Posted by rbanffy 2 days ago
A wooden frame supported an elliptical-shaped structure, 20 feet high, 6 feet wide at the ends and 25 feet across the middle. It contained 6 short tons of uranium metal, 50 short tons of uranium oxide and 400 short tons of graphite, at an estimated cost of $2.7 million. According to Robert Crease, CP-1 and preceding piles were "the largest unbonded masonry structures since the pyramids.
On December 2, 1942, Fermi announced that the pile had gone critical at 15:25. Fermi switched the scale on the recorder to accommodate the rapidly increasing electric current from the boron trifluoride detector. He wanted to test the control circuits, but after 28 minutes, the alarm bells went off to notify everyone that the neutron flux had passed the preset safety level, and he ordered Zinn to release the zip. The reaction rapidly halted. The pile had run for about 4.5 minutes at about 0.5 watts. Wigner opened a bottle of Chianti, which they drank from paper cups.
Really feels like catching the dragon by its tail.
Groves's book ("Now It Can Be Told") mentions the people that worked with the graphite bricks, that it got into their skin, and even after an after-work shower, they'd still ooze graphite for hours.
Firstly I wonder what their cover story for their spouses was.
Secondly it's clear that they should've had an on-site sauna. Get some deep cleaning going. That would've flushed the graphite gunk out of their hides.
He assumed that graphite of such high purity can be useful only for this purpose during the wartime.
- Biographies of the preeminent scientists of the 20th century
- A history of late 19th and early 20th century physics and chemistry. Much more technical than many history books, which is a drawback for some audiences, but probably an attraction for a lot of people here.
- A history of World War I and World War II
- A history of the engineering and operation of the Manhattan Project
Highly, highly recommended for this audience.
One caveat: I tried the audiobook and couldn't stand the narrator. Your mileage may vary, but I recommend reading it.
This was the only parts of the book I skimmed over / skipped. While interesting, many of them go back to their parents and childhood upbringing which, again are interesting, but being more interested in the science/engineering I would skip ahead until their story was more relevant.
A good book.
May I also recommend the In Our Time episode on the Manhattan Project.
https://www.bbc.co.uk/programmes/m00108h1
(The Richard Rhodes book is on the recommended reading list for this episode, listed on the linked website; as are other very good books on the Manhattan Project worth a read).
I recommend Igniting the Light Elements for people who want a keystone piece about the early thermonuclear. https://www.osti.gov/servlets/purl/10596 - it's an extensive Thesis on the history of early thermonuclear period. Also one of the last comprehensive looks before classification fully obscures the plurality of the programs.
Update, I tracked down the book. The guy was Ford, who worked for Wheeler: https://pubs.aip.org/physicstoday/article/68/7/46/415213/Bui...
This was an enormous undertaking in a relatively short amount of time, even during wartime. I can hardly fathom the scale and urgency of these operations. I suppose the Russians invested similarly massive resources to build their own A-bomb after the war.
Interestingly, it was believed at the time that German scientists were also very close to producing a nuclear weapon. As was later discovered after the war, they were not.
Yes this was the prime motivator, at least on paper. One can suspect Vannevar Bush or Leslie Groves of ulterior motives (Vannevar: fomenting a defense-fueled ‘Big Science’ infrastructure which he certainly achieved going into the postwar, Groves: creating a weapon to fend off the Soviets for the postwar).
> As was later discovered after the war, there were not.
Man this is a dicy one. There has been some scholarship in recent decades that the Germans may have got a lot farther than history has hitherto accepted to date, all the way up to minor (semi-fizzled?) detonations. Rainer Karlsch has been the main accumulator of relevant archives especially from the Soviet side. Todd Rider formerly of MIT’s Lincoln Lab has done yeoman’s work in piecing together the logic of Karlsch’a work and archive digging of his own & volunteers’. In short, we are not sitting on a consensus reality of just how far the Germans got in developing an atomic bomb, and we aren’t 100% certain on how little we relied on recuped German know-how in developing our own atomic bomb between May-August 1945, not how much we (ahem, Teller) may have relied in part on German know-how in developing the H-bomb. As I mentioned in another comment, the reference for this is
https://riderinstitute.org/revolutionary-innovation/#chapter...
Appendix D is the main one for this topic, and Chapter 8 for context.
For example, the USSR built plutonium production facilities and tested a working plutonium-based implosion bomb before they produced highly enriched uranium. The Soviet uranium enrichment program was also simplified compared to the US: they built out the most effective technology that the American program demonstrated (gaseous diffusion). They developed the marginally effective calutron enrichment process only to a trial scale and ignored the practically useless liquid thermal diffusion enrichment process.
[0] https://nsri.nebraska.edu/-/media/projects/nsri/docs/academi... [1] https://en.m.wikipedia.org/wiki/816_Nuclear_Military_Plant
I believe that the the "AD", "ADE-1", and "ADE-2" reactors here are the only underground ones:
https://en.wikipedia.org/wiki/Soviet_atomic_bomb_project#Plu...
https://en.wikipedia.org/wiki/History_of_the_Teller%E2%80%93...
The threat to the US was that, unless they are first to develop nuclear weapons, they’d risk the war could end up being fought on their land.
Behind that phrase is a whole story in itself, covered in the book "Wizards of Oz How Oliphant and Florey helped win the war and shape the modern world" by Brett Mason.
Mark Oliphant was heading a lab and tasked Otto Frisch and Rodolf Perierls with figuring out whether an atomic bomb was possible, as they were not cleared to work on radar. They concluded it was possible and wrote a two part memorandum: 'On the Construction of a "Super bomb"; based on a Nuclear Chain Reaction in Uranium' and 'Memorandum on the Properties of a Radioactive "Super-bomb"' [1,2]
Oliphant sent this report up the chain and it lead to the formation of the MAUD committee in the UK. The UK didn't have the resources to build an atomic bomb, so what was known was sent to the US. Oliphant hopped on a plane and did a tour of the US, doing technology transfer, mainly for radar, but also for an atomic bomb. Most people in the US ignored the MAUD report and Oliphant could not get traction on the atomic side. In desperation Oliphant breached security and briefed Ernest Lawrence who at the time was not cleared, also providing him with a summary of the MAUD report. Robert Oppenheimer joined the discussion between Oliphant and Lawrence. Lawrence phoned Arthur Compton in Chicago. From there the USA listened.
[1] https://web.stanford.edu/class/history5n/FPmemo.pdf
[2] https://en.wikipedia.org/wiki/Frisch%E2%80%93Peierls_memoran...
Nevertheless, I remember asking him what was it like to actually work on the project. He said that it was far less Hollywood-esque than many would imagine -- at least for him. He was just given math/engineering problems and was asked to solve them with no context. He never knew what he was truly working on, why he was working on these problems, etc.. The work was pretty isolating and contact was with others was pretty minimal. I do know that he met both Von Neumann and Oppenheimer on at least one occasion which is pretty awesome.
I wish I could find some records, but I do not even know where to look.
He had previously been working for a scientific supplies company in Chicago that was (unbeknownst to him) providing supplies to the Manhattan Project. Apparently his boss was aware of it, and when my grandfather's draft was called a letter from his boss convinced the draft board to assign him to Los Alamos instead. He was eventually able to get my grandmother, a secretary and typist, a job as a secretary in Los Alamos as well so that she could join him. She teased him the rest of their lives, because as the secretary to someone more important than a lowly technician, she had technically had a higher security clearance than he ever did!
The Atomic Heritage Foundation collects records about people who were affiliated with the Manhattan Project, as well as oral histories. Perhaps they have more information about your grandfather's work? See here: https://ahf.nuclearmuseum.org/ahf/bios/
I might trying contacting them directly though. Thanks again!
The National Atomic Testing Museum in Las Vegas had a room full of file cabinets full of records you could look through the last time I was there, that might be a start.
Maybe one of the national labs that currently works on stuff has public records?
"Need 10+ years of experience in nuclear detonation device."
https://www.bbc.com/future/article/20250829-the-bomber-that-...
spoiler:
probably the biggest engineering problem was the explosive lens