LLNL nuclear test films on YouTube

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Winston

Lorenzo von Matterhorn
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Frequently asked questions answered. Note why they say they're doing it - to validate computer code which simulate nuclear detonations. The digital film analysis allows 1% accuracy of interpretation versus 10% accuracy via previous human analysis. Since they have the precise designs of everything detonated we can INFER that they will do a direct comparison of what is seen in the films and what supercomputer simulations of those exact designs produce. Since they are also doing incredibly extensive and detailed non-nuclear and non-critical nuclear testing of every component of nuclear warheads as part of stockpile stewardship (making sure our existing nukes remain viable), the unstated additional likely benefit of that stockpile stewardship is to develop highly accurate computer code to design 4th generation nuclear weapons if that is ever needed:

[video=youtube;tsOrRWzmmUU]https://www.youtube.com/watch?v=tsOrRWzmmUU[/video]

LOOK at what they could do with the cro-magnon computing capabilities of 1956. Wow!:

Swan (nuclear primary)

https://en.wikipedia.org/wiki/Swan_(nuclear_primary)

The Swan device is the first design to incorporate a two-point ignition hollow-pit air-lens implosion assembly together with fusion boosting.

U.S._Swan_Device.svg


UNFORTUNATELY, the test films of the Swan primary, Redwing - Inca, and a thermonuclear device using that primary, Redwing- Mohawk, have yet to be digitized by LLNL. They started on the Redwing tests only last month.

Operation Redwing

https://nuclearweaponarchive.org/Usa/Tests/Redwing.html
 
I remember hearing at one stage that even when declassified, there are two key frames of film that are still removed from the footage for each detonation, as these are the frames that are key to determining the yield and other critical elements that are still considered not fit for declassification. I can't find any reference to this in a limited 15min googling exercise however..

Interested if anyone has any knowledge or reference for this..
 
I remember hearing at one stage that even when declassified, there are two key frames of film that are still removed from the footage for each detonation, as these are the frames that are key to determining the yield and other critical elements that are still considered not fit for declassification. I can't find any reference to this in a limited 15min googling exercise however..

Interested if anyone has any knowledge or reference for this..
Interesting, I've never heard that specifically. I have heard that the fireball's rate of expansion and size early on can be used for yield determination since lasting effects of obstruction by things like the shelter/enclosure and atmospheric effects are negligible compared to the forces of the fireball especially with high yield devices. In that case, I would think that dropping every nth frame in a high speed film would be better at hiding the actual yield than dropping just a few frames, but I'm no expert on this (as much as I'd love to be).

Operation Tumbler-Snapper test shot "How"

300 ft tower
14 kt

Lightweight design. First test to use a beryllium neutron reflector/tamper. It is believed to have used a spherical implosion assembly, levitated pit, and 92-point detonation. Using it, Ted Taylor lit his success cigarette mounted at the focal point of a small parabolic mirror he'd found at the lab.

tumbler-snapper-how.jpg


It's designer's story:

The Curve of Binding Energy: A Journey into the Awesome and Alarming World of Theodore B. Taylor

https://www.amazon.com/dp/0374515980/?tag=skimlinks_replacement-20

More on Ted Taylor without the need to buy the book:

Strange Love
Or, how they learned to start worrying and love to hate the bomb.


https://cdn.makezine.com/make/strangelove.pdf

TO LOOK A DEMON IN THE EYE: NUCLEAR TESTS AND RAPATRONIC IMAGING

https://atomicscout.wordpress.com/2...the-eye-nuclear-tests-and-rapatronic-imaging/

ultra-high-speed-photograph-of-shed-observed-at-moment-of-atomic-bomb-explosion-taken-at-eniwetok-ca-1952.jpg


This is a rapatronic image of a ‘shot cab’ at the moment of an atomic bomb explosion. The cab appears to be fluorescing with X-Ray energy making it transparent.(Photo via Edgerton Digital Collections, taken at Eniwetok, c. 1952)

ATOMIC-ANNIHILATION
...or how I learned to stop worrying and start a Blog

https://atomic-annhilation.blogspot.com/
 
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The more I think about the two key frames, I’m thinking this was the early declassified footage (before the most recent test footage releases) and might have been removal of the frames that showed the tell tale “double flash” frames maybe?
 
From the "Strange Love - Or, how they learned to start worrying and love to hate the bomb" PDF linked to above. Italicized text is quoted text:

Physicists love explosions. We owe our nuclear predicament to a quirk of human nature: designing, making, and testing nuclear explosives can be fun. “The sin of the physicists at Los Alamos did not lie in their having built a lethal weapon,” physicist Freeman Dyson (my father) has explained. “They did not just build the bomb. They enjoyed building it. They had the best time of their lives building it. That, I believe, is what Oppenheimer had in mind when he said that they had sinned.”

[snip]

What excited [Ted] Taylor most were really, really small atomic bombs. “It was curiosity, wondering, ‘What’s the limit?’ I wanted a panoramic view.” Taylor was interested in low-yield explosions not because he anticipated a need for them — or a fear of terrorism — but because he was intrigued by the delicate balances involved.

“I said, why don’t we build things with much less plutonium in there and see what’s going on in the middle with much more sensitivity. We can do things at around a kiloton instead of what was then the predicted yield of a stockpile bomb, 80 kilotons — it was that for years. To make small yields with big implosion assemblies, that got fascinating. I was pushing things as far as one could go, never mind that you wind up in some cases with shells less than a millimeter thick. Who’s going to make those? As it turned out, it was very worthwhile to find some way to make those.”


The "shells" he's talking about is the shell of a hollow (levitated) fissile pit, a "levitated" core. The reason the Fat Man pit was not levitated was because even the tiniest pressure asymmetry in the implosion wave compressing the core will disrupt the compression with the fissile material(s) squirting out of the lower pressure area(s) like a seed out of a squeezed grape. For many reasons, core levitation is much preferable to a solid core - excellent shock wave energy transfer to the pit instead of reflection, unimpeded acceleration of fissile materials to the center of the pit with resulting huge momentum, hollow center allows DT gas to be injected into pit for fusion boosting of the fissioning pit via massive numbers of very high energy neutrons produced from DT fusion - but the implosion wave must be extremely precise. The fact that an implosion wave can apparently be made so precise that it can successfully implode a hollow sphere with a shell less than one millimeter thick into a perfect, highly compressed solid sphere is simply MIND BOGGLING.

“Pursuing these limits became an obsession,” Taylor admitted. “What is the absolute lower limit to the total weight of a complete fission explosive? What is the smallest amount of plutonium or uranium 235 that can be made to explode? What is the smallest possible diameter of a nuclear weapon that could be fired out of a gun?” The answers were surprising. “I was narrowing my focus, getting the quantities of plutonium that one could use to make nuclear explosions down to less than a kilogram. Quite a bit less.”

The smallest tactically deployed nuclear weapon was the Davy Crockett, with a warhead weighing less than 60 pounds. It was not designed by Taylor. “I tried to find out what was the smallest bomb you could produce, and it was a lot smaller than Davy Crockett, but it was never built in those years,” he said. “It certainly has been since then. It was a full implosion bomb that you could hold in one hand that was about 6 inches in diameter.”

[snip]


I keep stumbing upon confirmation of my hunch about the MAJOR side benefit of the Stockpile Stewardship Program - precise warhead design via supercomputer:

There were four main technical obstacles to building an implosion weapon the first time: accumulating fissionable material; performing the computations necessary to validate the physics underlying the design; machining the components precisely in space; and firing the detonators precisely in time. Computers have shifted the landscape, and only the first obstacle still looms large. The average notebook computer has more computing horsepower than all of Los Alamos did while the weapons constituting most of our present stockpile were designed.

[snip]

The latest advance in the United States nuclear arsenal is the stockpile stewardship program, which claims to predict, purely from computer simulations and non-nuclear tests, whether our stockpile weapons will work or not. The next step in this arms race is a new generation of weapons whose designs are so simple, and so completely modeled using powerful computer simulations, that we do not have to test them to be sure that they will explode. But this favors potential adversaries as much as it favors us. The danger of not testing nuclear weapons is that we no longer know who has what.


Here's where he's apparently thinking about a 4th generation nuclear weapon of the directed energy type:

“I had a dream last night, about a new form of nuclear weapon, and I’m not telling anybody what this is, because I’m really scared of it,” Taylor told me in 1999. “I have tried, I thought successfully, to hold on to a vow of just not thinking about new types of nuclear weapons any more. And what’s happened, to put it simply, is that it has gone from my conscious to my unconscious, and it’s emerging as a dream; I cannot shut it off. I woke up at 2 a.m. and went back to bed at about 6 o’clock, and wound up filling up a page with notes. It makes me think of the prototypical example of what directed energy can do, making the transition from a pile of high explosive to a gun, as the Chinese did, after they invented it. What I am afraid is in the offing is people figuring out how to make a transition that’s as spectacular as trying to kill a deer at 200 yards with a pile of high explosive, or by shooting at it.”

Taylor had the time of his life designing bombs, and spent the remainder of it trying to get the madness of threatening to use them stopped.

---------

Ted's Super Oralloy (fission) Bomb, the backup if H-bomb development met a snag. The core was a highly levitated (thin-walled) sphere which was necessary to prevent the FOUR critical masses worth of highly enriched U235 from reaching critical mass just sitting there:

Ivy King - Mark 18 Super Oralloy nuclear bomb

https://en.wikipedia.org/wiki/Mark_18_nuclear_bomb

https://nuclearweaponarchive.org/Usa/Tests/Ivy.html

B-36 air drop - 18 Nov 1952, 11:30 hrs local
Airburst at 1480 feet ASL
500 kt

The Mark 18 nuclear bomb, also known as the SOB or Super Oralloy Bomb, was an American nuclear bomb design which was the highest yield fission bomb produced by the US. The Mark 18 had a design yield of 500 kilotons. Noted nuclear weapon designer Ted Taylor was the lead designer for the Mark 18.

The Mark 18 was tested once, in the Ivy King nuclear test at the Enewetak atoll in the Pacific Ocean. The test was a complete success at full yield.

The Mark 18 bomb design used an advanced 92-point implosion system, derived from the Mark 13 nuclear bomb and its ancestors the Mark 6 nuclear bomb, Mark 4 nuclear bomb, and Fat Man Mark 3 nuclear bomb of World War II. Its normal mixed uranium/plutonium fissile core ("pit") was replaced with over 60 kg of pure highly enriched uranium or HEU. With a natural uranium tamper layer, the bomb had over four critical masses of fissile material in the core, and was unsafe: the accidental detonation of even one of the detonator triggers would likely cause a significant (many kilotons of energy yield) explosion. An aluminum/boron chain designed to absorb neutrons was placed in the fissile pit to reduce the risk of accidental high yield detonation, and removed during the last steps of the arming sequence.

Beginning in March 1953, the United States deployed a number of Mark 18 bombs. A total of 90 were manufactured and placed in service.

The weapon had a short lifetime, and was replaced by thermonuclear weapons in the mid-1950s. The Mark 18 weapons were all modified into lower yield Mark 6 nuclear bomb variants in 1956.


More on Ivy King's construction:

The Ivy King bomb, designated as a Mk-18 bomb and named the "Super Oralloy Bomb", was a modified version of the Mk-6D bomb. Instead of using an implosion system similar to the Mk-6D, it used a 92 point implosion system initially developed for the Mk-13. Its uranium-plutonium core was replaced by 60kg of highly enriched uranium (HEU) fashioned into a thin-walled sphere equivalent to approximately four critical masses. The thin-walled sphere was a commonly used design which ensured that the fissile material remained sub-critical until imploded. The HEU sphere was then enclosed in a natural uranium tamper. To physically prevent the HEU sphere collapsing into a critical condition if the surrounding explosives were detonated, or if the sphere was crushed following an aircraft accident, the hollow centre was filled with a chain made from aluminium and boron which was pulled out to arm the bomb. The boron coated chain also absorbed the neutrons needed to drive the nuclear reaction.

[video=youtube;J7Z-mmu7f2E]https://www.youtube.com/watch?v=J7Z-mmu7f2E[/video]
 
I just ordered the book you linked. Should be a good read.
 
Very good video. Thanks for the post. I have always wondered why there was smoke trails in some of the nuclear test videos I have watched. :)
 
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