Saturday Snippet: Debugging the Oak Ridge nuclear plant

During World War II, Richard Feynman, then a very newly-graduated physicist, was sent from Los Alamos, New Mexico (the heart of the Manhattan Project to build the first atomic bomb) to Oak Ridge in Tennessee, where the nuclear material for the bomb was to be enriched.  He was tasked with making sure that the factory there would actually work, and that its design was technically and scientifically acceptable.  Needless to say, as a relative novice, he was more than a little unsure of his ground.

In his book “Surely You’re Joking, Mr. Feynman!” he describes what happened.


     I sat down and I told them all about neutrons, how they worked, da da, ta ta ta, there are too many neutrons together, you’ve got to keep the material apart, cadmium absorbs, and slow neutrons are more effective than fast neutrons, and yak yak – all of which was elementary stuff at Los Alamos, but they had never heard of any of it, so I appeared to be a tremendous genius to them.
The result was that they decided to set up little groups to make their own calculations to learn how to do it.  They started to redesign plants, and the designers of the plants were there, the construction designers, and engineers, and chemical engineers in the new plant that was going to handle the separated material.
They told me to come back in a few months, so I came back when the engineers had finished the design of the plant.  Now it was for me to look at the plant.
How do you look at a plant that isn’t built yet?  I don’t know.  Lieutenant Zumwalt, who was always coming around with me because I had to have an escort everywhere, takes me into the room where there are these two engineers and a looooooong table covered with a stack of blueprints representing the various floors of the proposed plant.
I took mechanical drawing when I was in school, but I am not good at reading blueprints.  So they unroll the stack of blueprints and start to explain it to me, thinking I am a genius.  Now, one of the things they had to avoid in the plant was accumulation.  They had problems like when there’s an evaporator working, which is trying to accumulate the stuff, if the valve gets stuck or something like that and too much stuff accumulates, it’ll explode.  So they explained to me that this plant is designed so that if any one valve gets stuck nothing will happen.  It needs at least two valves everywhere.
Then they explain how it works.  The carbon tetrachloride comes in here, the uranium nitrate from here comes in here, it goes up and down, it goes up through the floor, comes up through the pipes, coming up from the second floor, bluuuuuuurp – going through the stack of blueprints, down-up-down-up, talking very fast, explaining the very, very complicated chemical plant.
I’m completely dazed.  Worse, I don’t know what the symbols on the blueprint mean!  There is some kind of a thing that at first I think is a window.  It’s a square with a little cross in the middle, all over the damned place.  I think it’s a window, but no, it can’t be a window, because it isn’t always at the edge.  I want to ask them what it is.
You must have been in a situation like this when you didn’t ask them right away.  Right away it would have been OK.  But now they’ve been talking a little bit too long.  You hesitated too long.  If you ask them now they’ll say, “What are you wasting my time all this time for?”
What am I going to do?  I get an idea.  Maybe it’s a valve.  I take my finger and I put it down on one of the mysterious little crosses in the middle of one of the blueprints on page three, and I say, “What happens if this valve gets stuck?” – figuring they’re going to say, “That’s not a valve, sir, that’s a window.”
So one looks at the other and says, “Well, if that valve gets stuck -” and he goes up and down on the blueprint, up and down, and the other guy goes up and down, back and forth, back and forth, and they both look at each other.  They turn around to me and they open their mouths like astonished fish and say, “You’re absolutely right, sir.”
So they rolled up the blueprints and away they went and we walked out.  And Mr. Zumwalt, who had been following me all the way through, said, “You’re a genius.  I got the idea you were a genius when you want through the plant once and you could tell them about evaporator C-21 in building 90-207 the next morning,” he says, “but what you have just done is so fantastic I want to know how, how do you do that?”
I told him you try to find out whether it’s a valve or not.

And that’s how Richard Feynman developed an early reputation as an eccentric genius, one that was to stand him in good stead throughout his career.  I highly recommend all his books.  They’re good fun, and educational besides.



  1. My Father spent the War at Oak Ridge (he was a Physics major from Princeton), and told a story that I devoutly hope is true;

    In the early days of the Manhattan Project the military was not at all used to dealing with college kids. The first batch of half a dozen or so physics majors were sent to the Oak Ridge base before the enriching equipment was in place, so there was nothing for them to do. The army probably figured they would snide off, find the local brothel, or play cards, or fish. As I said, they weren’t used to dealing with college kids. It never occurred to them that what a college kid does when he knows there’s work coming up and he has free time, is study. The guys knew that what they were in Oak Ridge for had something to do with Nuclear Physics, so they all hied themselves off to the local bookstore and ordered the four books in print in English on Nuclear Physics. This resulted in the bookstore owner writing a letter to the FBI saying, in effect, “I don’t know what is going on at the Army base in Oak Ridge Tenn. I don’t WANT to know what is going on at the base in Oak Ridge. But I think you have a security problem.”

  2. Knew a guy who transferred out of Caltech after getting a D in freshman physics. A Feynmann D was like a graduate course B, but half the freshman class got D’s and left.

    I think I have the book boxed up. Need to re-read it. Part of his genius was in asking the right questions out of curiosity or ignorance, to learn.


    Is this a valve?

    Define object
    Engineers continue, translating chem engineering to physics
    Engineers like genius asking good question
    Good; done.

    Is valve stuck?

    Follow lines
    Good; done.

    Trace line back
    Is there a parallel path for unit ops?

    Rework plans and drawings.

    Trace back
    Switch to parallel path
    Clear stuck valve and lines
    Engineers approve of genius’ test
    Good; done.

  3. You would be shocked, shocked I tell you, to learn just how little “common sense” you can often find built into a lot of engineering and architecture.

    Clients showed up with a set of plans produced by a very high-end, very expensive architect working with a very expensive provider of timber-frame houses. We get the plans, go over them to bid on construction, and note a couple of salient features to the plan: One, the design is transected by a magnificent cathedral-ceilinged Great Room, and two, the place where they put the mechanical room for the forced-air HVAC system is in the basement below the front of the “prow” front window. Now, for that sort of HVAC to work, you almost have to have a “cold air return” at the highest point in the building, and for that particular building, there needed to be a pretty big one. One that would require some sort of chase going up the side of the living room, about three feet on a side. Lots of air volume, see…? Any other option was precluded by where things were. Additionally, the front faced a river (gorgeous site, BTW…) and you’d have to run all of the utilities through the house to get to it…

    Pointed these issues out, and included the bids for several options to work out the HVAC. Each was about a hundred grand, and roughly thirty or forty percent of that was due to the way the “professional architect and engineering team” had laid out the design. Clients didn’t want any nasty old chase running up a living room wall, concealing their magnificent timber-framed living room, soooo… Yeah. Wound up submitting a bid on that one which was way over their budget, and about 100% more than what the architect had told them was “typical” for construction around here.

    We were actually the lowest bid, and a bunch of the other people asked to bid it just… Didn’t. Too expensive to try and make the “vision” work, see…

    I’ve also seen designs turned over by the architect and approved by the client where there was no space at all provided for the mechanical stuff like the HVAC. One job specified a forced-air HVAC system, and we’re looking it over with our HVAC sub-contractor trying to figure out where it’s all supposed to go. Finally, completely baffled, we call the architect. He’s like “That’s your problem… I just design!”. That particular job, it turned out that there was no possible way to fit a forced-air HVAC system, and we had to offer an option to use nothing but mini-split systems. The whole thing blew up when the owner saw the price, and they wound up firing the architect and building a totally different design.

    A lot of the academic programs out there fail to instill any sense of the possible, or any common sense at all, sometimes…

  4. @takirks

    According to my Mother (who was an architectural historian) some decades ago Southern Massachusetts University needed a new Arts building. The Art department had an extensive list of physical requirements, such as a a loading dock and freight elevator for sculptural stone, a stage with wing and fly space, etc. The Building Committee failed to do enough oversight the VERY TRENDY architect that was hired to build the thing, and he pretty much totally ignored the requirements. The building was borderline unusable. The Art Department HATED it.

    Not to long after it was opened, the building burned down; a complete loss. The only people in the entire State who weren’t sure it was arson were the arson investigators. See, one of the flaws in the design was that the storage for volatile supplies (like turpentine) had far too little airflow, and once a fire started there the (idiotic) design of the building pretty much ensured that the whole thing would go up like Chinese New Year.

  5. Many years ago, I worked at a client site – a machine shop.
    They had an engineer, specilized in CNC, whose job was to make sure that the designed valves, manifolds, etc, as diagrammed could actually be machined.

    Automobile engineer ought to be forced to mske simple maintenance tasks on the cars they design.

  6. Feynman is evergreen. I know nothing about QED or anything and didn’t discover Feynman’s books until sometime in grad school, I think, or maybe even a bit after that. Don’t remember exactly. But Surely You’re Joking, Mr. Feynman! was one of my favorite reads ever in science.

  7. …another design hero of mine is Adm. Rickover. Before construction of any new ship reactor design was approved, he required a full-scale mock-up of the reactor and surrounding compartments constructed to ensure (despite even CAD now) that everything fit and could be operated and serviced.

  8. And we still needed extra elbows, eyes on our knuckles, and mutant ape strength to get to some flanges and connections…

    I spent 4 years in the engine room of a 688 as a machinist mate….

  9. takirks,

    Yeah, some architects seem to think air moves magically throughout a building (no ductwork needed). And plant operators seem to think that air flow can be magically adjusted to meet the demand regardless of duct size or system capacity. Had one experience where an office/computer room was changed into an office only, the computer was moved into a janitor’s closet to make room for more desks. Somehow it was “the ***ing HVAC system” that wasn’t keeping the computer cool enough to operate. No one bothered to tell the HVAC systems engineer about adding a few kilowatts of heat to a room with minimal ventilation, but it was still my fault.

  10. Peter – I had the honor and privilege to take a tour of the enrichment facility at ORNL not long before it was shut down. At that time it was still making enriched isotopes for medical research and materials science. They were still using a bank of the original “calutrons” for that work – they were HUGE mass spectrometers with magnets about two stories in height. I won’t go into the geeky details, but an interesting anecdote to the Manhattan Project is that these instruments used powerful electromagnets, and a LOT of wire was needed for their construction. Since there was a war going on, copper was in short supply. So General Leslie Groves, El Jefe for the entire project, took his letter from President Roosevelt that said, “Give this man anything he asks for!”, and he went to Ft. Knox and withdrew the entire silver reserve of the US and had it made into wire. After the war, the silver was stripped from the magnets, converted back into bars and returned to Ft. Knox. Try making that happen today!!

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