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Lawrence Denton’s Interview

Manhattan Project Locations:

A native of Northern Idaho, Larry Denton was recruited by his father to work on the B Reactor in Hanford, Washington. At the age of twenty-one, Denton served as a shipping clerk, where he received and issued welding gases. Later on, Denton worked as a reactor operator at B Reactor. In his interview, Denton discusses everything from safety measures to recreation activities to segregation, and offers his opinion on the decision to drop the atomic bomb.

Date of Interview:
September 1, 2003
Location of the Interview:


[Interviewed by Cynthia Kelly and Tom Zannes.]

Tell us your name.

Lawrence Denton: I’m Lawrence Denton, later named Larry when I came to Hanford. L-A-R-R-Y, D-E-N-T-O-N.

How did you get to work on the Manhattan Project?

Denton: I got to Hanford via my father. I was living in northern Idaho and working in a lumber camp, and I had an accident and cut my leg pretty bad. And I left the lumber camp and I called my father, who was down here working as a patrolman, and he said, “They’re hiring, so come on down.” My father was here because he was a Marine in World War I and chief of security was Mr. Lubenter, his captain in World War I. And he went around and saw all the hospitals and brought the able-bodied guys to come over and help him out until he could get his security forces going.

And so that’s the way I got to Hanford, and I was pleased with everything I saw here. The work was steady and there was more safety than working in the lumber mills, in lumber camps and lumber mills. In fact, it was demanding that you worked safely and did your job—didn’t guess. You did what you could do, and if you didn’t know what you were doing, you got somebody to help you.

So not being eighteen—twenty-one years old, I was unable to come to work out in the reactor buildings, or confined areas. I was assigned a clerk’s job, which was called a shipping clerk, but I was receiving and issuing welding gases. We issued somewhere around a million containers of helium and oxygen gases. And I ended up living in the barracks, in 52-B, in Camp Hanford. 

One of my roommates was a historical [inaudible] himself. He was a professional welder out of New York City. And they recruited him out here to do the—to teach the welders on the reactor because they knew that when they met a weld it had to be a good weld and last forever. And that was a gentleman by the name of Otto Lowers.

I went from the gas part to tearing down Camp Hanford, and shipping off all the construction materials that was accumulated here, which was miles and miles of piping and valves and big milling machines that were to—used for milling the graphite for the reactors, which I didn’t know anything about at the time. None of us really knew what was going on. We were totally amazed at all the stuff that was coming in. And the stuff that was going out was never used, so we weren’t producing anything. We didn’t know what was happening. But the DuPont Corporation did everything to have peace and harmony in the camp that I could see.

But one of the things that I couldn’t understand—there was a boy out of northern Idaho—I’d never been around black people, and they had black people segregated from the whites. That didn’t make sense to me. In the Christmas time when they—postal department was overloaded—they took us clerks and asked us if we would deliver mail. And I got the colored barracks and they still—confounded me more, why they segregated blacks and whites. But that was a fact and they accepted it and the whites accepted it.

They built a big theater and big rec hall for our entertainment, and we had outdoor theaters; they weren’t too good sometimes in wind storms in the outdoor theaters. You had to sit there with goggles on to watch a movie, but it was something to do. And then we could walk up to White Bluff and get an ice cream cone. Why, it was only two miles.

But it was an amazing experience for a man from northern Idaho to come into a camp of 50,000 people going day and night. The big mess halls, we would go in—meal tickets were almost nothing. Wages weren’t very much but they were great then: a dollar an hour, ten days a week—or six days a week, ten hours a day. It was a lot of money to us. And, like I said, they insisted on safety.

Then, as the construction ended, I did get transferred, I was twenty-one, into fuel fabrication in the 300 Area. And I was in on several experiments on improving the fuels down there that would be less fracturable and cause less problems during the radiation process in the reactors. And I learned those processes, and later, in 1948, was transferred out to the 100 F Area. And I got my operator’s category—or what do you call it—assignment and worked there for a year, and then I was transferred around to other areas. I went to B Reactor and was over here for a few months and then went back to H Area for the opening of H Area, and then to D Area, then back to B Area as a control room specialist.

And then I—in 1960 I went into the water department and became a supervisor of the River plant in the river pump house and head house, and then later on became supervisor of the power house. I never did get into the electrical end of the power department. And that was a substation out here all of its own, and they had the Bonneville power people transferred in for most of that. But I was, I guess, pretty much the relief supervisor for—after my tenure here at B Reactor, and then I served in the other power houses in all the areas. 

Then when they started shutting the reactors down my crew shut down D Reactor. We went out and locked the gate and the next day we reported back over to BC [100-BC Reactor] over here again.

And in this time, in the ‘50s, we had to become certified. It was, I guess, recognized by the Nuclear Regulatory Commission as capable of running reactors safely and I was—received the first reactor certification that was issued. And when the reactors, like I said, shut down, we dispersed and had to re-certify for other reactors. We were certified for C Reactor. And then when everyone closed it down, I went to N Reactor as a fuels manager, and then I transferred down to 300 Area to do experimental work, back on fuels again.

And I had to [inaudible] compaction process development, and then they assigned me to the zirconium production parts for N’s fuels, and we made the cladding and a lot of the smaller components and supplied the production line with materials. Then I became manager of the essential materials for United Nuclear, which was all the heating for the reactors and coal, oil, the chemicals required. And then I came out as manager of the—or, technician in the maintenance and surveillance, and became manager of maintenance and surveillance until my retirement.

You mentioned you were involved in tearing down the Hanford camp. Was that after the war?

Denton: No, it was at ’44.

In ’44.

Denton: We left Camp Hanford in Christmas of ’44 and moved to town and finished it up in the spring of ’45, before the war ended. 


Denton: Finished up our work as—

The camp?

Denton: Yes, it continued on, I understand, but it was all sold to different contractors and they took care of the rest of it. In other words, the camp was sold on a bill of lading to them and it was no longer government property. 

What did you do on B Reactor? 

Denton: Well, first job at B reactor was just a regular reactor operator. And our job was to pull duty in the control room. We usually had an hour, depending upon the supervisor, an hour to two hours at the console, and then we had to do the other duties around the control room for two hours, like reading the panellit board, taking the temperature maps. All this work was done by hand or mouth and there were Underwood typewriters at that time, so it took quite a while to read the tube pressures of the panellit board. You had to read one panel on graveyards shift, day shift, and the other one on swing shift, and you had to check to make sure that there were no changes.

Or if there were changes in the pressures, you had to find out what caused it, whether it was a total change in the supply pressure to the reactor, what it was, and you had to follow the physicists’ instructions on the rod configuration in the reactor to get optimum production, or follow the megawatt limits that you were required to operate at. And you didn’t have an automatic calculator to tell you that, so you had to do your own calculations on a Marchant calculator. So what levels you were at or—all times, and then you had your other—the reactor Beckmans that—if you got up to a level and the—you held Beckman to a certain curve, you probably weren’t going to change level. So you did have more than a feel—more than something to go feel for where you were at.

But you also had to keep track of the tube temperatures, and this was at an old telephone keyboard. The maximum tube temperature that I ever remember was ninety-eight degrees centigrade. And the only way you could tell what you had was just to go through the whole board and call off the numbers and temperatures and have the other guy write them down, and you checked the map to see where your heat spots were. The reactor would not raise a constant level all the way across the reactor and up and down; you’d have hot spots in various places and you had to readjust your control rods to take care of those conditions. Later on, when they got—in Cold War—do you want to go into that?

Let’s stay on B Reactor for now.

Denton: Anyway, they got to pushing the power levels and then we started having heat cycles where the heat would cycle around in the reactor. And we never really knew why, but it was a neutron production change and that caused a lot of problems when you tried to get total operating efficiency out of the reactor. When the reactor shut down, which was—if it was an unintended shut down and you couldn’t find the reason—if the reason was explainable, and it was safe, then you could start up your reactor.

And they had a limit there; you could raise your power level fifteen second periods and what that meant was you could double the power level in fifteen seconds, because the reactivity would be going away from you, in that instance. In a cold startup you had about a sixty—thirty to a sixty second period startup, but you—that was safe because you knew the xenon effect was going to get you. And what the xenon effect was, was that when you—reactor—when the reactor was first started up, here in B Reactor, they were operating around, I guess it’s somewhere around 100 megawatts.

And they started celebrating, and then the operator started to put in fuel rods, and nothing’s happening, and they went into big disappointment and the reactor died. Actually lost all reactivity and they—Mr. Fermi, I guess, into that room there behind me with his slide rule, and he was in there for a few hours and he came out with the answer that “The old girl just laid down on us and she’s coming back. She’s had her pups and she’s coming back and getting on her feet.” And we recovered in here for too long, so they just kept a watch out and sit here and waited. And they had the affirmation that—reactor was starting back up. So he called that “the xenon curve.”  

And so we had to—they had to figure out ways to get around that because that was a loss of production. And so they developed an enriched metal and they would charge the reactor with enriched metal and then they’d put in poison spines that they could offset the enriched metal. And when you get up to the turnaround period, which was a xenon curve, then they’d go out and pull the spines out and maintain our level without a shutdown and just keep operating.

And we could go into maybe whatever the operating period would be, thirty days to forty-five days. It wasn’t real long, in any instance, because your metal would reach maturity and—not total—but certain tubes would reach maturity and then they’d go up and discharge those. You’d shut the reactor down and lower the water pressure after the reactor cooled down. And the reactor was built with wondered redundancy. Everywhere you look, everything was failsafe as far as the reactor construction is concerned, that I could see.

The water supply was abundant, and it was in the 190 Building across the street. And it was stored in four big wooden tanks, about a million gallons a piece, and they were elevated to the height that—top tube of the reactor. And the only way the water could get out the reactor was to go in at all points in the front, and it escaped over the top, which they call a cross-header overflow discharge into a down-comer, which accumulated water to both sides and out the rear. 

And if the water supply failed, they had steam backup system and the—before that they had two 300,000 gallon high tanks, one on each side of the reactor. And the supply line checked off and closed and the high tank valves would open, Masoneilan valves would open, and allow water into the reactor until these last-ditch system could get online. And that was supplied by steam turbines in the 190 Building.

The four-boiler powerhouse had a turbo generator that would hold the electricity up for them to get their steam up and get their controllers turned over and then the 190 turbines would come on. And another thing that I failed to mention, they didn’t—in an event of a water failure, the 5,500 horsepower turbines in the—electric turbines in the 190 Building had two-ton flywheels, so that when you do lose your water pressure, they would continue to supply the water until the high tanks could come in and take over, and then the last-ditch system would come in.

And the last-ditch system was not filtered water. The water plant supplied three types of water: the processed water, potable water, and system water, which they used for literally everything. And the Hanford water system was unique. It was developed at Hanford and the filter systems had two—twelve filters on each reactor. And it was big egg-crate design filters, and they had big boulder—ceramic balls in the bottom of these egg crates because they—

[Tape Switch.]

(Question off camera.)

Denton: Okay, the construction camp was phenomenal as far as I was concerned. It housed 40,000 construction workers in barracks, another 10,000 in the training camp, and people that came from off—the local towns around to work here. They had no facilities, really, to take care of things like that, so they brought in railroad engines and parked them along the railroad track. The Milwaukee Railroad was—extended down into the town of Hanford. And the barracks were heated by steam, and these railroad engines provided the steam for the heating of the camp.

We had a hospital—I think there was a sixty-room hospital, a big administration building, men’s barracks, and women’s barracks. Women’s were segregated from the men in both cases, blacks and whites, and we had a grocery store. And, like I said, we had that big rec hall and we had some of the best orchestras in the world came and entertained for us.

In fact, in ’43, Kay Kyser came in and gave us a show, and in ’44 he came back and he said, “I can’t believe this.” He said, “The sand and gravel and wind when I was here last time,” he said, “The only thing you got now is all this darn safety equipment.” And he had on the toe guards and the shin guards and the clothing that they wore and the mask, and that was typical of DuPont. Safety was the most important thing as far as I was concerned. 

The mess halls—the tickets were cheap and you go in there and sit down. And if you emptied the platter of pork chops you just held the platter up, a waitress would come by, take it, and bring you a new one. And the best food in the world—it was Olympics catering, I guess, Olympics commissary that provided. And they had big rec halls.

And, of course, when you got the rec halls and beer and construction people, you’re going to fall down sometimes. One time I had to go over to get a bunch of bill of ladings signed for the material that was leaving the project, and I had to go past the rec hall. And the fire department was over there with their fire hoses washing the construction workers, hard hats and all, right out in the street. So they could stop fights. But it was an experience that—exciting to me.

The windows were hinged to throw out rowdy people?

Denton: I never heard that one. I wouldn’t be surprised at anything, but not in the mess halls. I never saw a fight in the mess hall.

The rec hall?

Denton: The rec hall, yes ma’am. The hard hat guys would come in, and they still come in from work; they still had the spud wrenches and everything in their belts. And they would each take a pitcher of beer instead of a glass. And so it didn’t take long to get out of order. And then when you—when I came out of there that night, or past there, I was going back to my room with these signed ladings. I had sto get them signed by the railroad man that was in here, and I’m over his barracks, and I stumbled over a bunch of guys playing craps out in the street. There was a lot of illegal gambling going on, you see. The patrol was around trying to break that up when they could. But no, it was a fast-moving life.

Why did they decide to bulldoze it down?

Denton: They didn’t really. They tore it down. They took it and re-salvaged—they salvaged the lumber. They shipped most of the lumber off to different sites around the country; like I remember one place that I shipped a big milling machine to go overseas someplace with a big milling machine to Port Hueneme, California. I shipped stuff to Mississippi. We had a lot of Army and Navy storage facilities around the United States that we shipped stuff to.

But the barracks mostly were dismantled by contractors that bought them. And I had heard that [inaudible] bid on just the air conditioning systems or something that they wanted over there and get the rest of the building around there. They had built this one three-room hospital that was fully furnished, never occupied, and that stuff was all right—categorized at—and I don’t know that that went to Bethesda, Maryland? It went to some place back east; all the equipment, the cots and mattresses and all that stuff.

So they didn’t come in and bulldoze the city down until after the useable material was taken. Some of the barracks were made into barracks downtown, and some of them were made into Camp Hanford and it went to the 300 Area. Or below 300 Area, where Battelle buildings area is now.

Did people know what they were doing here?

Denton:Working their tails off for a good check. They had no idea. I hadn’t met anybody yet that knew what was going on. Mr. [John] Rector said he knew, but I don’t know. He was a machinist of the graphite, but I don’t know. Even Mr. [Dee] McCullough didn’t know, and he was a Beckman developer. Sure somebody had to know. But I don’t know.

There were lots of stories about Mr. [Gilbert] Church being a god. He was the DuPont manager here and he—because of his status and worriedness about what they were doing, I understand they made the reactor work. It was designed for 1,500 tubes and he didn’t think that that was enough and he wanted it expanded. And because he did have it expanded, it was a fissionable product. And that was his thinking all the way through: if there’s a safe way to do something, think of two ways to do it safely. “Failsafe” was his motto, I guess. And that’s what I found here.

And the accumulators here are just in the room next door. In case of an emergency, you lost your power, and the rods wouldn’t go in—hydraulic rods—those accumulators would drop and force your rods in for control. Your vertical safety rods tangled on the first drop that they tested. And he stopped production until they—construction until they got some kind of a winch that would control the drop. And they got electromagnetic winches in it and added onto the height of the building. And those winches could control the drop of the vertical safety rod to get it. It was in a time limit because—to prevent a criticality event.

Then he said, “What if those things don’t go in?” And then they wanted to—some kind of a backup system, a third system, he said, so they made four big tanks up there until the boron carbide solution. And they put symbols around the holes for the vertical safety rods to go in, but the chief operator in here could pull this rope and open these valves and drop this boron and carbide solution into the reactor thimbles.

Well, that was real good for a few years but then the—because of the ruptures and the moisture got into the reactor, those thimbles rusted and began to leak. And then they were leaking hot gases out of the building so they got rid of those and developed the Balls-3X system, which replaced the third safety system so that there were hoppers around the rods and this rod-hopper door would open and drop the ball—3X balls in.

The original startup of the reactor—they had helium—is a total heat transfer for the graphite system, and there was a 115 building out back that circulated the gas through the reactor. Each tube-bearing block was channeled so that the gas could be forced into the reactor in the front and go through these channels to the back and relieve the heat and transfer the heat. And this—once they discovered trouble discharging a tube, and so they—in the far side—and so they got to boroscoping and found out they had distortion. The graphite was growing, which was of grave concern. 

And so they shut B Reactor down for a short period of time and kept D Reactor operating and introduced C02 gas. And they mixed about a fifty-fifty mixture of CO2 and helium, and that stopped the growth of the graphite. And in fact it did retrieve it a little bit, and so they continued using C02 and helium through the whole process.

In about 1949, I think, the government took over the control of helium and started putting restrictions on helium. Before that the helium came in here so dirty we had to—had purifiers over there, and they had to clean it up. Because—once they got the helium storage in Keys, Oklahoma and Amarillo, Texas and they started getting clean helium and we got it in cars and—good stuff. We didn’t have contaminated gases any longer.

But we did always have things to be worried about and we got inert gases around the building—the high power levels and they couldn’t figure out why because we—they knew that they had enough airflow around to discharge the gases in the stack, but it wasn’t happening. So one of the radiological engineers said, “Well, we need to control it.” So they went out to the work area in front of the reactor, C elevator, and dropped a curtain—made a great big curtain that dropped down to force the air down and up the front of the reactor, you know. And that took care of that problem. And later years they had to build a better purifying system for the air instead of just going straight through the stack.

What did people know about what they were doing?

Denton: Well, they were experts in their field of welding and concrete, construction, and they knew how to follow blueprints. And that’s what we came and did, as far as I can interpret your question. The only effect you had out here was your terrible windstorms. People would be—hundreds of people leaving in a windstorm, and other people come in and take their place. But they had to be professionals in what they were doing to machine the graphite to make a block the size that they have, less than—what is it, a sixteenth of an inch tolerance on the whole block of graphite?

So these people did this with carpenter tools. They didn’t have anything made to machine graphite with. And the concrete people were the same way. They came in and built concrete plants. They actually built back plants right here on the project. And this was what was so amazing. You come—go past the place one day and there was nothing there, and the next day there was an industry going.

And they had what they called “the central shops” up on the bluff, up there towards the 200 Area. We delivered some stuff up there one day and I went back the following Monday and it was gone. They moved it down to White Bluffs area. The whole thing was gone. The shops, the gas station, it was all gone, and things just moved around here. So the people they had in here were nothing but miracle workers, really. That’s my synopsis.

Were people surprised when they found out about the bomb?

Denton: Absolutely. Absolutely astounded. Yeah, I was—at that time I was in a ditch, a greener irrigation ditch down by Chief Joseph—or Carmichael High School, and—no, that was D-Day—when they blew the whistles—

When they dropped the bomb?

Denton: When they dropped the bomb was the same thing. We were surprised. At Hanford we were all proud, very proud. We didn’t have a bit of shame. And that’s when they named the high school team the “Bombers.” I don’t know anybody that was ashamed of it. We were ashamed of the killing that had to be done, of course; we were humanitarians, but our boys weren’t going to go through any more of that.

Were there people saying they knew that was what was going on?

Denton: Yes. There—like I said, we were surprised. There were very few people—and I suppose up in the DuPont end of town they all knew. But down where we lived and where we worked, I don’t know anybody that even had a hunch. I thought, because DuPont was in here, it had something to do with explosives, but I had no idea it was going to be anything like that. But we couldn’t figure out, if it was explosives, why they weren’t bringing the stuff in here that looked more like explosive material.

Do you think there was an attitude among the people that, “We’re at war, we’re just going to keep our mouths shut?” There had to be some patriotism involved.

Denton: Absolutely there was patriotism. Yeah, we even bought a bomber, which—we contributed a day’s pay to buy a bomber. They had rallies, [inaudible] rallies around, and I guess we just followed the DuPont attitude: “We’re in a war. We’re going to do our effort whatever it is.” I know I do sound stupid but, [laughter], I was stupid. I didn’t know what was happening and I don’t know anybody that did.

What do you mean, by the DuPont end of town?

Denton: Well, up which they call Hunts Point, along the river there was a section of housing that the DuPont people lived in and the high Army officials lived in, in that particular area.


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