WI: 1966 Palomares incident H-Bomb detonates nuclearly.

As part of operation chrome dome, in 1966 a B-52 carrying 4 Mark 28 H-Bomb was flying above spain when it collided with a KC 135 tanker, two of the bombs had their conventional explosive explode, spreading radioactive material over several km².

In 1961 a B-52 also carrying (Mark 39) H-Bombs crashed, as many know one of the bomb nearly ignited, according to a 1969 report "one simple, dynamo-technology, low voltage switch stood between the United States and a major catastrophe".

Many people pointed out before that the bomb couldn't explode to its full explosive power, according to a later report 'The tritium reservoir used for fusion boosting was also full and had not been injected into the weapon primary. This would have resulted in a significantly reduced primary yield and would not have ignited the weapon's fusion secondary stage." So here it may be more realistic to assume that the bomb has a much lower yield (hundreds of tons to a few kT) but it's likely it would still emit significant radiations (since much of the radiation of a H bomb is caused by the primary yield), also could someone more knowledgable tell if this flaw could have happened on Mark 28 bombs, and if not could a similar incident with Mark 39 bomb happen at around the same time in spain?


Now what if the fate of the bombs are not only switched, but the bomb whose fissile material nearly ignited did go off. A large nuclear accident above the soil of an (nominal, spain wasn't in NATO at the time) ally would be completely different than one over american soil. What would be the reaction of spain?

The global situation in 1966 would also be different with more us involvment in vietnam and more nuclear parity between the two superpower. Could this event, the same year as the french withdrawal from the integrated command, make other countries decide to leave? I think it's a given operation chrome dome would be immediately terminated in this case. What would be the effect of all european NATO allies refusing american nukes on their soil?

What would be some of the political and geopolitical effect of this accident? Thanks for your answers.

Thanks for your answers.
 
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mottajack

Banned
Well, for a start, a small chunk of Spain in a corner south of Valencia and close from Alicante is turned into a radioactive, glowing crater and wasteland. the radiation will be carried all over the Mediterranean, to France and Italy. Nice.

Meanwhile Franco finds himself in an impossible situation. His situation as a anti-communist bulwark in europe and NATO, with billions of dollars flowing into his country, has just blown into his face, and violently with that. Although Franco had Spain under strict ( = terror) control, by 1966 he was getting older and thinking about his successor - either Admiral Carrero Blanco (later send in orbit with his dodge car by ETA- Basque Country explosive space program running on dynamite) or Juan Carlos. This has potential to screw Spain transition to democracy.
I wouldn't want to be in Franco position ITTL -although as a dictator he don't need to justify his decision, a H-bomb explosion is one hell of a disaster to swallow for the spanish population.
 
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It really isn't plausible to have a nuclear detonation in such scenario.

What is highly plausible is for the chemical explosive to combust in an uneven manner and create a dirty bomb scenario with no nuclear explosion. This is exactly what did happen in Spain, 3 bombs had the chemical explosive combust. Less than a square mile was badly contaminated.

What is also plausible but highly unlikely is for a partial but uneven compression of the primary core to occur and cause a critical mass and thus nuclear explosion but of vastly less than the nominal yield of the fission primary. This scenario sees maybe the yield of a small tactical nukes (see Tom Clancy's Sum of All Fears for a fictional example of this). The tritium boosting is also a component of fully initiating the fission reaction of the primary (the extra neutrons are needed to achieve the higher fraction of the primary actually undergoing fission). Thus no tritium and it isn't even possible to achieve the full fission yield of the primary, let alone triggering the fusion secondary stage. Plausible yield with no boosting might be 1.7 kt, but since this is only a fractional compression and detonation then something between a tenth to third of that number might be reasonable as a guess. So a 0.17 to 0.6 kt yield, as a guess.

A lot of very complex and exacting things have to all happen precisely to design in a specific order for even the fission primary to function properly. It isn't sufficient for the chemical explosive merely to ignite, it must do so in the way the weapon designers intended, which is to say all the detonators need to fire at exactly the correct time.

We don't know exactly how this weapon was designed, in part because B28 variants served until 1991. That long service indicates that the weapon was probably viewed as sufficiently safe against accidents. The Palomares incident itself had 3 weapons impact the ground with minimal results, which itself supports the idea the weapon was basically safe.

The Mk 39 on the other hand had a relatively brief life and the accident may have played a part in that.
 
It really isn't plausible to have a nuclear detonation in such scenario.

What is highly plausible is for the chemical explosive to combust in an uneven manner and create a dirty bomb scenario with no nuclear explosion. This is exactly what did happen in Spain, 3 bombs had the chemical explosive combust. Less than a square mile was badly contaminated.

What is also plausible but highly unlikely is for a partial but uneven compression of the primary core to occur and cause a critical mass and thus nuclear explosion but of vastly less than the nominal yield of the fission primary. This scenario sees maybe the yield of a small tactical nukes (see Tom Clancy's Sum of All Fears for a fictional example of this). The tritium boosting is also a component of fully initiating the fission reaction of the primary (the extra neutrons are needed to achieve the higher fraction of the primary actually undergoing fission). Thus no tritium and it isn't even possible to achieve the full fission yield of the primary, let alone triggering the fusion secondary stage. Plausible yield with no boosting might be 1.7 kt, but since this is only a fractional compression and detonation then something between a tenth to third of that number might be reasonable as a guess. So a 0.17 to 0.6 kt yield, as a guess.

A lot of very complex and exacting things have to all happen precisely to design in a specific order for even the fission primary to function properly. It isn't sufficient for the chemical explosive merely to ignite, it must do so in the way the weapon designers intended, which is to say all the detonators need to fire at exactly the correct time.

We don't know exactly how this weapon was designed, in part because B28 variants served until 1991. That long service indicates that the weapon was probably viewed as sufficiently safe against accidents. The Palomares incident itself had 3 weapons impact the ground with minimal results, which itself supports the idea the weapon was basically safe.

The Mk 39 on the other hand had a relatively brief life and the accident may have played a part in that.

Thanks, I do realize it is unlikely and I did put in my first comment that the assumption for this explosion would a few hundred tons of tnt, still I guess it would emit signficantly more radiations than the IRL contamination, and if it explodes close to the ground the (small) fireball may touch the ground.

Yeah we don’t know much about the bombs, Wikipedia says he mk39 was still in service in 66, was it ever used on transatlantic/European chrome Dome flights? If so as I outlined before it does seem technically possible although very unlikely that this scenario could happen, if necessary on another flight .
 
Thanks, I do realize it is unlikely and I did put in my first comment that the assumption for this explosion would a few hundred tons of tnt, still I guess it would emit signficantly more radiations than the IRL contamination, and if it explodes close to the ground the (small) fireball may touch the ground.

Yeah we don’t know much about the bombs, Wikipedia says he mk39 was still in service in 66, was it ever used on transatlantic/European chrome Dome flights? If so as I outlined before it does seem technically possible although very unlikely that this scenario could happen, if necessary on another flight .
Low yield nuke will certainly scatter some nasty stuff, but it will necessarily be a surface or potentially even subsurface detonation. (The NC bomb burried itself to 180 feet and is apparently still there less the primary core.) The US intentionally made a number of surface detonations with no great lasting impact. It isn't the kind of thing to depopulate a vast area or anything like that. The blast site itself will be heavily contaminated. If the fallout drops in a concentrated fashion (rain depositing it in one spot) it could produce lethal results and severe contamination. Otherwise it gets spread so thin as to basically only being an uptick in the background radiation plus a scattered and rare case of someone in taking actual radioactive particles to ill results.

Anything is possible, but of all the scenarios that could cause an unplanned nuclear detonation this isn't a very good one. The things were designed to survive stuff like the aircraft being shot down, or crashing on its own base, or lightning strikes, and even sabotage without detonation.

From limited knowledge of the US nuclear arsenal, I think the most plausible accidental detonation is from one of the nuclear depth bombs. One of those designs apparently had no safety other than a depth based trigger and was essentially always armed as I understand it, though I hope that isn't actually true.
 
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