The Manhattan Project

Eugene Wigner's Interview (1986)

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When Eugene Wigner was 17, his father asked what he wanted to be and Wigner replied, "A physicist." His father wanted to know how many physicists there were in Hungary. "Four," Wigner replied. Following that conversation, Wigner studied chemical engineering and after getting his degree worked in a tannery for a time before going to Berlin to teach. Because his mother was Jewish, Wigner was fired from his Berlin position in 1935, after which he became a professor at Princeton. In 1939, Wigner and fellow Hungarian physicist Leo Szilard went to Albert Einstein and convinced him of the need for America to develop an atomic bomb before Nazi Germany. Einstein's concerns eventually reached President Roosevelt and helped spark government interest and research which evolved into the Manhattan Project. After the Manhattan Project was underway, Wigner, who had done important work earlier on neutron absorption, moved to the Met Lab in Chicago as head of the theoretical physics group. In 1963, Wigner was awarded the Nobel Prize for physics.
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[Interviewed by S. L. Sanger, from Working on the Bomb: An Oral History of WWII Hanford, Portland State University, 1995]

I shouldn't boast but it is generally said, you see, I was in charge of the group which designed the reactors built at Hanford, and these reactors really worked. Fermi constructed the first nuclear reactor that really was reacting, but it had virtually no energy. And Alvin Weinberg, he designed almost alone the Oak Ridge pilot reactor. But the bigger reactors, we all designed together.

Really, there was no invention at all (with the Hanford reactors). There were only decisions to be made. To decide what kind of reactor to build, and how to extract the heat. But such a thing has many many factors in it, that the uranium should be put into aluminum, for instance, is an important thing. How the water should be pushed through, how the uranium fuel slugs should be located. The form of the inner structure of the (fuel) tubes. Many, many little things.

You see, I was educated as a chemical engineer, which came in very well, because I learned a lot of chemistry and that was very useful. I remember an instance, I don't know whether I should tell this story, but the Du Pont Company felt we should put some chromate, potassium bichromate, in the water to destroy the hydrogen peroxide, and they didn't realize the result of such reaction is the production of chromium hydroxide. It would deposit on the aluminum and decrease heat conductivity. I told them they should not do that. There are many, many little things, not little things, many things they were in error about because they were not at all familiar with nuclear reac­tions.

With Du Pont, the rule was this, they made the drawings but they submitted every drawing to us at Chicago to review, and we reviewed them, Weinberg, Gale Young and I and another man. We worked together and we discussed everything, but we had no conflicts. If somebody made a mistake, we tried to point it out and said, "Well, we'll change it." We felt when Du Pont took over it will delay things and it did, although it didn't matter as much as we were afraid it would.

The design of the Hanford reactor was submitted for typing just about a week after the Fermi chain reaction. Well, the Hanford reactor was an easy, a relatively easy, calculation. I carried it out. If I want to build a gate, we'll say, I always can do it and be confident it will work.

It is right I was in conflict at times with Du Pont, because it took much longer than reasonable and we were certainly afraid the Germans were ahead. But the Germans surrendered and they were not as close as we thought. But we thought they must be.

Du Pont had to learn so many little things which we knew already. That delayed things very badly. They sent every drawing to us in Chicago to review. We did that and many had serious failings. They did not understand the details of why we designed in a certain way. Why pipes had two ribs, why the sides of pipes were as we proposed, and we had to explain. I think it (Hanford reac­tors) could have been built probably nine months earlier.

The site was not unreasonable, but it doesn't matter where it is. Water is very important, but I think it should have been built on the Potomac, at the end of the Potomac River. General Groves felt a remote site was best. We did not object. We objected, at least I strongly objected to the Du Pont Company, which had no knowledge at all of nuclear physics, and very little knowledge of the other engineering problems. Otherwise we did not feel it was important whether it was at Hanford or close to Washington, D.C. The way I remem­ber it we wanted to put it close to the end of the Potomac River. Chicago had two disadvantages. It had no fast river going through and second, eventually Lake Michigan would be contaminated. The Atlantic Ocean is much bigger than Lake Michigan, and the radiation was not much but just the same a significant amount.

Well, eventually Hanford worked, and Du Pont learned a lot. They did not close their eyes to facts of physics or engineering.

You know, I don't remember very well my visits to Hanford. I saw very little, and you see, when you see a nuclear reactor in operation, you see very little. They invited me, I think, principally out of politeness. It was a well-working reactor, unquestionably. Of course, it was our design. I was a little surprised at how large Hanford was, how much money and energy they put in. I thought it could have been done much cheaper, and much faster, much faster. Du Pont learned a great deal about nuclear physics at Hanford.

We were very much afraid of Hitler and I don't know the exact date but in Chicago we received a paper written by a friend, a German friend working on the German atomic effort and he was sent to Switzerland to do something. He was against Hitler and he told us, "Hurry up, we are on the track." You see, they were on the track theoretically, but in practice they were not. Hitler said Germany will win the war before this (atomic) weapon will be effective. Very few German physicists were really enthusiastic. In America, we thought it was very important to maintain freedom in the world and not a dictatorship of Hitler.

Perhaps I should mention that when the Germans surrendered and it was very evident it would be used against the Japanese, several of us felt it was unreasonable to destroy many Japanese lives in order to demonstrate it. We wrote, actually James Franck formulated it, a petition. We were practically all in favor of demonstrating the bomb in the presence of Japanese scientists and government men over uninhabited territory, hoping this will convince them. General Groves was very much against it. I don't know if the Nagasaki bomb was necessary, the first one apparently was necessary. I read a book by Feis (historian Herbert Feis), and he said it saved a million Japanese lives and perhaps 200,000 American lives. This struck me, and I asked my Japanese friends if an explosion as we proposed would have demonstrated the same thing and made it unnecessary to explode over a city. With one exception, they said it would not have convinced the Japanese emperor. You see, though, it is not a question which interests me because we can't change the past.