic airbeathers, all you *might* need to do is sprinkle a soup can full of nails into the air in front of said missile.

 

[Justo Miranda]

A nuclear tipped SAM may succeed once, but then the entire AA system would be rendered useless by the electromagnetic pulse. It would be enough to use the first intruder as a decoy and then send the real attack.

 

[Dilandu]

A nuclear tipped SAM may succeed once, but then the entire AA system would be rendered useless by the electromagnetic pulse.

Please. It is not Hollywood physics. All military hardware is shielded and grounded against EMP, especially weak EMP from kiloton-size warheads in stratosphere.

 

[zen]

Certainly the flipside of how many nukes is....how much ABM defence is needed. I think the UK, and France lack in that area. More necessary now since command and control need time to determine who has attacked and what response is appropriate.
In the past it was just the USSR. Now we face China, India, Pakistan as well as a possible future Iran and North Korea.
Limited attack can be defeated by ABM and a more substantial attack can have it's degradation of C&C delayed enough to give a chance at a appropriate response.

Arguably the French had the right approach with a limited number of high precision silo based ICBM, holding open the door for a First Strike, forcing general nuclear exchange....and a decent amount of SLBM for retaliation after an opponents First Strike.

Frankly I admire the French on this topic. Even if their systems are distinguishable from others and thus risk a limited response towards them alone.

The UK took the devious position that not only is Polaris and later Trident, cheaper than a domestic delivery system. It is indistinguishable from US delivery. Making a UK launch look like a US limited prelude to a general launch.
Since the greatest fear was the US would not launch and let Europe and the UK be destroyed in exchange for not being targeted by the USSR.

 

[zen]

Blinding by nuclear explosion is very brief.

 

[Justo Miranda]

A nuclear tipped SAM may succeed once, but then the entire AA system would be rendered useless by the electromagnetic pulse.

Please. It is not Hollywood physics. All military hardware is shielded and grounded against EMP, especially weak EMP from kiloton-size warheads in stratosphere.

Has it been tested in reality?
I wonder if the explosion wouldn't cause radar interference from ionized air.

 

[Zoo Tycoon]

Has it been tested in reality?
I wonder if the explosion wouldn't cause radar interference from ionized air.

All deeply tested during Operation Fishbowl (USA) and Project K (USSR).

Fishbowl’s very last test in the series (Shot Tightrope) was a stock Nike Hercules system with a W31 warhead. For all the tests, the instrumentation was extremely impressive with airborne transmitters lofted by sounding rockets (up to 31 in a single test) to positions around the burst and multiple ground receiving stations to investigate ionised transmission effects.

View: https://m.youtube.com/watch?v=ezrhY4AUGhY

I suspect Project K was similar but would love to know more.

 

[Orionblamblam]

especially weak EMP from kiloton-size warheads in stratosphere.

You don't really get EMP until you detonate in space. In anything resembling atmosphere, meaningful EMP basically doesn't exist.

 

[_Del_]

A nuclear tipped SAM may succeed once, but then the entire AA system would be rendered useless by the electromagnetic pulse.

Please. It is not Hollywood physics. All military hardware is shielded and grounded against EMP, especially weak EMP from kiloton-size warheads in stratosphere.

All that ionized air is going to do some interesting things to radar waves trying to find a new target in the area though...

 

[Zoo Tycoon]

You don't really get EMP until you detonate in space.

To really get the best bang for your buck you need a warhead within a heavy copper jacket;- Maximum beta decay product. These are not stock weapons.

Del - watch the video in post #23;- it explains the fireball diffraction effects at approx the 23 min mark.

 

[_Del_]

Del - watch the video in post #23;- it explains the fireball diffraction effects at approx the 23 min mark.

I'm not going to watch the video right now, but may later. Between ionization and temp/pressure effects, I can pretty safely say we won't be modeling it (radio wave propagation in the region of a nuclear explosion) with high fidelity. Certainly not in the real time methods one would need for accurate anti-missile defense. You're dealing with not only absorption and attenuation, but nifty bending, which could be in any direction from or even around the event. All your systems are going to assume that radio wave is traveling in a more or less straight line. Which is bad if we're trying to steer object M into the path of object W and both are moving quickly.

 

[shin_getter]

You need enough to destroy the enemies ability to destroy *you.*

Let's say that means you need to nuke 100 targets. That doesn't mean you need 100 nukes. That's the *minimum.*

....
Let's say you're unsure just how many targets actually need to be nuked. Say you double your estimate; now you need 6,400.

Given nuclear launch sites is a nuclear target and apply induction to all factions and soon the required number of nuclear weapons of all sides approach infinity.

Really this kind of strategy is only remotely feasible for the single hyperpower having vast economic superiority over threats. If there is a multitude of states with comparable capabilities this strategy would lead to arms race into economic collapse.

Perfect security is not attainable.

 

[Orionblamblam]

Really this kind of strategy is only remotely feasible for the single hyperpower having vast economic superiority over threats. If there is a multitude of states with comparable capabilities this strategy would lead to arms race into economic collapse.

At their peaks, both the US and USSR had nuclear arsenals measured in tens of thousands. That didn't collapse either economy. The US did quite well; the USSR collapsed because it was an inevitability of their economic system. And if, today, the US decided it needed to have tens of thousands more nukes, that would necessarily lead to a vast expansion of the US nuclear industry, with consequent side benefits such as nuclear power reactors. It would be an economic *boon* to crank out H-bombs again.

 

[Justo Miranda]

You need enough to destroy the enemies ability to destroy *you.*

Let's say that means you need to nuke 100 targets. That doesn't mean you need 100 nukes. That's the *minimum.*

....
Let's say you're unsure just how many targets actually need to be nuked. Say you double your estimate; now you need 6,400.

Given nuclear launch sites is a nuclear target and apply induction to all factions and soon the required number of nuclear weapons of all sides approach infinity.

Really this kind of strategy is only remotely feasible for the single hyperpower having vast economic superiority over threats. If there is a multitude of states with comparable capabilities this strategy would lead to arms race into economic collapse.

Perfect security is not attainable.

It is the problem of the three bodies

 

[uk 75]

The nuclear threshold in the Cold War was thoroughly discussed and examined.
The first use of a nuclear weapon was likely to be in the North Atlantic. NATO expected to use them against Soviet subs. The Soviets against US carriers.
On land the key moment was expected to come when SACEUR asked for permission to use Lance missiles and artillery against Soviet armoured formations
The next level was release of Pershing 1 units of the US and the German Air Force to hit key targets in the GDR and Czechoslovakia. At the same time US F111s and RAF Tornados would hit targets in Poland.
At this point most NATO exercises stopped.
The next phase was the release of US Pershing 2 and Cruise Missiles against targets including the USSR. After the INF Treaty this option ceased.
The next phase would then be selective US Poseidon strikes against military targets in Eastern Europe and the Soviet Union and possibly some key cities with rail/transport hubs.
This ladder of escalation was never put to the test. It took no account of what or when the Soviets would do (or for that matter the French).
A humorous take on this dilemma may be found in the first episode of Yes Prime Minister.

.

 

[shin_getter]

At their peaks, both the US and USSR had nuclear arsenals measured in tens of thousands. That didn't collapse either economy. The US did quite well; the USSR collapsed because it was an inevitability of their economic system.

A communist economic system not under pressure do not necessarily collapse, look at how the North Korean or Cuban economies have survived despite its inefficiencies.

Part of why USSR collapsed is that state warfare scale weapons do not do internal security nor can you pay off internal elites with nuclear or other weapons. The collapse of the Soviet Union was not due to grass roots revolution but elites upending the existing system to redirect wealth into their own pockets. It would have survived if the economy was set up to provide luxuries to the elites already as opposed to a huge military that does not influence state survival by dealing with the state's biggest problems.

Given the disparity in economies, a state like North Korea physically can not gain nuclear overmatch over threats. For states like South Africa, massive nuclear capability again solves very few problems for either the elites or its general population. A Pakistan leading nuclear overmatch strategy is also liable to run into huge problem in both economic feasibility and non-military counter action that could wreck state function given the known poor boarder control and internal disunity.

 

[Orionblamblam]

At their peaks, both the US and USSR had nuclear arsenals measured in tens of thousands. That didn't collapse either economy. The US did quite well; the USSR collapsed because it was an inevitability of their economic system.

A communist economic system not under pressure do not necessarily collapse, look at how the North Korean or Cuban economies have survived despite its inefficiencies.

To a rather depressing definition of "survive."

 

[uk 75]

The Cocom restrictions on the Soviet Union acquiring sophisticated new technologies played a major part in thwarting its military and economic progress
China has circumvented this and prospered by stealing and developing a hi tech society within a totalitarian state.
It remains to be seen whether this model can survive.

 

[Orionblamblam]

The Cocom restrictions on the Soviet Union acquiring sophisticated new technologies played a major part in thwarting its military and economic progress
China has circumvented this and prospered by stealing and developing a hi tech society within a totalitarian state.
It remains to be seen whether this model can survive.

Well, Xi recently announced a policy of "peaceful reunification" with Taiwan. So when the two reunite and the Taiwanese government regains control of China and ousts the illegitimate Communist junta, they can get rid of the totalitarians.

Any day now.

 

[jeffb]

At their peaks, both the US and USSR had nuclear arsenals measured in tens of thousands. That didn't collapse either economy. The US did quite well; the USSR collapsed because it was an inevitability of their economic system.

A communist economic system not under pressure do not necessarily collapse, look at how the North Korean or Cuban economies have survived despite its inefficiencies.

To a rather depressing definition of "survive."

Both Cuba and North Korea have been under sanctions for decades. It would be interesting to see where both would be if they hadn't been.

 

[Orionblamblam]

Both Cuba and North Korea have been under sanctions for decades. It would be interesting to see where both would be if they hadn't been.

Probably not much different. North Korea has been doing business with China; they're unlikely to have ever done much business with South Korea. Cuba has been happily doing business with virtually the entire planet, with one exception. If your contention is that a small island nation not doing business with a powerful nearby mainland nation will necessarily artificially trash their economy... Taiwan would like a word.

 

[Dilandu]

Has it been tested in reality?

Yes.

AIR-2 Genie was detonated at 5000-6000 meters altitude over a group of USAF officers volunteers in July 1957. Dose received by them was negligible, no significant EMP was noted.

 

[Desertfox]

An example of a successful communist nation would be Vietnam.

As for the original question, it boils down to two major points, how good is the target nation's ability to weather a nuclear strike (ie ABMs) and whether you want to to hold their nuclear arsenal at risk.

If your target doesnt have any defenses and you dont need to target their nuclear arsenal, ~300 warheads should be enough, as seen by the UK, French, and past Chinese nuclear forces. If they dont have defenses but you want to target their arsenal, the number is closer to ~1000 as seen by the US/Russian New START discussions.

 

[Orionblamblam]

An example of a successful communist nation would be Vietnam.

Yes, they successfully transitioned *away* from Communism. Their economy is hardly a free market capitalist one, but like China, they figured out that private property and the private pursuit of profit are the means by which an economy can prosper.