Lawrence Livermore on the brink of break even with Nuclear Fusion

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TheGreenGoblin
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Re: Lawrence Livermore on the brink of break even with Nuclear Fusion

#21 Post by TheGreenGoblin » Tue Sep 07, 2021 8:53 am

Prompted by this Livermore thread I have been reading about the development of the H bomb in Kenneth W Ford's 'Building the H Bomb' ,and how the initial work on the H bomb prompted the more pacific initial work on fusion as a possible source for the generation of useful power for commercial purposes as part of the Mattehorn project at Princeton University. The bomb issue yielded to these powerful brains within 2 to 3 years. and yet, here we are still struggling with developing a workable fusion reactor some +- 70 years later, despite the huge computing power we can now bring to bear on these problems!

It is interesting how Ford, who was a physicist on Wheeler's team in the development of the bomb, shies away from giving too much away about radiation pressure...

This is all he says about the key to the working bomb's success aside from general comments about the Teller Ulam process. It is interesting that despite this circumspection , his excellency book was censured for giving away nuclear secrets!
Not long after John Wheeler got back to Princeton after the test, he said to me, “Ken, we must have overlooked some energy-generating effect.” My response was, “John, given all of the approximations we had to make, and our seriously limited computing power, we were lucky to get within 30 percent of the right answer.” (I was counting down from 10, not up from 7.) Now, in retrospect, I have to wonder if my calculations underestimated the yield because we (the Los Alamos and Matterhorn teams combined) underestimated the compression. Perhaps the complex interplay of plasma pressure, ablation pressure, and radiation pressure (see page 157), studied with care in recent years by the independent analyst Cary Sublette,[12] added up to more than we took into account. We will never know. But it remains true that we squeezed remarkably good answers from a computer that today would be considered laughably inadequate.
Kenneth W Ford. Building the H Bomb :A Personal History...

Let it be noted that Kenneth W Ford is a pilot who has written about his passion for flying... In Love with Flying (a memoir) written in 2007.

The subject, even at its simplest, out of context of bombs and reactors, is fascinating...

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Re: Lawrence Livermore on the brink of break even with Nuclear Fusion

#22 Post by TheGreenGoblin » Tue Sep 07, 2021 11:33 am

His excellent book!

I plead the PN on this one.
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Re: Lawrence Livermore on the brink of break even with Nuclear Fusion

#23 Post by TheGreenGoblin » Tue Sep 07, 2021 12:49 pm

Ford goes a little further later on in his book but I shan't be able to craft my own thermo-nuclear weapon in my garage on the basis of this flimsy Mike design description.

I post this 'in toto' for those, like me, who are interested in this stuff...
As to other details, they are, technically, still secret. However, among the many unclassified published accounts, there is a broad agreement about the design of Mike. I report that consensus view here. At one end of the long cylindrical steel container is the fission bomb that will provide the radiation and get the thermonuclear process started. The fission bomb is the “match” that will light the rest. Working in from the outside of the steel cylinder, there is a layer of mostly low-density material such as polyethylene, which provides an easy channel for the radiation. (In his first design, Garwin proposed liquid hydrogen in this space, because he knew better how to calculate its behavior when flooded with radiation. Then comes a cylinder of ordinary, non-enriched uranium—reportedly five tons of it. Within that is a huge stainless-steel “thermos bottle” (a dewar) containing the liquid deuterium that is the thermonuclear fuel. That “bottle” includes evacuated layers to inhibit heat flow from the deuterium, which is at a temperature of just 24 degrees above absolute zero (about–249 degrees Celsius). There is also cryogenic “plumbing” to maintain that low temperature.* And finally, running along the axis is a slender cylinder of plutonium 239 (the highly fissionable isotope)—subcritical, of course until compressed. Within it, according to some reports, is yet a final detail—a pencil-thin space at the center containing a very small quantity of a deuterium-tritium mixture, just enough to “boost” the plutonium fission by providing additional neutrons from the DD and DT reactions. This axial plutonium is called the sparkplug. What then happens when the fission bomb “match” explodes? Its radiation runs out ahead of its expanding material and almost instantaneously vaporizes the polyethylene, creating a very hot plasma. The pressure of this plasma adds to the pressure of the radiation, pushing outward on the outer steel cylinder and at the same time inward on the uranium cylinder, thereby keeping the channel open long enough to let more radiation stream in. At the same time, the outer layers of the inner cylinder “ablate” (boil off), creating even more inward pressure. Before long—within microseconds—an inwardly imploding shock wave has compressed and heated the cylindrical container of deuterium and also, through compression, caused the plutonium sparkplug to go critical. The sparkplug, which is really another fission bomb, helps to ignite and then enhance the deuterium burning—hence the name “sparkplug.” Finally, energetic neutrons emitted in the thermonuclear burning (especially those of 14 MeV from the DT reaction) cause fission in the ordinary uranium that surrounds the deuterium as well as more fission in the sparkplug. Altogether quite a maelstrom. So this “H bomb” is really one part fusion and three parts fission. Its total energy release (its “yield”) is estimated, in fact, to have come about three-quarters from fission and one-quarter from fusion.
Kenneth W Ford. Building the H Bomb :A Personal History

Mike was a behemoth, it weighed well over 50 tonnes (excluding external cooling systems. All told the device weighed 82 tonnes) and had to be kept upright and encased in another dewar holding liquid hydrogen, once unclipped from the auxiliary cooling system, to keep the deuterium in its frigid liquid state. It was certainly not portable and was definitely a prototype and not a viable weapon in that it couldn't be carried by an aircraft.

mikedevice.jpg

Ivy Mike Tests...

mike1.jpg
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Flying into the Ivy Mike Cloud.

#24 Post by TheGreenGoblin » Wed Sep 08, 2021 6:44 pm

The Ivy Mike test resulted in the death of a USAF airman. The story behind the pilots who entered the boiling cloud after the detonation are not often told!


https://www.airspacemag.com/history-of- ... -35152524/
While we were going through the cloud, Robinson became disoriented and spun out,” Hagan recalls. Apparently, as Robinson pulled his airplane into a tight turn to escape what his instruments told him was a particularly hot part of the cloud, his autopilot disengaged, and as the jet stalled and lost altitude, he briefly lost control. Flight leader Meroney later reported hearing heavy breathing over the radio, as if Robinson had been holding down his mike button while fighting to control the aircraft. After Robinson reported that he had recovered at 20,000 feet, Meroney ordered him and Hagan to leave the cloud and rendezvous.

“I continued on out of the cloud and then went down to 20,000 feet to try to find him, but that didn’t work,” Hagan remembers. “There was a refueling tanker there but they couldn’t find us.” Electromagnetic aftereffects from the H-bomb explosion were also wreaking havoc with their navigational and radio equipment, while their fuel supply dissipated. After being forced to spend almost an hour at lower altitude, where fuel efficiency decreases, Hagan and Robinson had eaten into their scarce reserves. “I decided we better head for a runway somewhere, and Enewetak was the only one that was around,” Hagan says. He managed to pick up a radio beacon from the island and started off. Soon after, Robinson caught the beacon and followed Hagan.


Pacific cloud sampling missions had greater flying distances, so fuel was tight, and with F-84s unable to carry wingtip fuel tanks—that was where the cloud sampling filters were mounted—fuel capacity was even more limited. “When we got to Enewetak, my gas gauge was on empty,” Hagan says. “Luckily on final [approach], I was able to set up a pattern and land without fuel, deadstick.” On the hard landing, the right tire blew out.

Robinson wasn’t as lucky. He reported to Enewetak tower that at 13,000 feet his engine had flamed out, but he thought he could make the runway. By the time he’d dropped to 5,000 feet, with the island and runway in sight, Robinson radioed that he was bailing out over the water.

A rescue helicopter spotted Robinson’s F-84, wings level and gliding in, at about 500 feet, north of the atoll. To the rescue pilot, it looked as though Robinson had jettisoned his canopy but had decided to stay in the cockpit and try for a water landing. The craft hit the water, skipped smoothly over the surface, then hit a wave and flipped over. The rescue helicopter hovered over the jet as it sank rapidly. Robinson was nowhere to be seen.


“As I got out of my airplane,” recalls Hagan, “the people in the tower told me that an airplane had just gone into the ocean behind me. They didn’t see any signs of a parachute or anything.” The sampling pilots wore lead-lined vests, which, along with the rest of their gear, would have made even bailing out problematic, let alone staying afloat.

According to official reports, Robinson’s body was never recovered. “They searched but they couldn’t find anything,” says Hagan. “It’s pretty deep right there. I wasn’t around when they did it, but I heard later that they had tried and couldn’t find the airplane or Jimmy at all. There must have been currents in there that took the airplane away.” Captain Jimmy Priestly Robinson, age 28, would be awarded a posthumous Distinguished Flying Cross about a year later.


Mark Wolverton’s latest book is A Life in Twilight: The Final Years of J. Robert Oppenheimer.
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"To be alive
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Your destination remains
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Re: Lawrence Livermore on the brink of break even with Nuclear Fusion

#25 Post by TheGreenGoblin » Thu Sep 09, 2021 3:21 am

Some more flying form the Lawrence Livermore Labs...

Though you remain
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Your destination remains
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