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Lost Nuclear Bomb Found Off Georgia Coast?
securitas writes "Both CNN and ABC News report that a hydrogen thermonuclear bomb lost off the Georgia coast in 1958 may have been found. The 'Mark 15, Mod 0' nuclear bomb was jettisoned into the Atlantic Ocean off Savannah after a B-47 bomber and an F-86 fighter collided in mid-air. 'The 7,600-pound, 12-foot-long thermonuclear bomb contained 400 pounds of high explosives as well as uranium' and it was found off Tybee Island by retired Air Force Lt. Colonel Derek Duke,, who said that radiation levels were from seven to 10 times higher than normal. If it is the bomb that Duke has found, the question now is what, if anything, should be done with it?"
The United States lost 11 nuclear bombs in accidents during the Cold War that were never recovered, according to the Brookings Institution, a Washington think tank.
An estimated 50 nuclear warheads, most of them from the former Soviet Union, still lie on the bottom of the world's oceans, according to the environmental group Greenpeace.
This really doesn't fill me with happy thoughts... Bottom of the ocean is far too lax a description, you can practically paddle in the North Sea between the UK and the rest of Europe! The Marianas trench would be (just about) deep enough for me not to care...
Simon
Physicists get Hadrons!
I found this fascinating account of a hydrogen bomb accidently dropped in 1961 and still buried on a North Carolina farm. Although major portions were recovered, the uranium never was.
HIV Crosses Species Barrier... into Muppets
Its non-functioning, nukes have a shelf life of ~5 years before the plutonium turns into another isotope.
Steaming pile of bullshit. I swear, if the subject has the word "nuclear" in it, Slashdot's about as reliable as the Weekly World News.
The isotope of plutonium used in nuclear weapons is Pu-239. Pu-239 has a half-life of 24,100 years. After 5 years, almost all of the Pu-239 in a nuclear weapon will still be Pu-239.
In addition the Mark 15 Mod 0's an odd bomb.
Modern thermonuclear weapons are three-stage devices. There's a small fission trigger, whose yield is boosted by tritium injection. The radiation from the trigger ignites fusion in a second stage of lithium deuteride. Then the neutrons coming off of the fusion stage can be used to fission the bomb's tamper, made of uranium-238. U-238 won't sustain a chain reaction, but it'll fission merrily if you bombard it with fast neutrons. So, basically the boosted primary accounts for a minority of the weapon's yield, and the second stage, the fusion segment, accounts for the majority. But you can design things so that the majority of the yield comes from fission of the U-238 tamper.
The Mark 15's kind of an inversion of this. It was an early fusion bomb, back when they were still using liquid deuterium in some designs. In the Mark 15 Mod 0, the third stage is the bomb's casing, which is made of highly-enriched uranium, almost pure U-235.
Yes, the bomb's casing is almost-weapons-grade uranium. By making the case out of HEU, they didn't need to worry so much about efficient compression of the fusion stage, because the fissioning of that huge amount of HEU would send the whole thing thermonyclear. Inefficient, sure, but they hadn't quite figured everything out yet.
That's why this bomb's a concern. According to the Air Force, the primary, the 'pit,' wasn't placed in the bomb, so the primary can't detonate. Even if they're bullshitting, the twin traumas of impact and age have probably so screwed up the internals of the bomb that the only detonation possible would be low-order, a fizzle, biggest problem would be the environmental effects of scattering that much radioactive material into the river.
So that's not the concern. The concern is that whoever recovers it now has his hands on well over a ton of weapons-grade uranium, easily enough to make not one, but several crude Hiroshima-type nuclear bombs. I mean, this was a bomb that had a total yield of 1.7 megatons, and 1.3 megatons of that came from fission. That's a lot of U-235.
This was the device tested as Castle Nectar.
If it is the bomb that Duke has found, the question now is what, if anything, should be done with it?"
It should be retrieved. If this were a modern fission-fusion-fission bomb, it wouldn't be a concern. The Air Force says it doesn't have the fission trigger installed, so with a modern device that means you don't have a bomb. You need a fission bomb to ignite the lithium deuteride in the fusion stage, and you need the neutrons from the fusion stage to fission the U-238 jacket. So, again, no primary, no bomb. Leave it there, rivers already feed natural uranium into the oceans at a rate of 3.2x10^4 tons every year.
But this isn't a modern bomb, it was a transitional device between the earliest, liquid-dueterium monsters and modern three-stage designs. They weren't yet sure how to achieve efficient compression of the fusion stage, so they wrapped the bomb in highly-enriched uranium to be sure the fusion stage would light off. The bomb had a design yield of 1.7 megatons, and something like 1.3 megatons of that would be due to the fission of the U-235 jacket.
That means that this bomb contains a lot of almost-weapons-grade uranium. Again, 1.3 megatons of yield from the fission of uranium. The largest pure-fission bomb we ever detonated was the 500-kiloton Mark 18 prototype, and that used about 60 kilograms of HEU. Assuming linear scaling, that means we're looking at upwards of 156 kilograms of HEU in this bomb. Critical mass of uranium's about 16 kilograms. Double that to overengineer a bomb, and that means whoever gets their mitts on this thing could build 4 or 5 crude Hiroshima-type bombs, each with a yield of several kilotons.
That's bad. They need to retrive this thing, even if there's a risk they blow it up in situ. I'd rather have some of this stuff scattered in an unusable form offshore than have Mohammed and his band of Merry Pranksters get their hands on 4 or 5 cities' worth of U-235.
WEAPONS LOST/MISSING
March 10, 1956, Over the Mediterranean Sea
July 28, 1957, Over the Atlantic Ocean - somewhere between Dover Air Force Base (Delaware) and Atlantic City, New Jersey
February 5, 1958, Savannah River, Georgia (this story)
September 25, 1959, Off Whidbey Island, Washington. Since this is slashdot, I feel obligated to point out that this is about 30 miles from Redmond.
January 24, 1961, Goldsboro, North Carolina
December 5, 1965, Aboard the USS Ticonderoga (CVA-14) in the Pacific Ocean (only miles from the Japanese island chain of Ryukyu)
Spring 1968, Aboard the USS Scorpion (SSN-589) in the Atlantic Ocean - 400-500 miles southwest of the Azores.
Any slashdotters have a geiger counter, a boat, and some free time?
HIV Crosses Species Barrier... into Muppets
Very informative and very frightening. Googling "Castle Nectar" returned - among others - this interesting page: Project Castle with an image of the beast.
668.5
Close, very close, but not quite right. The trigger is a single fission bomb; the radiation it produces is redirected cleverly so as to compress the fusion charge (a concept referred to as a "Hohlraum"). In some designs there are more than two "stages" where fission triggers fusion, which then is used to trigger more fission or, in some cases, another fusion stage (the Soviet "Tsar Bomba" was a multistage fusion device of 60-120 Mtons. Check out the Nuclear Weapons FAQ for more info.
The "neutron bomb" was a planned attempt to replace the fission warheads with chemical explosives, creating a thermonuclear explosion with no radioactive fallout- a truly impressive feat if it were possible.
Not the neutron bomb I'm familiar with. It was a very low-yield fission-triggered device that had a fusion stage. There has long been a dream at LLNL to figure out how to initiate fusion with a conventional high-explosive trigger, but to my knowledge, no such weapon has ever been tested or fielded. The neutron bomb of the 80's would have created plenty of fallout and radioactivity; the point was it created less blast damage and so didn't sound as bad (the fallout was sort-of ignored).
He is talking about the tritiated lithium hydride,....Since the bomb was lost 46 years ago, which is about 4 tritium half lives, the maximum possible yield has in theory been reduced to 1/16 of what it was in 1958, and the actual yield is probably zero.
I think there is a small mis-understanding here. A fusion weapon of this type uses tritium to boost the yield of the fission trigger, NOT as a component in the fusion main stage fuel. The fusion stage creates the tritum needed at the time of explosion by neutron-spallation of the Lithium. So, after 4 half-lives the fission trigger yield will be greatly reduced - probably enough to prevent any significant second-stage fusion. This means that if it exploded, the yield would be in the 10-kiloton range, not the megaton range. However, if the fusion stage were to ignite, it would do so with as much yield as ever.
Human genome = 3 billion base pairs = 6 GBit. Windows + Office = 20 Gbit. Which is more impressive?
Don't know how accurate they are, but according to that show: the CIA already had pictures and knew where the sub was from 10 years earlier. It sank in the 1950's in the same month as an American sub the Scorpion (the accidents were unrelated). It had one missle on it (I may have missed what happened to the others, the graphic indicated it could hold 3). In the late 1950's an American sub was sent out there to locate it and photograph it and succeeded.
When Nixon was elected he was told about the sub and authorized raising it. The Glomar Explorer lifted the entire sub, but then the lifting contraption broke and 2/3 of the sub fell back to the floor. They got the front third and recovered six bodies (which they buried at sea in a russian-style ceremony), and they recoverd some code information (though I doubt codes from 1950's were much use in 1974!).
The Russians completely covered up the fact that they lost the sub, and the Americans did not say they had found it, so when the story about the Glomar Explorer leaked out, it was also the first anybody had heard about the sub sinking!
"The Emperor had been told that war could not be won as early as February 1942. In 1943, the [Japanese] navy had reached the conclusion that defeat was inevitable. In 1944 Tojo had been thrown out by a navy putsch. None of this made any difference. The fear of assassination was too great. In May 1945 Russia was asked to mediate. But Stalin sat on the offer, since in January at Yalta he had been promised substantial territorial rewards to enter the Japanese war in August.
... prosecute the war to the bitter end'. The final plan for the defense of Japan itself, 'Operation Decision', provided for 10,000 suicide planes (most converted trainers), fifty-three infantry divisions and twenty-five brigades: 2,350,000 trained troops would fight on the beaches, backed by 4 million army and navy civil employees and a civilian militia of 28 million .
On 6 June the Japanese Supreme Council approved a document, 'Fundamental Policy to be Followed hensceforth in the Conduct of the War,' which asserted 'we shall
They were to have weapons which included muzzle-loaders, bamboo spears and bows and arrows. The Allied commanders assumed that their own forces must expect up to a million casualties if an invasion of Japan became necessary. How many Japanese would lives would be lost? Assuming comparable ratios to those already experienced, it would be in the range of 10-20 million.
The Allied aim was to break Japanese resistance before an invasion became unavoidable. On 1 August, 820 B29's unloaded 6,600 tons of explosive on five towns in North Kyushu. Five days later America's one, untested uranium bomb was dropped on Hiroshima, Japan's eighth largest city, headquarters of the 2nd General Army and an important embarkation port. Some 720,000 leaflets warning that the city would be 'obliterated' had been dropped two days before . No notice was taken..."
-- Johnson, Paul: Modern Times
Read your history.