Talk:Swan (nuclear primary)

Two Point detonation delay
It was in the newspapers in the last couple of years that the Iranians were testing a two-point nuclear ignition system. News reports stated that earthquake detectors detected the tests, and the giveaway signature that it was a two-point nuclear test was that the two explosions were a fraction of a second one-after-the-other. Apparently, the way this system works is that the two detonators do not ignite at exactly the same time - they have to be precision-spaced one-after-the-other. Since the Iranians and everybody in the industry already know this, could somebody who knows about this please explain why the detonations are not/should not/cannot be at the same time. Thanks in advance to anybody who knows.Betathetapi545 (talk) 09:12, 3 October 2015 (UTC)


 * Never heard of such. I thought it might have been a single-point failure test, but that only has meaning when there is real stuff between the detonators, and Iran, AFAIK, doesn't yet.  Do you have a cite for that news report? SkoreKeep (talk) 21:48, 5 October 2015 (UTC)


 * I just reviewed the news reports (this is a typical one: http://www.theguardian.com/world/2009/nov/05/iran-tested-nuclear-warhead-design) and I think I might have read more into the reports than what is there. If Iran did a two-point implosion test, then how would seismic detectors detect that there were two separate detonations if they both occurred at the same moment and were only a couple of feet away from each other?  I therefore assumed that a two-point implosion requires detonations slightly off from each other.  I am not a nuclear physicist.  Thanks in advance.Betathetapi545 (talk) 06:45, 19 October 2015 (UTC)

Unless the Iranians have developed a very unconventionally shaped (and unheard of, and probably impossible) device, the detonators must go off at the same time, usually with sub-microsecond accuracy, if not nanosecond (ie: within a very small fraction of the time it takes a hypervelocity shockwave to travel the radius of the device). It is *not* "known in the industry" that the detonators must go off "one after the other". If it was a safety test, they may have deliberately miss-timed the detonators. However, the largest feasible time seperation of detonations would be the time it takes the shockwave to traverse the diameter of the device, which would be on the order of microseconds - it is hard to see how two detonators going off attached to the same mass of explosive could be determined via seismology. If the detonations were seperated by more than a few microseconds, it means that there were two discrete devices present - for it to be the same device, it would mean that during the explosion of several tens-to-hundreds of kilograms of hi-explosive, a second detonator (consisting of a few grams of explosive) going off was detected *mid-explosion*. I strongly suspect that whatever media it was that was reporting simply made an inexpert, off-the-cuff assumption.178.15.151.163 (talk) 08:44, 5 May 2016 (UTC)


 * Well, I guess my question therefore becomes, "How and why was this detected test described as 'breathtaking' given that it would have appeared as a single explosion on seismometer?"  That is why I read into it that Western seismometers read two explosions side-by-side.  So why would a test be described as "breathtaking"???  — Preceding unsigned comment added by Betathetapi545 (talk • contribs) 12:04, 31 October 2016 (UTC)


 * I can help here. This is my theory: They were testing a thermonuclear device. A primary, fission device detonates and the energy channeled from it ignites a secondary (and possible tertiary) stage. There would be a barely-perceptible delay in between stages. If the primary did not 'light off' the secondary, there would only be one energy pulse transmitted into the ground. They would expect two, or three. Just a guess! 174.196.4.96 (talk) 05:16, 12 January 2017 (UTC)


 * The US and the USSR (for two) each did a number of what were called salvo tests for various reasons. A salvo test is one in which two or more devices were set off at close to the same time and within close proximity of each other.  These were numbered as separate devices in a single test.  The USSR did a salvo test as the last test performed before they turned over Semipalatinsk to the Khzakhstanis, with eight devices.  This may have been the sort of thing that was witnessed.  India and Pakistan did their last tests as salvos of dissimilar devices, leading to confusion about how many tests they each ran.SkoreKeep (talk) 01:38, 21 November 2019 (UTC)