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National Museum of Nuclear Science & History

Paul Wilkinson’s Interview

Paul Wilkinson got a job at the Y-12 Plant Oak Ridge after graduating college. He supervised calutron work and some of the “calutron girls,” including his future wife, Dorothy. Wilkinson discusses the engineering behind the calutrons and some of the technical challenges they encountered and had to overcome. He also touches upon living conditions in Oak Ridge. He talks about the high level of security, the dormitories and his first house, and the dining facilities accessible to workers. He recalls meeting Frank Oppenheimer and Ernest O. Lawrence, and remembers a few funny stories, including the time a man drove his motorcycle through the dorm hallway.

Date of Interview:
September 12, 2022
Location of the Interview:


Paul Wilkinson: My name is Paul Wilkinson, spelled P-a-u-l W-i-l-k-i-n-s-o-n.

Cindy Kelly: Great, and we will start the same way, by your telling us where you are from and how you ended up at Oak Ridge.

Wilkinson: I am from New Jersey. I graduated from Williams College in November of ’43. Eastman Kodak was the contractor for Y-12. They sent a representative around and interviewed me for a job, no destination given, no workload, and no description of the work. Just, did I want a job, and I told them yes. So they said, “Okay, you are hired. Report to Knoxville, Tennessee and get with it.”

Another guy and I both came down here. We had bought a 1932 Chevy for $40, and we drove it down with gas ration coupons and arrived in Knoxville. We went to the New Empire Building, which I do not know where it is now, or even if it exists. But they sent us out here to the project. We followed our work bus from Knoxville out here in a cloud of dust. We got out here; there was a guard shack. They stopped us, and then they sent us on to the employment office, which was located where 901, the turnpike, is now. From there, they sent us to the housing office, which is where the Red Cross building is now.

Now the Employment Office was a great big room with a bunch of girls in it typing with carbon paper. Our paper said we were hired by the head of employment at Eastman Kodak. They took us out there, a bunch of these girls, and said, “Take your papers out of the typewriters, take care of these guys.” So they did. Then they sent us out to East Village for our housing, and we got the last two rooms in the dormitories at East Village.

From there we went to training buildings, which was at 2714 buildings, which are right behind the DOE headquarters building here. We went through training there, and then they said to catch a bus out to Y-12. We got on a bus, we said, “We want to go to Y-12.”

The driver says, “Where is that?” Somebody on the bus knew how to go, so they pointed out to him the directions to get out to Y-12. We got out there and we had badges, which were 3 x 5 cards with printed instructions on it. The guards came in and looked at them and said okay, and sent us in

We were to report to one of the buildings out there, but nobody knew where it was. I was walking down the street and met this big, rather impressive-looking fellow, and asked where the building was. He says, “Oh yes, my name is Harvard L. Hull. I am Head of Process Improvement here, and that is where I was going.” He sent us to the pilot plant out there for the calutrons, Building 9731 XAX, and there were a whole bunch of us in there. They started training us additionally right next door in 9735. Those are all building numbers out there.

We went through training there. Then we went over to the building, and they put us on shift work. The first job we got on shift work was to change a dry ice strap in the vacuum system. Well, the reason for changing it was that they had a power failure, and the dry ice strap had a whole bunch of crud on the outside that had been collected out of the vacuum system. We were supposed to get the trap out of there, clean all of the crud off the outside, put it back, seal it up again, and refill it with dry ice and acetone.

Then they put us on that cubicle that was different than the one that Dorothy worked on – this was the Alpha-1 cubicle. I do not know whether you have seen anything of the secret city, but this was a two-arc calutron with two collectors, and we were separating U-235.

We worked in there for a while, and then they sent some of us out to Berkeley, California. They had decided that the two-arc was not big enough and not fast enough, so they built four-arc calutrons, and the pilot jobs for that were out in Berkeley. They sent six of us out there to Berkeley to work on it. We went through the pilot jobs out there and came back here, and ran through pilot work here and trained people here on how to work them.

Then we went into the production buildings, where they had changed from the Alpha One system to the Alpha Two. The Alpha Two system was four Js, Alpha One was two. So we worked on those systems for quite a while.

We were sent to Berkeley to work on the development of a larger calutron unit, which had four arcs, four Js, and four receivers for enriched uranium, which would produce, supposedly, enriched uranium at twice the rate that the previous calutrons had, since we needed more of it more rapidly.

We went through that and then we came back to Y-12. They had the equipment in Y-12 at that time, which started up running that same equipment.  Now, we had trouble with some of the insulators and high voltage.  High voltage on the calutrons was thirty-five kilovolts, and we were breaking insulators rather rapidly. So we got different insulators instead of the Westinghouse insulators, with a particular type of bushings. They went to the Coors Company, made them out of zirconium, and that worked very well. 

We had a few interesting experiences, as you might expect with the start-up of a new system, like water leaks and then trying to dry out the tank because water doesn’t go with vacuum very well.  But then we went on from that. We got into metallurgy to make bomb parts, components for atom bombs, and we started processing uranium metal at Y-12 and machining the uranium metal to make bomb components. 

From there they started making components for thermonuclear weapons. Well, in making the components for the thermonuclear weapons, they needed fuel for the thermonuclear.  The fuel for the thermonuclear is a lithium compound, lithium hydride or deuteride. Deuterium is an isotope of hydrogen, one of the heavy isotopes. The lithium-6 isotope gives you the fusion, which gives you the big boom for the thermonuclear bombs. 

We had trouble with the magnets and the electromagnetic process. The problem being that the welded pipes for the cooling of the magnets, they did not sandblast them after they welded them, so they had slag in the pipes. When you turned on the magnet, the slag went to the insulators, around the conductors, and it shorted them. We had shorts between the conductors and the housing for the cooling oil.

The conductors in these were silver bars that were about three inches by a quarter inch thick, and the government had borrowed 45,000 tons of silver from the Treasury Department and made these conductors.  Silver is one of the best conductors of electricity around; it’s better than copper, as a matter of fact. We couldn’t use copper because that was going into ammunition for the troops in the war. So they sent silver down here all rolled up in bars, and as conductors in magnet coils and sealed them up in steel and pumped oil around them and ran it through cooling towers to take care of the power that was dissipated in running the magnet. 

The magnets were run with big motor generator sets. Motor generator sets were so big that they had to call TVA before they started one up, or else it would have broken a whole bunch of breakers and shorted things out. So when they went to start it, they would tell everybody and lights would dim and then the motor generator set would get up to speed. The lights would come back up and everything would be fine, hopefully. Actually, they did work very well. 

But when they got them shorted out, they had to send many of the magnet coils back to Aliss Chalmers, who were the people who had wound the magnets in the first place. They had to re-open them up, rewind them, and somebody had to sandblast all the pipes and clean it all up and change the insulators from Masonite to paraffin-injected maple. That was a big hurry up job because they couldn’t operate without the magnet. 

Kelly: After that incident, General Groves was concerned about sabotage, and they hired GIs to be sitting amongst the Y-12 workers.

Wilkinson: We had GIs in here as workers; we didn’t have enough workers.  I didn’t know that he had any of them in there as counter-espionage.  But he had people that were here as counter-espionage, like me for one. “If you see anything that’s out of line, report it immediately to your supervision.”

We had one new man come in to go to work, and you’re supposed to wear your badge in plain sight. The supervisor on one of the shifts had his badge on his shirt, but he had a sweater over his head and the sweater covered up the badge.  So one of the guys goes up to him and says, “Hey, don’t you know you’re supposed to wear your badge in plain sight?”

And he said, “Yeah, it is.”

He says, “It is not. Where is it?”

And he says, “Under my shirt here.”

So the guy grabbed the bottom of his sweater and pulled up the sweater over his head and he says, “Oh yeah, I see it now.” I thought he was going to lay him out cold on the floor about that point. 

Kelly: That’s great. What were you told about the purpose of the work at Y-12? What did you know?

Wilkinson: We weren’t told anything, except to enrich the uranium.  Well, we were told that it was uranium and that we were enriching it, but since many of us were either chemists or physicists or both, we figured it out fairly early. 

Kelly: I’m curious, because a lot of people I’ve interviewed say they refer to some particular textbook, and that they poured over this textbook.

Wilkinson: You couldn’t find any books in the library or anywhere around that had anything to do with uranium. They were all removed. 

Kelly: So you figured out it might be for a bomb?

Wilkinson: We figured out that it was for a bomb, and that we would get a great big yield from it.  Of course we didn’t know the details of what kind of yield we would get.

Kelly: Did you tell the girls in the cubicle? Did you tell anyone outside?

Wilkinson: No, no, no. There were signs all over the place, “Loose lips sink ships.” Is that right, Dorothy?

Dorothy: Yeah.

Wilkinson: Now there was some interesting personal tales, like we used to have eighty-hour weekends because we were working shifts. So we came back from one eighty-hour weekend, and when I came into work one of the girls that I was supposed to be supervising sent word that she wanted to see me. I went up to see her and I checked out her equipment and there was no problem with it. So I said, “What’s the problem?”

She says, “Well you know, we just had an eighty-hour weekend.”

I said, “Yeah.”

She says, “Well I went down to party as soon as it started and I got drunk, and then when I woke up I was in bed with a strange man and he said we were married. Now what do I do?”

I said, “You talk to your counselor,” because the company had hired more adult mature women as counselors for all these women because there were lots of them around. 

Kelly: What was the average age of the girls working on the cubicles?

Wilkinson: The girls were all under twenty-five, and as was I at the time.

Kelly: Did you know people from other parts of the project at K-25?

Wilkinson: No, we didn’t have any association with other parts of the project at all in the early days.

When I first got here, I lived in a dormitory in East Village called EV2, and then I moved from there to a dormitory in Jackson Square called M7. Then when we got married, we got assigned a one-bedroom flattop in East Village on Altoona Lane.  My parents had come down for the wedding. I took my dad by to see the flattop and he says, “You mean you’re going to live in a chicken coop like that?”  But everybody had chicken coops, so yes, that’s where we lived.

Dorothy said something about explosions or something. Soft coal, if you ever try to heat with it, you got to leave the flame in there burning when you bank it at night or else the gasses collect in there. If they’re not burned, they collect and then when a flame comes up they blow; when they blow, they blow open the ash pit door and you have ashes and soot and smoke all over the house. That is a stinking mess. Now, we had so much black soot around from the soft coal that we had to clean the houses every few months because all the walls and everything were all black with soot.

Kelly: Did you do that yourselves, or was that provided?

Wilkinson: We did it. The coal is provided, the electricity and the water, and if we had a leak in the pipe they would come around and they would take a rag and pour salt in it and wrap it around the leak, then go away, and it would rust closed.

Kelly: If you can keep going with sort of the details of life in Oak Ridge?

Wilkinson: Well, whenever you went to visit somebody, you wore boots or galoshes or something like that and took them off on the front porch before you went in the house. That was normal. Nobody had cars, hardly. We had buses that ran certain routes, so you took buses to get closest to where you were going. 

Kelly: Can you describe the busses? Somebody described the busses as like a cattle car.

Wilkinson: Oh, what they had done, they took flatbed eighteen wheelers and put plywood bodies on the flatbed and seats running up and down each side of the flatbed inside. That was a bus. You had a cord in there that you pulled when you wanted to get off. If the driver didn’t have a girlfriend up in the cab with him, he might stop where you wanted to get off.  If he had a girlfriend up in the cab, he might have been distracted. 

Kelly: I’ve heard about the tennis courts with dances. What did you do for entertainment?

Wilkinson: Back then? Work, work, work. In my case, I was hired in on special payroll where I got paid for overtime, ninety-five cents an hour with straight pay, and overtime was time and a half. We got paid every two weeks, and my first checks with overtime were something like 120 hours and 160 hours, so we didn’t have time for much else but work. 

Kelly: Did everybody work as many hours as you did?

Wilkinson: No, they didn’t work that much. There were a few of us, groups of us, that worked that hard. 

Kelly: Which groups? The GIs?

Wilkinson: No, the GIs did not. They had a bunch of GIs, and some of them came here because they were drafted. They were drafted right out of the working gear and they returned as GIs. They were making less money when they returned than when they left, so they were rather unhappy. 

Kelly: So you were a lucky one?

Wilkinson: Yes, they sent me down to Fort Oglethorpe for a pre-induction physical. After it was over, the sergeant says, “See you in twenty-one days, general military service. Do you want to volunteer?”

I said, “No sir, Sergeant.”

“Supposing you’re a draft classification 2B,” he says, “are you another one of those SOB’s from Oak Ridge?”

I said, “I’m from Oak Ridge. You can speak for yourself on the rest of it.”

“Get the hell outta here.”

Kelly: You said that one of your other classmates from Williams came down, is that right?

Wilkinson: Yes, I lost track of him shortly after we arrived. 

Kelly: You had been a chemistry major?

Wilkinson: Major in physics and minor in chemistry.

Kelly: Well, tell me about 9131, that’s a building we’re trying to preserve.

Wilkinson: 9131?

Kelly: I mean 9731.

Wilkinson: 9731 is still in existence, it’s still running. It’s doing separation of stable isotopes now. But it was the pilot plant for both the Alpha and the Beta calutron. Half of it was for the Alpha calutrons – the XAX half – and the other half for the Beta calutrons. They were separately classified, and you did not go from one side of the building to the other. 

Kelly: So did you actually work inside this building, the pilot plant?

Wilkinson: Oh yes, yes. When they sent us out to Berkeley, Frank Oppenheimer was one of the directors, it was JR’s brother. Then they accused him of being a communist after the war was over and all that monkey business.

Kelly: What was Frank like? Did you meet him?

Wilkinson: Very, very hard worker, very considerate of the people, very smart, and smoked like a chimney.

Kelly: Did you meet Ernest Lawrence?

Wilkinson: Yes. I just met him once; very short meeting. He thought a lot of Ernest Lawrence. Ernest Lawrence was a man that had a very high opinion of himself. 

Kelly: It sounds like you liked Frank.

Wilkinson: Frank Oppenheimer did not exhibit that same kind of feeling.

Kelly: How about General Groves?

Wilkinson: Never met him, don’t know anything about him. But my understanding was, he was a rough and tough general and he said, “This is the way it’s going to be.” I heard stories about him. Somebody was complaining to him that they couldn’t get copper for something or other, and Groves said, “You better keep your damn mouth shut and do what you’re told.” 

Kelly: Do you think that these young girls with no more than a high school education – how did they do operating these fancy machines?

Wilkinson: Initially, the people at Berkeley thought that it would take PhDs or Master’s degrees for the people to operate the calutron, and then they hired all these high school graduates. The high school graduates did better than the scientists in operating these things, because they wouldn’t always try to experiment with it and change something or other, which didn’t need to be changed.  So everything went a lot more smoothly with the high school graduates as cubicle operators than it would have with college graduates. They didn’t know enough to try to make changes. They were told “Do this, do that, move this needle this way, that needle that way,” and that was it. 

Kelly: Did you ever try to operate?

Wilkinson: Oh yes, yes, yes.

Kelly: So what did it take to get the maximum amount of product?

Wilkinson: To get the maximum product, you adjusted the conditions of the arc, and you adjusted the accelerating voltage for the ion beam so that you maximized the amount of material that went into the enriched uranium receiver slot. You tried to focus the beam as closely as possible.  In as much as you had both the accelerating voltage to fool with and a focusing voltage, which is called the G-voltage. You fooled with the G-voltage to see if you couldn’t get the beam to focus a little better in a slot.

Kelly: Now, were you involved in the sort of second step of the process, or could you describe it, where they had to take the slots out and bring them into a bath and tried to remove –

Wilkinson: No. I was not involved with the recovery of the product from the receivers. 

Kelly: So everything was strictly compartmentalized?

Wilkinson: Oh very much so, yes. Absolutely.

Kelly: Did you ever get down to the basement of the Beta-3 calutron building?

Wilkinson: Oh yes. 

Kelly: Describe that.

Wilkinson: The basement contained vacuum equipment, mechanical pumps – Kinney pumps, they are called – which are rotary pumps that evacuate the calutron tanks, because in order to get an ion beam you had to have a vacuum. Otherwise, the air would destroy the ions and you wouldn’t have any ion beam.

At that time, a lot of the operations were segregated security-wise, so there was a fence around different parts. You had to have a different clearance to get into the different parts of the security fence. One part where we were in was the Alpha buildings, and there was particular security clearance there. Some of the guys had a late date after the three to eleven shift, and it was quite a walk from where they were to the guard gate to get out for their date. So they decided that they were in a hurry to get to their parking, and they decided to climb the fence. They climbed the fence, and just as they got up on top of the fence – here came the guard patrol. Needless to say, they missed their date and they spent some time in guard headquarters.

We also had another guy here who liked to hike all over the mountains and hills here. He was working here, so the FBI was curious as to what he was doing when he was not here in the plant. They started trying to follow him around. They finally called him in and told him, “Please don’t climb up and down so many mountains, you’re wearing our FBI people out.”

Another one bought a motorcycle, and it was delivered by railway express in Knoxville. He went in and picked it up, and he was driving it out here. It caught fire on the road. So he put the fire out, and he got somebody to bring the parts back and bring it into the dormitory where he was living. He rebuilt the motorcycle in the dormitory up on the second floor, then in order to try it out, he drove it up and down the hall in the dormitory.  I’m not sure anybody really enjoyed the “Vroom, vroom.” 

We had a few people that did not comply with all the rules. We were parked in front of a dormitory getting better acquainted one time. All of a sudden, a car comes up there, whirls around and comes to a stop. The door flies open, a woman comes flying out, and the car drove off.  So we went over by the girl, and she’s lying in the gravel and says, “Where is my goddamn badge, I got to go to work. I got to get my goddamn badge.”

We helped the house mother get her into the building, and the house mother took her up to her room. Then just as I was leaving, I drove in on the turnpike and there was a hill in front of the dorm there on that side. She comes out of the dormitory there and falls down on the hillside, and rolls down just like a piece of firewood or something and says, “I got to get my badge. Where’s my goddamn badge?  I got to go to work.” Never did find out what happened to her. 

Kelly: There were obviously people who couldn’t handle all the freedom?

Wilkinson: Right, and the place was dry around here so you couldn’t drink, supposedly.  Of course you could get moonshine, you could get whiskey. You could get a fifth of liquor if you bought a gallon of moonshine. The moonshine was yuck, it did not taste very good. 

Kelly: So if you had a celebration, let’s say, would there be liquor?

Wilkinson: Oh yeah, somebody would be able to smuggle it in.  But if the MPs caught you at the gate, they would confiscate it.  Of course, we never did find out exactly what they did with it once they confiscated it, but we had suspicions.

Kelly: So did you eat in the cafeteria?

Wilkinson: Yes, ma’am. The first meal I had here was in the so-called central cafeteria, which was just off the turnpike by Jackson Square. This was a dinner. I had fruit cocktail, roast beef, mashed potatoes, peas, and milk, and it cost me fifty-five cents. Then we had several other cafeterias, and the head cafeteria is just a plant. Now some of the cafeterias at the plant were not necessarily too sanitary – used to frequently have Montezuma’s revenge. 

Kelly: When you got your own house, did you still eat at the cafeteria or were you eating at home?

Wilkinson: We ate at home mostly, I think. Well, ate some of the meals at the cafeteria. When I was working shift work, I ate part of my meals at the plant, at the cafeteria. But there were not many restaurants around town. There was one in Rose Center, there was Adam’s Cafeteria out near the east end of town, one in Jackson Square as I said, and one on the east end of town. There are shops there now. 

Kelly: So can you think of any other things that I haven’t asked you about that I should have, about the Manhattan Project or your experience?

Wilkinson: We didn’t ever hear very much about Manhattan Project as such. We knew it was Clinton Engineer Works and we knew we were building bombs and bomb parts, but that was it. 

Kelly: So how do you feel about your contribution to ending World War II?

Wilkinson: We thought our work here was a worthwhile effort and a worthwhile contribution to winning World War II. Talked to one of the fellows in the retirement center now and he says, “Yeah, I was on Okinawa about to invade Japan when they dropped the bomb over there, and man was I glad.”

I said, “Well you’re more than welcome. We were glad to help.”

Copyright 2015 The Atomic Heritage Foundation. This transcript may not be quoted, reproduced, or redistributed in whole or in part by any means except with the written permission of the Atomic Heritage Foundation.