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55th anniversary of the first airborne Hydrogen bomb test. LIFE photo collection.
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| idoru |
omginb4nou
Edit: 55th anniversary was last year. |
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| srussell0018 |
| quote: | | Friday marks the 55th anniversary of the United States dropping the first airborne hydrogen bomb on the Bikini atoll in the Pacific Ocean. The test was a success and symbolized a huge leap in the nuclear arms race. |
http://news.yahoo.com/s/yblog_upsho...-in-photographs |
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| Joss Weatherby |
Yes, this is the anniversary of the first deliverable hydrogen bomb being tested, though we had non-tested air deliverable fusion weapons for at least two years prior to this, maybe more if I am remembering wrong.
The test in question was during Operation Redwing at the Pacific Proving Grounds on Bikini Atoll. The shot was Redwing and yielded 3.8MT (or 3.8 million tons of TNT).
The test actually came after the largest US test in 1954, the dry-fuel experimental device, Castle Bravo (Op. Castle, shot Bravo) which yielded more than twice the expected yield. The first true hydrogen device tested was tested two years prior to Castle Bravo during Operation Ivy, shot Mike. This was a wet-fueled cryogenic device (the hydrogen fuel was liquid, and demanded a large cooling system to keep the components in a liquid state). There were some fusion boosted fission tests in prior series as well.
Ivy Mike, well a variation there of, was actually weaponized as an emergency program soon after and was actually deployed as part of the emergency stockpile.
Castle Bravo showed that these designs could be forgotten with the use of dry fueled lithium deuteride. The unexpected yield came from lithium-7 not being accounted as a reactive element in the fuel, only the lighter lithium-6. This proved to be quite beneficial as ultimately higher yields could be achieved with less and cheaper fuel.
Very interesting events in scientific history! |
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| srussell0018 |
| Wasn't the Soviet Tsar bomb like 2.5 times the yield of either of those? What kind of bomb was that? |
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| Joss Weatherby |
| quote: | Originally posted by srussell0018
Wasn't the Soviet Tsar bomb like 2.5 times the yield of either of those? What kind of bomb was that? |
Russia detonated a number of bombs with a higher yield than Castle Bravo's 15 megaton yield.
Tsar Bomba is the most famous of them, because it was of the highest yield, but in the weeks leading up to that test the Soviets detonated a number of very high yield weapons in the high teens and twenty megaton range.
Tsar Bomba itself was a standard hydrogen weapon. It consisted of two stages, the primary fission stage and a large secondary hydrogen stage. It literally was just a hydrogen bomb of normal design scaled up.
The original design called for a third stage, which is a where the tamper, which is the outer casing of the fission/fussion devices and usually is made to reflect and contain neutrons during the explosion, uses a reactive material like natural uranium.
When the third stage is made of a reactive material like natural uranium then it undergoes what is called "fast-fission" under the intense neutron bombardment of the first and second stages reactions. This then pours neutrons back into the already burning fuel and increases the efficiency of the reaction, and also contributes to explosive yield through its own fission reaction. This design is also called a fission-fusion-fission weapon.
If they had used a natural uranium tamper in the third stage the yield would have been around 100Mt instead of the 57 (commonly misquoted as 50) megatons of the actual test. In Tsar Bomba this stage was assumed to be lead (and I believe that has been confirmed now).
The biggest "problem" with three (and potentially additional) stage weapons is that fallout is increased drastically. The natural uranium tamper is so large that by the time it begins to burn and contribute to the explosion the pressures and heat from the first two stages is already beginning to blow the the actual functional parts of the weapon apart. This causes a lot of this fuel to be vaporized, and in some cases radically activated, and begins to become a very harsh radiation emitter!
This is good for a weapon in use, but for testing this was a big draw back. Had Tsar Bomba been detonated with an active third stage it would have increased world-wide fall out levels in 1962 by 25%!
Another interesting thing to note about materials used in tampers, is that you can use some seriously nasty material in there. For example, cobalt-59 can be transmuted to cobalt-60, which is a radioactive isotope of cobalt that has a very high energy output for its half-life. This can create radioactive fallout in an area that could potentially be lethal for many many years, possibly 20-25 years in some concentrated areas! Cobalt has never been known to be used in any weapon design as a fundamental part of the weapon, but the British did test one device that used cobalt as a radio-isotope tracer for tracking fallout in small amounts. |
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| tubularbills |
| fun fact: you can go to the Trinity Site in NM where the first bomb was dropped twice a year: the first weekend in April, and the first weekend in October |
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| Joss Weatherby |
| quote: | Originally posted by tubularbills
fun fact: you can go to the Trinity Site in NM where the first bomb was dropped twice a year: the first weekend in April, and the first weekend in October |
Yea I've always wanted to do that. |
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| idoru |
The LIFE photos are from 1945 (56 years ago) and a different event, save for one or two pictures. Note the timestamp from 2010 on the first comment on the LIFE page. |
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| srussell0018 |
| Yeah not all of the photos are from the first Hydrogen bomb test. They're from a number of different tests, including the first atomic bomb test. |
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| Trance Nutter |
| quote: | Originally posted by idoru
The LIFE photos are from 1945 (56 years ago) |
you may want to check your maths there. |
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