The Manhattan Project

Cyril S. Smith's Interview

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Cyril Stanley Smith was a metallurgist who worked on the Manhattan Project at Los Alamos and at the Met Lab in Chicago. Smith helped develop the methods for refining radioactive uranium and plutonium into solid metal form and then shaping them into the spheres that were used in the Trinity, Hiroshima and Nagasaki bombs. He discusses the extensive process involved in making the cores, including the casting of the spheres and making of uranium and plutonium alloys. He also discusses the challenges that went into set-up the day before the Trinity test. After the war, he served on the General Advisory Committee of the Atomic Energy Commission. He discusses life after the Manhattan Project, as well as knowing now-famous spy Klaus Fuchs at Los Alamos.
Manhattan Project Location(s): 
Date of Interview: 
1986
Location of the Interview: 
Cambridge
Collections: 
Transcript: 

[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:

The plutonium we metallurgists received was actually a fluoride, a dry powder. It came to Los Alamos from Hanford as a kind of syrupy nitrate, which was treated by the chemists in a series of ingenious purification processes. I had essentially nothing to do with that. The powder, being color blind I never notice these things, but it was kind of a pinkish color, a pale pink. 

On the plutonium the job was to take the fluoride, and convert it to solid metal, and later we discovered these amazing transformations in the metal, which it undergoes with the crystal structure change, with a very big differ­ence in volume.

We had to be very careful from the health standpoint, which complicated matters a bit. At first our health precautions were nothing more than wearing masks and being careful. When we realized what we were up against, which we didn't in the beginning, we built glove boxes, sealed containers where you work with rubber gloves. These served rather well.

Plutonium is an alpha emitter, with no long-range penetrating gamma radiation. The main danger was simply getting particles of it around, because you might breathe them. By the time it was a lump of metal it wasn't so bad, even then though it was a little dangerous because you were afraid little bits of it would abrade off.

The first thing we did, we worked on a scale of one gram. Mostly, we got tiny ingots, and with these we were able to find out a little bit about the strength, the hardness, the density. And we heated it, and noticed how it changed length. At about 125 degrees C. there was a 20 percent increase in volume. That's extremely unusual.

Tin changes by 18 percent, in its low temperature form, but tin falls apart into a powder when it changes. Plutonium, for reasons I still don't quite un­derstand, doesn't. It will crack, and deform: If a little flat sheet goes through this transformation it warps and ends up in a highly-distorted form. So, obviously we were in for a great deal of trouble in shaping it accurately. It was our job to first find out how to do it, then do it.

Many alloys of plutonium were made to study the effect on the transfor­mation temperature as well as to find out about their strength and the ease of working them at various temperatures. Every bit of plutonium that arrived on the Hill was reused many times in a carefully scheduled series of metallur­gical, chemical and physical experiments, being recycled through chemical purification and reduction. Before Hanford came on line, we were getting these little bits from Oak Ridge.

Plutonium in its high temperature form is a very plastic material, beauti­fully easy to shape. The alloy can be shaped easily by rolling, extruding or pressing in dies. At first we avoided machining because we wanted to get every bit of available metal into the bomb cores, not in turnings.

Before we got to the hemisphere shaping phase, for the bomb core, we had to do a lot of work with plutonium alloys. We had to be very careful, you see, if you get this volume change, because you could get a lot of the lower density material in the bomb, and that material would compress to a higher density. It was more efficient as an explosive device to use the lower tempera­ture form.

It was desirable to have it alloyed because it was more easily shaped, to get all these things to fit together. So we wanted to find some means of re­taining this high temperature low density form. It is a bit like trying to retain the high temperature form of iron, steel actually. You quench steel in order to make it hard and you quench plutonium in order to make it soft. It is still the same kind of change of structure with temperature, you see. Anyway, as with steel, if you put in enough nickel you can retain the high temperature form at room temperatures. With plutonium if you put enough of various things in you can retain this at low temperatures.

So, the actual plutonium core of the bomb was not pure plutonium; it was an alloy of plutonium. The first thing we found that did what we wanted, metallurgically, was plutonium-aluminum, but aluminum was bad because it reacted with the alpha particles arising from the natural radioactivity of plutonium and generated enough neutrons to produce premature explosion on compression.

We looked around for something that might have the same metallurgical effect but which wouldn't saturate the thing with neutrons. We made alloys of plutonium with almost all the metals on the periodic table. We did it purely empirically. There was no theory to guide us. We made the alloy to see what would happen. I have no idea what they use nowadays, but the one we ended up with was gallium. Plutonium and gallium. Gallium is an element quite like aluminum.

These days, of course, theory is in such a state that one could get a fairly good guidance as to what to try. Back then, we simply followed hunch, not science. That was in a stage where science didn't help much. You did some-thing empirically and observed what happened.

We knew fairly early how big the bomb's core would be. Of course, we also knew that if we got a little bit too much in our crucibles we would be in for trouble - it would react, and undergo fission. We played safe. We worked with a very small amount, so that even getting two pieces together under the worst conditions it could not form a super-critical amount. There was a group responsible for the safety: plutonium was taken from one operation to another by these people. It all worked like a railroad switching operation, in fact the plan was worked out by a man who had been a railroad switcher. We had no trouble. We arranged it so the stuff was always stored where there was plenty of boron around in plastic containers, to absorb any neutrons. I think we were excessively cautious, but after all we did not want to spend our time finding out under what conditions you could get a chain reaction. That was the physi­cists' job.

The first stage for making the core was making little plutonium buttons, the second was melting plutonium, alloying it, and the final end was to pro-duce a couple of hemispheres like this.

The initiator was a special little device which when compressed released neutrons and caused the chain reaction. The core would fit rather easily, and even rather pleasantly, in the hand. It was warm, and felt like a piece of warm metal.

Although the metallurgical preparation of the plutonium had been com­pleted a week before the Trinity test, I was unexpectedly involved intimately with the actual assembly of the core. The hemispheres had been shaped by hot-pressing to exact shape. Then they had to be coated by electroplating with silver to prevent corrosion and to avoid contamination of the environ­ment, including the fingers of anyone who handled them. A clean plutonium surface has a slightly dark steel-gray color, but when exposed to air it rapidly develops a dark gray tarnish.

There was a tiny imperfection in one of the pieces and some plating solu­tion had become entrapped; it slowly reacted to form a little blister so that the two parts didn't fit exactly together. This would have caused trouble during the implosion because of the phenomenon known as jetting-an explosive wave encountering a cavity actually causes some of the material to squirt out ahead of the main compression. If, in the implosion of the final Gadget, that squirt had hit the initiator before the main mass of plutonium had reached maximum density, the premature burst of neutrons could have resulted in a very low-grade explosion.

Someone hit on the idea of filling the space around the blister with spe­cially crinkled gold foil to stop the jet, and it was up to me to personally make the foils and insert them carefully into the assembly. Toward the end of the project I had been telling other people what to do and, since I'm an experi­mentalist at heart, I was pleased to have some task for my own fingers.

Another thing we were doing was making the uranium to go around this core, a massive sphere of uranium which served both a nuclear and mechani­cal function. It was between the core and the explosive lenses. I suppose it was a matter of between one and two hundred pounds, but I have forgotten. It was reasonably pure natural uranium metal.

Two things had to be done to assemble the core. The center of the thing was essentially a solid, but split in two. One plutonium hemisphere was put in, the initiator was put in, these little gold foils were put on, then the top hemisphere was put in place. My only memento of the project is one of these little gold foils which was there to go into the bomb but wasn't needed and ended up in my personal collection. Anyway, the foil was put in, and the sec­ond half of the cylindrical part of the uranium tamper was put on and locked with rings, and this whole thing was lowered later into the rest of the assem­bly. My job was over after the appropriate amount of gold foil had been fitted in and the core assembled.

We put the core together at the McDonald ranch house. The core ended up as a cylinder, as I remember it, approximately, four inches in diameter and 12 inches long with spherical ends because it was part of the larger sphere of uranium which had the explosive lenses around it. It was like a large Polish sausage with rounded ends.

When the time came for the final assembly in the tent at the base of the test tower, the core wouldn't slide into place for it had expanded partly because of the heat generated by the plutonium and partly because of the desert heat. However, it cooled when in contact with the massive tamper and eventually went in smoothly. I no longer had anything to do at this stage, but I watched the assembly and saw it hoisted to the top of the tower. 

Later in the day, when all the electrical connections had been made I climbed the ladder and spent a minute or two alone looking at the portentous device. I had been intimate with many of the components but had never seen the whole thing. There were a large number of wires going all over the place. I suppose it looked a little bit like the earlier sea mines, a sphere with little things sticking out here and there. One had a kind of feeling of doom. Then I went back down and back to the base camp, where I watched the test the next morning.

 

Full Transcript:

Sanger: This is an interview on the last day of March 1986 in Cambridge, Massachusetts with Cyril Smith, a metallurgist at Los Alamos in 1945 who had charge of the Hanford product. The interview was at his home at 31 Madison Street in Cambridge.

Cyril Smith: I would like to know what you did.

S. L. Sanger: Make sure it is working. The red light is on. Do you recall what the plutonium was like physically when you started dealing with it?

Smith: Well, the stuff that the metallurgists received was actually fluoride, which was a dry powder, Plutonium tetrafluoride.

Sanger: Before that, what was it?

Smith: Well, it came to Los Alamos as a kind of syrupy nitrate. That was then treated by the chemists by a series of purification processes, which were worked out very ingeniously and very effectively by the chemistry group. But I had essentially nothing to do with that. I was their customer.

Sanger: What did the powder look like? What color was it, do you remember?

Smith: Being colorblind, I never noticed these things. But it was kind of a pinkish color, a pale pink.

Sanger: What was your official title of responsibility then as far as that was concerned?

Smith: I was the Associate Division Leader, the Associate—what was my title? [laugh]

I was the Associate Division Leader of the Chemistry Metallurgy Division and then I was in charge of metallurgy.

Sanger: And that was turning the powder or whatever into metal that would be?

Smith: We were responsible for all of those requirements of a metallurgical special material characteristic only for the project. There was a great deal of our work actually that was concerned with providing materials for physicists’ research. We did a lot of work with beryllium oxide and with tungsten carbide and various boron compounds. And we made uranium hydride and essentially were kind of a model factory for anything the physicists wanted in any shape they wanted it in and of any purity that they wanted. So it was a very exciting period.

On the plutonium, though, the job was to take the fluoride and convert this to solid metal. And later, after we discovered these amazing transformations in metallurgy, undergo the crystal structure change with a very big difference in volume. And then we would work on the alloying so as to be able to stabilize some of the higher temperature phases which are slightly lower density and considerably more workable than the lower temperature phase.

Sanger: Can you say how many steps you had to go through to reach the final product?

Smith: Well, at first, we did a lot of work trying to find the best way to reduce the metal and we put emphasis on reducing it with metallic calcium at a fairly high temperature. I mean it just reacts; it is kind of a low grade explosive in a way.

Sanger: And that is metallic calcium you said?

Smith: Metallic calcium. And the metallic calcium produces calcium fluoride and plutonium metal. If you do it under the right conditions, the calcium fluoride will melt so then the heavy drops of plutonium metal will just sink to the bottom of the slag and be collected in the bottom.

Sanger: Was that a fairly straightforward, simple process?

Smith: We ended up having it a fairly straightforward, simple process but it took us quite a long time to find the proper condition for using it. We also had to be very careful from the health standpoint, which complicated matters a bit. Then because there was so little of the stuff available, we had to have an extremely high recovery rate. In a typical commercial operation, if you get ninety-five percent of your product in the final form you are clean. But this, we wanted to get ninety-nine point five percent. And retrospectively I’m surprised we did so well, because we really did get ninety-nine point five percent of it.

Sanger: What sort of safety precautions did you take when you were doing it?

Smith: At first, nothing more than wearing masks and being careful. Then rather quickly, when we realized what we were up against—which we did not right at the beginning—we built what we called glove boxes, which were sealed containers where you worked through with rubber cuffed gloves and handled the thing. And this worked quite well.

Sanger: You did not do that at first, though.

Smith: For the first few little bits, we did not, no.

Sanger: It was dangerous especially when it was in the fluoride form, I suppose?

Smith: Well, its main danger was simply getting particles of it around.

Sanger: By the time it was in metal form?

Smith: By the time it was a lump of metal it was actually not so bad. But even that was a little dangerous because little bits of it would have dried off. And then, of course, the slag and the remains of the refractor all of these things got contaminated. Anything that had been in these glove boxes where we had been working on was always very carefully collected and sent over first for the recovery of what plutonium could be recovered and then for careful disposition of the remaining stuff.

Sanger: But these were not very large volumes?

Smith: Oh, no, very small. The people in Chicago in the Met lab, had done a lot of really beautiful work on very, very small scale of microchemical reduction. And they had learned a little bit about the properties of the metal, but they had not discovered the transformations. They did not even know what the melting point was. We had made quite a bit of uranium by the bomb method where we used a high temperature to melt it.

And then another process, which was quite attractive but for various reasons we decided not to use it as the main production method. That’s the electrolytic method. This gave us the first indication that plutonium had a relatively low melting point. [Morris] Kolodney mentions that in his article. Little drops of molten plutonium that he got working at sixty degrees centigrade was a great revelation to us.

Sanger: Can you talk a little bit about the transformations and how that may have amazed you or surprised you?

Smith: Well, in the first place, the work at Chicago, working on a microgram scale, with pieces of metal you can hardly see, determining a few of their properties. They measured the density just by weighing the thing on the microbalance. You would have to see it [laugh] by weighing it and measuring it so as to get the volume and so to get the density.

The Chicago data curiously fell into two groups. A good many of them turned out at about sixteen and a good many of them turned out about twenty with nothing in between. That was very, very puzzling and there was a speculative argument about what the density of metal was. Because quite often in metal, it will be a little bit impure, a little bit unsound, and kind of a spread of densities. But these are here or there. I mean, so what was it? That suggested that there might be a transformation of some kind.

In fact, there was a rather interesting bit took place between Joe Kennedy and John Chipman—Kennedy at Los Alamos and John Chipman in Chicago. At dinner one evening after one of the monthly conferences, they were talking about this and actually set up a bet, [laugh] with John Chipman on the lower density and Kennedy on the higher. They put up stakes at ten dollars on this. Now I was left holding the stakes. I finally decided that they were both right, just returned.

But then at Los Alamos, we worked on a scale of one gram, which would not work on anything significantly less than that, though it did work a bit on half gram stuff, most did. Our earliest work was done on a one-gram scale. So we got a little ingot no bigger than that cylindrical piece. With these, we were able to find a little bit about the strength, the hardness, and the density. And then we heated it and noticed how it changed in length with heating. And the curve comes out and it does that. But this temperature is about a hundred twenty-five degrees centigrade. And the twenty percent increase in volume at that point was an enormous change.

Sanger: That is very unusual.

Smith: It is extremely unusual. Tin changes by eighteen percent in its low temperature form. But tin falls apart into a powder when it does this. Plutonium, for some reason that I still do not understand, does not. And it will crack and deform and you start with a little flat sheet and it goes through this and it will end up in a highly distorted form. So you are obviously going to be in for a great deal of trouble in shaping it accurately.

Sanger: And you were responsible for that, too? Shaping?

Smith: Oh, yeah, yeah. It was our job, first to find out how to do it and then to do it.

Sanger: Did you have to wait until you got some fairly significant amounts before you could?

Smith: Well, I mean, as every bit of plutonium came onto the hill, we very carefully decided what we were going to do with it. The chemists had their work to do. Most of the stuff, though, was put in the form of metal first. They could work more conveniently on a very, very small scale than we could with metal. We were working on the one-gram scale. We took each gram and decided all the things we were going to do with each little piece of this metal. Some of it would be alloyed and something would be done with it and something else would be used for shaping experiments and then find out effective temperature and workability and this sort of thing.

Sanger: I suppose you were anxious to get the first fairly significant amount then.

Smith: At Los Alamos, we could not do anything with plutonium—and we did not attempt to—until we got to the gram scale. But before this, we had done a lot of work with uranium, which we thought would be rather like plutonium in its metallurgical characteristics. It wasn’t. Then we also did a great deal of work just getting familiar with techniques of handling material and developing methods of casting and shaping it accurately.

Sanger: Was uranium somewhat more straightforward in the way it would behave?

Smith: Well, a lot more was known about it and we could [work with uranium] on a reasonably decent scale and then develop the techniques.

Sanger: You did not go through these transformations then.

Smith: Uranium does have transformations but the volume change is not nearly what it is in the case of plutonium. It has got a higher melting point and the plutonium. After it melts you get essentially a dull red heat while uranium is much higher.

Sanger: Colonel Matthias, who was the Corps of Engineers man in charge at Hanford, said that as he recalled, the first shipment of plutonium to Los Alamos, which he carried to Los Angeles and put on the train, was about fifty to one hundred grams. Do you have any recollection of that?

Smith: I would be surprised if it was quite that large. It might have been, I just do not know.

Sanger: Because he said that there was a lot of interest in getting that in larger than laboratory amounts.

Smith: Yeah.

Sanger: So they hurried up the first process.

Smith: My recollection is that there was a shipment of a rather smaller amount first. Then it rather rapidly moved up to the hundred-gram scale, and it normally came up in fifty grams to one hundred.

Sanger: I do not know. Later, when it got underway, they transported it in converted ambulances. I believe there were twenty casks of about forty grams apiece, something like that, that they would send in a convoy. But that was sometime probably after the first shipment.

Smith: Yeah.

Sanger: Theoretically, each reactor could make two hundred and fifty grams of plutonium a day. That’s in the reactor and before they separated it, of course.

Smith: Of course, before Hanford came on the line, we had been getting a bit of stuff from Oak Ridge. How much did we get from them, I do not know.

Sanger: I supposed you would have gotten a pretty significant amount from Oak Ridge.

Smith: Yeah, but I do not know what the total maximum amount was.

Sanger: I think I have read that. That was obviously more than laboratory amounts.

Smith: Well, no, it was all laboratory amounts at that time [laugh]. What did you mean by that?

Sanger: Well, I mean small amounts.

Smith: Yeah, yeah.

Sanger: Then how long would it take generally to change it from the fluoride into a metal? Was that a very long process?

Smith: Well, by the time we got the fluoride and by the time we had gotten the necessary refractories ready and the calcium and all this kind of thing, the operation itself was really quite short. It was just mixed and put into the refractory line, or little reaction bombs, and heated. And it would be all over in fifteen minutes.

Sanger: Oh, and then it would be in a metal form.

Smith: Then it would be in metal form—a little button at the bottom. This, of course, was subsequently treated at first simply by shaping or hot press. We made a great deal of use of hot pressing. When it was in the high temperature form, it was a very plastic material. It was beautifully easily shaped and you would shape it as easily as you would shape lead at room temperatures. Just by pressing it in dyes, you could very actively shape it.

Sanger: And then these buttons could be fused or whatever?

Smith: Yeah. And they were usually remelted into a somewhat better shape because the buttons would be kind of a little bit like that in shape, you see. Just sitting in the bottom of the reaction vessel.

Sanger: How much would one of the buttons weigh?

Smith: Well, we began with about a one-gram scale and then moved up to ten grams. And then most of the time, I think we worked on the hundred grams but I am not quite sure of that.

Sanger: That would be about that big?

Smith: No, that must be about a twenty-gram piece there.

Sanger: Oh, okay.

Smith: So it worked—It must have been about that size and round.

Sanger: Then that would go for the Trinity device and you would proceed from there to make the hemisphere?

Smith: Yeah. Before we got to that stage, we would have to do a lot of work on the uranium alloys. We had to be very careful. You get this volume change. Because you could get a larger amount of the lower density material in the bomb and it would compress, you see, at a higher density so it was more efficient as an explosive device to use the low-temperature form. So it was desirable to have it alloyed. It was also desirable to have it alloyed because it was more easily shaped and all of these things fitted together.

So we wanted to find some means of retaining this high temperature, low-density form. It is a bit like trying to retain the high temperature form of iron with steel or something. You press steel in order to make it hard and you press plutonium in order to make it soft. But it is still the same kind of change of structure with temperature, you see.

And as with steel, if you put enough nickel in steel, you can retain the high temperature form at room temperatures. That is a non-magnetic form of stainless steel. And with plutonium, if you put enough various things in it, you can retain this at low temperatures.

Sanger: So the actual core of the bomb was not pure plutonium.

Smith: No, no, it was not.

Sanger: It was alloy?

Smith: It was alloyed plutonium. Alloyed plutonium gallium, actually. The first thing we found that did this was plutonium aluminum. But aluminum was bad because with the alpha particles coming from the natural alpha decay of uranium, it just generated a large number of neutrons by reaction with aluminum.

Sanger: Oh, it did?

Smith: We looked around for something that might have the same effect that would not saturate a thing with neutrons and produce a premature explosion. But we essentially made alloys of plutonium with all the metals on the periodic table. Did this purely empiric. There was no theory to guide us at all. We just made the alloys to see what would happen.

Sanger: But then you settled on what?

Smith: I have no idea what they use nowadays, but the ones we ended up with was gallium, plutonium and gallium.

Sanger: What is that? Gallium?

Smith: It is an element quite like aluminum in its properties. It is the third one down on the periodic table. But it is in the same column in the periodic table.

Sanger: So you would just try each various one to see which worked the best.

Smith: Yeah. Now, of course, the theory is in such a state that one could get a fairly good guidance as to what to try. Then we simply followed hunch, not science. And that was in the stage when science did not help very much and you did something and found out what happened.

Something which has always interested me is how, if you work with a class of material for a long time, you kind of get a feeling of what is going to happen, which is not scientific, it is a hunch. It will guide you in doing all kinds of things. And sometimes your hunches will be right, sometimes they will not, of course, you know. You only find this by testing.

Nevertheless, the sort of feeling does direct you into an area that is profitable research even though it does not give you a final answer.

Sanger: Did you have a good idea how large the core should be?

Smith: Yeah, we knew that fairly early. And of course, we also knew that if we got the material we were working on a little bit too large, [laugh] we would be in for trouble.

Sanger: Because it would not fit?

Smith: No, that it would react. [Laugh]

Sanger: Oh, I see.

Smith: So the physicists, of course, were much more in control of this kind of thing but we played very safe in chemistry and metallurgy. We worked with such a small amount, so that even getting two of them together would not go super critical. Then we had a whole staff of people that were in a group that was simply responsible for the safety of these things and nothing was taken from one project to the next except via these people. And it all worked just like a railroad switching tracks. And the fact is it was actually run by somebody who had been a railroad switcher.

Of course, we had no trouble at all. They almost had a catastrophe, of course, at Oak Ridge with the uranium plant because they did not pay enough attention to that. That is one thing that [Richard] Feynman told us in his book.

Sanger: Yeah, I have read that part.

Smith: But we were extremely careful on that because there are people who worked on things who were never allowed to take things to another stage of the process. We arranged it so that it was always stored under conditions with plenty of boron around, a boron-loaded plastic container for these things.

Sanger: And that was to absorb any neutrons?

Smith: Yeah. In retrospect, I think we leaned over backwards. But after all, we wanted to get on with metallurgy and not spend all of the time finding under what conditions you would get a chain reaction. That was the physicists’ job. The physicists, of course, they got a little careless. And you know, of course, with the early accidents they had.

Sanger: You were, I would imagine, very safety conscious, were you?

Smith: No, not much more than we needed to be, I think.

Sanger: Well, then after you got to the metal stage, then what do you remember about the actual getting it ready for the first bomb?

Smith: Well, the first stage was getting these. The second stage was melting it, alloying it. Then the final end of the plutonium was to produce a couple of hemispheres. This is roughly natural size.

Sanger: That is about the size?

Smith: Roughly.

Sanger: This is what, for the initiator?

Smith: That is where the initiator is. The initiator, of course, was a special little device, which when it was compressed, would produce a nuclear reaction.

Sanger: And that was about as big as a small orange, yeah?

Smith: Maybe it was bit bigger than that but not much.

Sanger: And what did that weigh? About twelve or fourteen pounds or so, do you remember?

Smith: At one point, I knew the critical mass.

Sanger: I think it was; one book I read says thirteen and a half pounds.

Smith: It is something like that, yeah.

Sanger: Something like that?

Smith: Yeah. You could easily calculate it.

Sanger: That would, I think, surprise most people that that is all the bigger it was.

Smith: No, fitting easily, and even rather pleasantly, into the hand.

Sanger: It was warm, I suppose?

Smith: And it was warm. Even a small piece like this would be perceptibly warm. A piece like that, there is just no doubt about it.

Sanger: What did it feel like?

Smith: It felt like a piece of warm metal [laugh].

Sanger: What was the temperature? Do you remember?

Smith: Oh, I suppose, if it had just been sitting out in the air, it would be perhaps forty degrees centigrade, maybe not quite that.

Sanger: What was your particular responsibility as far as the test was concerned?

Smith: I had two responsibilities. When we shaped these things, we did it by hot pressing. We made a mold and the other was cast pretty much to shape. And then it was pressed in a mold that we made. This is a plunger and this is fitting inside that. And that just compressed that and produced this shape. And plutonium, in the high temperature form, is really quite plastic so it is very easy to shape it.

Then it has to be protected against corrosion and also, to make it handleable. At first, we electroplated it and then we used a carbonated nickel coating. And the electroplated stuff we used for the first test at Trinity, there was a tiny little imperfection in the filters, a little crack. And during the plating, some of the plating solution got in there and then it slowly reacted and formed a little bubble like that.

Sanger: I have heard about that.

Smith: That is considerably exaggerated but it is essential up there.

Sanger: And it was on this part so it would not fit.

Smith: It would not fit exactly. If the parts were being perfectly machined, that would essentially be like throwing metal in—I do not know whether you know about the phenomenon of jetting, do you?

If you compress something, put explosions on this and detonate the thing there, the explosion weight moving down here will move these things in, see. And here, you have got such an extremely high pressure. It will actually squirt out something. Now if in the bomb that squirt had hit this prematurely, the explosion would have occurred long before there was just a moment to reach critical mass and enough to get a good explosion.

So we hit on the idea. There seemed to be some uncertainty and there were three people, all of whom think it was their idea [laugh]. And they are probably all right because they were discussing it at the time. But hitting on the idea of putting some crinkled gold foil in here, and the high density gold would actually stop anything squirting in there.

Sanger: So this is just a very, very thin gold foil.

Smith: An extremely thin gold foil, yeah.

Sanger: Well, what happened with this bump then?

Smith: Then the bump, you see, pressed into the gold foil but without preventing the things fitting as well as they could anyway. But it filled in all the intermediate space with high density gold in a low-density configuration.

Sanger: So that worked?

Smith: Actually, I spent most of my time toward the end of the project essentially telling other people what to do. And I did very little with my own hands though I always like to do things with my own hands. Obviously, I could not do that under those conditions. But the one thing I did do with my own hands was to make these little gold foil things.

Sanger: Are you one of the three people who thought it was your idea to do that?

Smith: I am one of those three people.

Sanger: Who were the other three?

Smith: It probably initiated with the physicists, and I said how to do it practically, that kind of thing.

Sanger: Was this the only bump that appeared?

Smith: The surfaces were not exactly planed.

Sanger: Well then, so then after you made the hemispheres, then what happened?

Smith: They were made and then they were plated.

Sanger: And this was electroplated?

Smith: It was electroplated for the first ones.

Sanger: What was that? What did that look like then?

Smith: Oh, it looked like a mass silver ball in two parts.

Sanger: What did plutonium look like before it was plated?

Smith: It is a slightly dark steel gray color when it is completely untarnished but it very quickly develops a blackish or a dark gray tint.

Sanger: Is that from reacting with the air?

Smith: By reacting with the air, yeah.

Sanger: About what temperature would it begin to be malleable or get soft?

Smith: Well, if it is alloy, it is malleable at room temperature, slightly malleable anyway. But when it is past this hundred and twenty-five degree point, it becomes very soft.

Sanger: Well, how would they keep it in a strictly hemispherical form if it would be soft at room temperature?

Smith: Well, it is hot enough to keep its shape.

Sanger: Oh, I see.

Smith: You can imagine a lead sphere would hold its shape in the sun.

Sanger: Well so then, so you had this made. So then the test was coming up and what was your position?

Smith: Well, another thing we would be doing, of course, we are making the uranium to go around this because outside of this, there was a very, very massive sphere of uranium, which served both a nuclear and a mechanical function.

Sanger: That was 235?

Smith: That was between this and the explosive lenses.

Sanger: Uranium 235?

Smith: It was just natural uranium.

Sanger: Oh, it was. Okay, how much of that?

Smith: Oh, I do not know. I supposed it was between one and two hundred pounds, I think. I have forgotten.

Sanger: But it was purified natural uranium.

Smith: It was just reasonably pure and natural uranium that had been—see how little one remembers. I remember the design of the thing and I do not remember how we fabricated it.

Sanger: Was it metal?

Smith: Oh, metal, yeah. And we developed a scheme for vacuum casting uranium on a scale that was far greater than anything being done in industry at the time. We also worked with uranium carbide and worked that on a scale much greater than anybody was doing in industry. It was really rather exciting. A lot of amateurs, but we had to get on with the job and we all were rather experimentally inclined, so we did.

Sanger: So then after that was done, what is your recollection of your actual physical placing the core in the device?

Smith: Well, there were two things that had to be done. The center of the thing was essentially a cylinder, which was split in two, with spaces for these two things. It would sit inside something like that and it was then sat inside a much larger thing. And so this opened up to something roughly that big, and then with a hole in the middle for the plutonium. And so the plutonium was put in, the initiator was put in. Then these little gold things were put in and then the top piece placed on it and putting more and more gold in until it actually started separating these things and the purpose of the gold was simply to fill in the space and not separate it. So it involved putting a few of these things in until they got to that point.

Actually, my only memento of the project is one of these little gold pieces, which was there to be used if necessary but was not used and ended up in my personal connection. Though I cannot show it to anybody because apparently it is still secret [laugh].

Sanger: Oh yeah?

Smith: I was not arrested when I asked the question whether it was or not [laugh]. Anyway, so this was put in and then the second half of the cylindrical part of the uranium tamper was put on and locked in with rings and this was lowered into the whole assembly of the bomb.

Sanger: So that was done before. I mean, you were not working with the bulbous pieces? That was lowered in later.

Smith: No, my job was over once I got the appropriate amount of the little gold foil in there and closed the thing.

Sanger: So you did that personally?

Smith: I personally did the assembly of what you see here.

Sanger: That would be called the core?

Smith: It was the core, yeah. The assembly team had been drilling itself for weeks to be sure that everything would go all right. But all the mockups did not have this in, did not need that in it. So at the last minute, I became a member of the assembly team without any prior training.

Sanger: Well, is this so that at first it did not fit because it had expanded?

Smith: I knew it would not fit because the surfaces were not completely planed. So something had to be done about it.

Sanger: I thought I read to where it said the heat had expanded it somewhat.

Smith: Yeah, that is this part.

Sanger: Oh, that is that part.

Smith: At the time that this going in it was relatively cool. But by the time that had sat in this thing, you see, the whole thing sat around for a day in the desert heat, the whole thing was really fairly warm. So that had to be lowered into the main assembly. At first, it was a little too large.

Sanger: And that is because the plutonium had expanded somewhat?

Smith: Well, because the whole thing had expanded partly because of the desert heat, partly because of the heat coming from this.

Sanger: But then after a while, it cooled down, obviously.

Smith: Then it cooled down when it was in contact, you see, with the rest of the assembly.

Sanger: And that was the uranium that you were lowering down.

Smith: Yeah, at least that is the standard explanation. I have always been a tiny bit skeptical of the explanation.

Sanger: What do you think might have happened instead?

Smith: Perhaps simply a little more compression on that.

Sanger: Where was this happening? At the bottom of the tower?

Smith: It was happening in the bottom of the tower, yeah. This assembly I mentioned was at McDonald’s Ranch.

Sanger: That is when this part was put together.

Smith: That was the end of my job.

Sanger: And that is where you were at the Ranch house?

Smith: Yeah.

Sanger: In that room there?

Smith: In the little room.

Sanger: That is where the core was assembled?

Smith: Yeah.

Sanger: But how big was that whole apparatus when it was done? Do you remember?

Smith: It ended up being a cylinder about this long of uranium with this in the middle of it.

Sanger: You mean like this and then about that long?

Smith: Well, it was roughly that diameter and roughly that long but with spherical ends because it was a part of the larger sphere of the uranium, which had the explosive lenses around it to complete it.

Sanger: Well, is that roughly what, the size of a slightly oddly shaped shoebox?

Smith: I would not have thought of that analogy. It was more like a large Polish sausage, I think [laugh] about this diameter.

Sanger: About a foot long?

Smith: About that long with slightly rounded ends.

Sanger: About a foot long, I guess then.

Smith: I don’t know, something.

Sanger: So then that was taken to the tower.

Smith: That went to the tower.

Sanger: By that time it was sealed up. All they had to do was put it in?

Smith: Yeah.

Sanger: So when it did not fit, that was in the ranch house.

Smith: No, that was the base at the tower.

Sanger: Oh, I see. And then where did you watch the test then?

Smith: Well, I watched the assembly. I did not have anything to do—I was one of the few people around there who were just watching it. And I watched it hoisted up to the top of the tower and then after it had all been assembled, I asked for permission to go to see it. And I went up the ladder and looked at it. I remember it.

Sanger: Was that during daylight?

Smith: Yeah, yeah.

Sanger: The afternoon before?

Smith: It was the afternoon before the test, maybe even the morning before.

Sanger: And is that the first time you had ever seen the entire apparatus in one place?

Smith: The entire real gadget, with all of the components. I was very familiar with it before.

Sanger: What did it remind you of? Anything in particular?

Smith: No. There were a large number of wires going all over the place. I suppose it looked a little bit like some of the earlier sea mines with little things sticking out here and there on it. But, of course, those did not have the wires on the outside. One had a kind of feeling of doom [laugh]. Then I went down and back to the base camp.

Sanger: Was that where you watched it from then?

Smith: I watched from the base camp, yeah.

Sanger: Let me see here. I guess I should have started with this. Could you give me a little bit of your background? This is all on your reminiscence, I know. But before the Manhattan Project, how you got into that just briefly?

Smith: Before the war, I was a research metallurgist for the American Brass Company in Waterbury, Connecticut. In 1942, I went to Washington as a supervisor for the War Metallurgy Committee. I must confess I hated my Washington job. It was a desk job and I wanted to do something that I thought was real work [laugh]. And I disliked the Washington atmosphere. I think I would have taken almost any job that came up that was seriously related to the war effort.

I knew just the tiniest bit about the project. I knew there was work on uranium going on. There was a little of the work with the War Metallurgy Committee. But we knew absolutely no details of it.

At the American Brass Company before I went to Washington, I did a little bit of work on the diffusion barriers for Oak Ridge, again without knowing very much about it. I produced a number of copper alloys with the right kind of porosity for the fusion experiment and suggested the use of powder metallurgy techniques to be used in these things. But I did not really have any intimate connection.

But then early in ’43 when the Los Alamos staff was being assembled, Joe Kennedy somehow ran across my trail and asked me if I would be interested in going to a place. He did not tell me what it was doing, he did not tell me where it was, did not tell me anything about it.

Sanger: Okay. That was '43.

Smith: That was in February 1943. I joined the project very shortly after that.

Sanger: You were there very early?

Smith: I was one of the founding fathers. I was there at the orienting conference in April.

Sanger: Did you stay at Los Alamos until the end of the war?

Smith: Yeah. I left on New Year's Eve, 1945. I went into Chicago the next morning and took up my job with the University of Chicago.

Sanger: As a what?

Smith: At Chicago, I was a professor of metallurgy and director of the newly formed Institute for the Study of Metal with one of the three researchers that used to perform there.

It was pretty much my idea to develop a study of metals with the interaction between chemists, and physicists, and metallurgists. It was a quite exciting period. The lab became a kind of a model for subsequent academic materials research organizations.

Sanger: Did you ever have anything more to do with the government or nuclear weapons after that?

Smith: Yes, I did. For a time I was a member of the General Advisory Committee of the Atomic Energy Commission.

Sanger: But after that you did not. Did you come to MIT, then?

Smith: I came to MIT in 1961 from Chicago.

Sanger: Are you still an emeritus there now?

Smith: I am emeritus and I have been for quite a long time.

Sanger: You have lived in Cambridge?

Smith: Since 1961. When I was on the General Advisory Committee, I had quite a bit to do with discussions of atomic energy policy generally. I participated in the vote on the crash program on the hydrogen bomb, voting with other seven members of the committee against it. But our recommendation got nowhere at all. But then that is a different story.

Sanger: Yeah.

Smith: Well, we will not go into it. I resigned after the Princeton meeting because I wanted to get back to research.

Sanger: As far as Hanford goes, was it the perception at Los Alamos that it was basically a place where just a factory environment where plutonium was produced and sent to you?  Was there ever any thought that it had any other value to science other than that?

Smith: No, I mean, it was a factory. A very good one, making use of all the science it could get and developing some aspects of its own science, and working how to do things.

Sanger: In case it’s on that card, why don’t you tell me the last name of the man you were talking about, the metallurgist?

Smith: A.B Greniger, G-R-E-N-I-N-G-E-R.

Sanger: G-R-E-N?

Smith: – I-N-G-E-R.

Sanger: Okay. Do you think he still lives there?

Smith: I just do not know. I think it is possible that he died some years ago. I do not know.

Sanger: Well, let us check.

Smith: I know he retired a good many years ago. He was a physicist at Harvard when I first knew him. I mean, a metallurgist at Harvard. We were good friends.

Sanger: You were from England, originally?

Smith: I was born in Birmingham, England.

Sanger: How did you come to the United States?

Smith: By boat [laughs] No, seriously, I wanted to see the world a bit.

Sanger: But, you had not been involved with any atomic research before Los Alamos.

Smith: No.

Sanger: Except what you said about the—

Smith: No, because I was the only one of the senior members there who hadn’t been in the business for a quite a long time.

Sanger: This is one question I asked people just in general about the necessity of using the second bomb, the Nagasaki bomb. Did that come up at that time? 

Smith: Of course, at Los Alamos we had absolutely no control over that at all. In retrospect, I think the first bomb was necessary in order to educate the world. I think it has to be used in anger, too. I think a demonstration on an uninhabited island would have done no more than the test in New Mexico, whether it was a rather pretty little green bowl in the desert. It needed a great intellectual step to go from that to what else it could do. I think it had to be used in a way that would destroy something. But the Nagasaki bomb was completely unnecessary. This seems even more true in retrospect when you learned what was happening to the Japanese.

Sanger: Was that the sense at the time, too that it was unnecessary?

Smith: I think.

Sanger: Was the feeling at the time, at least amongst some people, that the second bomb was not needed? 

Smith: Yes, I think so. Though, of course, at Los Alamos, we had no control over this. In terms of the nature of the bombs, there was really very little difference between the U-235 and the plutonium one. As far as those of us at Los Alamos were concerned, our job had been successfully done with the first explosion.

Sanger: Did you have something directly to do with the Nagasaki bomb, too?

Smith: Nothing more than the following and the shape; the preparation and the shaping of it. I did not particularly handle it at any stage. There was a possibility that I would have gone to the Pacific with them. I got all of the necessary indoctrination and inoculation to do that. But it turned out to be not necessary.

Sanger: You mean, in a sense of taking the core?

Smith: Yeah. Just in case any metallurgical peculiarities developed.

Sanger: Was the core made at Los Alamos and then shipped?

Smith: Yeah, but it was essentially identical with the gadget, as far as my part of it is concerned. It was identical with the two things.

Sanger: You mean with the Trinity device?

Smith: The Trinity test, yes. Eric Jette, by the way, was the man under me who was in direct charge of the plutonium metallurgy research. J-E-T-T-E.

Sanger: Where is he?

Smith: He came from Columbia University. He stayed at Los Alamos after the war. He was head of the division.

Sanger: What was his role, would you say?

Smith: In charge of plutonium metallurgy.

Sanger: Okay.

Smith: Do you know this, by the way, do you not?

Sanger: Yeah, I have read parts of this. This is [David] Hawkins, I guess. Yeah, I did not know that. I have seen this in other forms. I did not know it was in a book.

Smith: It was produced just in time for the 40th anniversary.

Sanger: It was?

Smith: Yes.

Sanger: I wonder where this is available?

Smith: I think you can buy it anywhere at any good bookstore, if there are any.

Sanger: No, I have not seen this.

Smith: It is just a reprint of Hawkin's. The subsequent one is by Ralph Carlisle Smith.

Sanger: You have probably looked at the official history by Hewlett and Anderson?

Smith: Yeah, which is very good.

Sanger: Now that is very authoritative, right. I should probably try to find this thing. They probably sell it down—

Smith: It is hard to find out whether they published it and who the publisher is. It is part of a series, you see on the history of physics.

Sanger: Did you buy this here?

Smith: No, I was given this at Los Alamos at the 40th anniversary. I expect you can run it down rather easily under the authors' names.

Sanger: Yes.

Smith: There is another book you ought to know about.  Have you ever seen this book that was published early in 1945 on plutonium?

Sanger: Which one is that?

Smith: The one edited by Johnny Thomas.

Sanger: What is the name of it?

Smith: Yes, it is referred to here in this article, which you have got a copy of.

Sanger: I have never seen this, no.

Smith: You ought to. It is quite central; it essentially deals with everything that was done up to the actual production stage both of at Los Alamos and at Hanford.

Sanger: Well, I have a copy of this article by you so I could.

Smith: That is a very important book. My company out here at the moment is on exhibition in the Science Museum in London.

Sanger: Is that right?

Smith: Because it was part of the demonstration on nuclear energy. But it is declassified. It is certainly available.

Sanger: You had one of the original ones?

Smith: Yeah.

Sanger: I think I tried to find this, and could not. Maybe I did at the University of Washington.

Smith: There is a copy. Well, you get this through the government printing offices.

Sanger: You can?

Smith: I suppose. I do not know.

Sanger: You probably can.

Smith: I know that it has been declassified. There are a few Xerox copies around. It is a very important book for you. Of course, there are all of the other stuff that is coming out of Los Alamos on the Los Alamos history and its various stages.

Sanger: I was speaking with Robert Wilson who was at Cornell. He was at the University of Washington last summer as a visiting professor.

Smith: He is a wonderful chap.

Sanger: He was and he suggested that as far as the Second World War was concerned or the end of it, that perhaps a plutonium project was not even needed to end the war. I suppose that works into the question about the necessity of the second bomb.

Smith: Yeah. I would agree with him, actually.

Sanger: Which is rather ironic.

Smith: In retrospect, I was rather surprised to hear that. But the more I think about it, the more I agree with it. In other words, I mean, there was uranium 235 coming along by that time. There would not have been another one ready quite as soon as the plutonium one. But it would not have been much later.

Sanger: U-235, I suppose it was not produced as fast as the plutonium, was it? 

Smith: I do not remember, no. I think the rate of production was, in terms of bomb units must have been about the same. It was not an enormous difference. But I do not remember the number.

Sanger: Well, I wonder in retrospect, was there any real purpose for the plutonium project at all? 

Smith: Well, there was plenty of purpose for it at the time.

Sanger: I mean, just in a sense of what, having it?

Smith: You did not know if it was going to work. They began, of course, by using several different methods of separating the uranium 235. The development of the plutonium was quite a different route. No. I think it was a necessary and wise policy in the environment at the time.

Sanger: Yeah, that is obviously true. What was your primary motivation in working so hard on it?  Was it the fear of the Germans basically?

Smith: Yeah. I find that it is so hard for youngsters today to reconstruct it. The students at MIT by-and-large think anybody who had anything to do with the project during the war was some kind of a moral outlaw. I think at the time that with the threat of Hitler, it was anything but that. By and large, I have essentially done what science I wanted to do because I was interested in it, and have not really been a good citizen,

I suppose. But the one time I was a good citizen doing what my country demanded was working on this damn bomb; which raises some rather interesting questions, I think, about morality, and environment, and environment on what level? I have been strongly opposed to the country's continued multiplication of nuclear weapons. I think our present nuclear weapons policy is just plan crazy.

Sanger: Because of the multiplication of it?

Smith: Yeah. Right. It is just beyond any sensible need.

Sanger: Well, that is essentially what everybody else has told me, too.

Smith: I think there are very few people who have any intimate knowledge who do not feel this way.

Sanger: Everybody has stressed the importance of realizing the context of their work with the atomic bomb, also.

Smith:  Have you seen my wife's book, by the way?

Sanger: Well, I have as a matter of fact.

Smith: Yeah.

Sanger: Yeah. I did and I have not read the whole book. It was recommended to me by a professor at the university. That is one of the things that made me start thinking about the necessity for the second bomb. She mentions that briefly; it is somewhere in the book.

Smith: Yeah.

Sanger: It is not really particularly relevant, I mean, and perhaps to what I am doing. But on the other hand, it provides kind of an ironic twist to it.

Smith: Yeah. I think it gives you a last paragraph of your book.

Sanger: Yeah. I had an interesting chat with Alvin Weinberg.

Smith: Yeah. I know Alvin.

Sanger: I asked him that question about the second bomb. He said that it was not necessary. I asked him if he had any idea of why it was used?  He said that in his opinion it was purely Groves doing, and that he had a conversation with Groves some several years later while drinking whisky at some hotel bar in New York City where Groves admitted that more or less that it was probably was a mistake to use the second bomb. That was in the perspective of time.

Smith: I think you could even ask whether even the first bomb was absolutely necessary at that stage. With a project of this kind, you start it with the very best of motives. This is an enormous impetus that carries you on. But if you were to stop and reconsider what you were doing every day, you will not do anything at all. I think you essentially have to make a decision once, and then go ahead for a time. But I think it is so essential to have an external view on things. I mean, one needs a continued technology assessment by somebody who is intelligent enough to know what is going on, but sees it from an external view.

Sanger: I did happen to see a fairly recent book by a man named Spector about the war against Japan. He suggested in there that no one knows for sure.

Smith: You ought to be talking to my wife on this level of things.

Sanger: Is she here?

Smith: She is; let me bring her down.

Sanger: Okay. I was hoping that she might be here because she probably knows more about this than anybody.

Smith: Alice? Could you join us? Even the people in Washington did not know enough to make a retrospective wise decision.

Sanger: Some of these people that I have talked to, especially the engineers with DuPont, I do not think necessarily have thought a lot about it. But they said well, it was an available target. It was a one, two punch. It was insurance.

Smith: You must notice the fact that the engineers and the physicists and the chemists tend to hold different views both politically and specifically on the use of the bomb.

Sanger: The engineers are much more just doing their jobs.

Smith: Yeah. The metallurgists are torn between the two views.

Alice Smith: What is that? You were talking about arts and sciences, or something.

C. Smith: We have gotten to the bomb now. We are talking about what happened afterwards.

A. Smith: Well, okay, fill me in. Because I thought you were talking about something totally different.

Sanger: I am trying to do a book on the Hanford engineer works, the plutonium.

A. Smith: Yes.

Sanger: I read parts of your book.

A. Smith: There was not very much about Hanford.

Sanger: Well, there was a little bit. You went into briefly the discussion about the necessity for the second bomb, as I recall. It made me include that question when I have talked to these people—if they thought if it was necessary? Because it was plutonium and it has a direct connection with Hanford. Well, everybody has said “no,” they did not think it was necessary. Which calls into question, of course, the entire operation at Hanford. Or, the plutonium project in general. I suppose just as a scientific experiment that was interesting.

But the feeling is by most people that the second bomb was kind of irrelevant in the sense of ending the war and unfortunate that it was used. I spoke with Alvin Weinberg last week in North Carolina where he had gone to give a lecture. He said it was not necessary. He said he blamed it on Groves, it being his idea to use it. He said he talked to Groves several years after the end of the war in New York City once. They apparently drank a lot of whiskey together. He said that Groves more or less admitted that it had been a mistake to use it.

A. Smith: Well Groves probably knew something of the decision making process that none of the scientists certainly did. I don’t think Oppenheimer—even Bush and Conant, those people—were supposedly as close to the center, the decision making process. I think for all of the scientists, it was an ex post facto thing rather than that something that they approved or did not approve at the time. This Phil Morrison is somebody who was at Tinian; Norman Ramsey—wasn’t he there?

Sanger: He is, yeah, right. He was the one. I think he assembled it or part of it.

A. Smith: I think they thought that well, both of them played a very crucial part in the end there. Since the first bomb had not ended the war, they did not know. They certainly did not know about the whole complicated diplomatic situation. It took a long time for historians to disentangle it.

Sanger: You mean, the reaction of the Japanese?

A. Smith: The question of the reaction of the Japanese. It was a long time before there was any public knowledge, several years before the book on the attempt to unseat the emperor in Japan, for instance, became known to historians who were interested in post-war things. And of course, there was the whole question of official attitudes toward Russia and wanting to get the thing out of the way before they came into the peacemaking process.

I doubt there were any scientists who were actually at the front; I was thinking of Ramsey and Morrison and the people who went with the bomb, Cyril. They certainly had no way of knowing how effective the first bomb had been diplomatically. I do not suppose they knew how effective it had been physically

Sanger: Was there a sense that Truman or the commander there, the top people had decided to just keep using them until Japan surrendered, period?

A. Smith: Well, at first they only had two.

Sanger: Yeah.

C. Smith: The others were coming along, though. There would have been one in another couple of weeks, certainly.

Sanger: There was?

A. Smith: After all it was only three days. My understanding of it too is that the weather played quite a part. There was five days but the weather was closing in. They had originally been told it was five days leeway. But then, it turned out to be less.

Sanger: Yeah. Apparently they almost did not even bomb Nagasaki because it just made the final run when the weather opened. Otherwise, I do not know what they would have done with the bomb because they passed up on one target at least and had gone on to Nagasaki. As I recall, the weather cleared momentarily, and that’s when it was dropped. I do not know. What would have happened to it, if they had not been able to get rid of it? 

C. Smith: I do not know, if they had some contingency plan for it.

Sanger: They were out of gas, the plane was. It got back with a teacup full of fuel, apparently. I interviewed a man who was at Nagasaki that day and was a prisoner of war. He was a Dutch Indonesian who was a POW working at the Mitsubishi shipyard or armaments factory. But he was away from that somewhat. Otherwise he would have been killed. But he described it. He was not hurt.

He just recalled it. He said a sudden brilliant white light. He was inside a wooden building. He said the building collapsed around him. Then he fled to the hills. A few days later, they came back. But by then, the war was over. That was an interesting story. He now lives in Seattle. He came to the United States. He works for Boeing.

A. Smith: Well, I really cannot contribute much to this or anything, probably, that you two don’t already know. I guess that is the only thing I would emphasize: the more that is known about this whole business of the decision, and the more clear it seems to become that almost nobody had a complete picture. Truman, of course, was briefed. But it is a question how much really understood the information, the diplomacy, the science, and the actual events.

Sanger: It is safe to assume that he thought it was basically a super weapon and had no particular idea of the radiation dangers, and that sort of thing. I know that people are always talking about how the atomic bombs were not any particularly more monstrous than the fire bombings except for the radiation—long-lasting, that angle. And of course, they knew very little about the genetic or maybe nothing about that at the time, I suppose. Was that ever brought up in your recollection—any long-term dangers from the radiation?

C. Smith: I think so. The intention was always to detonate it sufficiently high so that there would not be much persistent particle radiation.

A. Smith: Someone you might not have run into who is currently in the Cambridge area and has worked particularly on this question of radiation and is working on it right now is a woman named Vilma Hunt, who is based at Penn State, although she and her husband are about to retire to Magnolia, north of Boston.

Sanger: Hunt, H-U-N-T?

A. Smith: H-U-N-T, yeah, and her first name is Vilma, V-I-L-M-A. She is currently for the rest of this year associated with the Science and Technology at the Society at MIT. It might be worth calling her, because she has been asking me questions that I could not answer about radiation. She has an interesting background.

She was one of the first fellows at the Bunting Institute at Radcliffe back in 1961. She was a dentist from New Zealand who could not practice in this country because they did not allow foreign certificates. She came with her archeologist husband who was back here at Harvard. She got interested through him in teeth; she was studying prehistoric dentistry.

Then she had a grant to work with one of the labs at the School of Public Health. She identified the polonium in cigarette smoke and made her reputation that way. Then went on to become interested in radiation in the various kinds, and has worked at it steadily in the last ten years or so since she has been at Penn State. But I think they are retiring. But she is available here in Cambridge, I saw her a few weeks ago at MIT.

Sanger: Before I forget, you mentioned in your book, there was no agitation that you turned up at Hanford over the use of the bomb, right? I asked a physicist, John Marshall who was there about that. He said he does not recall.

C. Smith: John Marshall was at Los Alamos.

Sanger: Well, later and he was at Hanford for a while before.

A. Smith: But John was not at Los Alamos during the war. He was in Chicago during the war.

C. Smith: Was he?

A. Smith: Yeah. He went there during the war. We never met them until after we went to Chicago. I did not even know he had been at Hanford.

Sanger: Yeah He and his wife both were there for a year during the war. She worked with Fermi. He did too, but he was also what they called a babysitter on the reactors to be there to give a physicist's advice.

A. Smith: Yeah. Well, I never really tried to get into the picture at Los Alamos and Hanford because I was basically working with the groups that were established after the war.

Sanger: Well, I think that one of the characteristics of Hanford was that there were not a lot of scientists there. There were some physicists and that was about it. And they did not necessarily stay too long. They were there essentially to see that reactors would start and become operating and producing plutonium. Then they tended to leave.

C. Smith: There was a wonderful story about xenon poisoning, as I am sure you know.

Sanger: Apparently that was the most interesting scientific incident during the whole Hanford time. That is what John Wheeler talks about. He was a key person in figuring out what had gone wrong.

A. Smith: I do not remember, does [Stephane] Groueff, in that book that emphasizes the engineering side of the Project, does he say much about Hanford? I do not remember that he did.

Sanger: He does. He is the only person who really does much.

A. Smith: That is what I remembered.

C. Smith: I liked his book because he showed that the bomb may have come from physics, but it was built by engineers and metallurgy.

A. Smith: I thought it was wonderful also because it showed that engineers all came from sturdy Scandinavian pioneers, instead of European intellectuals. I thought it was a very interesting sociological book.

C. Smith: Have you ever heard of the Cyril Smith incident?

Sanger: No.

C. Smith: Quite unwittingly, I played a role in the relations between the U.K. and the U.S. There are several pages in the Congressional Record on the Cyril Smith incident.

Sanger: What is that?

C. Smith: It was concerned with plutonium; again, there has been an exchange of information. I have been authorized to discuss with the British at the time they were opening up after the first freeze. I have been authorized to discuss matters dealing with the pure metallurgic plutonium, but nothing to do with the fabrication. But when I was in England, Sumner Pike found out about this.

They were trying to get hold of me to tell me I was to on no account to mention plutonium on my visit to Harwell. But we happened to be out on a vacation out in the Northwest coast of Scotland. They could not get a hold of us. As luck would have it, I did call before I went to Harwell. But it just as well could have been afterwards. Then all hell would have broken loose. It was part of Pike’s claim, I mean, of incredible mismanagement. Remember that episode?

A. Smith: They got a hold of him. We were there primarily to visit his mother that year with our children. We had not seen her since before the war. They had gotten hold of us through his sister where we were staying. I just happened to catch him before he had gone off to Harwell.

Sanger: What would have happened, if you had discussed it?

C. Smith: I suppose Sumner Pike's claim that the Atomic Energy Commission had been incredibly mismanaged would have seemed to have some validity in some people's eyes, but certainly not mine.

Sanger: Do you ever see many of the people you worked with at Los Alamos?

C. Smith: Occasionally, yes.

Sanger: Did you have much to do with Kenneth Bainbridge?

C. Smith: Yeah, I have known him very well. He was the only physicist on the Hill we knew before.

Sanger: He was? He is here. He lives here, does he not?

C. Smith: He is what?

Sanger: He lives in Cambridge or Boston?

C. Smith: He lives in the area.

A. Smith: He lives out in Weston.

C. Smith: Weston.

Sanger: That is right, yeah. I corresponded with him when I was doing the newspaper series because we were concentrated somewhat on the Trinity test.

C. Smith: “They are all sons of bitches.”

Sanger: Yeah.

C. Smith: He was quite helpful, though. He had had a bad experience with an interview by telephone, he said recently. He said he did not want to be interviewed by telephone. He wrote some letters. He was helpful. He does not have any particular connection with the Hanford business.

A. Smith: Well, we see constantly our Los Alamos friends, those who live around here. In fact, for us, they just revolutionized our whole pattern of friendships. The Bainbridges actually we had met in Cambridge, England back in '33 and '34, but that was just by chance. They were the only people that I knew on the project. Cyril, of course, knew some of the metallurgists that we brought there but I had never been a great meeting goer to wives' affairs. They were liberating, though, and the people that I knew are the people we see the most of here.

C. Smith: Just a month ago when Rudolph Peierls was here from England, we had a party in this house with all of the people from Los Alamos.

Sanger: You did?

C. Smith: Yeah. How many did we get together, do you think?

A. Smith: I think there were fourteen, fifteen, sixteen or something like that.

C. Smith: It was a very high concentration, the Los Alamos people from this area.

A. Smith: Everybody turned up who was—there are a few others but not people that Peierls had known particularly.

Sanger: Yeah. Somebody was talking about him. I guess it was Wheeler, talking about him and his experience with Klaus Fuchs, the spy. He told an interesting story about a jailhouse interview he had with him after he was arrested.

C. Smith: You’ve seen Peierls’ book, haven’t you? It was published very recently.

A. Smith: But that tactfully does not say very much about the Fuchs’ relationship. I did not ask Rudy about it when we saw him, but I think they really had been very close to him. And there was a very personal letter, the ones that we saw once that Fuchs wrote trying to explain his curious ambivalence.

C. Smith: What all happened to that letter? When I first saw it, it was only about two weeks old. It was already dog-eared from having been read and folded many times.

A. Smith: Well, I am sure it is with Rudy’s papers somewhere in England. But I think there was no point in making this very personal statement on Fuchs’ behalf in his book. It did not have anything to do with the Peierls directly except that they had been awfully kind to him. Fuchs said he began to have reservations about what he had done when he was greeted with so much friendship by various people at Los Alamos.

Sanger: Did you know him?

A. Smith: I did not know him well. Because I do not think many people did. He was very shy and retiring.

Sanger: What did he do at Los Alamos?

C. Smith: He was a physicist. I do not at this point remember exactly what part of it he was concerned with. I did not have any direction with him the way I did with the people like [Hans] Bethe and [Edward] Teller.

Sanger: Was he not an expert on the gaseous diffusion earlier?  Was that not his real strength?

C. Smith: Was it?  I do not know. I just do not know.

Sanger: I think so. I do not know what he did at Los Alamos.

C. Smith: I know gaseous diffusion was at Los Alamos.

Sanger: Yeah, that was. I think he had been at Oak Ridge. Or, maybe he had worked on that in England.

C. Smith: Let us see what it says in this about him.

A. Smith: Do you have the Hawkin's book there?

C. Smith: Yeah.

Sanger: Yeah, that was a fascinating story. Did he have many friends, do you remember, at Los Alamos?

A. Smith: I think the answer would be no because he was a very quiet person. He was single and lived in one of the dormitories I think. But, we met him at parties at the Peierls’ and I think he saw more of the Europeans there just because that was a natural kind of connection. He certainly was not somebody like [Richard] Feynman who went out and made connections all over the place. Feynman was single in those days, too. There were a number of the unattached young men who were very sociable. But nobody thought anything about the fact.