Weapon physicist declassifies rescued nuclear test films

[Winston]

FINALLY, something I've for years wondered why they weren't doing, being done not just for history preservation but primarily for much more accurate data extraction. I wish they'd do the same for NASA films although that would be primarily for historic preservation, so don't hold your breath.

These recently declassified nuclear test videos are utterly mesmerizing, terrifying
Sat in vaults for decades, Lawrence Livermore National Lab is putting them on YouTube.

https://arstechnica.com/gaming/2017...st-videos-are-utterly-mesmerizing-terrifying/

[video=youtube;pWpqGKUG5yY]https://www.youtube.com/watch?v=pWpqGKUG5yY[/video]

For some strange reason, the few LLNL posted test videos linked to in that Ars Technica article are UNLISTED on YouTube, so you won't find them by looking at the Lawrence Livermore National Lab's YouTube home page. I'd love a DVD or some DVD sets of all tests, but as with the NASA film restoration, I won't hold my breath.

[video=youtube;uYbNlgQyz84]https://www.youtube.com/watch?v=uYbNlgQyz84[/video]

[video=youtube;54PCN1MF1RU]https://www.youtube.com/watch?v=54PCN1MF1RU[/video]

[video=youtube;L_jFQw78uzo]https://www.youtube.com/watch?v=L_jFQw78uzo[/video]

The entire LLNL playlist so far:

https://www.youtube.com/playlist?list=PLvGO_dWo8VfcmG166wKRy5z-GlJ_OQND5

Some great DVDs that ARE available with digitally restored (film grain & scratch elimination, contrast and color corrected) test films can be found here:

https://atomcentralstore.mybigcommerce.com/

 

[Nytrunner]

That is some incredible footage. Those aerial detonations look like the surface of the sun for a split second, and the ground disruption ~25 second mark of the second video reminds me of the Death star test shots in Rogue One.

I guess there is less weight to keeping them classified since nuclear weapons really aren't a secret anymore.
Everyone knows that the world ends when those get used,

 

[XolveJohn]

Most of them look the same. Find one on Castle Bravo, was supposed to be 5MT but turned out to 15MT, someone forgot a term in the yield equation. Almost burned dudes up 100 miles away.

I saw a simulation done on the old Cray supercomputer. The display was round and monochrome.

With a digital counter reading in nanosec. It is all over in about 30nS. What you see is the aftermath.

 

[aerostadt]

The first two show air bursts near the ground. It is interesting to see the collision of the spherical shock wave with the ground. In Shapiro's old classical book on compressible gas dynamics (which use to be the bible for classical gas dynamics and might still be) he set up several problems at the end of the chapter where he proposes ratios of static temperature to stagnation temperature and likewise static pressure to total pressure for atomic bomb blasts. As I remember the temperature ratios and pressure ratios were in the millions.

 

[Nytrunner]

The first two show air bursts near the ground. It is interesting to see the collision of the spherical shock wave with the ground. In Shapiro's old classical book on compressible gas dynamics (which use to be the bible for classical gas dynamics and might still be) he set up several problems at the end of the chapter where he proposes ratios of static temperature to stagnation temperature and likewise static pressure to total pressure for atomic bomb blasts. As I remember the temperature ratios and pressure ratios were in the millions.

I'm going to say we skipped the "nuclear devastation" section of Shapiro's book when I took Thermo 2 and compressible flow.

 

[Cabernut]

It's really cool that in the first two, you can actually see the tower and it's support cables being vaporized. It almost seems as if the explosion travels faster through solid matter. I have a DVD documentary narrated by William Shatner that goes through the entire nuclear weapons program and shows much of the declassified and cleaned-up footage. If I remember correctly, these were shot at something like a million frames per second. The third video I believe is a high-altitude burst.

 

[Winston]

Most of them look the same. Find one on Castle Bravo, was supposed to be 5MT but turned out to 15MT, someone forgot a term in the yield equation. Almost burned dudes up 100 miles away.

The Bravo device used natural Li metal because they didn't have enough Li-6 which they would have incorrectly preferred at the time. They had a bad theory predicting a LACK of fusion contribution from the more common lithium isotope Li-7 which was found to be not true in reality. It worked just fine. Oops! As a result, the Bravo shot contaminated an area of 5000 square miles with levels of radiation that would have been lethal to unprotected personnel. I recall that the north end of one occupied island was contaminated at levels that would have been lethal after only one hour of exposure, but vastly lower at the south end of the island. Luckily, everyone was at its south end and the winds weren't in just a very slightly more southward direction.

An anecdote related to that Li thing. The nuke program initially wanted to extract and use only Li-6 since they incorrectly thought that Li-7 would be a drag on the fusion process instead of the positive that it turned out to be. They secretly extracted it from all of the lithium they could find in the US. Unfortunately, some guy not working on nuclear weapons came up with a clever idea for a neutron detector which used lithium metal. Unfortunately, it required that the natural percentage of Li-6 found in the metal be present and, normally, there'd be no reason why it wouldn't be. His device didn't work and, if I recall correctly, he actually troubleshot the problem and discovered the lack of Li-6. I don't recall if he ever discovered or was told the reason why it wasn't there.

I think he might have suspected the reason as I might have. Another anecdote on that particular point - years ago in a very large library near my assigned USAF base I was looking up books on nukes. There was this old 50s or early 60s book on Plutonium Metallurgy for use by nuclear reactor designers since in the 50s and 60s they were still experimenting with breeder reactors. It wasn't in the stacks were it should have been. I asked for it and the guy behind the desk went somewhere and brought it back. Strange, huh? ("You're on a list, son. Oh, he's in the USAF with an outstanding record? No problem then.") Anyway, inside was a periodic table marked to show all metals which had been experimentally alloyed with Pu. All of the metals were marked as having been tried and whose characteristics would be in the book... all except for gallium. I thought, "I'll bet that's what they use in nukes." Sure enough as I found out some time later when I saw a publicly available technical report listed in the National Technical Information Service's catalog of reports entitled something like "Corrosion of 1% Gallium by weight Pu239 alloy in hotbox atmospheres" and the source of that report was the Rocky Flats facility... where the Pu239 pits for nukes were made.

That's a small example of how the late, great Chuck Hansen pieced together his extensive tech data about nukes, except his efforts were like mine times 10^10.

Chuck Hansen

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

 

[Winston]

The first two show air bursts near the ground. It is interesting to see the collision of the spherical shock wave with the ground. In Shapiro's old classical book on compressible gas dynamics (which use to be the bible for classical gas dynamics and might still be) he set up several problems at the end of the chapter where he proposes ratios of static temperature to stagnation temperature and likewise static pressure to total pressure for atomic bomb blasts. As I remember the temperature ratios and pressure ratios were in the millions.

A most awesome spherical fireball and shock wave photo is from the Upshot-Knothole Grable (atomic cannon) shot. I managed to find a very large, hi-res version that I think I've already linked to here in another thread. I'll look for it. On another interesting nuke topic:

Rope trick effect

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

Many more Rapatronic images here:

https://www.google.com/search?q=rap...HZOwAksQsAQIGQ#tbm=isch&q=rapatronic+images&*

 

[Winston]

Photo from the excellent book, "Britain and the H-Bomb":

The Orange Herald Small device

From wikipedia:

Orange Herald was a fusion boosted British fission nuclear weapon, comprising a U-235 primary surrounded by lithium deuteride. 'Herald' was suitable for mounting on a missile, utilizing 117 kg of U-235. However, Britain's annual production of U-235 was only 120 kg at this time, which would have made such weapons rare and very expensive.[1]

Two versions were designed - an "Orange Herald Large" with an overall diameter of 39 inches (1.0 m), and an "Orange Herald Small" with overall diameter of 30 inches (0.75 m).[1]

The Orange Herald Small version was tested once, yielding 720 kt of explosive power on 31 May 1957, during the Grapple 2/Orange Herald tests on Malden Island in the Pacific.[2] Orange Herald remains the largest fission device ever tested.

It is thought that the fusion boosting failed to increase the yield. A higher compression but smaller fission pit American weapon, the Mark 18 Super Oralloy Bomb, had a yield of 500 kilotons from a pit with slightly over 60 kilograms of highly enriched uranium, around 8 kilotons per kilogram of uranium, about the practical maximum 50% fission yield efficiency for very large or very highly boosted fission weapons. Even with less compression, the larger 117 kg pit of HEU in the Orange Herald Small should have had a roughly similar efficiency, but the observed 720 kiloton yield equals only just over 6 kilotons per kilogram of uranium.

Orange Herald was the first British nuclear device to use an external neutron source.[3]

Brit nukes:

https://nuclearweaponarchive.org/Uk/UKTesting.html

 

[Johnly]

The Bravo device used natural Li metal because they didn't have enough Li-6 which they would have incorrectly preferred at the time. They had a bad theory predicting a LACK of fusion contribution from the more common lithium isotope Li-7 which was found to be not true in reality. It worked just fine. Oops! As a result, the Bravo shot contaminated an area of 5000 square miles with levels of radiation that would have been lethal to unprotected personnel. I recall that the north end of one occupied island was contaminated at levels that would have been lethal after only one hour of exposure, but vastly lower at the south end of the island. Luckily, everyone was at its south end and the winds weren't in just a very slightly more southward direction.

An anecdote related to that Li thing. The nuke program initially wanted to extract and use only Li-6 since they incorrectly thought that Li-7 would be a drag on the fusion process instead of the positive that it turned out to be. They secretly extracted it from all of the lithium they could find in the US. Unfortunately, some guy not working on nuclear weapons came up with a clever idea for a neutron detector which used lithium metal. Unfortunately, it required that the natural percentage of Li-6 found in the metal be present and, normally, there'd be no reason why it wouldn't be. His device didn't work and, if I recall correctly, he actually troubleshot the problem and discovered the lack of Li-6. I don't recall if he ever discovered or was told the reason why it wasn't there.

I think he might have suspected the reason as I might have. Another anecdote on that particular point - years ago in a very large library near my assigned USAF base I was looking up books on nukes. There was this old 50s or early 60s book on Plutonium Metallurgy for use by nuclear reactor designers since in the 50s and 60s they were still experimenting with breeder reactors. It wasn't in the stacks were it should have been. I asked for it and the guy behind the desk went somewhere and brought it back. Strange, huh? ("You're on a list, son. Oh, he's in the USAF with an outstanding record? No problem then.") Anyway, inside was a periodic table marked to show all metals which had been experimentally alloyed with Pu. All of the metals were marked as having been tried and whose characteristics would be in the book... all except for gallium. I thought, "I'll bet that's what they use in nukes." Sure enough as I found out some time later when I saw a publicly available technical report listed in the National Technical Information Service's catalog of reports entitled something like "Corrosion of 1% Gallium by weight Pu239 alloy in hotbox atmospheres" and the source of that report was the Rocky Flats facility... where the Pu239 pits for nukes were made.

That's a small example of how the late, great Chuck Hansen pieced together his extensive tech data about nukes, except his efforts were like mine times 10^10.

Chuck Hansen

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

Li-6 is still the preferred isotope as the neutron absorption cross-section for Li-6 is over 20,000 times larger than that of Li-7(960 Barns verses .045 Barns).
While the D-T and T-T fusion reaction produces a release in energy, the primary mission (except for ER designs) is to produce additional neutrons to completely fission the plutonium components and as much of the fissile neutron/ x-ray reflector as the design permits. This design generates the greatest yield/kg. which is a critical design parameter. Hard to say exactly why they didn’t account for the tritium production by the Li-7 production in the Bravo test, but some things to consider. The neutron flux in the Bravo device was 10^12 times higher than that found in power/breeder reactor designs; not to mention that most reactors operate using thermal neutrons, while the Bravo device was almost 100% fast neutrons. Given those constraints, it would have been exceptionally difficult for them to calculate the outcome in advance. Hindsight is 20/20

 

[XolveJohn]

I think all bombs only use fast neutrons. Chuck Hansen is new to me, check out Theodore Taylor if you have not heard of him, made great strides on fission weapons when everyone else gave up on them. Like the levitated core, suspended by wires in a hollow pit with the tamper and HE spaced away. The tamper gathers speed before hitting, increases yield 4 times, I think. Like a hammer and nail, it is hard to just push the nail in with the hammer, but if you swing at it the impact does it easily. Book: The Curve of Binding Energy, by John McPhee. Also liked Day of Trinity by Lansing Lamont. These toys are very dangerous, and we may learn we cannot handle them. One nut like Kim could start a chain reaction across the world. Also check out the Davey Crockett, the smallest nuke made, launched by recoiless rifle (WHERE WERE THE ROCKETS???). https://en.wikipedia.org/wiki/Davy_Crockett_(nuclear_device)

 

[markkoelsch]

I think all bombs only use fast neutrons. Chuck Hansen is new to me, check out Theodore Taylor if you have not heard of him, made great strides on fission weapons when everyone else gave up on them. Like the levitated core, suspended by wires in a hollow pit with the tamper and HE spaced away. The tamper gathers speed before hitting, increases yield 4 times, I think. Like a hammer and nail, it is hard to just push the nail in with the hammer, but if you swing at it the impact does it easily. Book: The Curve of Binding Energy, by John McPhee. Also liked Day of Trinity by Lansing Lamont. These toys are very dangerous, and we may learn we cannot handle them. One nut like Kim could start a chain reaction across the world. Also check out the Davey Crockett, the smallest nuke made, launched by recoiless rifle (WHERE WERE THE ROCKETS???). https://en.wikipedia.org/wiki/Davy_Crockett_(nuclear_device)

Ted Taylor was brilliant.

 

[XolveJohn]

Yes. Maybe he figured out tritium gas boost. Teller was smart, but needed Ulam to do the best work.

The H-bomb. Light compression. Tons of force from miserable photons.

 

[Johnly]

I think all bombs only use fast neutrons. Chuck Hansen is new to me, check out Theodore Taylor if you have not heard of him, made great strides on fission weapons when everyone else gave up on them. Like the levitated core, suspended by wires in a hollow pit with the tamper and HE spaced away. The tamper gathers speed before hitting, increases yield 4 times, I think. Like a hammer and nail, it is hard to just push the nail in with the hammer, but if you swing at it the impact does it easily. Book: The Curve of Binding Energy, by John McPhee. Also liked Day of Trinity by Lansing Lamont. These toys are very dangerous, and we may learn we cannot handle them. One nut like Kim could start a chain reaction across the world. Also check out the Davey Crockett, the smallest nuke made, launched by recoiless rifle (WHERE WERE THE ROCKETS???). https://en.wikipedia.org/wiki/Davy_Crockett_(nuclear_device)

Correct, almost 100% fast neutrons in weapons. A plutonium 238 fission only has 1/3 of the thermal energy delayed neutrons as compared to uranium 235, which is why it is exceptionally difficult to fuel a commercial power reactor with plutonium. Not sure if the assembly holds together long enough for them to me emitted by the fission fragments to assist in the yield.

Not to be out done by the Army, the US Air Force had the GAR-1 Genie. Short range and unguided, the pilot had to fly directly at the bomber formation at high speed, then divert their flight path to avoid the flash and blast.

 

[XolveJohn]

Cool, wear your sunglasses! The Genie was a fun missile. I believe it was unguided. Just shoot it and run.

https://www.boeing.com/history/products/mb-1-air-2-genie-missile.page

The Genie was the world’s first nuclear-armed air-to-air weapon and was the most powerful interceptor missile ever deployed by the U.S. Air Force.
In 1954, the Douglas Aircraft Co. began work on a small unguided nuclear-armed air-to-air missile and started full-scale development a year later. In 1955 and early 1956, F-89D Scorpion aircraft made the first test firings. The top-secret project had several code names, including “Bird Dog,” “Ding Dong” and “High Card.” Finally, it was designated MB-1 and called the “Genie.” The MB-1 became operational in 1957, and the first and only live firing of a nuclear Genie was July 19, 1957.
Powered by a Thiokol SR49 solid-fueled rocket motor, it was armed with a 1.5-kiloton nuclear warhead and had flip-out fins for flight stability. F-89J, F-101B and F-106A interceptors carried the Genie. The firing aircraft had to pull away in a sharp turn to escape the blast after launching the weapon, a challenging feat.


There is an interesting document out there called The Los Alamos Primer. It was written just as the war started, to list the total information known about fission. Most is over my head, but might add to your knowledge.

 

[Winston]

I think all bombs only use fast neutrons. Chuck Hansen is new to me, check out Theodore Taylor if you have not heard of him, made great strides on fission weapons when everyone else gave up on them. Like the levitated core, suspended by wires in a hollow pit with the tamper and HE spaced away. The tamper gathers speed before hitting, increases yield 4 times, I think. Like a hammer and nail, it is hard to just push the nail in with the hammer, but if you swing at it the impact does it easily. Book: The Curve of Binding Energy, by John McPhee.

I own that book. Ted tells of his lighting a cigarette from a test of one of his designs at the focal point of a parabolic mirror he found laying around. Later in life, he became very much anti-nuke.

Also check out the Davey Crockett, the smallest nuke made, launched by recoiless rifle (WHERE WERE THE ROCKETS???). https://en.wikipedia.org/wiki/Davy_Crockett_(nuclear_device)

A cool design, but about as dumb, but not quite, as the Army's atomic cannon.