How many nuclear weapons do we need?

[zen]

If one only concern with death and destruction of civilians, then airburst over cities is the most efficient means. Lots of instant death, fires, broken buildings and a lot if lingering death. But fairly light on fallout, and the bigger the bang the more efficient the use of Uranium.

If you want to destroy civil/military infrastructure.....well it depends on how much your likely opponent has.
China, the US and Russia being the worst cases. Due to the sheer amount of it spaced out.
It often requires a lot of ground burst. Limiting the radius of effectiveness but throwing up vast amounts of radioactive material.

The only good news is that communist states have highly centralised command, and so targeting that command. While it may not hit all the leadership, will endanger sufficient numbers of it for them to exert influence on the top tier.
And such senior figures tends to congragate around the leader.
A failure by the top tier to afford measures of protection against nuclear death for their immediate subordinates creates a division that can rupture the control said top tier possess. After all they depend on their subordinates to actually get things done.

So a swathe of upper middle tier leadership, facing extermination caused by bellicose leaders, have every reason to remove said bellicose leaders and negotiate a less dire outcome.

Thus even in a society held in check by fear of powerful leaders and Secret Police, when faced with the terrorising power of nuclear armagedon, will seek an outcome that does not involve their inevitable destruction.

By this measure, China requires more weapons to achieve this balance of terror. Due to the sheer size of their population.

This dread balance is of course based on mostly rational people.

What runs a much greater risk is if the state is subject to a religous millenial view that the End of Everything is something to desire.

 

[Nik]

Hence my Convention SF's 'Sanku Prayer for Fanatics': "May the next die harmlessly, also..."

 

[uk 75]

There is a broader question: what types of nuclear weapon do we need?

The US and Russia continue to maintain
the Triad of
Land based ICBM (The Soviet Union had deployed road and rail mobile as well as fixed ICBM. The US had developed but not deployed a mobile small ICBM)
Submarines with SLBM
Aircraft with freefall bombs, missiles and cruise missiles
Added to the Triad as a new category are hypersonic weapons and space gliders

China has ICBM and SLBM but as yet no sophisticated aircraft

France had its own triad of weapons but like the UK now only deploys SLBM

India has IRBM and limited SLBM.
Israel, Pakistan have IRBM

N Korea I am confused whether they have a deliverable weapon but they claim ICBM and SLBM.

From the above listings it is clear that the ability to deploy a range of systems improves the accuracy and survivability of the force.
SLBM are the most survivable but land based ICBM/IRBM offer bigger loads and greater accuracy.
Will the new generation of hypersonic and spaceplane delivered weapons change the situation again.
Lower level nuclear weapons also need to be taken into account. The US up to the 80s deployed the following
Operational theatre systems (Pershing, Tomahawk, Freefall bombs)
Battlefield systems (Lance, Artillery rounds, Demolition Munitions (ADM))
SAM (Nike Hercules)
Air to Air missiles (Genie)
Naval weapons ( Tomahawk, ASROC, SUBROC, Depth Bombs, Talos and Terrier)
As the accuracy and power of conventional weapons has grown these have replaced the nuclear versions.

By the end of the Cold War it was generally accepted that "limited use" of nuclear weapons was at best problematic. "Use or lose" summed up the argument that one side would be compelled to launch or drop weapons before they were overrun, destroyed or not as effective against their chosen targets.
Climbing the ladder to strategic exchange was inevitable. This in one sense reinforced deterrence as any conflict between nuclear powers risked their annihilation. So far this has worked even for India and Pakistan.
Unfortunately there are some nuclear weapon owners like N Korea or possible non state groups for whom annihilation is not a deterrent as they think they are faced with this even from conventional weapons. Putin's Russia is also beginning to react like this. The impact of the use of Western airpower in the Middle East and the dangers of "regime change" have made Putin much less cautious than his Soviet predecessors.
Nuclear weapons and their delivery systems remain hideously expensive and in democracies politically controversial. Politicians want as many as they can get within these constraints. For the UK this has settled down to 4 submarines but with fewer missiles and warheads perhaps.

 

[zen]

For the UK this has settled down to 4 submarines but with fewer missiles and warheads perhaps

And yet the basis for current levels has, to be frank, changed. Which is why government has declared that they will expand numbers.
I would suggest that such is going to change further under the pressure of changing political environment.

 

[Hood]

Which is why government has declared that they will expand numbers.

No they said they might take the cap off but wouldn't tell Parliament anything in terms of numbers ever again so nobody could ever tell whether we had 10,000 or 1 nukes at sea, that's not the same thing.

 

[Archibald]

My answer would be: for a medium-power like France or Great Britain, post-cold-war.
An average 5*SSN with 16 tubes each, three warheads per missile: total 240 nukes.

Note that post 1991 France disbanded most of its nuclear arsenal - AN-52s tac nukes, Pluton * Hadès, Plateau d'Albion.
Only ASMP/ ASMP-A survived as a more flexible option.

 

[bloody sky]

I think our world need 100000 nuclear weapon……so that our world could be more peaceful.

 

[Deleted member 2278]

We need at least 99 to take down all those red balloons.....

 

[zen]

I think our world need 100000 nuclear weapon……so that our world could be more peaceful.

Ahhhh
Peace through superior megatons!

 

[zen]

Which is why government has declared that they will expand numbers.

No they said they might take the cap off but wouldn't tell Parliament anything in terms of numbers ever again so nobody could ever tell whether we had 10,000 or 1 nukes at sea, that's not the same thing.

No they said they were raising the cap, but declined to state if they were aiming to reach the new limit.

But that is digression from the main point of my post, which was the downward pressure may now be reversed and more weapons produced.

 

[Hood]

No they said they were raising the cap, but declined to state if they were aiming to reach the new limit.

Yes you are right, my scepticism was a little too high. As I posted at the time the limit was raised from 180 to 260 and Parliament gets the nod before it can happen (which I don't think has happened unless its been tabled and we've missed it): https://www.secretprojects.co.uk/threads/bae-systems-successor-ssbn.28044/page-2#post-444855

Even with 200 operational warheads, that's 40 Tridents with 5 warheads each, enough for 3 boat loads. Hard to imagine that we'd need much more than that given three boomers are hardly (if ever) at sea at once.

 

[Archibald]

We need at least 99 to take down all those red balloons.....

 

[zen]

If...207 warheads
9 RVs a bus
That's 23 missiles.....but that assumes the cross range of each RV is such that 3 targets can be stradled by 3 RVs within the bus's flightpath prior to re-entry.

More disparate targets might increase the missile count without increasing the RV/warhead number.

So considering the variable density of targets and the difficulties of planning an efficient flightpath. Various RV loads per missile may be needed.

 

[uk 75]

I recall reading that a Trident submarine could fire its missiles while berthed. This makes the second and even a third submarine load out reasonable.
Whether the submarine would get its missile off before an incoming nuke arrived might be a problem.

 

[zen]

That might be an argument for limited ABM for Faslane. Buy enough time to launch from dockside.

 

[sferrin]

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.

Not with a hardened system. (Else things like Safeguard and Russia's ABM system would be completely useless after the first shot.)

 

[zen]

Time to quote an expert. Sadly passed away this year and much missed. As is his forum.

Multiple Independently-Targeted Re-Entry Vehicles (MIRVs)

Why they exist Although MIRVs are often regarded as a development of MRVs, in fact they come from a totally different logic. In a ballistic missile site, the missile itself represents only a small proportion of the cost of the system (usually 10 - 20 percent). The bulk of that cost is represented by the silo and the command control system that goes with it. That cost is dorectly related to the number of missiles, not the number of warheads on each missile. Therefore, it is much less expensive to built 100 missiles with ten warheads each that 1,000 missiles with one warhead each. All the money saved can be invested in making the silos much harder and thus more difficult to destroy (meaning the enemy must fire more missiles at them to guarantee their destruction).

How it works The missile bus containing the warheads is designed so that it can make changes in its attitude and pitch between discharging warheads. It is then programmed so that, at the appropriate time, it can make those changes before discharging a warhead and can, thus, aim each warhead at a separate target. In theory it can aim all its warheads at different targets, in reality things are much more complex.

The problem is that the system has to discharge its warheads one at a time. It cannot discharge the whole lot at once. This puts a limit on how many it can discharge in the time available. Also, the degree of manoeuvering is strictly limited. So, the targets engaged by a single MIRV missile are limited toa relatively restricted footprint. Also, there are a lot more variable, many random and unpredictable, in aiming and discharging the MIRV bus which mean that MIRV missile-delivered RVs are a LOT less accurate than unitary RVs. So much so that if the launch distance is too far back from the target, the MIRVs are likely to miss by so much that they will be useless. So the distance at which the MIRV can discharge is severely limited. It should also be noted that the MIRV bus is very complex and very sensitive.

Effects on ABM MIRVs are also often promoted as a way of beating an ABM defense by "swamping it", apparently on the assumption that each descending RV would have to be destroyed individually. In fact, this is, again, not the case. Using nuclear-tipped ABMs, the relatively tightly clustered MIRVs would be taken out by a single shot. However, the simplest technique of eliminating MIRVs is, once again, to kill the bus before it discharges its warheads. This needs some extended range - the effect of MIRVs on the Nike-Zeus program was to upgrade the Zeus interceptor so that it had the range necessary to kill the MIRV bus before it discharged its warheads. That's why the range was increased from 250km (more than adequate to kill an MRV bus) to 740km (way more than adequate to kill any projected MIRV bus. Also, as a bonus, it needed only tiny amounts of damage or disturbance to render the MIRV bus ineffective. Far from being a way of beating an ABM defense, MIRVs were only credible in the absence of ABMs of adequate range.

and

Put in a nutshell, decoys don't work. That's about as simple as it gets. There are more than three dozen technologies available to distinguise decoys from real warheads. The decoy question was throughly investigated in the early 1960s and all the practical forms of decoy were discounted. By 1964, the decoy problem was essentially solved. Since that time, decoy developers have been trying to produce better decoys and the counter-decoy people have been devising ways of distinguising between the decoys and the real thing. At the moment, the filtration techniques are so far ahead that decoys have been discounted as a viable technique.

To work, a decoy would have to be exactly the same size, shape, weight, weight distribution, appearance, thermal characteristics and thermal distribution as a real warhead; if one's going to do that, why not just use a real warhead? By the way, before anybody repeats the old line "don't make the decoy look like a warhead, make the warhead look like a decoy", that was one of the earliest ideas that was tested. It doesn't work.

The British based an entire Polaris update around the use of decoys (it was called Chevaline). Chevaline ran years late and was horribly over-cost, the problems with the decoys being the primary and largest single cause of the problems. In fact, those problems were never solved. By the way, even using decoys from a ballistic missile is not as easy as it sounds; there's quite a few problems there that have never been solved either. Mostly because it wasn't worth spending money solving those problems when the decoys wouldn't work anyway.

 

[drejr]

Think I'll stick with Lawrence Livermore on this one even if they directly contradict him on most points.

 

[publiusr]

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.

I wish I could have been there