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Ralph Lapp’s Interview

Manhattan Project Locations:

Ralph Lapp was completing his PhD in physics at the University of Chicago when he joined the Manhattan Project. After the war, he worked for the War Department and served as a scientific advisor there before leaving the government to start his own firm. Lapp went on to write several books and advocate for peaceful uses of nuclear energy. In this interview, he discusses how he stumbled upon Enrico Fermi’s team working under Stagg’s Field in December of 1942, and was hired on the spot to work on the development of the atomic bomb. Lapp recalls witnessing the 1946 Bikini nuclear tests, and discusses the controversy over the Lucky Dragon boat, caught into the fallout of one of 1954 Castle Bravo hydrogen bomb test. He examines how nuclear weapons have changed the course of human history.

Date of Interview:
September 12, 2002
Location of the Interview:


Ralph Lapp:  I am Ralph Lapp, L-A-P-P. I am a physicist, nuclear physicist, an author, and a consultant. I have engaged in finance and technology.

Interviewer: Great. What can you tell us about your role in the Manhattan Project?

Lapp: Well, my role was quite a small one, but to me fascinating. I was in charge of instrument development, Geiger counters, and technology associated with the bomb. I was based and working in Chicago. It was called the Metallurgical Laboratory. It was a code name, because radiation could not be used in the outer-world; it was secret.

So the Metallurgical Lab, or Met Lab, was the place I happened to be when the war broke out. I was working on cosmic rays. I found a use for Stagg Field, which was a football field that Alonzo Stagg fielded back in the late ‘30s. Alonzo Stagg was not the attraction for me to come to Chicago; Arthur Compton was. Nobel Prize winner in X-Rays.

I was working at Stagg field, which I found a use for because Robert Maynard-Hutchins, the chancellor of the University [of Chicago], was against sports. So here was the big sports arena of Stagg Field on which there was no longer any football played. I am a fan of the Chicago Bears.

But I was completing my research on cosmic rays, and in those days, we had very little money and very little equipment. What we used was slave labor. Slave labor was a PhD candidate. We made our own Geiger counters. If you made one Geiger counter, you made enough.

I needed to get rid of all buildings around my equipment. I was measuring very high-energy events. There was the press box of Stagg Field, the football field. I was in the process of doing my research. I would go up at night, because I had photographic film taking in the data. Usually I would go up at night, but one day, it was daytime, I looked and I saw there was a doorway.

One day, I was hauling up lead from sea level to the press box, and I noticed that the door was open. Thinking that I could use it as a shortcut, I went in. There was a man with a revolver and a badge, and he wanted to see my photograph. I had stumbled into the atomic bomb project. Arthur Compton said, “Well now that you’ve stumbled in, you might as well work full time.”

I started working as a physicist, and I was blessed by working with Arthur J. Dempster, a Canadian, who was in fact the discoverer of uranium-235. Now it is the fissionability of uranium-235 that really counts. Here was this Canadian-born, rather small physicist, and he was very difficult for people to work with. I managed to succeed in dealing with him on a human basis. That got me into the project.

After the war, I was made Assistant Director of the Argonne National Laboratory. I was lucky. I had three choices. I could stay on the project, but I was working for a man that I did not care to work for. I could work for Arthur Compton at the University on cosmic ray research. Or I could accept the invitation of Captain [Hyman] Rickover to come to Washington.

Well I did, I came to Washington, interviewed, and I was not going to work for the Navy; I just knew that. There was too much brass. But walking home through Georgetown, a car pulled up on the side of the curb and said, “Ralph.” It was a colonel who had been at the Bikini bomb test with me. Well, he invited me to dinner, and as a result of that dinner, he persuaded to join the Pentagon and be a physicist working as a science advisor. So I joined for two years.

I joined the Manhattan Project working very closely with General [Leslie] Groves, who was featured at this conference today. So this is a somewhat jaded trajectory that I had, in getting from the university to working in Washington.

After several years, I quit the Pentagon and became entranced with national security. I could not write, which is what I wanted to do. You could not write, except with great difficulty. So I gave a series of lectures in the Pentagon to the military, in order to brief them on the text of nuclear physics. This turned out to be very tricky, and it led to the origin of a book I have with me. The first book called Radiological Safety, in which the Bikini bomb experience is chronicled.

At the Bikini in 1946, I was present. I was the first one to re-enter the lagoon after the bomb exploded underwater. You will remember, if you look at the photographs, it was a huge, bay surge of water vapor and radioactivity from the bomb. I was the first one in, and I coasted right in to the target fleet. My meters, my Geiger counters, started to go clickity-click-click. They said it was secure. Well, I was so new to the military, I did not know what “secure” meant. Well, it turned out it meant for everybody get off the ship. I was on a submarine chaser. So that was fine with me, except we came with twenty-three or twenty-four men on board. So a submarine chaser.

We pulled up to an island, anchored, and everybody got off except the captain and myself. I said, “After you,” and he said, “I cannot abandon ship.”

He said “The Articles of War; I have to stand mast.”

“There is nothing in the Articles of War about radioactivity.” I waved the boat off and said, “I cannot leave with you here, so we will stay the night.” We stayed the night, and that was how I got involved with the fallout from the bomb.

That fallout has turned out to be the difference between the normal growth of weapons, and the spectacular growth of killing power by taking the atomic debris—split atoms of uranium. We know them as strontium-90, cesium-137—things with long half-life.

I worked by myself to discover just what it was that took place in a bomb explosion, later at Bikini. This was March 1, 1954, and they exploded a 15-megaton bomb. That is 15-million tons of TNT equivalent, or a thousand times the power of the bomb that collapsed buildings in Hiroshima and Nagasaki. This was spectacular by itself, to have such a big bomb. But the radioactive fallout occurred over an area of thousands of square miles.

Ninety-two miles from where the bomb exploded, there was a tuna trawler from Japan called the Lucky Dragon. The crew had been searching for tuna fish up north, but not finding good fishing. They had sailed down to where—they did not know—but the bomb was being exploded. The crew was up just before dawn, and one of the men looked and saw a great flash. He cried, “Pikadon! The sun rises in the west!” This intrigued me, but I was on a very busy schedule of lecturing and writing.

I was a critic of the Atomic Energy Commission. This won me no great degree of acceptability because I was a critic, and the Atomic Energy Commission did not like criticism. The admiral in charge of the Atomic Energy Commission saw to it that I could not get my passport renewed, and I had to get a lawyer and sue for a passport. They thought that I was working for the Soviet Union, which was weird. I hired a lawyer and in eighteen hours, I got my passport.

I wanted to go to Japan. I had just married. My wife—who is here today—and I were hooked up, and she went with me to Japan. I visited the Japanese fishermen who had been on board. There were twenty-three fishermen, one of whom died.

They were outdoors, on this little boat when the bomb went off. Several hours later, the radioactive debris of a chalky nature—the coral was made of chalk. This drifted down and descended on the decks of the Lucky Dragon. The men took it off their shoulders and off their heads. They were very lucky; the Lucky Dragon had a good name. They were very lucky because if the bomb had been bigger, there would have been more radioactivity and it would have killed them. As it was, it did not. Only one man died, and I think he died of a blood disease.

Well, the story of the Lucky Dragon blew the lid off secrecy, because the Atomic Energy Commission could not keep it a secret. This story had to be told. Because in my thinking, in the history of weaponry, we have an unusual situation in which the weapon’s area of destruction is measured in thousands of square miles. A 15-megaton bomb is only ten times more lethal in terms of its striking distance than the Hiroshima bomb. Here was a tremendous change in warfare. In addition, there was a persistent effect of radioactivity with long half-lives that persisted and could deny territory to normal use. Furthermore, there was the fact that some of the chemicals in the fallout were highly toxic fission products, and this means that strontium-90 could be a health hazard.

This, to my way of thinking, represented a historic change. Events like this bisected human history. Anything before was pre-atomic and anything after is normal, so to speak, but it was not. It would have been normal, except for these weapons. Now, these weapons have kept the peace for many decades, but we now find ourselves in an utterly new situation with regard to hostility of other countries.

I think that the one lesson that we have to learn is that there can be no more strategic wars, because the weapons have such power, and they are so complex in their physiological effects, that we have entered a new era. These weapons have bisected human history. The future requires that we do not use nuclear weapons in a hostile way. Now, it is easy to say, but extremely difficult to do.

On the bright side of things, I would say that the A-Bomb development showed us that our technology is tremendous. We can do things that we have never thought of or dreamed of doing.

I think in particular, I recall an event during the war. We worked at the University of Chicago. The mathematics building was where the Met Lab was centered. My laboratory was on the first floor right next to where the elevator came down. The elevator connected the first floor with the upper floors, which had Enrico Fermi, Leo Szilard, Arthur Compton, Robert Mulliken—all Noble Prize winners. Leo Szilard was not one. But I used to keep the doors to my laboratory open at night. We worked seven days a week, eighteen hours a day. I was blowing glass and I had to have ventilation.

The elevator came down and Eugene Wigner—a Nobel Prize winner—looked at me and came in. He said, “I thought you would like to see this.” It was a black envelope stamped “Secret.” “Prototype Design up to 500,000 Kilowatt Reactor.”

Six weeks earlier at Stagg Field, the United States triggered a chain reaction, which generated half a watt of power. Half a watt. These are kilowatt—this is a kilowatt here. Half a watt, and they were proposing to go a billion times more in power.

Now, we did not tell the University of Chicago what we were doing. The work was confined to stacking up graphite and uranium, tons of it, to see if the chain reaction would work. There was not a bomb; it was an apparatus—a reactor. We had no other name for it. We called them a pile. Now we call them reactors, but that was undignified in those days.

So to think that we could jump from such a flicker of flame—the reactor—to something a billion times more, and build it in less than two years, is really fantastic. It shows the enormous power of organized science and technology.

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