The Manhattan Project

Miles Leverett's Interview

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When World War II began, Miles Leverett was a young PhD chemical engineer working for Humble Oil & Refining Co. in Houston. One day his boss, who had recently disappeared from Houston, telephoned from Chicago and asked Leverett if he wanted to work on a war project. Leverett did, and eventually became associated closely with the helium-cooled reactor proposal at the Met Lab. In addition, he was part of design engi­neering for the mechanical aspects of the Hanford reactors, and was initially in charge of the engineering group attached to the X-10 Graphite Reactor. After the war, Leverett continued a distinguished career in nuclear engi­neering, a field he pioneered, with an emphasis on reactor safety. In this interview, Leverett describes the importance of DuPont and the relationship between the industry and the academics. He also discusses his work on nuclear-powered aircraft after the war.
Manhattan Project Location(s): 
Date of Interview: 
April 24, 1986
Location of the Interview: 
Palo Alto

[At top is the edited version of the interview published by S. L. Sanger in Working on the Bomb: An Oral History of WWII Hanford, Portland State University, 1995.

For the full transcript that matches the audio of the interview, please scroll down.]

Book version:

When my boss T.V. Moore asked me if I wanted to come to work on a war project, the whole thing sounded pretty flaky because he couldn't tell me what I would be doing or where I would be located. I told him I would need some time to think it over. So, a couple of weeks later he called again. He said you've had time to think it over now, and I want you to come up to Chicago and meet me at the Miramar Hotel on 63rd Street in south Chicago, by a certain date, which I think was May 18 of 1942. I did. That evening, when I got to Chicago, he met me and took me to the hotel where he was staying, and he and Dick Doan, R.L. Doan, told me what the project was all about. He went into enough detail to say it was an atomic weapon, describe its power, what the Metallurgical Lab was trying to do, what its role was, an idea what I would be doing. Of course, that was a tremendous shock, the idea there could be anything that big, and that powerful, and the chance of working on it was obviously something I couldn't pass up. I stayed.

We knew Germany was working on the same thing. That was a strong motivation. I remember T.V.'s remark "If some morning you wake up and read in the newspaper that half of Germany has disappeared, well, you'll know what the reason was."

My first assignment at the Met Lab was to work on the helium- cooled reactor. Chemical engineers are supposed to know something about heat trans­fer, fluid flow and this reactor was supposed to be cooled by flowing helium, so the job was to work on heat transfer and to some extent on the mechanical aspects of it.

It wasn't long after that that the Army brought Du Pont into the picture, late '42. Also, the physicists were pushing the idea that the reactors should be water-cooled. I think not because they thought it was inherently better but to have a second string to the bow. The more we went into the helium-cooled thing, the more we realized high temperatures were going to be a big prob­lem. When Du Pont came in they looked at the helium-cooled reactor and said we can get it loaded and we can get it unloaded once, we can't guarantee that it will be more than that. Because of mechanical problems. The fuel handling mechanism in the helium-cooled design was located in the bottom of the reactor which was the highest-temperature location. They felt very uneasy about the long life of that part.

There was an advantage to helium because it is a chemically inert gas, it doesn't combine with anything so it would not corrode the graphite which was to be used as the moderator, would not corrode steel, would not corrode uranium or the coating on the uranium. Those were the principal reasons. As gases go, it was a good coolant, and provided a low absorption rate for neu­trons, much less than water, in fact essentially zero. But, people felt so much more at ease using water-cooling and aluminum tubes. We had succeeded in cladding the uranium in aluminum shells. It was not long before everyone agreed that approach probably should be the main line.

There was some doubt at first that water would work because it is a fairly good neutron absorber, the hydrogen atoms in water are good neutron absorbers. But water also would moderate the neutrons, which we wanted. The experiments that were done indicated you probably could make a chain reaction with water cooling and aluminum tubes. There would be enough reactivity to make it work. I think basically it was Du Pont's decision. They were brought in to do the engineering work, and this was obviously an engi­neering decision.

It was my job primarily to review the Du Pont designs as an engineer, from the point of view of the Metallurgical Laboratory. Du Pont knew noth­ing about nuclear engineering, in fact there wasn't any nuclear engineering.

My direct connection with the Hanford reactors essentially ceased when I moved to Oak Ridge, in September '43. Before that, it was a matter of work­ing on the cladding of the uranium, looking at the preliminary drawings of the Hanford reactors. There was additional heat exchange work to be done, but Du Pont had people who were quite capable in that area. There was a lot of corrosion work which had to be started.

I don't recall there was a great deal of worry that the Hanford reactors wouldn't work. If there were a deficiency of neutrons, if "k" were not quite big enough, you'd simply have to build the reactor bigger. If "k" got to be less than one, of course, no matter how big, it still wouldn't work. I don't think there was much concern it would be that bad. In fact I have a joint patent with Fermi in which the very ingenious solution we came up with was, if you don't know how big to build a reactor, build it bigger than you think you have to. Put in some extra holes. Fermi, incidentally, was a very nice person to work with. He was meticulous in his work, but there was nothing pretentious about the man at all. No pomposity or anything of that sort which you saw in some of the scientists, particularly the Europeans.


Full Version:

S. L. Sanger: If you could maybe just describe me, just in general, how you got involved in the Manhattan Project, and then we can go on. I’d like to ask you something about the helium water reactors, since you were involved in that, and some other odds and ends. But mainly if you could just sort of get into it by talking about how you got involved there, and what you were doing.

Miles Leverett: Well, the climate, World War II came along, I was working for what was then called the Humble Oil and Refining Company, which later became Exxon USA. All of us there were looking for ways to get into war work. My boss, T.V. Moore, disappeared. We understood he was on a war project of some kind, but nobody would talk. He called me up one day from some place and said, “How would you like to come work on this war project with me?”

Well, I was very much interested. I said, “What would I be doing?”

“I don’t think I can tell you that.”

“Where would I be located?”

“It might be Chicago, it might be St. Louis, it might be Detroit, it could be Cleveland.”

“How long would this last?”

“Oh, I don’t know about that.”

He couldn’t discuss it anyhow. The whole thing sounded so flaky, I said, “I’d like some time to think this over.”

A couple of weeks later, he called again and he said, “You had enough time to think it over now.” He said, “I want you to come up to Chicago and meet me at the Miramar Hotel on 63rd Street, South Chicago,” by a certain date, which I think was May 18th of 1942.

So I did. That evening, when I got to Chicago, he met me and took me to the hotel where he was staying. He and Dick Doan, R. L. Doan—

Sanger: That’s D-o-a-n?

Leverett: D-o-a-n, yes. Told me what the project was all about.

Sanger: Did they go into total detail?

Leverett: Well, enough to describe it was an atomic weapon, described its power and what the Metallurgical Lab was trying to do, what its role was, gave me an idea what I would be doing. Of course, that was a tremendous shock, the idea that there could be anything that big and that powerful. The chance of working on it was something that, obviously, I couldn’t pass up, so I stayed.

Sanger: You were a chemist, huh?

Leverett: I was a chemical engineer.

Sanger: Was this mostly in the context of Germany, or did they mention that?

Leverett: Yes. In fact, I remember T.V.’s remark, “Some morning, you wake up and read in the newspaper that half of Germany has disappeared, well, you will know what the reason was.”

Sanger: So then you decided to join?

Leverett: Well, I stayed on. I phoned my wife to get rid of the house, either to rent it or sell it, whichever she could.

Sanger: Where were you working and living then?

Leverett: In Houston, Texas.

Sanger: I think it’s this New World book mentioned you had been working for about ten years in industrial projects.

Leverett: Well, yeah, I had. I got a Bachelor’s degree in 1931 from Kansas State, a Master’s degree from Oklahoma the next year. Then I worked for three years and went to MIT for doctorate work. I got my doctorate’s degree in 1938 and went to work for Humble at that time. By 1942, I had been working for Humble for about four years.

Sanger: How old are you now?

Leverett: Seventy-five.

Sanger: What was your first job then with, after you joined the—

Leverett: The project?

Sanger: Yeah.

Leverett: Well, I was assigned to work on the helium-cooled reactor.

Sanger: Right away?

Leverett: Right away. Chemical engineers are supposed to know something about heat transfer and fluid flow, and here was this reactor that was supposed to be cooled by flowing helium. The job was to work on the heat transfer, the fluid flow aspects of that reactor. Also, to some extent, on the mechanical aspects of it.

Sanger: Were you in charge of that at that time, or was somebody else?

Leverett: No, T.V. Moore, who had been my boss at Humble, was in charge of it, although he stayed there only about six months. That made me the oldest engineer, or at least the engineer with the most on-the-job seniority on the project. It wasn’t long after that that the Army brought DuPont into the picture.

Sanger: That was just early what, late ’42 or early ’43?

Leverett: That must have been late ’42.

Sanger: Yeah, I think it was soon after the chain reaction. At that time, you were probably, I suppose, aware that it might be water-cooled, huh?

Leverett: That idea was being pushed by the physicists, but I think not because they thought it was inherently better, but just to have a second string to the ball. But the more we went into the helium-cooled thing, we realized that the high temperatures were going to be a big problem. When DuPont came in, they looked at the helium-cooled reactor and said, “Well, we can get it loaded, and we can get it unloaded once, but we can’t guarantee that it will be more than that.”

Sanger: Why was that?

Leverett: Just mechanical problems. The fuel-handling mechanism was located in the bottom of the reactor, which was the highest temperature location. They felt very uneasy about the long life of that mechanism.

Sanger: What was the advantage of helium, or why was it discussed at any time?

Leverett: Well, helium is chemically inert. It doesn’t combine with anything, so it would not corrode graphite, which was to be used as the moderator. It would not corrode steel, would not corrode uranium. At that time, we weren’t sure that we could put a coating on the uranium. Those were the principle reasons. As gases go, it’s a good coolant.

Sanger: Did it have a low absorption rate for neutrons?

Leverett: Oh, yes, it did.

Sanger: Much less than water, I suppose.

Leverett: Oh, yeah, much less than water. In fact, it’s essentially zero.

Sanger: Slowly it became obvious that water would be it?

Leverett: Well, the DuPont people felt so much more at ease using water and aluminum. By that time, we had been successful in cladding the uranium and the aluminum shells, that it was not long before everyone agreed that probably should be the main line.

Sanger: You’d still have a chain reaction with water, apparently. It didn’t absorb as many—

Leverett: There was some doubt about that at first.

Sanger: At first?

Leverett: Water is a fairly good neutron absorber. The hydrogen atom in water, neutron absorbers, but also moderates the neutrons, which we wanted. But the experiments that were done indicated that probably you could make a chain reaction with water cooling and aluminum tubes and graphite moderator.

Sanger: Because it would be enough excess reactivity, as they had—

Leverett: Enough excess reactivity.

Sanger: To make it work.

Leverett: It would work.

Sanger: Well, then DuPont made the decision to go with the water approach?

Leverett: I think it was basically their decision. They were brought in to do the engineering work, and this was obviously an engineering decision.

Sanger: Then you switched over to water then, huh?

Leverett: Yeah.

Sanger: Then what was your responsibility with? For that and for technique?

Leverett: During the time that—let’s see, I was in Chicago up until September of ’43, and C.M. Cooper came in as the director of the technical division. I was the associate director, and it was my job, primarily, to review the DuPont designs, as an engineer, but from the point of view of the Metallurgical Laboratory.

DuPont knew nothing about nuclear engineering. In fact, there wasn’t any nuclear engineering. So it fell to me to look at the drawings which they were producing, primarily at that time, for the Oak Ridge test reactor, what became the X-10, the graphite reactor.

Sanger: You sort of oversaw, what, the technical or the engineering end of that?

Leverett: Yeah, right.

Sanger: That was air-cooled?

Leverett: That one was air-cooled. I also had a hand in some of the experimental work that was done in connection with the water-cooled reactors.

Sanger: I suppose you worked with [Eugene] Wigner then?

Leverett: Yeah, Wigner.

Sanger: Oh, that was on the water getting cooled?

Leverett: [Enrico] Fermi.

Sanger: The design was done by the time you left then to go to Oak Ridge?

Leverett: A lot of work was done, certainly. I wouldn’t say that all of it was done. I suspect that the lattice was fixed by that time. I would say the parts of the design that the Metallurgical Lab had to fix up been pretty well fixed by that time.

Sanger: What did you then technically do on the ones that were built at Hanford? What was your connection with those?

Leverett: Well, my direct connection with them, essentially, ceased when I moved to Oak Ridge.

Sanger: That was in September of ’43?

Leverett: September of ’43.

Sanger: What did you do on it before that, then?

Leverett: Before that, it was working on the cladding of the uranium, looking at the preliminary drawings for the Hanford reactors, so design review. There was additional heat exchange work to be done, but DuPont had people that were quite capable in that area. There was a lot of corrosion work, which had to be started. Again, DuPont had a pretty good group in that field, too.

Sanger: You were mainly sort of checking things?

Leverett: Yeah.

Sanger: For the drawings and design that had been done by somebody else?

Leverett: Yeah. Cooper, as director of the technical division, Cooper had charge of the development of the fuel, the graphite, the control mechanisms for the reactors. As his associate, I saw all of those things and worked on all of them.

Sanger: That control? You mean the rods, the safety rods?

Leverett: Control rods.

Sanger: Control rods and so on. You were involved mainly, would it be accurate to say, largely in the mechanical end of it? Just how the thing worked?

Leverett: Mechanical, and in the chemical aspects of the reactors, too. Particularly corrosion work is quite—

Sanger: What did you do in that area?

Leverett: We set up corrosion loops in which we tested various aluminum alloys for their ability to withstand corrosion by water, depending on various impurities.

Sanger: Did you work radiation into that too, or not?

Leverett: Not at Chicago, no.

Sanger: How did you handle that? I mean, I assume that it would have an effect.

Leverett: Well, that was one of the reasons for building the gas-cooled, air-cooled reactor at Oak Ridge. Down there, I did get involved in experiments on that phase of it.

Sanger: Earlier, did you have much trouble because you didn’t really know if the reaction would work, and how many excess neutrons there would be? Was that a serious problem, when you were doing the preliminary design work?

Leverett: I don’t recall that there was a great deal of worry about that, that it was a matter of concern. If there were a deficiency of neutrons, if k were not quite big enough, you’d simply have to build the reactor bigger.

Now, if k got to be less than one, well, then, of course, no matter how big you build it, it still wouldn’t work. But I don’t think there was much concern it would be that bad. In fact, I’ve got a joint patent with Fermi in which a very ingenious solution we came up with was, if you don’t know how big to build the reactor, well, build it bigger than you think have to, some extra holes.

Sanger: You remember, [Alvin] Weinberg was saying that his recollection was that at best it might be 1.08 or so. But he said it really amounted to about 1.01 when everything was worked into it, the absorption of the water and aluminum and so on. Is that what you remember, do you recall?

Leverett: That sounds about right. I long since ceased to think much about the numbers.

Sanger: He said it was barely, it was one, I guess, just one period. He said the reactor would be, have to be huge to work.

Leverett: Yeah.

Sanger: I mentioned that to Wigner. I don’t know anything about it, really, I’m not a scientist. But, he said that, “Well, if it was 1.01,” he said, “it would run away in a matter of seconds.” But I suppose that’s why you had—

Leverett: Well, I think he was talking about the uncontrolled reactor.

Sanger: Oh, I see. Yeah, I guess he was.

Leverett: In operation, the reactor’s controlled so that k is a k effective as exactly one, so the power is steady. If you want to increase the power, why, you withdraw the control rods a little bit, and k goes to a little more than one. The power begins to rise, and then you put the control rods back in when it reaches a power level that you want to hold.

Sanger: Incidentally, when the reactor was started, or any reactor, I guess, is there a source of neutrons that’s involved? Or does it start on its own?

Leverett: There are neutrons all around us in the atmosphere. I think the number that people quote is about one neutron per cubic centimeter. Actually, nowadays when you start up a reactor, you bring in an artificial source of neutrons. It makes things easier all around.

Sanger: What is that, usually?

Leverett: Oh, the one that’s used now is americium and beryllium.

Sanger: That’s just put in the rod, or what?

Leverett: That’s put it in a rod.

Sanger: That gets it going?

Leverett: It’s a capsule containing americium and beryllium mixture. It gives off neutrons all the time as the americium decays.

Sanger: That’s kind of sort of a booster start?

Leverett: Yeah, they call it a primer or something.

Sanger: But that wasn’t used at Hanford that you know of?

Leverett: I don’t think it was, although it might have been if things like that were available from some of the laboratories like Berkeley, where they had had cyclotrons that could make radioactive materials, which on decay would produce neutrons.

Sanger: In a bomb, that’s called the initiator?

Leverett: Yeah.

Sanger: It’s usually in the middle?

Leverett: Centrally located.

Sanger: I knew there were free neutrons around, but I didn’t how they did it at Hanford, if it was allowed to start on its own or whether it was induced.

Leverett: Frankly, I don’t know myself. But in the experiments that were done at Chicago in the graphite piles there, I’m pretty sure they did not have any artificial source of neutrons.

Sanger: Did you go out to Hanford during that period?

Leverett: I don’t think I got to Hanford until 1946.

Sanger: After the war?

Leverett: Yeah.

Sanger: Because I was wondering if you’d gone out there, what it was like. I usually ask people what their recollections of it was.

Leverett: Well, of course, I’ve heard many, many stories about it, but I didn’t experience it myself.

Sanger: Another thing, a technical point—when they were talking about, say, a 250,000 kilowatt reactor or a 500,000, what does that mean exactly?

Leverett: A kilowatt is a measure of the rate of heat generation. An ordinary light bulb is about a tenth of a kilowatt, and that’s the heat coming from the cell. When you say 250,000 kilowatts, that means something like the equivalent of two and a half million lightbulbs in there. That amount of heat that—

Sanger: Oh, I see. I sort of knew that, but I just wanted to confirm it. Also, another minor thing, were you working for DuPont [00:21:00] then?

Leverett: No, I was on leave from Humble. My salary was paid to Humble by the University of Chicago.

Sanger: Oh, I see. So, you were one of the people who didn’t work for DuPont?

Leverett: Right.

Sanger: I guess the people who went to Hanford worked for them, but the people back at the Met Lab—

Leverett: Almost everybody who went to Hanford worked at DuPont, yeah.

Sanger: Yeah, but the Met Lab people worked for the University of Chicago, technically.

Leverett: Yeah.

Sanger: Do you remember in your experience there at Chicago, if there was much—I know there was some—but from your standpoint, much tension when DuPont came in? Because I know that the physicists like Wigner, especially, were agitated about it.

Leverett: They were and I think that attitude propagated itself around the laboratory fairly extensively. People were very suspicious of industry in general.

Sanger: Were those the academic people?

Leverett: Yeah.

Sanger: Mainly?

Leverett: In fact, at that time, you know, there was essentially no nuclear science in industry at all, because there just wasn’t any. Everybody who had any nuclear science capability was academic. The academic people and the industrial people were just not used to working together.

Sanger: Was there much, from your standpoint, much problem from that? Delays or wasted effort?

Leverett: I don’t think so. I think both sides recognized the importance of the project and they tried very hard to work out their differences without losing time.

Sanger: I suppose that you had quite a bit to do with the DuPont people?

Leverett: Oh, yes, quite a lot.

Sanger: As time went on, I suppose, they became more and more expert in what they were doing in the nuclear end of it.

Leverett: Oh, yeah.

Sanger: Do you remember any particular ones you worked with more than others?

Leverett: Well, there was one guy that I worked with that later he came to General Electric, and later became my boss at General Electric, Rod Beaton.

He was a DuPont guy who was sent to Oak Ridge and worked under me at Oak Ridge. Then DuPont transferred him to Hanford.

Sanger: You know what he did there in the chemical end there?

Leverett: He was involved in the chemical processing operation.

Sanger: Maybe I have seen his name. Did you have much to do with [Glenn] Seaborg?

Leverett: Yeah, quite a little bit.

Sanger: In what sense?

Leverett: Oh, quite a little bit socially, actually. At work, I guess we didn’t see as much of each other. But his wife and my wife were very friendly.

Sanger: Do you still see him?

Leverett: Yes, not too often any more.

Sanger: I’m going to go over to his office tomorrow. He has—maybe you’ve seen it—a four-volume journal, unpublished journal of the Met Lab.

Leverett: In fact, I have a copy of that.

Sanger: Oh, do you? Is that horrendously long?

Leverett: Yes.

Sanger: Yeah, that’s what I was afraid of. I was mainly interested in whatever Hanford aspects I could—

Leverett: It’s almost a transcript of his diary.

Sanger: It’s never been published, I guess. Although I suppose he took from it for the books he’s written.

Leverett: Yeah. He had access to his own files, of course, and project files to write the thing.

Sanger: I thought I would at least look at it, quickly at least. When you left Chicago to go to Oak Ridge, what did you do there?

Leverett: Initially, I had charge of the engineering group that was attached to the air-cooled reactor. Our job was to make sure that the reactor worked properly in a mechanical sense; mechanical, electrical, and hydrodynamic and all that end of things. The reactor was built in order so that physicists and others could do experiments on it. We got involved in those experiments.

Later, then, while the war was still going on, I became involved in the chemical end of things and designed and built and operated a facility for making radiobarium. It was shipped out to Los Alamos. We did a lot of work on radioactive waste handling and disposal.

Sanger: Oh, you did?

Leverett: And some work on uranium recovery from radioactive spent fuel. Also, did some of the first work on dispersion of radioactive gases in the atmosphere.

Sanger: This is all at Oak Ridge?

Leverett: All at Oak Ridge.

Sanger: There’s something recently in Washington, having to do with the Hanford waste of the wartime period. It’s a continuing issue. Apparently there were some papers, documents, found which indicated—I haven’t seen the stories—but there was some venting of radioactive gas, I believe, more than was thought. Of course, it’s long gone. Also the seepage from the tanks—I don’t know—out into the Columbia. I think they were too far, but—

Leverett: Too far up in the river, yeah.

Sanger: But more than apparently had been thought. Everyone knew they leaked some, some of them. [Ray] Generaux told me that he designed them, that they had never intended that they be permanent storage.

Leverett: That’s true.

Sanger: In fact, he had suggested that there would be a concentration plant built at Hanford at the time to attempt to deal with the waste. But he was told that no, they didn’t have time to do that, he could do that later. Of course, then DuPont left and I don’t know what happened after that.

Leverett: That suggestion comes up, I won’t say annually, but fairly frequently. So far, I think, the fact is that the government has just not been willing to dig up the money to do it.

Sanger: Apparently, the waste there in the big tanks from the processing plants is no longer liquid.

Leverett: It’s solidified, yeah.

Sanger: It’s sludgy. It’s an interesting—I’ve never gotten into that. But, Generaux remembered it, of course, since he designed it, but he said mainly that they never intended it to be permanent. If he’d had his way, they would have done something about it at the time. But they weren’t interested in doing it then, because they wanted to build the bomb and worry about the rest of it later.

Leverett: Well, they had no idea how long the place was going to operate.

Sanger: Yeah.

Leverett: So in retrospect, it may not have been a particularly smart decision, but hindsight is always a lot better.

Sanger: After the war, did you go back? You went back to private industry?

Leverett: After the war, I went back, for a year, back to Humble in Houston. That was getting a little bit dull. I had a call from MIT to consult with them on the so-called Lexington Project, which was the nuclear-powered aircraft, which I did for most of one summer. Shortly thereafter, there was an opening developed in the Fairchild Engine & Airplane Company, which was the contractor who was running the airplane project. I went there to be the technical director of that.

Sanger: That’s for nuclear-powered aircraft?

Leverett: Nuclear-powered aircraft. It was the so-called ANP project. Aircraft Nuclear Propulsion.

Sanger: Whatever happened to that?

Leverett: Well, after three years, the Air Force and the AEC [Atomic Energy Commission] decided that the project was far enough along that they should turn it over to companies that had more resources than Fairchild did. They picked out Pratt & Whitney and GE to work on the propulsion systems. There were two types, and they picked out Convair, Boeing, Douglas, and I believe North American to work on the airframe. I went with the GE portion of the project. I was the manager of engineering for GE for, I guess, eleven years, until the project was finally cancelled.

Sanger: How was that going to propel an airplane? In what way?

Leverett: Basically, you would use the heat from the nuclear reactor in place of the heat which is generated by burning jet fuel from a jet engine. In concept, you would simply take the combustion section out of an ordinary jet engine, put a reactor in its place. In the GE version, then air is sucked in through the compressor to be pumped through the reactor, be expanded through the turbine, come out the rear end in the jet, which would give the propulsion force.

Sanger: It would be heavy, wouldn’t it?

Leverett: Yeah. Although we decided that an airplane somewhat lighter than the present 747s would be sufficient.

Sanger: Oh, really? Was there concern about, in case of a crash, what would happen, as far as the radioactivity was concerned?

Leverett: There was that concern. The reason for the cancellation of the project, though, was that it was in competition with the anti-ballistic missile. The estimates were that either project would cost about $20 billion.

Sanger: So they went with the missile.

Leverett: They figured that they couldn’t support both of them, and they selected the missile.

Sanger: So that’s never been revived?

Leverett: No, no. I think in the present climate, it probably couldn’t be. There would be too much fear of what would happen if there were a crash. But the idea then was that most of the flying, the test flying, would be done over the ocean. In Idaho Falls, we built a test station. We laid out an airfield there, which could be used for flying from Idaho Falls to the Pacific. The idea was, you would take off on conventional power, just conventional jet engines, and then when you get out over the ocean where you want to do your test flying, you would turn on the nuclear.

Sanger: Oh, I see. When did you go to Hanford, then?

Leverett: That was at the conclusion of the aircraft nuclear propulsion project in 1961.

Sanger: What did you do there, at Hanford?

Leverett: Oh, for the first years, I sort of bummed around as a consulting engineer in the Hanford laboratories. Then I became in charge of research and engineering on what was called the New Production Reactor, the N Reactor.

Sanger: Oh, yeah, that’s still going.

Leverett: It’s still going. In fact, I’m still consulting on that.

Sanger: Oh, are you?

Leverett: Yeah.

Sanger: How big is that? What’s the megawatt on it?

Leverett: The rating on that is about 4,000 megawatts, so it’s a big one.

Sanger: Oh, so you’re still involved with that?

Leverett: Yeah.

Sanger: What was Hanford like in those days?

Leverett: Well, Hanford had become a rather pleasant place to live at that time, by that time.

Sanger: Compared to the ‘40s, I guess.

Leverett: Compared to the ‘40s, yeah.

Sanger: You were there for what, six—

Leverett: Six years, yes.

Sanger: Lived in Richland, I suppose?

Leverett: Yes.

Sanger: Do you remember how many reactors were going?

Leverett: Oh, I think at that time, there was probably eight, I think. I forget the numbers.

Sanger: Yeah, I guess the B Reactor, the first one, was shut down in the early ‘60s, I believe.

Leverett: Yeah. I think B and C and I think there were two reactors at D, and there were two at K, and that makes six.

Sanger: Yeah, I think there were eight altogether.

Leverett: I think there were eight, yes.

Sanger: They, essentially, were the same as the one you’d helped design, I suppose?

Leverett: Yeah.

Sanger: They were all graphite?

Leverett: All graphite, once-through cooling with the Columbia River water. By present day standards, very simple machines.

Sanger: Have you been back there?

Leverett: Yeah.

Sanger: I mean, in connection with the N Reactor?

Leverett: Yes. In fact, I’m going back there in a couple of weeks.

Sanger: Are you? That’s unique, isn’t it, because of the dual purpose?

Leverett: Yes, it is.

Sanger: I was over there once. It’s kind of an impressive place. Did you have anything to do with the xenon poisoning, the earlier decision that DuPont made to add the extra tubes?

Leverett: No, not directly. Although I guess I mentioned a few minutes ago, this patent that Fermi and I had, which said in effect, if you don’t know how many tubes are going to be required, put in more than you think are necessary.

Sanger: Oh, I see.

Leverett: Apparently, Fermi followed that prescription in the case of the N or the Hanford reactors, so the extra holes were there.

Sanger: Yeah, that’s right. This is another question I ask people: have you ever had any second thoughts on your work with the bomb, since those days?

Leverett: No, I never have, really. It seemed to me that the decision to use the bomb was the right one, was right on that, and I still think it was the right one.

Sanger: There have been some—

Leverett: I know that some people, the particularly sensitive ones, are having second thoughts, in some cases, or have had.

Sanger: Although most of the people—in fact, all of the people, I think, I’ve talked to—have had certain reservations about maybe the numbers of nuclear weapons now days. But they have no reservations about working on the Manhattan Project.

Leverett: I don’t understand myself why we need as many as we apparently have, but I don’t know much about it, either.