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National Museum of Nuclear Science & History

Glenn Seaborg’s Interview

Glenn Seaborg, winner of the 1951 Nobel Prize in Chemistry and co-discoverer of plutonium, was in charge of the separation process for removing plutonium from irradiated uranium slugs at the University of Chicago during the Manhattan Project. In his interview, he discusses the pressure to obtain high yields of plutonium, and how he eventually decided on the bismuth phosphate process, which was extremely successful. Seaborg also describes the difficulty of recruiting top scientists to work on a top-secret project, as he was not allowed to explain the importance of his work unless they agreed to join.

Date of Interview:
November 2, 1965
Location of the Interview:


[We would like to thank Robert S. Norris, author of the definitive biography of General Leslie R. Groves, Racing for the Bomb: General Leslie R. Groves, the Manhattan Project’s Indispensable Man, for taking the time to read over these transcripts for mispellings and other errors.]

Dr. Glenn Seaborg: Well, I arrived in Chicago on a rather wintery day, April 19, 1942—I remember this because it was my 30th birthday—with one coworker, Dr. [Isadore] Pearlman, that I referred to earlier and who was at the University of California Radiation Laboratory in Berkeley at the present time. We were the nucleus of the group that set to work to study the chemical properties of plutonium in order to work out the separation process that would be used in connection with this manufacture of the nuclear reactors.

At that time, of course, it wasn’t known whether a nuclear chain reaction with uranium was possible, but plans were already being made to chemically separate the uranium and plutonium and fission products after the chain reaction had taken place in order to be ready in case the chain reaction was successful. 

Beginning with just the two of us, we worked to get other people to join the group as chemists. By summer, we had perhaps fifteen or twenty chemists working there. I hit upon the idea that if we could work with very small amounts under the microscope and have extremely small solution volumes, that it would be possible to make enough plutonium with the neutrons from a cyclotron to work with weighable amounts—amounts that amounted to micrograms. One microgram is about one thirty-millionth of an ounce.

So, we prepared such plutonium by cyclotron bombardment with neutrons. Some microchemists that we brought into our group succeeded in isolating this material in working with these microgram amounts under the microscope. They even succeeded in weighing, quite accurately, amounts of plutonium as small as a microgram. These chemists—chiefly Burris Cunningham and Lewis Werner and Michael Cefola and their associates—were able to then work out and confirm the chemical procedure, which was required in order to separate the plutonium from the uranium and fission products after the chain reaction.

The uranium after the chain reaction to produce the plutonium was extremely radioactive. It had radioactivity equivalent to more than thousands of tons of radium. So, it was necessary to work out a process that could be operated by remote control behind huge walls of shielding. It was necessary to test the process at the same concentrations that would exist in the chemical extraction plant—the plant that was later built in Hanford, Washington. This was possible with the extremely small amounts of material working on this small scale was more sensitive than microchemistry. It, in fact, was called ultra-microchemistry.

The chemical process itself was worked out by other chemists, but the testing of it at the actual concentrations was done by the ultra-microchemists. This was necessary in order to be sure that the process could work at the concentrations of plutonium that would exist in the plant. This meant that there was a scale up from these micro test tubes under the microscope to the actual plant at Hanford, Washington of about a billion—a billion fold from what you might call the pilot plant to the final plant. This is the biggest scale up in the history of chemistry and chemical engineering.

Stephane Groueff: Were then the conclusions that you reached on this small amount, could you extrapolate one billion?

Seaborg: They were valid.

Groueff: They were valid?

Seaborg: They were valid, yes. There were a number of people who bet that they wouldn’t be valid. A lot was at stake. There were those in the laboratory who just said that this would be a huge boondoggle and would probably be Seaborg’s folly—something like this as a monument after the war. But, we stuck to our guns and insisted that the work would be valid.

When the plant was built—first a plant at Oak Ridge, which tested the equipment in gross form but not at the high concentration and not at the actual concentrations that would exist at Hanford, because the nuclear reactor at Oak Ridge ran at smaller power. After this testing at Oak Ridge and after the plant at Hanford had been built, it began to operate at Hanford successfully and with high yields almost immediately—yields of 70% or 80% the first week, and then yields within a month or so of more than 90%, and very shortly thereafter, yields of more than 95%. It was very successful.

Groueff: But when you started, the amounts were not visible even under microscope, no?

Seaborg: That’s right. Before we went to Chicago, the first plutonium was produced at the University of California at Berkeley by bombardment of the uranium with deuterons. This, of course, was less than visible. This was just tracer amounts. Here the chemical studies were just carried on by what we call the methods of tracer chemistry or radiochemistry, where you didn’t try to precipitate the material alone, you had what we call a carrier. You precipitated another material from the solution, and then these invisible or tracer amounts were co-precipitated or carried down with the other precipitate. From this, you deduced as best you could the chemical properties of the new element.

The new element, plutonium, was discovered by such deuteron bombardments in the sixty-inch cyclotron at Berkeley, late in 1940 and early in 1941. That’s right. Then we worked with it on this tracer scale all of 1941. This included Arthur Wahl and Joseph Kennedy, my coworkers. It continued in 1942 and continued in Chicago working on the tracer scale after Pearlman and I arrived in April of 1942. But such experiments couldn’t be definitive enough, could not be reliable enough to develop a process that would operate at the high concentrations—I say high concentrations, they’re not high, but at the concentrations of plutonium that would be produced in the uranium in the Hanford reactor.

It was then necessary to produce visible or weighable amounts of plutonium, which was a daring idea at that time. It hadn’t been possible to produce visible or weighable amounts of material inside the cyclotron bombardment. The idea was to attempt this, again considered by some to be not feasible. But by bombarding hundreds of pounds of uranium with neutrons over a period of days at a time, it was possible to produce micrograms.

The uranium was bombarded with neutrons at two cyclotrons. The same sixty-inch cyclotron at Berkeley had been used in the discovery of plutonium some eighteen months earlier and a similar cyclotron at Washington University in St. Louis.

Groueff: I see.

Seaborg: And from these two—

Groueff: You didn’t have cyclotrons in Chicago?

Seaborg: We didn’t have a cyclotron in Chicago that was operating satisfactorily for this purpose at that time. There was a smaller cyclotron there that would be used for other work, but it was not suited to these rather intensive bombardments, which required the largest and most powerful cyclotron available at that time. They were these two cyclotrons: the one at Berkeley and the one at Washington University in St. Louis.

Groueff: Well in Chicago, your group was a part of Dr. [Arthur] Compton’s laboratory—the Metallurgical?

Seaborg: Our group was all a part of Dr. Compton’s laboratory, the Metallurgical Laboratory. The laboratory included Enrico Fermi, who headed the effort among the physicists to design nuclear reactor that would operate on the nuclear fission reactions with natural uranium to produce the plutonium. There were the physicists who produced to develop the nuclear reactor, to operate first on a small scale, right there in Chicago, and on a slightly larger scale down at Oak Ridge, and then finally on a production scale at Hanford. And there were the engineers that translated that into the actual construction stage.

Groueff: The DuPont people?

Seaborg: Along toward the summer of 1942, the DuPont Company began to loan engineers to the project for this purpose. Later, the DuPont people came in as the contractor responsible for the building of Hanford.

There were the chemists that I mentioned—my group that had to do with the development of the mechanical separation process of the plutonium. There were other chemists that studied the fission process in more detail and studied the effects of radiation on material. There were biologists who studied the biological effects of radiation to be sure that all of the work could be carried on safely. There were metallurgists to develop the uranium in metallic form for use in the reactor. And of course administrators—all headed by Dr. Arthur Holly Compton, and administrated by a group of competent assistants who worked with him.

Groueff: But your group was in close touch with the physicists? You personally, for instance, did you work independently, or in the same building?

Seaborg: Well we were in close touch, but we worked fairly independently because the problem of separating uranium and plutonium and fission products after the chain reaction had been operating for the required length of time in the reactor was a sort of a separate problem from us.

Groueff: You were in charge—you personally?

Seaborg: I was in charge of developing the separation process. We worked on the fourth floor of Jones Laboratory—Jones, just like the simple American name—Jones Laboratory, one of the chemical laboratories on the University of Chicago’s campus. We worked there until about December of 1942 when we moved into a new chemistry building that was built about two blocks away—a building that was thrown up, obviously, beginning in the fall of 1942 and finished by December.

It was thrown up in rapid time, and we stayed in there. Actually the first isolation of plutonium that I referred to took place in August and September 1942 while we were still in Jones Laboratory. The room in which those ultra-microchemists worked was a very small room; it was only about seven or eight feet wide and maybe ten feet long.

Groueff: What did it look like, working in this room?

Seaborg: Well, very crowded, all the equipment piled on a bench there.

Groueff: Several people?

Seaborg: There were several people working in this small room.

Groueff: Dressed in laboratory coats?

Seaborg: Yes, dressed in white laboratory coats and working very efficiently and working long hours. We worked six days a week and came back every night, five nights a week—that is Monday, Tuesday, Wednesday, Thursday, and Friday nights—either to the laboratory or to some kind of a meeting, and then had another coordinating meeting that ran all day all Sunday morning. That was our schedule. We had Saturday night off and part of Sunday afternoon and Sunday night. That was our time for recreation.

Groueff: Did you help with the building of Fermi’s pile, or that was a different group?

Seaborg: That was a different group.

Groueff: But you knew about them?

Seaborg: I knew about it, and of course knew the progress in detail and knew when it became chain-reacting on December 2nd, 1942—knew it within minutes.

Groueff: In other words, you didn’t work personally and in close contact every day with people like [Enrico] Fermi or [Leo] Szilard or [Eugene] Wigner?

Seaborg: No. No.

Groueff: It was a completely different group?

Seaborg: They were in a different building, carrying out a different part of the assignment of the work.

Groueff: You reported directly to Compton?

Seaborg: Actually, I reported to a chemist because there were broader chemical problems than just the separation process. So there were various directors of the chemistry division that I reported to.

Groueff: You were just a subdivision of the chemistry department?

Seaborg: Yes. Yes.

Seaborg: Yes. What they call a section; I was what they call a section chief.

Groueff: For separation?

Seaborg: Yes, or really for the chemistry of all the transuranium elements, but chiefly for the separation of the plutonium from the irradiated uranium. There was a chemistry division director, and then there were several sections under him, and I was a section chief. Then under me there were a number of groups or group leaders. I had, reporting directly to me, about one hundred chemists.

Groueff: One hundred chemists?

Seaborg: About one hundred chemists.

Seaborg: Yes, it started by two of us, and then maybe fifteen the summer 1952 [1942], and then maybe at the peak by the end of—

Groueff: ‘42, yeah.

Seaborg: ’42, and then maybe at the peak at the end of ‘43 and early ‘44 there were about one hundred chemists.

Groueff: Did you move to Hanford at that time?

Seaborg: I didn’t, no, but my key men did. One key person, Pearlman, moved to Oak Ridge—because that started first—and then to Hanford. Several key persons, of course, moved to Oak Ridge. Then a little later in the summer of 1944, a number of key people moved to Hanford and I just traveled.

Groueff: Traveled regularly?

Seaborg: Regularly. I went to Oak Ridge. From the summer of 1943 to 1944, I went to Oak Ridge on the average of about once a month for meetings, two-day meetings.

Groueff: By train?

Seaborg: By train almost always. Once or twice by airplane, but air travel wasn’t very successful in those days. Train travel wasn’t very comfortable either. It was very difficult. The trains usually didn’t have any food. If you got to the dining car at all late, the limited food was gone. The trains usually ran late. It was quite difficult to travel by train. I remember several times, the train might be half a day late getting up from Tennessee to Chicago. You had to change trains at Cincinnati. There wasn’t a train all the way through.

Groueff: To Hanford you went by plane?

Seaborg: No, entirely by train to Hanford. It wasn’t feasible to travel to Hanford by plane at that time. We went various ways across the country—in Northern Pacific, in Great Northern, in the Union Pacific.

Groueff: You went [to Hanford] often also?

Seaborg: Yes, but not that often.

Groueff: I see.

Seaborg: Not as often as I did to [Oak Ridge].

Groueff: So you remained in Chicago until the end of the war?

Seaborg: Yes, until after the end of the war, actually, until May of 1946.

Groueff: Could you tell me in a few words, what were the main unprecedented difficulties about separation? From the chemist’s point of view or even the engineering point of view, was it something incredibly difficult to do like in the other programs, like gaseous diffusion or electromagnetic [separation] or the reactors? They were things that had never been done before, because the separation of plutonium had never been done before.

Seaborg: No, it was feared to be quite difficult. The element had just been created. It had rather unusual chemical properties. It was highly radioactive. The process had to be carried out entirely by remote control behind ten feet of concrete. You never saw the uranium that you were dissolving. You never saw the materials that went down the separation line until it had emerged after literally hundreds of chemical operations at the end.

Groueff: Who invented or who designed the process? The group in Chicago?

Seaborg: Yes.

Groueff: Or at Hanford?

Seaborg: No, the group in Chicago designed the chemical steps in the process.

Groueff: Did you a build a model in Chicago?

Seaborg: We had what we called semi-works there, but the key was just the chemical steps in the process and the reagents to use—what to precipitate and so forth.

We had an unusual process. We found that bismuth phosphate would carry the plutonium. We could precipitate bismuth phosphate from the solution, and then that would extract the plutonium along with it. Then you dissolve that and carried on to a next step, but this was a very unexpected property of bismuth phosphate, and it was subject to much discussion.

It was a very good process because bismuth phosphate was not corrosive and could be handled quite well in centrifuges and in a chemical separation, but it wasn’t understood why bismuth phosphate did this so well. Again we had our skeptics—those who felt that the process couldn’t work because it didn’t seem to conform to theoretical expectations.

Groueff: How did you find that it did?

Seaborg: Experimentally.

Groueff: You tried different things and you hit bismuth?

Seaborg: Yes. We tried many things and we found that bismuth did the job best. Well, we had some reason to expect, but it was not considered a good bet at the beginning and there were skeptics, because the chemical form of bismuth is such that it should not have this ability to carry plutonium. 

This was one reason why it was imperative to do the ultra-microchemical test experiments, because it could have occurred that at the trace concentration of bismuth phosphate would carry plutonium, but not at the concentrations that counted at Hanford. That’s why.

Groueff: And not in the pound—

Seaborg: And maybe not in the pound quantity. But once we found that the concentration in the ultra-micro experiment was the same as it would be in Hanford in the pound quantity, then we felt that everything was the same except increasing the volume, which seemed safe. But there were those who were skeptical.

Groueff: That was one of the major breakthroughs?

Seaborg: That was one of the major breakthroughs that we found, that bismuth phosphate would do this, and that we could test it, and that we had the confidence to see it through to the end. Of course, it would have been a catastrophe if this confidence had been misplaced.

Groueff: Was there a great deal of guessing and gamble at the beginning, especially, before you obtained visible, microscopic amounts? Didn’t you have to make assumptions and just hope for the best?

Seaborg: Well, it wasn’t a gamble exactly. We tried out a lot of the precipitation reactions to see which one would carry plutonium.

We found a number that would. One that would carry was lanthanum fluoride. But when they tried that out in the larger equipment, the reagents that were required in order to precipitate lanthanum fluoride were so corrosive that they dissolved the equipment. Lanthanum fluoride might have been just as good as bismuth phosphate, but the equipment wouldn’t last.

So we had these constraints. We had to find something that would carry the plutonium well, it would precipitate efficiently, it could be centrifuged out, it was not corrosive, and which would work at the concentrations that were existent at Hanford, and which could be dissolved again so that you could go on to the next step in the process. It may be that bismuth phosphate is the only precipitant that could have been developed in the time available. This was done all in a fantastically short time, of course.

Groueff: I don’t fully express it well because I don’t have a scientific background, but at the very beginning, before you had microscopic amounts of plutonium, your group started on the assumption that probably the plutonium will have similar characteristics of uranium?

Seaborg: Yes we did.

Groueff: And it worked, but if I understand correctly, it didn’t work for the right reasons. In other words, later when you had enough plutonium, you found out that it’s a very different element, and your assumptions probably theoretically were not correct. But the main things that you—

Seaborg: Well, it isn’t quite that way. We thought that plutonium and the elements following plutonium would all be like uranium. Plutonium, in the sense that’s important here, was and is like uranium. It’s just that you need stronger oxidizing agents to put it through the same oxidation states as you do uranium. That never turned out to be wrong.

But when we went on to look for the next element—plutonium is element 94 in the scale, uranium is 92 and captures neutrons and undergoes two electron changes. When we went on to look for 95, we assumed that it also would be similar to uranium and neptunium and plutonium, in that it would have the same range of oxidation states that you could get an aqueous solution. This we started to do in 1944 after we’d solved some of the other problems, and [Element] 96. This turned out to be wrong.

It turned out to have other properties and to be more like the rare earths or to be more like actinium, element 89. When I got that idea—this was my idea—then in the summer of 1944, I can almost remember the time and place when I got this idea, we conceived of experiments that made it possible to identify element 96 right away. In other words, we had it in our solutions in the laboratory, but we were trying to treat it chemically as if it would behave like uranium and plutonium, and it didn’t. It would not oxidize, in other words.

As soon as I got the idea that it shouldn’t, then we used other procedures. Then in July of 1944, we did discover element 96. Later that year, we discovered element 95. This was the key, then, to finding the whole string of transferring elements later after the war. This is what’s called the actinide hypothesis for the structure of the transuranium elements.

Groueff: So with plutonium, you were not wrong, but if you had assumed the same thing for the 95 and 96, you would have been completely wrong?

Seaborg: Wrong, yes. Plutonium we found almost immediately at Berkeley that it had the same range of oxidation states as uranium. It was just a matter, though, that it took different conditions to change from one oxidation state to the other.

Groueff: But otherwise the two elements are very different, no?

Seaborg: Yes, they’re quite different. The metal is different. The plutonium metal is different than uranium.

Groueff: I understand that they had quite a fill of surprises and difficulties in the metallurgy of plutonium.

Seaborg: Very much. Very much, yes. I can tell you about that.

Groueff: That will be very interesting

Seaborg: It’s one of the most exotic metals in the periodic table—maybe the most. It has about six forms. It undergoes change in ways that are different: in expansion, in contraction, in heating and the effect of temperature on electrical conductivity and things of that sort are all anomalies.

Groueff: But even physical to a layman’s sight, to me, I would see the difference, and it would expand differently?

Seaborg: No, well, you wouldn’t. No, because it’s a metal and you wouldn’t be able to do anything.

Groueff: I see, but for the metallurgists?

Seaborg: For the metallurgists, it’s a very fascinating element.

Groueff: And very difficult?

Seaborg: Very difficult to handle and work with, yes. Of course, a piece of plutonium is hot all the time because of the radioactivity; you hold it in your hand, it’ll be hot. But if you hold it in your hand, it’ll look like a piece of uranium, for example.

Groueff: I see.

Seaborg: You couldn’t tell the difference. Plutonium, the ornery element.

Groueff: I’d be interested.

Seaborg: I mean that’d be a good source of material.

Groueff: Because I understand that later, even in Los Alamos, they had tremendous difficulties in the metallurgical.

Seaborg: Yes, they did. First it looked like it had too low a density so that it wouldn’t be nearly as effective as a nuclear weapon, but that turned out to be just one of the many forms. As I said, it has about six forms and they just found one of the—

Groueff: Nobody knew that?

Seaborg: Nobody knew it. They thought maybe that was the only form. So there were a few weeks there when people were pretty blue. See, they didn’t know.

Groueff: That’s an aspect that I want to underline. There is a new element that nobody had ever seen. If there were some experts on that in the world, it was you and your group, because you discovered it.

Seaborg: Yeah.

Groueff: And even you had never seen it.

Seaborg: That’s right.

Groueff: Yet you were, in a matter of months or one year, expected to produce kilograms?

Seaborg: That’s right.

Groueff: And not only to produce it, but also to know the characteristics.

Seaborg: All the characteristics, the chemicals and everything, that’s right.

Groueff: So that sounds like.

Seaborg: Almost unique in the history of the world, yes, it’s hard to think how you’d repeat that again.

Groueff: How did that affect you and your colleagues? In what form did the demand come to you? Compton would ask you to do this and that, or Groves?

Seaborg: Oh, it was usually Compton. Well, it was so clear what needed to be done that it hardly required any conferences.

Groueff: I see. So you knew that you had to produce—

Seaborg: These chemical separation processes—learn all these processes. It was interesting when people came into the laboratory. I insisted on interviewing each chemist as they came in. Well, first to decide whether I wanted to hire him, because I didn’t want people who weren’t quite good in the group. I’d rather have no one then, you know, some dead weight, because it takes a lot of effort to oversee the work of a hundred men. So you didn’t want any who were actually doing things wrong so it detracted from progress.

So I interviewed each of them as they came in and formed my own opinion as to whether they would be an asset to the group. I had a great deal of fun asking them, before I told them what we were doing, what they thought they were doing. See, they couldn’t have the slightest idea, you know.

 I can remember one of them saying that “Well, I don’t know what you’re doing, but I’m sure that you’re working with one of the known 92 elements,” he said just like this. You know, he was going to be sure of that. Of course, he was even wrong on that. He was even wrong on that. I got a great pleasure out of watching these young fellows’ eyes pop, you know.

I’d say, “Well no, we’re working on a new element. We’re completely synthetic. You’ve never heard of it before and it has the atomic number 94 and we’re going to try to make it into a nuclear chain reaction. If we do that, we’re going to try to separate it, and we’re working to work out its chemical properties.”

Groueff: And their eyes would pop?

Seaborg: Up until then, this was almost impossible in the experience of the young fellows.

Groueff: Contrary to the dogmas of your time?

Seaborg: Yes, oh yes. Absolutely. Yes sir.

Groueff: Wasn’t your discovery publicized?

Seaborg: Not at all; it was voluntarily withheld from publication by our group because of its potential. No, no one knew.

Groueff: When you discovered it, you didn’t pull the usual steps concerning your paper?

Seaborg: No, we didn’t. We registered the paper with the journal to be published after the war when it was released by us, you see.

Groueff: So even the top chemists in this country didn’t know about what you?

Seaborg: No. In fact, I had trouble getting recruits. I would write to a young fellow at a university, and he would write back that he was doing something important. I don’t know, you know, he was synthesizing an anti-malarial compound or something, you know, another one, and he just couldn’t come. I would write back, and I couldn’t tell him. I would write back, “Well look, just trust me.”

It was very often my people I’d met earlier in life—schoolmates at UCLA or something like this. I can remember writing back that, “You just come. We’re working on something that’s more important than the discovery of electricity.”

Groueff: I see.

Seaborg: “You just come here and I’ll tell you what it is.” This almost always brought them.

“My God, more important than the discovery of electricity?” You know, so they’d turn up. 

Groueff: Because in your field, you didn’t have people with a great name like in the other projects. I know they used to use the names—they would say Professor Urey or Lawrence.

Seaborg: Well they knew me. No, I had already been in— 

Groueff: You were only thirty then, no?

Seaborg: Yes, but I’d been in the nuclear field ever since I’d started graduate school at the age of twenty-two, you see, and had published lots of papers and tables—

Groueff: You were well known among the chemists?

Seaborg: Yeah. Yes, probably as well known as any nuclear chemist in the United States. They had an idea. They had some idea. In fact, some of the professors would tell their men—they would guess. They’d say, “You should not go and work with Seaborg, that’s just a big boondoggle because I have it on authority or I have a good hunch that he’s probably trying to work on atomic energy.” He’d use that, and several professors convinced their people that they shouldn’t come work with us because they were sure we were working on atomic energy. 

Groueff: Atomic energy, that was impossible?

Seaborg: Oh, that was impossible, yeah. I mean, what a waste of time. 

Groueff: A waste of time in time of war. 

Seaborg: So we lost a number of first class men because their professors told them not to.

Groueff: They had more important things to do?

Seaborg: Yeah, they had more important things—they were working on some organic synthesis of some compound, of course that nobody’s ever heard of since. But they worked during the whole war on that because they weren’t going to be trapped into going to a project where they were trying to work on atomic energy. 

Groueff: But once you had them, did you tell them, the young scientists, or was it not necessary, about the bomb and everything?

Seaborg: Oh, yes sir. As soon as they came, I told them everything.

Groueff: But not before?

Seaborg: Not before.

Groueff: You couldn’t take the risk of telling them and them turning you down? 

Seaborg: No, I never told them before. We hired them, and then they came on faith, and then I usually took them into a room.

Groueff: That’s an interesting element because for a lot of them, it meant a big effort and leaving families or moving to another city. Why would they do it? You had to convince them pretty well. 

Seaborg: Yeah, I had to convince them.

Groueff: About the separation process, how would you describe it in a few words for laymen? What is a separation problem—uranium after the process of the pile of the reactor comes out of the plutonium?

Seaborg: Uranium has embedded in the plutonium and the radioactive fission products. Then that’s dissolved. 

Groueff: Chemically? 

Seaborg: Chemically. The acid is put on to the uranium, and it dissolves the uranium and the plutonium and the fission products. Then you precipitate bismuth phosphate, and that carries the plutonium down. Then you separate through a centrifuge the uranium and fission products that remain in the solution. Then you dissolve the bismuth phosphate and the plutonium, and carry on a process that’s somewhat complicated, but that’s the idea.

Groueff: Each reactor in Hanford had its own separation, or the separation area was one for all the reactors—what did it look like?

Seaborg: Well, it was pretty much each reactor had its own. Maybe two reactors would have the same separation plant.

Groueff: This canyon that— 

Seaborg: That’s the separation plant.

Groueff: It was highly radioactive, so you couldn’t go near there? 

Seaborg: That’s right. That’s right.

Groueff: So the remote control?

Seaborg: Yes, you had to have tons of the—

Groueff: Was that engineering-wise, was it some extraordinary difficulty or not as much? 

Seaborg: It was very difficult. The engineers set the chemical separation plant, and that’s where the DuPont Company did a tremendous job.

Groueff: Who were the people that you worked with on this part? [Crawford] Greenewalt?

Seaborg: Greenewalt, yes, and a number of other people with the DuPont Company.

Groueff: The constructors there are people like [Slim] Read?

Seaborg: Read, yes. 

Groueff: I found that you—

Seaborg: I have them all in there. I think they’re going to find that interesting.

Groueff: Yeah.

Seaborg: Probably the best source of names that you could find on that, they’re all in there.

Groueff: You didn’t have contact with the military, [Leslie] Groves or [Franklin] Matthias? 

Seaborg: Yes.

Groueff: Oh you did?

Seaborg: Yes, and [Kenneth] Nichols. 

Groueff: Nichols?

Seaborg: Yes. Yes, I did. But not so much.

Groueff: In conferences?

Seaborg: Yeah, in conferences, and once in a while he wanted something changed or done differently. He’d get right in touch with us, come into our laboratory once in a while.

Groueff: Who was directing the separation operations at Hanford? Was it anybody in particular, or was it the whole organization?

Seaborg: The man who was sort of down in the chemistry part at my level, you know, right for whom the chemists worked directly, was called John Willard. 

Groueff: John Willard?

Seaborg: John Willard. 

Groueff: That’s not John Wheeler?

Seaborg: No, that’s John Willard. John Wheeler’s the nuclear physicist. John Willard is a nuclear chemist at the University of Wisconsin. He’s still there. He came to me from the University of Wisconsin on a leave of absence basis, then went back. 

Groueff: He came to Chicago and then to Hanford?

Seaborg: [He went to] Hanford and then back to Wisconsin directly.

Groueff: Were you present when the first operation started—the startup of the reactor or for the separation? Did you go to Hanford?

Seaborg: Yes. There is no single day, though. 

Groueff: Yeah. That’s what I wanted to know.

Seaborg: Yeah.

Groueff: So I couldn’t describe it, “It was two o’clock in the afternoon?”

Seaborg: No, there wasn’t any single day. I remember we had to go there just before it started and we had to initial all the processes, you know, to be sure to sort of certify it.

Groueff: So that was done between Chicago people and DuPont and the military? 

Seaborg: Yeah. Well, this was Chicago and DuPont.

Groueff: Chicago and DuPont. But there was no moment that you can say that the 16th of August or something like that, everybody waits and then, you know?

Seaborg: No. The moment I remember is the 1st of June 1943. That was the day we all assembled and finally chose the bismuth phosphate process.

Groueff: Where was that?

Seaborg: In Chicago.

Groueff: Could you describe the scene?

Seaborg: It was just a very intense meeting with Crawford Greenewalt there and myself and other key people in the laboratory. We spent the day discussing which process it should be, of which the bismuth phosphate was only one. Essentially, they finally just took my recommendation.

Groueff: So it was decided on your level and Greenewalt—not Compton?

Seaborg: No, it was really myself and Greenewalt at that meeting.

Groueff: You were strongly favoring the bismuth?

Seaborg: Greenewalt turned to me at a critical stage and said, “Could I [Seaborg] guarantee a yield of at least 50% by the bismuth phosphate process?”  

I said, “With the other process, the lanthanum fluoride, you might not get anything. You might only chew up your equipment, and it would dissolve, and your plutonium would go down the drain.” 

Bismuth phosphate wasn’t corrosive, but it had these other problems, not being quite clear in the minds of some why it worked. It was clear in my mind, but he had his advisors who advised him that it would never work. He turned to me at a crucial point and said, “Could [you] guarantee that it would have a yield of at least 50%?” 

I said, “Yes. I could guarantee that it would have a yield of at least 50%.”

Crawford Greenewalt says, “Okay, it’s the bismuth phosphate process.” That’s the way the meeting went. 

Groueff: At that time, you had only laboratory work?

Seaborg: Only laboratory work, yeah.

Groueff: With very small amounts?

Seaborg: With very small amounts, that’s right.

Groueff: But all during those long months, weren’t you a little bit scared?

Seaborg: Sure, sure. I wasn’t telling anybody.

Groueff: It was a fantastic hope?

Seaborg: It wouldn’t have been a bit good for my reputation if that hadn’t worked. It probably would have affected my entire subsequent career. 

Groueff: Sure. There were millions already spent?

Seaborg: Oh, millions, yeah.

Groueff: At Hanford, hundreds of millions?

Seaborg: Oh yes. Oh, it was a very great strain.

Groueff: The reactors without separation are no good?

Seaborg: No good. No. Worthless.

Groueff: How big is a separation operation? Is it in the hundreds of people or thousands?

Seaborg: Thousands.

Groueff: Thousands of people. 

Seaborg: Yeah. Well, one plant, one chemical separation plant—of course, it operates three shifts— was probably a thousand people. I really don’t know. 

Unidentified Male: About 1,500 out there now, so I imagine in those days it was about a thousand.

Seaborg: Yeah.

Groueff: And it worked all the time, non-stop? You don’t have to stop it to get out the material? It’s automatic?

Seaborg: It works non-stop. It could work batch, but it just inefficient to get everything warmed up and closed down and pipe lines de-clogged and everything. 

Unidentified Male: It’s not that one single process, its several stages.

Seaborg: Yeah. They use different processes now. 

Groueff: So if I went now? 

Seaborg: You wouldn’t get it. Oh they’d show you the old bismuth phosphate plant. It still stands.

Groueff: I intend to go.

Seaborg: I don’t know, is there anyone there? Is there one left that’s completely unused? They’ve been using it for other things, you know, discovering uranium— 

Unidentified Male: I think you can go in and walk around. 

Groueff: I intend to go and see them.

Seaborg: You can recapture a lot of that there.

Groueff: There’s the whole atmosphere.

Seaborg: You’ll even find people there who were—a few, I think maybe—who were present. I don’t know who.

Seaborg: There weren’t too many who were there right when that plant started up, the Chem plant. But, you might find someone if you tried.

Unidentified Male: You could probably find some high school kids who were operators then.

Seaborg: Yeah, you might find that.

Groueff: That is interesting.

Seaborg: A lot of the key people were DuPonters, you know. They left right after the war. A few of them stayed with General Electric, but there aren’t too many of those. I know one of those is Gregory, you know. But he’s moved on. He’s still with General Electric, but he moved down to San Jose.

Groueff: The separation people?

Seaborg: Yeah.

Groueff: Once the plutonium was separated, it came as a liquid in a solution or as a powder?

Seaborg: The last step was a plutonium peroxide precipitate, and then that was dissolved in solution and shipped.

Groueff: It was shipped as solutions?

Seaborg: As solutions.

Groueff: When did you start shipping the very first? It was very close to the bomb I think, no?

Seaborg: Oh yeah, in the spring of ’45.

Groueff: Everything was tremendously close.

Seaborg: It’s hard to realize how compressed things were. A week made a lot of difference. 

Groueff: Everything going together, like laboratory, power plant, the construction, and production of everything at the same time.

Seaborg: Well, plutonium was discovered in about, let’s say, right close to January 1, 1941. It was isolated in pure form in September 1942. That’s fantastic, you know, to think you could make it in weighable amounts. The first bismuth phosphate precipitation that showed that bismuth phosphate carried plutonium—it had never even been tested that way—was made in about December 1942. They built the plant and were getting plutonium out of it at Oak Ridge in around January 1944—just a year later.

Groueff: In ’43 you decided already on—

Seaborg: On June 1st we decided—

Groueff: On bismuth.

Seaborg: We just found that it carried it on tracer amounts in December of ’42. By June 1st, we decided to put it into that plant where we had done all the microchemistry and everything. We got a milligram of plutonium out of Oak Ridge already by January of ’44. By the spring of ’45, we were getting kilograms out of Hanford. By July of ’45, we had d exploded a bomb. I mean, that’s just fantastic. You hadn’t even heard of the element. 

Groueff: Four years from complete scratch.

Seaborg: Yeah, four. You’re right. Four and a half because July of 1940, you hadn’t even heard of the element. 

Groueff: That’s really from scratch.

Seaborg: Yeah.

Groueff: This kind of information, the general public is not aware. I think it’s fantastic what has been done and the difficulty.

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.