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US Will Clean Area In Spain Where Hydrogen Bombs Fell (nytimes.com)
HughPickens.com writes: Rafael Minder writes in the NY Times that almost 50 years after coming close to possibly provoking a nuclear disaster, Secretary of State John Kerry, following years of wrangling between Spain and the U.S., signed an agreement to remove contaminated soil from an area in southern Spain where an American warplane accidentally dropped hydrogen bombs. In 1966 a bomber collided with a refueling tanker in midair and dropped four hydrogen bombs, two of which released plutonium into the atmosphere. No warheads detonated, narrowly averting what could have been an explosion more powerful than the atomic strikes against Japan at the end of World War II. Four days after the accident, the Spanish government stated that "the Palomares incident was evidence of the dangers created by NATO's use of the Gibraltar airstrip," announcing that NATO aircraft would no longer be permitted to fly over Spanish territory either to or from Gibraltar. The U.S. later announced that it would no longer fly over Spain with nuclear weapons, and the Spanish government formally banned U.S. flights over its territory that carried such weapons.
Neither Kerry nor Spanish Foreign Minister García-Margallo said exactly how much contaminated soil would be sent back, where it would be stored in the United States, or who would pay for the cleanup — some of the issues that have held up a deal until now. Spain has insisted that any contaminated soil be sent to the United States, because Spain does not have plants to store it. Concern over the site was reawakened in the 1990s when tests revealed high levels of americium, an isotope of plutonium, and further tests showed that 50,000 cubic meters of earth were still contaminated. The Spanish government appropriated the land in 2003 to prevent it being used.
Neither Kerry nor Spanish Foreign Minister García-Margallo said exactly how much contaminated soil would be sent back, where it would be stored in the United States, or who would pay for the cleanup — some of the issues that have held up a deal until now. Spain has insisted that any contaminated soil be sent to the United States, because Spain does not have plants to store it. Concern over the site was reawakened in the 1990s when tests revealed high levels of americium, an isotope of plutonium, and further tests showed that 50,000 cubic meters of earth were still contaminated. The Spanish government appropriated the land in 2003 to prevent it being used.
Of course there wasn't. This isn't nitroglycerin, and there are SO MANY layers of safety devices on these bombs this just not a possibility. The bomb has to be employed intentionally.
After a couple neutrons are captured. Am-241 is the most common isotope (half life of 400-odd years). Pu-239 captures two neutrons (rarely), then undergoes beta decay to become Am-241.
Since this normally requires a specially designed reactor to produce, the amount produced casually by four bombs will have been minuscule.
Which is not to say it shouldn't be cleaned up. Just that the urgency of the cleanup is pretty much consistent with taking 50 years to get around to it.
Note the amount of material being discussed (50000 m^3 of dirt). Cleanup can be done with one of those big earth movers used when strip mining in a few months, tops....
"I do not agree with what you say, but I will defend to the death your right to say it"
The highly toxic US equipment left scattered over the years can be found and recovered by US crews that are used to dealing with such rather common events.
The US has mentioned it had a few nuclear related issues due to the huge numbers of nuclear armed flights around the world, crew issues, equipment issues.
United States military nuclear incident terminology https://en.wikipedia.org/wiki/...
List of military nuclear accidents https://en.wikipedia.org/wiki/...
has other details over the decades surrounding issues like accidental criticality, non-nuclear detonation of an atomic bomb, partial meltdown, weapons jettisoned and not recovered, fire, release of nuclear materials, nuclear bomb lost...
Most nations like to be seen to clean up after their own crashes to fully recover secrets, methods, materials and put a good media spin on been nice to nations where they have bases or want to have more bases.
Domestic spying is now "Benign Information Gathering"
Because nuclear weapons tend to require carefully timed simultaneous detonations of explosives in a controlled manner in order to compress the fission core to a supercritical mass, it is unlikely that simply dropping the bomb (unarmed) or even having some of the explosives used for core compression go off will create an actual nuclear scale detonation.
However, the explosives for the explosive lens can go off and distribute radioactive material over a relatively wide area. This was more of a threat in the past, when explosives used in the bombs were somewhat more sensitive. Additionally, some explosives become more sensitive over time, so bombs stored for long periods could have somewhat more sensitive explosives and react badly to an accidental drop or crash.
All of that being said... an actual accidental nuclear explosion is extremely unlikely, but not entirely impossible in the case of an accident, and it was much, much more likely back when these bombs were dropped in Spain.
Also, there was one time where a bomb was lost where all but one of the safeties had been deactivated. And that was a mechanical breaker which could well have been flipped. Luckily, that sort of thing was much more common when SAC was actually doing regular strategic deterrent missions and bomb design had not progressed as far as it has today.
Yea it won't take much to clean this up, that's for sure...
One thing, I'm guessing the Am-241 was in the original fission material of the bomb and not really from Pu-239 decay, but either way, there is going to be so very little of it. Given it's spread out over about 500 acres by the conventional explosives, I'm wondering why Spain is still pushing to get this clean up done. It's been over 50 years now and all a huge excavation project will really accomplish is to make a mess.
Well, if it pumps some dollars into the local Spanish economy it might be worth the trouble... But really, what's the big deal at this point? Couldn't we just pay them for the land, put up a fence with "keep out for 3,000 years" signs and be done with this? Or is having this material so dangerous to Spain that it's worth taking a few million cubic meters of dirt and dumping it in the ocean?
"File to fit, pound to insert, paint to match" - Aircraft Maintenance 101
Although people associate uranium with radioactivity, it is only very slightly radioactive (half life > 1 billion years), so if you don't assemble a critical mass the danger is actually chemical. (Heavy metals have a strong tendency to be toxic.)
Other posters have said that here we are dealing with plutonium-239, which has a half life of 24000 years. That is orders of magnitude greater activity (shorter life) than uranium. I've reached the end of my knowledge here - which is worse, is the radioactivity or the chemical toxicity of plutonium-239?
TFA suggests they are worried about radioactivity: "A main concern has been that the remaining plutonium was being allowed to degenerate into other radioactive components like americium, which emits gamma rays that travel farther and are hard to block" but concern is not always well founded, and reporters don't always get it right.
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The posters here with the blase attitudes regarding nuclear weapons accidents ought to consider reading the book "Command and Control" and marvel at the fact we made it thru the cold war at all.
Regarding clean-up: when accidents happened on US territory we cleaned it up, even at Thule AFB, which is about as close to the end of the earth as you can get. We also contaminated the other end of the earth for good measure (leaky reactor at McMurdo Station Antarctica). In both cases the contaminated soil was 'disposed of' at the Savannah River Plant.
Americium is NOT an isotope of plutonium, it is a decay product of Uranium/Plutonium, specifically
That was the first thing that struck me when I read OP.
And I think it's probably fair to say that the fact that they didn't blow up was far from an accident; they were designed that way.