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Dee McCullough’s Interview

Manhattan Project Locations:

Dee McCullough began working as an instrument technician at Hanford in early 1944. As a former sound engineer, McCullough was tasked with installing nuclear safety monitors on the reactors at Hanford. McCullough, who worked closely with many of the famous scientists at the Manhattan project, discusses his interactions with Enrico Fermi and Leona Woods Marshall. In addition, he talks about the various safety methods DuPont put in place to protect their workers.

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


[Interviewed by Cynthia Kelly and Tom Zannes.]

Dee McCullough: I go by my second name. My first name is Jessie but I go by the second name, which is Dee. D-E-E. My last name is McCullough. M-C-C-U-L-L-O-U-G-H.

What was your job here?

McCullough: Started out as an instrument technician, became a supervisor, instrument supervisor, and then ended up as a senior engineer. I don’t recall the—I think they had several engineering jobs. Each time—I worked for a good number of years and retired and was brought back to follow a job for—a remodeling job, so they elevated my position. And then I retired once again and came back again to cover the write-up of the project for renewing N reactor for another twenty-five years, which was then reduced to ten years and cancelled together. So at the time they cancelled it, then I retired from the last time. 

How did you first hear about Hanford?

McCullough: I was working at the Utah Ordnance Plant as an instrument technician when I inherited the patrol radio system. I maintained that and worked for a fellow that had charged the telephone office, telephone exchange. And then when they indicated that the plant was going to be closed down due to the fact that there—other factories making more machine gun shells and what could be fired, they—even though the war was still going, they closed the plant down, and said that I would be transferred. 

I could either be transferred to Hanford, and I said, “I’d rather stay here and follow the shutdown of the telephone system.” They said, “Oh no, we’ll get older men to do that. You either go to Hanford or go to the Army.” So I went to Hanford. [Chuckles.]

What did you find when you got to Hanford?

McCullough: I arrived at Hanford in January 3rd of 1944 and was taken by bus at the Pasco depot, brought out to Hanford, and there went through long lines of sign-up. And the fellow that was escorting me bypassed all the construction workers to—so I wouldn’t have to stand in the long lines. And I was signed up, assigned to a barracks at Hanford. I spent about three weeks in the barracks there.

And one of the experiences I had there was, the fellow I came with said one night, “Let’s go to the movie.” They had had a movie in a tent up until that time and they just started up a movie—permanent movie house out there, so we went over there for the opening night, stood in long lines waiting to—at the ticket booth. Usher came by, asked me—told us that there’d be a delay because they’re having trouble with the sound system. Well, the fellow I was with said, “Well, you’re a sound engineer. Why don’t you tell him?” I’d been a sound engineer before I went to Utah Ordnance Plant. And so I said, “I won’t bother.” 

Well, the next time the usher came by he told her, so they brought me into the booth, went into the theater, took me to the door to the theater—to the picture booth, and yelled up that they had a sound engineer down there. And, “Well, we don’t need any. We’ve got one from Seattle.” So they said, “Well, go in and sit down. Buy your tickets and go in and sit down. There’s no use you’re going outside.”

A few minutes later here walked down a man down the other aisle which I knew. And he’d been a competitor of mine at the theater supply house I worked at before the war. So I yelled his name and he turned around and said, “Dee? If there’s anybody I want to [laughter] see, it’s you tonight.” [Laughter.]

So my experience at Hanford was to go with him and we used voice wire phones and rang out the lines, which had been extended. And the color codes of the lines going to the speakers were different than that going out of the booth. So we rung out the lines and had a show going very shortly.

So that’s my experience with Hanford, other than the fact that we could have our dinner there in an eating hall that settled 2,000 people per building. And we could go in and they’d lead us down seat by seat, feed us all we could eat, and if we emptied the plate we raised it up and they’d come and pick another, take that off, and restore it so we could eat all we could eat for sixty-seven cents. So I stayed there for about three weeks and moved into the first dormitory in Richland.

[Question off-camera.]

McCullough: I was told to buy two books. The second one was on the—for laboratory experiments and university, covering measurements of alpha particles and gamma rays and that sort. So I knew that I’d be working with something involved with gamma and alpha particles and that sort. Then I—first work was in the 300 Area and I added a test reactor.

When I first had my first lunch in the 300 Area, I was brought in from Hanford for a monthly sightseeing tour, but they introduced me to the engineering department and they made all drawings available to me regarding instrumentation, especially in the thermal test reactor. So I went to lunch with a fellow that had come up from Utah earlier—from the Utah Ordnance Plant earlier, and he said, “Well, I don’t know why you can’t go into that building.” He said, “All they have is a big U-shaped piece of concrete that—people came out from Chicago telling us how close we had to make holes in the back face of that concrete.”

Well, it turned out to be the walls of the thermal test reactor in 300 Area. They filled that reactor area with graphite, with holes through just like we do in the present reactors. And we would fill those holes with uranium slugs, and we would measure them with test instruments that we had. In fact—I maybe got ahead of myself.

At the—before we started to load, I was assigned to all of the installation of the three nuclear safety monitors in this other test reactor. They were—the circuit diagrams for those amplifiers is completely different than what I was experiencing in theater equipment. But anyway, we installed the three and—with chambers underneath the reactor, with ion chambers, that fed these meters. 

These meters are micro-microammeters, or picoammeters. They were used to measure one millionth of a millionth of ampere. And we had a problem with them that if we moved the signal cable to it, the meters would go full scale and back. They were so sensitive that, any static charges, they would cause problems.

Well, my later experience, I’ll go to that after. But we loaded this reactor partially, take measurements. And the physicist that was there, which—I don’t remember his name—said, “Oh, we need more fuel.” So they loaded more fuel in and finally we got to the point where he said, “There’s sufficient.” And we said, “What power are we getting?” He said, “Oh, about 1000 watts.” [Laughter.]

So they closed down and let the construction come back in and put cement blocks on the front face and had it enclosed. The reactor was built with a scaffold that would feed a channel of either graphite or fuel elements into the reactor, so we would set the measurements so it would be reading normal. Then we’d insert a channel of either fuel or graphite and watch the effect of it, and that determined whether the fuel was pure or what the purity of the fuel or the graphite, which we were testing.

So the primary purpose of that reactor was just to determine the purity of what went out to the big reactors at the plant. The problems we had was static problems. I was given ten of these instruments, micro-microammeters on the wall in my—the instrument shop, and my job was to try to determine what the—what was causing the static installation problems that we had.

Was this at the test reactor or the B Reactor?

McCullough: At the test reactor. 

And that was—

McCullough: That was a few months after I was there and—in fact, about the second month. Then I finally made several changes and the supervisor come in and he flipped it like a—flipped a fluorescent light on and off, and these meters fluctuate. And he said, “What have you done to this one?” And I said, “Nothing.” He said, “It’s more stable than any of the others.” So then we finally went—did more tests and finally—when we decided what it was, it was a little wire-wound resistor. That’s only two ohms in resistance wrapped around a—either, I guess, a metal spool along with some other resisters in it. By putting a very large capacity across that little resistor they would settle it down considerably. 

So we decided what we would do was rewind that resistor, instead of winding it all the way around one away, we wound it halfway around, then turn it back and run it around to make it non-conductive. And then, when we got to this one that was from the stable one, we found that the wire had been—the resistor had been wound by a wire considerably smaller in diameter than the others so it took far less turns. So then it verified the fact that we had found it. So then we had the Deckman Company in Los Angeles make those changes, and the amplifiers for the ones that were out to the plant.

When did you get involved with the B Reactor?

They sent me to the Deckman factory for three weeks in April of ’44 and after that I was sent out to the B Reactor, so that was in the early—May of ’44. And there I followed the installation of these Deckman instruments. And they’re not only used in the nuclear safety system, but they were also used as area monitors around the building and also around the area. But they were—the chambers that supplied the current was located underneath the reactor.

The reactor stands on about ten feet of concrete—or twelve feet of concrete—excuse me, twenty feet of concrete, and there’s channels going underneath through that concrete, and then from those channels there’s chimneys going up to the bottom of the reactor. And we’d place these chambers underneath these chimneys. And then we’d check the response, or we put a strong radium source in the reactor—that was before any fuel was loaded—and determine the sensitivity of it. We decided the chambers were too sensitive, so we pulled them out about halfway so they were only halfway exposed, and decided that would be sufficient to take care of the installation.

So then they started loading fuel. When they loaded fuel to the point where they started to turn—well, actually they loaded fuel so far ‘til we had activity, with no water going through the reactor. Then after we got to that point where we thought—what we called “dry critical,” that’s what the scientists—Enrico Fermi and such—figured it was dry critical, then they started water flow to the reactor, loaded the reactor the rest of the way with fuel.

And I might say that the early design was to only have about 1,300, I think, fuel elements, and the—or fuel channels—and they loaded them up and started the reactor. Then they got involved with this xenon poisoning which—the reactor level was starting to go down, meters began to go down off scale, so Enrico Fermi asked me if I could—he says, “I can only bypass one of these four channels at a time. Do you know which channel belongs to this meter?” “Yes.” “Well, you go down there and remove that one—restore that one to the reasonable position.” “Okay.”

So I went back and yes, that was all right. Now I’ll bypass number two. Well, those—we were still having trouble with the signal cables, removing them, so I had to make sure that I didn’t touch any cable underneath the—that went underneath the reactor except the one that I was supposed to. But anyway, we did that for all four instruments that was there. So that was my experience with Enrico Fermi.

So you’re telling me he came out for—

McCullough: Yes. He was following the instruments at the time that this was taking place. Now, we also used similar chambers for the galvanometer systems that were at the small lights that went back and forth across the screen for the operator to use, to determine power level. So those chambers—and we had similar problems with them that we had to work with. So that was my involvement.

What kind of a person was Enrico Fermi?

McCullough: Well, I never had too much experience with him, except just talking to him at that. But he was very, as far as I could say, personable. Now, when he came out here he was called Dr. Farmer. And I had to have somebody from—that came from Oak Ridge said, “Oh, we knew him as Enrico Fermi back there.” But out here it was Dr. Farmer.

Tell me about Leona Woods [Marshall].

McCullough: There’s John Marshall and his wife—prompt me on the name.

Leona Woods.

McCullough: Leona Woods Marshall. She had a twenty inch slide rule that she did all of her calculating for these other engineers, the—John Marshall and John [Archibald] Wheeler and somebody else, I think—oh, Enrico Fermi. Those three engineers or physicists were there and she supplied all of the calculations for them, that I can remember, but she sat in the room right back of the—I can remember her working. [Laughter.] I was familiar with the ten inch slide rule but I never had seen a twenty inch one before.

She came out with them when the reactor first went critical?

McCullough: Yes. And I have a booklet—“Hanford History,” I think— that she has an article in there where she said that she and the other physicists were standing on the back wall, I guess in front of the panelist system, watching as they started up. And when they were dying down, they were all laughing, making comments about—well, they were trying to determine how long it would be before they could determine what was wrong and when they could getting started. And these physicists were making bets with one another as who would be able to find the problem and start the thing up again.

How long did it take?

McCullough: Well, that shift I went off and the next morning I talked to another instrument shift supervisor that had been a neighbor to me, and he said they started it up, so it was over the night and they started it up.

Had they analyzed the xenon?

McCullough: Yes, and what they finally had to do was determine that they had to have more power—more fuel elements—so then they went and they ordered the full 2,003 channels of fuel. But the early engineers—early studies said it only needed—I think it’s 1,300. But the local designers decided, well, we’ll just go that much more to take care of any possibilities. So it was good thing they did.

Does the name George Graves mean anything to you?

McCullough: I think so. I can’t remember all of the names.

Tell us about the safety.

McCullough: The early design of all of the reactors here was—they were very serious about safety. And our control rods were hydraulically operated by oil hydraulic pressure. Well, as you come into the control room, the room right before that you’ll see three big tanks that were filled with heavy rock. And before the reactor would start they would pressure them up, raise them up high, so if we lost power to our hydraulic pumps, these big tanks that supplied the hydraulic pressure to operate the rods. So that was one of the main safeties.

The panellit gauge behind us is the—another one that monitored the flow through each process tube, not on the total flow, which we also had—monitoring for total flow, that would— loss of flow would shut it down, but loss of any flow through any one process tube would shut the reactor down. Therefore we had 2,003 of these tubes all with little mercury switches in them that, if one of them would open circuit, the reactor would go down. So we had to do—be very careful to maintain that very well.

And above the reactor there was safety rods, twenty-nine of them hanging up above, and they would fall by gravity into the reactor. And if we needed more safety, then they could release the catches on those and drop those twenty-nine rods into the reactor, to shut the reactor down. Then again, safety after safety. 

They said, well, in case of an earthquake, that would cause those channels to be disrupted, so these rods wouldn’t fall in. So they provided a boron liquid solution in tanks above the reactor. So if the rods wouldn’t work they could dump that solution into the reactor. Well, we never had to use that, thank goodness, but before long they replaced that solution with boron balls. Small, three-eighths inch diameter balls, that were boron that were up there so they could drop down. We’ve had to use them a couple of times. They could be vacuumed out.

Can you talk about the reason for the balls?

McCullough: It’s just a third safety. The control rods here, the vertical safeties, and the boron balls. And of course we protected ourselves by lots of water. If a fuel element should expand and cause the water to—floated—would stop going through a tube, then we’d get a low flow trip on a panellit gauge. If a channel, fuel channel, should break and allow water to go into the reactor and cause a high flow, then a high flow trip on the panellit gauge would shut us down. So they had—

Is there some aspect of the B Reactor that you think we ought to know about?

McCullough: Well, we started out with a maximum power, if I remember correctly, about 150 megawatts. And one day, came in and I said they had an excursion run up above that. We got to remove all the charts and put new charts on because we didn’t want to show these at high level. And so then, of course, later on advancements went to the point where I think these reactors were operating—instead of 250, they were operating at 1,000 watts or more. But just the fact that we were able to change the amount of flow and other features that would allow us to get more flow, more power.

Is there a technical feature that stands above all others?

McCullough: I’d have a hard time—we had more problems with the panellit gauges. These pressure monitor gauges back were causing SCRAMs than any other system, because the little mercury switches and all. So in the N Reactor, we replaced the pressure monitor with an actual flow monitor. These pressure monitors read the—took their signal off from a line beyond an orifice in the process tube, so it was only reading the downstream pressure. They had to keep the pressure from the pump building constant in order to make them work. 

Well, at that N Reactor flow monitors there was a complete differential pressure type device. We didn’t have that problem, so I had to do with the development of the flow monitor for the N Reactor.


Copyright 2012 The Atomic Heritage Foundation. This transcript may not be quoted, reproduced, or redistributed in whole or in part by any means except with the written permission of the Atomic Heritage Foundation.