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National Museum of Nuclear Science & History

Daniel Friel’s Interview

Daniel D. Friel was a chemical engineer for the DuPont Company who joined the Manhattan Project at the University of Chicago in 1943. Friel was assigned to design the optics for remote operations in Hanford’s T-Plant, a state-of-the-art chemical separations facility. Under Charles M. Cooper and George Monk, Friel invented equipment based on preexisting military technology to see behind walls at the separation plant and the B Reactor. Friel discusses the use of television and periscopes, describing how challenging it was to create a completely new technology without any precedent to refer to. After the war, Friel continued working for DuPont and making inventions.

Date of Interview:
September 12, 1965
Location of the Interview:


Stephane Groueff: So Mr. Friel, you were with the optical side in Chicago project?

Dan Friel: Yes. My interest and activity was in the optical end. The job was to make it possible to see through walls and to see into equipment where otherwise the radioactive level was too high to operator or to work. We knew, of course, that we had to be able to see behind these walls, and we knew in many cases that we would not know what we would be looking at, because there were new and strange phenomena going on. This indeed turned out to be the case.

There were certain operations where we could predict that we would need to manipulate beyond the wall, you need to turn a valve or lift an object or uncouple or decouple or to pick out a radioactive slug that maybe spilled in an area then making it contaminated. There were other areas where we did not know, for example, how plutonium would react—behave physically—and some of its salts in vessels, in the containers in pipelines. We had to be able to see into those and be able to observe—

Groueff: What was your specialty? What was your background? Could you tell me a few words about your education and where you come from and how you happened to be connected to the Manhattan project?

Friel: This is an interesting point. I was trained as a chemical engineer at Johns Hopkins and graduated in ‘42. I came with the DuPont Company with great ambitions to be a good chemical engineer. I was assigned to the explosives department and set out first to our explosives plant and put to work as a chemical engineer solving problems on the plants, trying to make them run properly. I spent about a year at this and during this period was at several locations with the explosives department. During this time, of course, DuPont Company got the mandate to work on the atomic project and to bring its people into it. Well, I was apparently available and a flexible young character. So I was told on about twenty-four hours’ notice to get to Chicago.

Groueff: When was that, in ‘43?

Friel: This was early ‘43.

Groueff: How old were you then?

Friel: I was twenty-three at the time, and a very green chemical engineer, but one full of energy and interest in a lot of things other than chemical engineering. So at this particular time, it was—must have been within a few days of my getting married, I remember I ride to Chicago and Charlie Cooper said, “Well Friel, I understand you want to get married.”

I said, “Yes, I plan to take off two weeks to do this.”

He said, “Well I’ll tell you, you can have the weekend off.” [laughter]

So we got married in Baltimore and came to Wilmington [DE] on the honeymoon, spent one or two days in Wilmington, then I flew back to Chicago.

Well, when I arrived at Chicago, Charlie Cooper said, “We need an optics expert. You’re a good chemical engineer, and we’re going to retread you into one.” [laughter]

Groueff: It had nothing to do with your training, no?

Friel: Had nothing to do with my training. So he assigned me to work under Dr. George Monk, who was at the University of—

Groueff: Monk?

Friel: M-O-N-K, Dr. George S. Monk, who is an expert in optics and was the head of the physics department there at the time. Well, George did retread me pretty fast with his help and throwing me into optical problems that were well over my head and with study and working some, I guess, eighteen hours a day. I retreaded myself and was able to cope with the problems that were assigned me pretty quickly, with George’s help too.

Groueff: But did you know what was the whole thing about, that you were working on the atomic bomb?

Friel: Yes, yes I did. As a matter of fact, when I arrived, Charlie Cooper asked me what I thought the project was all about. I said, “I do not know exactly, but I am sure it has something to do with nuclear energy.”

Groueff: You guessed?

Friel: Well, there were enough small articles and leaks in the newspapers to suggest that this was being worked on in this country, too. There were raids, if you recall, publicized raids, on heavy water plants.

Groueff: And also New York Times had and Life Magazine—[Ernest] Lawrence had some articles.

Friel: And US News and World Report had a few.

Groueff: Columbia University was doing some.

Friel: There were a number of articles, and as a matter of fact, after being established at Chicago for a while, a young graduate came up from one of the universities there not far from Chicago looking for a job. After checking his credentials and his experience and interest, I said, “Why do you want to work here in this establishment? You know nothing about it.”

He says, “Well, my professor says that this nuclear energy field is a good one to be in, and I ought to be up here at the University of Chicago.”

So in spite of the fact there was high security, there were enough academic contacts, apparently, prior to the security clamps so that a few people knew that this had something to do with atomic energy, even though they did not know the exact route whether it was plutonium or [uranium-] 235 or things of this sort. But in spite of all of this, apparently our security was excellent.

Groueff: When you arrived in Chicago, Cooper was your boss?

Friel: Yes.

Groueff: He asked you, “Do you know?”

You said, “Yes I guess,” and he confirmed. He gave you some more details?

Friel: Yes, he told me the nature of the project, what we were trying to do, and emphasized of course the security of the whole thing, and pointed out that the number of people who would know would be very limited, but in view of my particular job—and as a matter of fact, I would say ninety percent of the technical staff at the University of Chicago knew the intent of the project. We did not talk about it to each other, because we were not sure that the other man really knew, but there never seemed to be any barriers.

For example, we were exposed and trained rather broadly in a very short period. Not only was I trained in optics, but I was told to go to the lecture series on pile reactor theory, at which [Enrico] Fermi and [Alvin] Weinberg and [Leo] Szilard and [Eugene] Wigner and others gave lectures on the pile theory. So I just sat there and soaked up the whole pile theory in a number of other training sessions such as this, by staff meetings which we had rather regularly, and it was interesting that a young character such as myself was really, in many ways, given so much responsibility so soon.

Groueff: In what laboratory did you work that time in Chicago?

Friel: I was in Eckerd Hall and in Ryerson Hall. These were connected. We first worked in Eckert Hall and then the hallway was opened up to Ryerson. Both of those buildings were taken over by the project.

Groueff: Was that the same building where Fermi and Wigner were?

Friel: Yes, that is right. They were up on the third floor and I was on the first floor.

Groueff: And Dr. [Arthur] Compton was sort of the boss of [Samuel] Allison.

Friel: Compton was there, yes, correct, Allison was there.

Groueff: What was your particular contribution there? You developed all the devices for seeing through the walls?

Friel: For seeing through walls, devices that would look down into the back end of the reactor so you could see slugs or capsules of uranium ejected from the reactor after processing. Devices for looking at the separation equipment to remove the plutonium from the other materials of the nuclear reaction. Devices to look inside tubes where the slugs would be carried through the reactor—looked directly into the reactor, in other words. Devices for looking through walls and big tanks filled with water or salts, and lenses on these tanks in some cases so that you could not just look through a window, but look and see 180 degree angle beyond the wall, a device which we called a fly eye, for example.

Groueff: I see. But did you apply devices which already existed?

Friel: No, that was one of the interesting challenges. It was of course during the war. The optical companies were all tied up making devices for the military. We realized that not only were they tied up in making these devices for the others, but it would take too long to manufacture systems from scratch. So we salvaged—we took existing optical systems such as the submarine periscope and revamped that. We took the submarine periscope, which as you know is a fixed length device—it goes up and down on a submarine as a unit. We used this in one of the chemical separation areas on a crane and made it movable so it could extend in and out. The operator could stand in the cab on this crane, the cab was shielded from the chemical separations area, and the periscope went up and over a wall and out on the crane and moved with the crane. So the operator could move the head out over the canyon and he would look down in the—

Groueff: Did you invent this device?

Friel: With DuPont, other DuPont people and George Monk at the University of Chicago. We worked jointly on this.

Groueff: And who made it physically, the company?

Friel: The optical components were purchased from the Kollmorgen Optical Company.

Groueff: Which one?

Friel: Kollmorgen, who did make at that time all of the submarine periscopes for the US Navy. Kollmorgen is an old German family that made them for Germany at one time and came to the states.

Groueff: You bought the components, and you assembled it yourself?

Friel: We had the parts and all the mechanical components were made by DuPont in the DuPont shops here in Wilmington. So we had in-house, inside the DuPont Company, the facilities for making all of the components including the cranes. Well, the basic crane, of course, was supplied by a crane manufacturer. But then we hung all the special devices on it including this optical device. We mocked it up here in Wilmington behind barricades and the entire situation and then shipped it out to the West Coast, installed it over these chemical separation tanks.

Groueff: When you developed it, it was made between Wilmington and Chicago, and once it was produced you shipped it to Hanford?

Friel: To Hanford in that particular case.

Groueff: Did you personally live in Hanford or work there?

Friel: Yes, yes, I came to Wilmington—I worked in Chicago, this was one of the units we designed. I came to Wilmington to work on it here while it was being assembled. Then I went to Hanford and was there for a year and a half during the startup of all of these many optical units that we designed. What may have been as many as fifteen or twenty different optical units.

Groueff: And most of them were without any precedent?

Friel: Yes, yes.

Groueff: Never existed before?

Friel: That is right. That is right.

Groueff: I see.

Friel: Nothing of this sort. For example, one of the problems was to look at, closely, microscopically, the slugs as we call them, that came from the reactors.

Groueff: Inside the reactor?

Friel: Well, not only inside, but outside after they were discharged. Each one was looked at to see what the corrosion problems were, et cetera. These were, of course, extremely radioactive. They were so radioactive as you may recall that they glowed in the dark in the water at least. These were collected under water, and the radioactive emissions from these slugs caused the water to glow.

But the problem optically was to look at these microscopically. Of course, you could not bring them up to the surface and look at them in the microscope because of the radiation. So we had to build microscopes that would work under water and would go down as far as twenty or thirty feet.

Again, we were faced in all of this work with a most interesting problem. It came as a surprise but should not have to any of us, the first optical equipment that we built at University of Chicago and put in a reactor, the glass turned black, as black as the cover on your recorder there. So ordinary glasses did darken and darken very rapidly in high radiation levels.

Groueff: You did not know that because nobody—

Friel: We did not know that at the beginning. So in our early optical designs, we had not only to shield the operator from the radiation, but we had to shield the glass, the optical units, from the radiation. We found early that plastics were not subject to such darkening as were ordinary glasses. So in the case of this underwater microscope, for example, where the slug was very close to the optical element, almost by definition, as it was in several of our other special instruments, we could not use glass. It would just darken too quickly. So we used plastics.

In this case, we found that the government was making these large three-inch diameter periscopes with plastic lenses using combinations of polymethacrylate and styrene instead of flint and crown glass. So we used those and used them rather successfully. As I mentioned earlier, everything we used was government surplus of some sort, or not surplus, but being used for government purposes. These fly eye lenses that we used on the back of these big water tanks were really lenses designed to go under the B-29 bombers.

Groueff: I see. So your job was actually to adapt some of the existing military instruments, adapt them to this project?

Friel: Yes, take the elements, take the lens—

Groueff: But only the optical part or also the hands or whatever you called with which you manipulate inside radiated?

Friel: No, just the optical part.

Groueff: The optical part.

Friel: We just took the lenses and built the new mechanical parts around it. We did not use any of the mechanical parts from the military.

Groueff: Did you call it periscope?

Friel: Periscopes, microscopes, and boroscopes.

Groueff: So the normal names?

Friel: The normal names, that is right. We did also use some television units to look behind barricades. The television at this time was very, very poor. If one had to predict the future of television based on the quality of units we had, you would say it would never get off the ground. They were maintenance headaches, very complicated. But we did use them in a few cases and satisfactorily.

Groueff: Inside the reactors and separation areas?

Friel: In the separation areas particularly, yes.

Groueff: So a man sitting in a room in a cab could watch exactly what was—

Friel: Watch what was going on through the television, as well as through the periscopes.

Groueff: The whole plan being automatic, all the controls doing through these optical things?

Friel: Through the optical things, yes.

Groueff: You say there were about twenty different devices?

Friel: Twenty different, that is right. All were developed, engineered, produced in a matter of roughly one year.

Groueff: Each one, of course, multiplied several fold?

Friel: Several fold, oh yes. For example, these cab periscopes, we had a large number of them.

Groueff: Yes, and how did you ship them there?

Friel: They were boxed and crated and shipped out by I believe rail.

Groueff: From Wilmington?

Friel: Wilmington, where they were assembled, yes.

Groueff: Here you had to establish a special workshop for a small plant, actually?

Friel: Yes, that is right. These periscopes were really quite gigantic. I may have not really given you fully the concept of how large these things were on the cranes.

Groueff: How big was it more or less?

Friel: Well, the castings were a foot to a foot and a half in diameter, a good foot anyway in diameter. They were heavy castings. The weight of the periscope was substantial, and of course the entire crane assembly had to be designed so that when it lifted heavy objects with the normal operation of the crane, that there was not so much deflection as to cause the optical system which was hung on the same crane and of course moved in and out, enough deflection to cause a problem.

Groueff: How tall was the periscope? Like a submarine?

Friel: It was maybe sixty feet long total.

Groueff: Sixty feet?

Friel: Sixty feet long.

Groueff: So it was a very huge. I thought it was something like this room or—

Friel: No, it was about sixty feet. It ran along the base of the crane, and optics fed back into the cab. As a matter of fact, the crane operator had two of these. He could look through one on the left side of his cab or he could look through one on the right side of his cab, and in effect get a stereoscopic, simulated stereoscopic view. At least he could see an object from two different viewpoints. We did make them as—

Groueff: When you got this assignment, weren’t you a little bit worried or afraid? Because you didn’t have any experience.

Friel: There was no time to be afraid; there was a job to be done. In the initial period, there were plenty of people—

Groueff: Did you ever have any inclination or any interest in optical problems before?

Friel: Yes, but I think this was probably more coincidental than anything else. I always had an interest in optics, but I do not think that is why I was assigned.

Groueff: What was your specialty in chemistry?

Friel: I was in chemical engineering, which it was just broad processing technology. No particular area of specialty there, although I had really a strong interest in physics and should have been a physics major.

Groueff: How many people were your team?

Friel: We had varying sizes. In Chicago, it was probably on the order of six or seven. At Hanford, it was at maximum at Hanford—just those interested in optics—was in the order of three or four. But the total manpower of course installing these things and working with them was in the tens. Twenty or thirty people.

Groueff: You were in charge of the group inventing the things?

Friel: Yes, that is correct.

Groueff: Who was your immediate boss? You reported to whom for development?

Friel: At Hanford, I reported to Bradford, who is now here in Wilmington with DuPont Company Metals.

Copyright 1965 Stephane Groueff. From the Stephane Groueff Collection, Howard Gotlieb Archival Research Center at Boston University. Exclusive rights granted to the Atomic Heritage Foundation.