Talk:Castle Bravo

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Enhanced the image to remove glare and bring out detail. I think we would all agree it looks much better now.PiccoloNamek 07:15, Sep 26, 2004 (UTC)

I like the color adjusting but the "detail" is grainy and looks bad and unrealistic (clouds are not grainy). I'll scan a new copy of it out of a book I have and see if I can't bring out the detail and color without it being grainy... --Fastfission 06:22, 3 Nov 2004 (UTC)
What about this image? It isn't grainy and I think it really represents the sheer power of Bravo very well. [1]PiccoloNamek 06:05, Feb 2, 2005 (UTC)
Personally I prefer one of the mushroom cloud rather than the fireball. The reason for this preference is three-fold: I think it gives you a better idea of scale (you can tell you are viewing this thing from pretty far away), it resonates better psychologically (the mushroom cloud is certainly a more poignant cultural image than the fireball), and it connects better with the issue of nuclear fallout (which is one of the main significances of the Bravo incident). I'll try to add a better picture of the mushroom cloud in a few days, I'm sure I've got one around here... --Fastfission 17:26, 11 Feb 2005 (UTC)
I suppose that's true... I still like the fireball image more though ;)... I have a lot of good Bravo cloud images here though, I might share some of them. I'm worried they don't have the same sense of scale as the one we have now though.PiccoloNamek 19:29, Feb 11, 2005 (UTC)

Contents

[edit] "received 10 R of radiation (equivalent to 10 chest X-rays)"

R is not a unit of radiation nor of human radiation exposure. The former unit is roentgens; the latter is rem (an acronym Roentgen equivalent man). R is ambiguous in this context.

Also, 10 rem of radiation would be equivalent to about 1000 chest X-rays[2], not 10 chest x-rays. For this reason, I've removed the parenthetical text pending correction. Ikkyu2 23:37, 8 February 2006 (UTC)

[edit] This article is packed with erroneous information

The maximum megatons of above ground nuclear tests was far greater than stated. I believe I remember them being approximately 100 Megaton for the Soviet Union on Novaya Zemlya and possibly as high as 80 megaton for the United States.

No wonder Henry Ford said "History is bunk!", it keeps getting distorted over time.

Drdyer 04:55, 1 March 2006 (UTC)Drdyer

[edit] 10 megaton from fission?

First sentence of "Fallout accident":

Of the total 15 megaton yield, 10 megatons were from fission of the natural uranium tamper.....

10 megatons from fission seems a lot, I would expect the vast majority of the yield to be from fusion.

Whether it "seems like a lot" or not, the fact remains that 10MT of the yield came from the tamper. I've reverted the change; please sign your contributions and use (at least) google prior to changing easily confirmed data. mdf 16:52, 1 March 2006 (UTC)

Actually, there does seem to be something wrong with the yields. If the majority of the yield was from the uranium, then how was the yield of "three times what was expected", because of the lithium-7? I also think this "High yield cause" section is a bit mis-leading in that it counts the extra yield twice: "This resultant extra fuel (both lithium-6 and tritium) contributed greatly to the fusion reactions..." - the breakdown of Lithium-6 to tritium was expected, and a necessary precursor to fusion; what was apparently not expected was that Lithium-7 would also create tritium. According to Fusion_power , the lithium7>tritium reaction is endothermic. I haven't made changes to the article since I don't know definitive answers. (Please note I am not the originator of this thread) Loris 18:05, 1 March 2006 (UTC)

The fusion stage produces a heavy neutron flux that initiates the fission of the tamper. See the nuclear weapon design article for details. mdf 20:36, 1 March 2006 (UTC)

Aah, I see. I was mistaken. Essentially the role of the lithium/deuterium reactions is to provide more neutrons (causing more of the uranium to fission), rather than producing the bulk of the energy released. If I've got this correct could I suggest changing/adding to the section to make this clearer? (The article you point to seems much more clear on the subject)
Just to check I've got this right:

7Li+n >> T+4He+n (no net change of neutrons)
T+D >> 4He+n (net gain 1 neutron) ------------- profit : 1 neutron
Whereas the designers were expecting:
6Li+n >> T+4He (net loss 1 neutron)
T+D >> 4He+n (net gain 1 neutron) ------------- no change in neutrons
...presumably with some proportion of D+D >> 3He+n to actually give a net gain of neutrons.
Loris 16:01, 2 March 2006 (UTC)


sorry to insert here but is the term RACER 4 really a bomb type (which is something I haven't heard of although i've read a fair amount on this subjuct) or is it vandalism?

It's an actual bomb type, though I don't know if it's an acronym or just a code word. EASports 19:30, 15 June 2006 (UTC)
RACER IV was supposedly the primary for the Shrimp, i.e., a specially configured fission device. (Although with the caveat that as with all nuclear weapons, exactly what does what is not well known and *facts* are subject to revision when new info is discovered). Mytg8 13:35, 25 August 2006 (UTC)


Remember, this was a fission/fusion/fission device. Most of the dirty fission yield came from the U238 (normally non-fissionable) casing and tamper, NOT from the initial fission detonator. 147.145.40.44 19:34, 22 January 2007 (UTC)

[edit] Lithium-7

Rhodes (Dark Sun) quotes someone (Rosenbluth?) to the effect that the missed reaction was

7Li + n -> 6Li + 2n

In other words, a chain reaction that will convert 7Li into 6Li, plus a fast neutron flux that is available to fission 238U. With multiple reaction paths in play, it's best not to show 'overall' reactions that obscure mechanisms.

"Of the total 15-megaton yield, 10 megatons were from fission of the natural uranium tamper. Thus the direct effect on the yield of the fusion was in this case smaller than the fission's effect of enabling fusion."

Shouldn't that read as follows? "Of the total 15-megaton yield, 10 megatons were from fission of the natural uranium tamper. Thus the direct effect on the yield of the fusion was in this case smaller than the fusion's effect of enabling fission." Tannin 09:59, 16 May 2006 (UTC)

[edit] 25,000 times more powerful than Hiroshima and Nagasaki?

"Though some 25,000 times more powerful than the atomic bombs which were dropped on Hiroshima and Nagasaki during World War II..."

How do you get this? The Hiroshima bomb was about 13 kt, and the Nagasaki bomb about 21 kt. That makes Castle Bravo at 15 Mt about 1,000 times more powerful, not 25,000.

Karn 20:45, 30 August 2006 (UTC)

Anyone have any more information about the yield being different than 15Mt? For example, Guinness Records for years stated that Bravo had a yield between 18 and 22 megatons--where did they get those numbers? As far as the *official* 15 Mt, that figure was estimated from cloud dimensions, which are still imprecise at best. The crater volume is at least double that of Ivy Mike which was 10.4 megatons. I've read internet accounts of up to 45 megatons.Mytg8 04:05, 31 August 2006 (UTC)

They determined the actual yeild of Bravo by analyzing the chemical and fission byproducts at the blast site and in the fallout. When the reaction blasts the critical mass appart, the fission/fusion conditions cease and the atoms are no longer changing--except by well known decay processes. From the chemical signatures of particular isotopes in the debris, it's possible to determine what the fuel was like the moment the reaction stopped. Since the fuel composition is known both before and after the reaction, it's possible to calculate the amount of energy released (with reasonable accuracy). This is how they know that 10 Mt was from the U238 tamper fission; because the ratio of U238 to U235 was way, way, off.

As far as the yield estimates for Bravo, a lot of the early reports were based upon all manners of indirect measurements such as cloud size, brightness of the early pulse, duration of the late pulse, speed of the blast wave, and so on. Most of the equipment was woefully out of calibration for the actual size of the blast (or outright destroyed), and that led to a lot of misleading early reports...anywhere from 9 Mt to 17 Mt. Also remember that the exact standard for 1 Kt = 1012 calories (and 1 Mt = 1015 calories) wasn't set until sometime well afterwards. That too can make wandering yield estimates since the early kiloton baseline against the damage for an equivelant blast of TNT, not the energy released. The official report from Castle (submitted in the summer of 1954 and declassified in 1983 along with the Castle Series summary) used the chemistry analysis to show a 15 Mt blast and corrected a lot of the earlier estimates in the initial report. As far as I know, that the only factual value for the yeild. Imaginos 02:17, 13 September 2006 (UTC)

Calculating the rough yield of nuclear weapons by chemical and fission byproduct analysis has been in place since Trinity(they got 18.6 kt, while now the yield was believed to be 23 kt). But the Bravo test suffered inconclusive results from the yield determination tests that were compromised by the unexpectedly high yield. For example, the blast wave breached the station 200 bunker at the end of the pipeline on Nam, where many experiments were located. Scientist Herbert York(later director of UCRL), in his book "The Advisors: Oppenheimer, Teller and the Superbomb" was present and stated that the yield(14.9 Mt, BTW, possibly rounded up to 15 in the DOE/NV-209 document) was estimated from cloud dimensions since the experiments were inconclusive and/or compromised. I assume initial determinations were all over the place because they only had one multi-megaton test to compare with--Ivy Mike. Yield estimates from cloud dimensions are all over the place for many reasons--one of the most important, meteorological conditions, and have to be considered ball park figures. After the Castle series was completed they were able to get a better number from the instrumented Yankee, Romeo, etc. tests. As for the 10 Mt fission figures, I read the DNA's Castle Series tome and I saw no fission results for each separate test. They were indirectly deduced by researchers from late 1950's statements to Congress sub-committees covering total fission yields from all tests to date, and are therefore very rough figures. On the other hand, comparison of the published Ivy Mike and Castle Bravo crater dimensions--the Bravo crater is double and possibly triple the volume, would indicate a similiar multiple of the Mike yield(10.4 Mt) is likely. Therefore more in tune with the Guinness statement of 18-22 Mt. While hardly a scientific enterprise :), the Record Book is known for astudiously checking their facts. After all, I was just wondering if anyone knew how and where they got that figure.Mytg8 04:05, 16 September 2006 (UTC)

I can't edit this because my father is no longer among us to back up this statement in any way, and for that matter I have no way of knowing the credibility of his source... but he was an engineer aboard the USS Bairoko at the time of this test and he told me, among other things, that 15 MT was reported rather than a more accurate estimate upwards of 20 MT. Again, I hate to bring up an unverifiable, possibly apochryphal story but it seemed relevant.

[edit] third most powerful nuclear explosion?

According to [3], Russia conducted a test detonation of a 24.2 megaton device after Tsar Bomba. I assume that would make Castle Bravo the third most powerful device ever detonated? If so, what would the third, fourth, fifth, etc, detonations be? A list of detonations sorted by power would be interesting to see, but alas, I don't think such a list exists, yet TerraFrost 06:10, 1 December 2006 (UTC)

One week before Tsar Bomba (23Nov61), the Soviets tested a ~25 megaton weapon. After Tsar Bomba, a ~30 megaton weapon in August of 62. They did three more test between 20 and 25 megatons in September of 1962, then one more the following December at around 20 mt. All of these were air dropped at Novaya Zemlya, but the attention tends to get focused on just Tsar Bomba because it was a political weapon rather than anything that could be effectively used or delivered to a battlefield (it was a terrible waste of fuel and almost completely impractical, but it did get people's attention). Bravo is number 8 on the list, followed by most of the test of the Castle Series with a mix of others.Imaginos 06:59, 2 December 2006 (UTC)

[edit] Reverted to 26 NOV version

I reverted changes by 128.208.95.16. That JTF-7 proceeded to shoot when they "knew that the change in weather would cause the test to affect areas of ocean that had not been cleared, they decided to proceed with the test" does need a citation because there are great volumes of documentation to the contrary, not the least of which are the communications from JTF-7 and that the winds were within the AEC guidelines established for Castle.Imaginos 20:34, 12 December 2006 (UTC)

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