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John Tepe’s Interview

Manhattan Project Locations:

Louisville native John Tepe began working for the DuPont Company in 1939 after he received his bachelor’s degree and his master’s degree in chemical engineering from the University of Louisville. In 1942, Tepe was transferred to the University of Chicago where he worked on a wide variety of problems in areas such as synthesis and chemical separation that proved integral to the design and construction of the plants at Hanford. Tepe recounts the remarkable cooperation among top Manhattan Project scientists, many of whom he saw nearly every day in the halls at the University of Chicago. Tepe describes some of the chemical experiments that were conducted in the west stands under Stagg Field and alludes to the famous chain reaction that took place in the doubles squash court under Stagg Field. Tepe explains the enormous scale-up required at Hanford and describes the Manhattan Project’s revolutionary impact on industry. Finally, Tepe acknowledges the link between The Manhattan Project, private corporations (such as DuPont), and academia whose efforts combined to make the development of an atomic bomb successful.

Date of Interview:
November 1, 2003
Location of the Interview:


[Interviewed by Cindy Kelly and Tom Zannes.]

Tell us your name.

John Tepe: I’m John Tepe, T-E-P-E.

Tell us about where you grew up and went to school.

Tepe: Well, I grew up in Louisville, Kentucky, which was my family hometown. My family had been there since 1794, and I was the first to leave. But as an undergraduate, I went to the University of Louisville, for both Masters—Bachelor’s and Master’s degrees in chemical engineering. And then from there I went to Yale University and took a Doctor’s degree in engineering, finishing in ’42.

In the meantime, I had worked for DuPont the summer of 1939, and when I finished in ’42 they were very kind. They said, “Whatever kind of work you want to do, we’re prepared to offer you that kind of work.” So I interviewed with five different departments and went to work in the engineering department, which at that time had a very famous research organization, which more or less wrote the textbooks for chemical engineering.

I was there, as you said earlier, a year and a half—working on a wide variety of defense projects for different groups like the Naval Research Laboratory, a chemical warfare service, National Defense Research Council, the Tennessee Valley Authority, etc., etc.—when I was overnight transferred to the explosives department and sent to the University of Chicago. 

And at the University of Chicago, I was in an engineering group under a well-known man named Charles N. Cooper. And I supervised a group of about twenty people. Well, there was more than twenty because seventeen of them were G.I.s—people who had been drafted but had some training in chemistry. And they were very well qualified and very helpful. And we ran seven days a week, twenty-four hours a day, and they handled the operating of what we used to call “semi-works facilities,” in other words, small-scale facilities for doing the same thing that was done full-scale at Hanford.

I’m sure you’ve heard from others that one of the amazing things about the Manhattan Project was the enormous scale-up from very small operations to full-scale production. And I think that’s one of the ways in which the atomic experience of World War II affected industry, is instead of scaling up tenfold—maybe 100 would be exceptional—they started scaling up tens of thousands-fold from very small data to big data, big scale of production, which is what, of course, we did at Hanford.

At Chicago, we worked on a very wide variety of problems in all areas—synthesis, separations, and others—with the idea of furnishing reliable information for use in design and construction and operation of the plant at Hanford. We were only concerned with plutonium. The uranium work was done elsewhere. So we worked with all of the people in physics and in chemistry.

And you’ve heard, I’m sure, that there’s a great deal of compartmentalization of the work for security reasons. You knew everything you needed to know, but you didn’t know what you didn’t need to know. And of course we worked with very high priorities, so anything we needed in the way of equipment or materials we could get promptly. And I think the accomplishments there were quite remarkable.

I mentioned I was located—my office in Ryerson Hall, which simply happened to be where so many of the Nobel Prize winners were located. So every day, all day, [Enrico] Fermi and [Leo] Szilard, [Eugene] Wigner, [Arthur] Compton, [Luis] Alvarez, [James] Franck, [Glenn] Seaborg—all the Nobel Prize winners, Szilard’s an exception, Phil Morrison—were up and down the hall all day long. It was kind of a big one-room schoolhouse. Yes. And the working cooperation among all these people was perfectly remarkable. I mean, it was just as easy to sit down with somebody famous, like Fermi, and chat the same way you and I would.

Among other things, the legendary group ran a school—a night school—to train the people who were on their way from other locations to Hanford to run the plant. And our faculty were essentially all Nobel Prize winners; Franck and Fermi and Seaborg and the others gladly accepted invitations to lectures, and they were able to talk at the level of the, you might say, the undergraduate engineer.

The nature of the problems—the chain-reacting pile, as you know, generates an enormous amount of heat. And dissipating that heat to keep it from melting down, as they say, was a big engineering problem, so we did a lot of work on that. And then, of course, we were trying to increase the yield and increase the purity of the product, and so we were seeking optimum operating conditions, for example, in the separations area. And some of the early operations were pretty awkward, and we were seeking more efficient ways of doing the separations and the synthesis.

We used the west stands [of Stagg Field] for a lot of our experimental work. One of the reasons is we had great headroom in the stairwells and you could put in a separating tower—liquid-liquid extraction, or something like that—and they’d be 100 feet tall. And of course, the story’s famous about the first chain-reacting pile in the doubles squash court. So it was kind of interesting to be playing squash in the singles court next to the doubles court, in which they were running this graphite-moderated pile.

We also had experimental facilities south of 63rd Street, which was an old brewery that we called “B Factory.” And in there we did a lot of our experimental work. 

There’s an awful lot of things going on at one time. And everybody had a well-defined program and problem to work on, and there was exceptional cooperation. I never ran into anything else but ready cooperation. And you could argue with these Nobel Prize winners just like the guy at the next desk, and sometimes you’d win.

DuPont was there for the purpose of building the Hanford plant?

Tepe: Yes. That was our focus; Hanford was our focus. That’s correct.

Can you talk about the B Reactor not coming up to speed?

Tepe: I think you have to recognize that engineering calculations are not as precise as scientific cal—

Start that again.

Tepe: You have to recognize that calculations made by engineers are not as precise as calculations made by physicists, who get down to the fourth and fifth decimal place. And engineering always has in mind, before anything else, safety, so that you always make very careful that our results are on the safe side. And all of the design calculations for boilers and pressure vessels, piping, and all that sort of thing are always safe-side calculations. And I can tell you interesting stories about that, but a ten percent or fifteen percent over design would not be uncommon in engineering work. And that may have been what they ran into in this problem in the reactor, which I did not participate in or encounter.

You were involved in the chemical separations work?

Tepe: Yes.

Can you tell us about the design of the T Plant?

Tepe: Well, what we did—in Chicago, we had small-scale, actually, manufacturing facilities. Our product would be contained in a test tube, but of course the product for Hanford was much more than that. We ran the fractional precipitation process under all kinds of different conditions to try to establish optimum conditions for running it, and then we worked on alternatives to the precipitation process.

One of them was liquid extraction, in which we used these tall towers in the stairwells of the football stadium. The work with the chain-reacting pile in the doubles squash court had been done a year earlier than our work. And although I think they were still doing experimentation, I don’t know what it was. I didn’t work on it. If we didn’t need to know, we didn’t ask.

All of our work on separations was with Glenn Seaborg, and he was a very impressive chemist that—we’d sit down in the morning and plan experiments—sit down Monday, maybe—and plan experiments for the week. And he’d give us his guesses as to what answers we’d get, and it was quite remarkable how often he was right on the button.

So in that respect you’d say, well, you were confirming what was expected or what was predicted from theory. And again, as I said before, it was just quite remarkable the way theory was proven out in practice on this whole project. Somebody said that it was just a chain of highly improbable coincidences that made the whole thing work.

Could it be done again?

Tepe: Yes, I think it could. I’ve heard—

Can you use the word “Manhattan Project” in your answer?

Tepe: Well, in answer to the question, “Could an effort of the magnitude of the Manhattan Project again produce exceptional results?” I think the answer’s absolutely yes. The focus on the plutonium and uranium production was absolute. We had unbelievable talent, we had priorities for materials that were just absolute—we could get what we wanted and needed. And when it got into the construction phase, we had, you might say, unlimited resources—both of technical and management and crafts.

There’s no question, if you could have that kind of concentration again, you could do wondrous things. Whether we could cure cancer or AIDS, I don’t know. But that kind of focus, which was absolute, just produces perfectly remarkable results.

What was it like to be a part of this when your buddies were off in the trenches?

Tepe: That was interesting because, as you say, graduating class in engineering, essentially everybody went into the service—everybody who was physically fit. And it’s kind of a mystery for anybody to be around twenty-five years old and physically fit to not be in the service. But the question really never came up, because I think it was understood that some people had critical jobs to do and they were doing it. [Laughter] It came up, for example, if you had to cancel a lease, which I had to do when I left Chicago in 1945.

The landlord could say, “Well, wait a minute. You’re responsible for another six months’ rent.” 

And I remember on that occasion I said, “Take a good look at me.” I’m twenty-six years old at the time. “I’m physically fit. I had four years in the ROTC, and you see me in civilian clothes here now. Do you want to let this question get beyond the two of us?” 

He said, “Oh no. Forget it. Yes.” 

But mostly the question really never came up. I think everybody understood. [Laughter].

Almost immediately after I returned to commercial work, I was drafted. And when I turned up for induction, they said, “It says here that you’re married.” 

And I said, “That’s right.”

He said, “Well, go home. We don’t want married men.” 

And like I said, I had tried desperately to get commissioned, not only when I finished college but during my two or three years of work, because I wouldn’t have had to be explaining to the draft board all the time or have anybody else write. But they always just said, “Forget it. Do your job; we’ll take care of that. Do your job and forget it.” [Laughter.]

And I went up to South Ferry in lower Manhattan and was ready for induction. But I was quite happy to go in. My brother-in-law was a prisoner of war, my wife’s uncle was a prisoner of war, and everybody in the family other than me was in the service. I was quite happy to go in. As a matter of fact, I wanted to. I wanted to be commissioned because I thought I had earned the commission.

What was known about the physical hazards of plutonium?

Tepe: Well, the information we had was that it was as hazardous of a material as existed. It was tremendously poisonous, and we treated it as such. The problem that we faced a good deal was the radiation problem, because we were handling radioactive materials all the time. And we wore badges, which would indicate when we were overexposed. From time to time one of us would get a couple of days of vacation to let our blood count get back in line. But we were very, very careful, and we had shielding. And most of the operations were conducted by remote control with optics to observe what was going on, and I don’t know of any serious accidents in the operations at Chicago.

Could you talk about the scale of what you were doing in Chicago versus the T Plant?

Tepe: That’s correct. I used to know all those figures. I don’t remember them anymore, but it was far beyond any previous practice. What we worked with was the kind of thing you’d see every day in a brewery or a food processing plant, relatively small.

Mention the word “plutonium” in your answer.

Tepe: Well, with respect to the scale of operations, the engineering group at Chicago was not working on the bench laboratory scale in capillary tubes and under microscopes. We were working at a larger scale than that, but still not remotely at the scale of the Hanford plant. The vessels that we used might—if we had a tower, it might be six, eight inches in diameter and maybe 100 feet tall, whereas similar pieces of equipment at Hanford would be twenty feet in diameter and still 100 feet tall.

The material we produced—the only time I’ve seen plutonium was in the bottom of a capillary tube and about a quarter of an inch of white powder, plutonium oxide. Later on, of course, we had to make kilograms in order to provide explosives material for military devices.

I have never been to Hanford. I’ve been to Oak Ridge. I’ve heard a lot of figures about how big everything was, how many acres it was spread over, but I didn’t see that. I fully expected to go from Chicago to Hanford but, just like the draft, they said, “We don’t need you out here now. Go on back to Wilmington and get back to commercial work for the DuPont Company,” which I did.

But the scale-up was enormous and, as I mentioned earlier, that was one way in which the project, Manhattan Project, impacted industry; we changed our ideas about how far you could scale up from the small operation in the laboratory, or as we say, semi-works, to a commercial operation was greatly increased. And from then on—and I think we benefited greatly from the experience—but we wouldn’t hesitate to scale up by a hundredfold, a thousand-fold, whereas at one time we thought the tenfold scale-up was big.

So it really changed the way industry worked?

Tepe: It did. It had a big impact. You’re absolutely right. Yes.

Did the experience lead DuPont to become more involved with people in academia?

Tepe: Well, the kind of work I was in, which, for the first number of years at DuPont was research work; we had a lot of contact with university personnel. Even later we did. I would say that during my forty-year career with DuPont, we always had a very active cooperation with university people, and also, because of the nature of the work we were doing, a lot of people left the kind of work I was in to go into university jobs. Bob [Robert] Marshall became dean of engineering at Wisconsin, Bob [Robert L.] Pigford became dean of engineering at Delaware, and I had a lot of good teaching offers. I taught at Columbia myself for several years. And I would say there was always—in my kind of work—a very close cooperation.

In 1950, I guess it was, I asked to get out of research and to get into engineering design construction because I felt I wasn’t learning much about the commercial operations in research. It was almost like being on a university campus. And even there we always had a year in industry program, in which there’d be a couple university professors in the DuPont engineering department observing how their products, their graduates, worked in industry.

And that was always very profitable for both sides. We learned from them and, of course, sometimes they wanted to tell us how to run the DuPont Company, but we learned from them and they learned from us. And they were usually excited about what they were doing. They stayed one full year. And a lot of my old professors showed up; Gordon Williams from Louisville showed up for a year, and others.

But I would say they were always, not on a big scale, but always an active participation. Of course, DuPont and University of Delaware have always been very close. But also DuPont and MIT and University of Illinois, very close. We also had a lot of consultants from university faculties. We had Professor Adams from MIT for years in my organization. 

Do you remember minority members at the University of Chicago?

Tepe: I can’t remember personally ever working with any of them. There’s quite a few females, of course. One in my group, Mary Ann Monet, was very competent.

Do you remember Leona Woods Marshall?

Tepe: Marshall was her last name?

She married in ’43 or ’44.

Tepe: No, I don’t remember her. There were about 600 of us there on the campus, something like that.

Do you have any comments about Crawford Greenewalt?

Tepe: I would know when he was there but I—

Use his name.

Tepe: I would know when Crawford Greenewalt was present on campus, but I never had occasion to work with him on a problem. As I said, we kept our noses on the grindstone in our own areas, and I can’t ever remember Crawford Greenewalt being interested in anything I was working on. Of course, at the DuPont Company over the years I encountered him more often.

Do you have comments about how you felt about the project?

Tepe: Well, I was transferred overnight from the engineering department, where I was working on a variety of defense projects, to the DuPont explosives department and informed that my location would be the University of Chicago. I went in town to get indoctrination, and the man I met [chuckle] proved to be my future father-in-law.

I was married in 1944 while I was on this project, and I remember his words—Arthur W. Scary was his name—I remember his words very well. 

He said, “Jack,”—he knew I was dating his daughter—he said, “This is a highly secret project.” And he explained what it was and he said, “You will receive a great deal of classified information.” And he said, “If you reveal any of that information to someone who is not cleared to receive it, that will be treason. And treason is punishable by death.” That was his message.

He was the administrative head of the so-called TNX organization, and then a chap named Roger Williams was the technical head. So he was responsible for all the housing and recruiting of personnel, and salary administration, and everything. He’d been the director of production for military explosives and had built the smokeless powder plants for England and for the American military also.

Could you talk about how many people worked on this project?

Tepe: On the question of the project as a whole, I think it’s important to recognize that producing the fissionable material and then using that material, like, say, nitroglycerin, to build a weapon were almost like two entirely separate projects.

And when people mention the atomic bomb, you almost always think of Los Alamos and Oppenheimer and Alamogordo and Hiroshima. But basically, as I understand it, what they did at Los Alamos, they received the nitroglycerin, the plutonium, or uranium-235, and then their problem was how to build a device which would detonate that material; in other words, create in lightning speed a critical mass, so it would create this enormous release of energy and at as high efficiency as possible.

Now within the organization—to figure out how to produce plutonium in my case—it started with the particle for nuclear physicists that you mentioned earlier and the very basic chemical research. Then it began to involve engineering problems, of course.


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