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According to Wikipedia on the 1966 Palomares B-52 Crash:

The first weapon to be discovered was found nearly intact. However, the conventional explosives from the other two bombs that fell on land detonated without setting off a nuclear explosion (akin to a dirty bomb explosion).

Are there any authors who said that those nuclear weapons could have detonated and destroyed a good part of Spain? Are there any relevant nuclear expert who support this thesis?

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    Well, it is a counter factual question. Further, you may wish to do some preliminary research in safing and surety forUS nuclear weapons. That being said, I’m sure there are authors who speculate, but whether such speculation has any basis in fact is a different question. – Jon Custer Jun 18 '18 at 13:47
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    Remembering a quote from the History channel isn’t exactly research. – Jon Custer Jun 18 '18 at 13:57
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    I'm not sure there will be an answer to this, given than earlier in the 1960s there was an incident at Goldsboro where all 4 of the safety mechanisms that are designed to stop unintended detonation of a Mark 38 nuclear bomb failed (although thankfully on 2 different bombs) its entirely possible that the "perfect" storm could have occurred. Seeing as details on the Goldsboro incident were only declassified in 2013, its likely than any information on the Palomeres crash is still classified. – Kobunite Jun 18 '18 at 14:23
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    destroyed a good part of Spain I don't see how that could've been possible at the yields in question. – Semaphore Jun 18 '18 at 15:03
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It seems unlikely that the 1966 incident could have resulted in the nuclear explosion of one or more of the four hydrogen bombs that fell at Palomares, and I am not aware of any serious claims to the contrary.


Some background documentation

The 1975 summary report on the Palomares Incident has been declassified and is available as a pdf file on Archive.org. It notes that:

Small as it is, the probability of a nuclear yield in an accident makes nuclear weapon safety the first concern at all levels of military command, including that of the Commander-in-Chief. In response to our national policy with regard to nuclear safety, weapons designers employ a number of means to insure against an unplanned nuclear detonation. In general, weapons are designed so that a positive event or sequence of events peculiar to its planed mode of delivery or attack must occur before a weapon will produce a significant nuclear yield. It is reassuring that the safety engineering that was employed in the weapons was successful in preventing a nuclear explosion at Palomares and it is important to note that there has never been· an accidental nuclear explosion involving United States weapons.

Now, the US State Department also carried out an investigation into the so-called Broken Arrow incidents at Palomares and Thule. Their report is also declassified and available to download as a pdf file.

There is a 2009 report into the Palomares incident by the Danish Institute for International Studies (DIIS), titled The Marshal's Baton.

Finally, you might find a 2009 Master's Degree dissertation titled Dropping Nuclear Bombs on Spain - The Palomares Accident of 1966 and the U.S. Airborne Alert by John Megara interesting.


The four hydrogen bombs that fell on Palomares were not armed. It is actually not an easy matter to detonate an atomic weapon (for obvious reasons), and it is standard practice to ensure that the weapons are not armed until they are intended to be used. In this instance,

... the bombs could not be armed without the bomber crew flipping two different switches inside the plane that would cause the necessary circuits to be closed inside the bomb.

  • Dropping Nuclear Bombs on Spain, p34

Some of the high explosive contained in two of the devices however did explode. This distributed the fissile material contained in the weapons over a large area. The state of the weapons is described in some detail in the DIIS report listed above.

When the weapon is deliberately deployed - as intended - these explosives detonate in a very precise order to create the initial nuclear explosion (which itself then acts as a trigger in the case of a hydrogen bomb). Although the details are classified (again, for very obvious reasons), the simplified sequence of steps required to cause a thermonuclear explosion are set out on the Wikipedia page on Thermonuclear Weapons. A simple detonation of part or all of the high-explosive, resulting from the impact of an unarmed device initiating the Mild Detonating Fuse (MDF), cannot do this.


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    Not wanting to downplay that concern or going all relativistic about it: one drop of all four bombs going off as designed would still not "destroy a good part of Spain" (if good means "large", not "the best part")? And the "dirty" part from the WP is really badly phrased. As I read it, there was just that: a dirty nuclear bobm incident? Bad enough. – LаngLаngС Jun 18 '18 at 17:25
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    @LangLangC In fairness, "a good part of ..." can simply mean "a large area" e.g. Merriam-Webster. I'm not sure how the OP intended the term to be read (and English may also not be their first language!). The detonation of four thermonuclear devices is certainly capable of devastating a large area. However, semantics notwithstanding, there was no reasonable prospect of the devices causing a thermonuclear (or nuclear) explosion in this case, so the point is largely moot. – sempaiscuba Jun 18 '18 at 19:18

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