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National Museum of Nuclear Science & History

Walter Simon’s Interview

Manhattan Project Locations:

Walt Simon was Hanford’s first Operations Manager. Before joining the Manhattan Project, he was Plant Manager at DuPont’s Wabash River Ordnance Works. He moved to Richland in the summer of 1944. He recalls the early “friction” between scientists, specifically Enrico Fermi, and the DuPont Company over the design of the B Reactor. He also recalls watching the B Reactor go critical and then shut down due to the Xenon poisoning. This interview does not have a corresponding audio recording.

Date of Interview:
September 12, 1986
Location of the Interview:


[Interviewed by S. L. Sanger, from Working on the Bomb: An Oral History of WWII Hanford, Portland State University, 1995]

When I was called to Wilmington from Terre Haute in 1943 and told what we were getting into, I was flabbergasted. I couldn’t sleep that night and the next day I thought, “Well, I better find out more about this.” Atomic energy wasn’t my field. I went down to a bookstore and I picked up a book on the subject that had all the current information. It was “Applied Nuclear Physics” by Ernest Pollard and William Davidson, published in 1942. I still have it. There was quite a debate about withdrawing that book from the market, but it was decided that would be a sure sign of what was going on. I was asked if I wanted to take part, and I knew it was an atomic weapon. They were pretty sure I would say yes because I was already involved in war work and there was nothing else to do until the war was over.

In the summer of 1944, I moved to Richland from Wilmington as the plant manager-designate. We had groups of men training at Oak Ridge and Chicago, others were scattered around in small numbers at other Du Pont plants, small enough not to attract attention. They were learning everything they could about uranium and plutonium.

One error in some accounts is that Hanford was chosen because of the availability of Columbia River water. When Hanford was chosen, the concept of a water-cooled reactor had not been developed completely. Later, when this was decided upon, the presence of a good water supply was a matter of unbelievable good fortune. So many things like this fell into place in the life of the project that it seemed to have been blessed with a special element of luck.

The night B Reactor went critical we had a lot of high-ranking technical people watching this startup, and when it went critical and then shut itself down, the silence was deafening. It was complete consternation. As back-ground to this, the scientific people, the Chicago people, the Nobel Prize winners, Wigner and Fermi and Szilard, were all much more on the risk-taking side than Du Pont was. Du Pont was a conservative organization. For instance, if someone asked for a two-story building, Du Pont design would put enough steel in it for four stories, being convinced that sooner or later someone would add an extra floor or two. Du Pont conservatism paid off on the reactors. Enough extra fuel tubes had been added to overcome the fission product poisoning.

There was a great deal of team effort in this whole thing. There were no autocrats who could say, you know, take the cigar out of his mouth and say, “Do this or do that.” Things were pretty much decided in a consensus of judgment. The whole project was like a three-legged stool. The military, the scientific community and the commercial corporations were built on differ­ent philosophies. Spurred by a common fear of Nazi Germany, the three groups got along reasonably well as the results indicated, but this did not eliminate their fundamental differences. Each one needed the other two.

There was friction between the scientists and Du Pont, honest differ­ences of opinion on how to get the job done in the quickest way. Friction may be too harsh a word because we were all on speaking terms. They were annoyed, lets say, that Du Pont people were exercising some degree of judg­ment, but on the other hand people in the Corps of Engineers had encouraged Du Pont to exercise judgment. They often said that is what we hired you for. At one point, we weren’t too keen on technical dissension. We had to go.

At the beginning, looking at it frontways, the reactor looked more formi­dable than the separation process, which was a chemical process. The main problem with separation was it had so much radiation, it had to be manipulated with various automated equipment, but as a process it was understand-able to our chemists. Protecting people from radiation added a dimension that made it a little more difficult. The scientists were absolutely astounded at our ability to design arms and devices that could do these tasks. They stood a little bit in awe of how it all worked out. It was technically very good.

Another thing that worked out. There was a discussion in the scientific group as to whether you should build a reactor with a solid material like car-bon or a liquid like heavy water. The Germans were making a great point about making heavy water in Norway and shipping it to Germany. Of course at that time everything the Germans did was considered very smart. So, the design problems of a heavy water plant looked insurmountable. Keeping it from leaking, the corrosion, all sorts of things. A solid material, carbon, looked like a practical solution. The heavy water advocates, of course, always thought we were going down the wrong path.

Fermi was very discreet about disagreements. He was a very pleasant person. He had a mind that raced all the time. For instance, if there was a little time to kill while they were loading the reactor, he would do equations in his head, with someone next to him with a calculator. You know, multiply 999 by 62 and divide by this and that, and he did that for amusement. His mind raced so much the only way he could relax was to walk on the desert. They would try to take him to a movie, and he would sit there and in five minutes he would have the whole plot figured out. He had a tremendous intellectual capacity, absolutely. Fermi was interested in chess and one or two of the men who were run of the mill technical people had spent a lot of time playing chess. Boy, when he found a good chess player, he tied him up. One boy was not particularly intellectual but he was a supremely good chess player. Fermi would come around calling for him, “Where’s so and so?”

In early 43, there was quite a bit of discussion on how the government was going to operate Hanford. There was some thought you might put everybody in the military. After all, they would not be any worse off than if they went to Europe or the Pacific. Groves reacted very violently to this pos­sibility and, I think, wisely. He wanted it run as a civilian operation, to get the maximum output from a voluntary force.

Now, one of the most difficult problems we had before plutonium pro­duction began was making the uranium fuel slugs. The uranium was held in an aluminum can, a slug, about eight inches long and an inch and five-eighths in diameter. The can had to fit very tightly with no air space or bubbles. They couldn’t leak because if water got into the uranium it destroyed the ability to react. So the concept was that the scientific people would find out how to do this and give us instruction. They found out how to design it but they never made a slug in the laboratory that didn’t leak.

Well, the summer of 44 was coming along and the reactor was shaping up and there would be nothing to put into it. We had a production superintendent at Hanford named Earl Swensson, who was a real dyed-in-the-wool production man. This was a case where one man did sell an idea. He said you know they’ll never make one of these in the lab, even if they work on it for 10 years. Its a statistical matter. Why dont we make a thousand a day, we’ll examine each one and test them all, and the poor ones we’ll strip the aluminum can off and save the uranium and the next day we’ll make another thousand. The first day a thousand failed, but there were maybe 10 better than the others and we tried to figure out why these 10 were better. The next day maybe they had 18 that were better. And they kept doing this and lo and behold after about three weeks there was one perfect can. Purely statistical. If you made a thousand a day for three weeks, you had made 20,000 until you got one good one. They made five good ones the next day, and 10 the next and after a while out of a thousand they were making 500 and then 600 a day that were all right. That’s how they did it. It was a little terrifying because if we didn’t have them it would stop the whole thing. The reactor would be ready on September 15 and we would have nothing to put into it.

I do want to say that the director of Du Pont’s plutonium effort, the TNX Division, was Roger Williams, and the success of the project was due to his skill and guidance. He was a genius. The books to date on the Manhattan Project rarely mention him. He was a modest man and avoided the limelight.

After the first reactor started, there was extreme pressure to produce a certain specified number of grams of plutonium which in retrospect must have been enough for a test bomb and the Nagasaki bomb. Several deliveries were made, the first one on February 2, 1945, and the final (wartime) portion was June 15, 1945. After this, the pressure decreased markedly, both because the Germans surrendered on May 8 and the achievement of the required quantity. I don’t know how much plutonium we shipped. We were strictly forbidden to keep notes or diaries.

We shipped it in a solution. I remember I wasn’t very excited when they showed me some. It looked like brown molasses. We shipped enough by June that we were cleaned out. We had the goal, we accomplished it. After June things began to settle down. We had already shipped enough. We wanted to avoid accidents. There was an air that things were winding down. It was only five weeks until Hiroshima. I took a week’s vacation in late June with my family, to visit Seattle and Victoria, British Columbia. So the pressure was really off.

After that we began returning surplus Du Pont personnel to the com­pany and planned for the end of the war. The Du Pont contract expired nine months after cessation of hostilities and we fully expected the plant would shut down by that time. The Du Pont Company was dead serious about withdrawing when the war was over.

I want to mention something else, the Japanese balloon bombs. They were a real worry. Everybody at the plant was always looking up because of the statistical chance of one falling. I remember seeing 40 at one time going over. The Navy planes at Pasco chased them regularly but they had poor luck. Matthias and I went over to prod them about getting better protection. They never managed to shoot one down, although a number came down on the project, but away from the buildings. The bombs never went off, but the balloons blew around and the military were a great sight trying to round these up without being blown up them-selves. The only balloon that caused any damage to Hanford was the one that landed on the power line from Grand Coulee Dam, and it knocked out the reactors very briefly, the only American war plant shut down by enemy action during the whole course of the war. We mentioned that to Groves and he said, “I suppose all you fellows will apply for the Purple Heart.“‘`

Something else is radioactive releases. We put very high stacks on the separation plants. We did worry about gas emissions when the uranium from the reactor was dissolved to separate the plutonium. We monitored them very carefully, and in that period up to June, 1945, if there was a good velocity of wind to distribute them, we might have taken some chances. Naturally, all of these things were being done for the first time and time was of the essence. Forty balloons in the air reminded us time was of the essence. I do remember that at the beginning some of the first batches of uranium being dissolved left off a little more gas than we would have liked, but we learned to control it. But, up until June when the amounts they wanted at Los Alamos had been delivered, the pressure was tremendous.

We watched everything that went into the river. We had a whole building where the effluents were monitored. We had big tanks with fish in them. The effect on the fish was watched. I dont recall any problem with anything going into the river.

Now, a great number of idealistic technical people hoped the chain reac­tion would not work, that it would be impossible to have a nuclear explosion. The ones who visualized what nuclear weapons would be were sober about the whole thing. The outburst of enthusiasm when they were used came from knowing the job was done and that the war would be over. After five years, the people in this country were getting tired of war, tired of shortages, tired of people being killed. It was a subconscious weariness. But something that suggested the war was going to end was really something. There would be no invasion of Japan. After the experience of Okinawa anybody who had rela­tives in the Far East was scared. The death toll on Okinawa was beyond all expectations. One man said the bombs cost a lot of lives but also saved a lot of lives, including his. The apprehension among people who would be going into Japan was tremendous. They knew there would be a lot of criticism about dropping the bombs, but at the time it was the biggest relief they had ever experienced.

Copyright 1989 S. L. Sanger. This transcript may not be quoted, reproduced, or redistributed in whole or in part by any means except with the written permission of S. L. Sanger.