Everett Weakley: My name is Everett Weakley. E-v-e-r-e-t-t, W-e-a-k-l-e-y.
Where did you go to school and how did you get to Hanford?
Weakley: I was hired by General Electric in 1950, right out of University of Idaho, which isn't very far from here, Moscow, to come down here at the height the Cold War. Things were coming up. My first assignment was out on the tritium extraction, which is nothing to do with the old days. I was there for a year and then I was transferred down to the 300 Area working fuel elements. I was there a year, and then went back out to the tritium extraction again, finished that up before they transferred that down to DuPont. Then I spent forty-two years in fuel production.
I'm a chemical engineer and you say, what was a chemical engineer doing making fuel elements? But there's a lot of chemical processes, plus metallurgy is nothing but solid state chemistry anyway. I became kind of a historian of that; worked a lot with Michelle Gerber when she wrote up everything about 300 Area.
So I was working on the changes in the old reactor fuels, starting in '51. Then when they went off and started the one for the N Reactor, I worked on N Reactor fuels, too, till that was over with. We're here to talk about Manhattan Project primarily, and I reviewed a lot of the history of that. I say, was into this business, and when the reactor—in the first ones that [Enrico] Fermi made back in Chicago in '42, in December, got that going—that reactor, the material, uranium, was primarily uranium oxide with some metal.
It had been 150 years before that reactor was built, that they discovered uranium metal itself, the uranium itself. But the process of making uranium was actually very complicated and very dangerous at that time; they didn't have much uranium metal. So when he came up that this is going to work, uranium is going to work, in 1943 they spent about a year developing how to make uranium metal from the ore. Mallinckrodt Chemical Company in St. Louis did most of that work.
They had pitchblende at that time, with the main ore source from Belgium Congo. Well, the war was on, it was hard to get pitchblende in here, so they had to develop to get the ores from southwest part of the United States. That's a different ore than pitchblende, and Mallinckrodt developed that. They started out by making uranyl nitrate, they heated that, made uranium oxide, U03. Then they'd react that with hydrogen, made U02, and then they would react it with HF, hydrogen fluoride to make UF4—called green salt, because that's the color of it. So people in Tennessee at the Oak Ridge process needed UF6. So they would take UF4, react it with fluorine gas to make the UF6 for the process in Oak Ridge. We got the UF4 out here. The process then was to take UF4 and they would mix it calcium metal, which is fairly rare, or magnesium metal.
UF4 is uranium tetrafluoride. UF6 is uranium hexafluoride, which is a gas, which what they needed in a gaseous diffusion plant. UF4 is green salt, they called it, because it was green. And that's what they then used out here in the 314 building. That's where they finally made these—started it. Well, they'd ship the uranium UF4 out here, and they had a process. They put this in a bomb, they mix it up with calcium metal for a while, that was hard to get, and then they switched to magnesium metal, which is a little bit easier to get. And they would mix that up, put it in this so called “bomb,” heat it up and the reactor would be exothermal. It'd take off and you end up with molten uranium which would float to the bottom, it would sink to the bottom, and then the calcium or magnesium fluoride would float to the top.
They would clinch that and they'd come out with what they called the “derby,” about this big around, weighed about 350 pounds. They would take these derbies, a couple of these derbies, and after the process was going, they'd have rod ends that they talked about from machining the cores or and they'd have briquettes from the chips that they compacted. They put all this together in a vacuum furnace and then they would melt that up into a billet, about 1200 pounds.
Then they would use that billet. They’d machine it down and extrude it or roll it, depending on the process they were using at that time. They would either gamma extrude it, which is a phase of above 770 degrees centigrade, to melting as a gamma phase. That was the easiest to extrude in. And then in what they called alpha phase, below 660, and they alpha phased the uranium, they would roll it. They would send that off site to roll it and then the rods would come back. So the early days was gamma extruded here [Hanford].
Now, uranium, as I said, has three different phases. The one up to 660, the alpha phase, is a complicated orthorhombic structure and if you heat that, it changes. It’ll grow in two directions and shrink in a second direction. This made it very complicated for making fuel elements, because they had to control that. So they found out in the metallurgy, looking at the metallurgy, they had to heat it up into what they called the beta phase. The beta phase, between 660 and 770, they would then quench that back down. That would randomize the grain structure so you wouldn't have the fuel element growing in the reactor or making pimples out the side like an old cucumber. It would stabilize the uranium.
Now, in making the fuel element for the reactor, there were a lot of requirements that were put down by Fermi. It had to be processes that you could get commercially. You had to have it clad with something, so they picked aluminum. It had to be bonded, so they'd have good heat transfer between the uranium core and the cooling water. You couldn't have any voids or you'd have a hot spot. And if the water got in to the uranium, it arranged uranium oxide in a hurry and it blows up and you have a failure. You'd contaminate the water, you'd have to shut down, discharge the reactor, clean things up a little bit, and it would delay your production. So they had to have a good bonding.
Now they tested a lot of things here with bonding at the early days. They tried zinc, they found a bunch of other metals, and they had something called a whiz-bang machine which didn't work very well. You probably heard it in the history about whiz-bang. And they finally come up with the triple dip process, which was talked about a little while ago by John Smith.
Let's start with that triple dip process.
Weakley: The triple dip process was developed finally and it proved beneficial. What they did, they took these uranium rods in 313 and they machined them. In fact, my first walk to the 313 Building when I first got here, I looked at all these lathes with the rods and machining them, and there was a fire. Every one of them, there was a fire going all the time from the chips, they were pyrophoric. It was pulling off the uranium oxide, smoke and I thought, “Boy, this is kind of dangerous-looking.” But they controlled the smoke, but it was pyrophoric. So that's one of the dangers of uranium. It is pyrophoric. It had to be protected.
So what they did, they machined them at that time into 8 inch, about 1.4 inch diameter, 8 inch at that time they started out, solid pieces. And so in machining these, they would send one over to the test reactor, which was built and got going in I think February of '44. They would test each one of these rods, make sure there wasn't some impurities in it, boron, or cadmium, or some of the high cross section element that would poison the reactor. So every rod got checked; at least one of them.
Anyway, they'd take these elements, these solid pieces. They would etch them in nitric acid. That cleaned off the oxide, just before they went into the canning bath. Somebody would inspect them for cracks or anything else that was harmful-looking before they put them into the triple dip process. The first bath that was explained was a bronze bath, which is a copper tin mixture and it was up in the beta phase. This was the way they controlled the structure. They got it up into the beta phase and held it there. Then later on in the process, it was quenched back down into the alpha phase. That bronze bath was covered with a flux, a chloride flux. So the bronze would tack and start making a structure on what you call a bond, well, it was a bonding I guess, with the bronze. You'd have a layer formed, of copper and tin, on the uranium.
And then they'd go over and they washed it off in a tin bath, a molten tin bath. Wash off the excess bronze. They went to this centrifuge; they'd whip off the excess tin. And then they went to the AlSi [Aluminum Silicon] bath, where they assembled them in aluminum cans. Now the aluminum cans were cleaned, chemically cleaned, so they wouldn't have any oxide on them, and they were put in a steel sleeve. And the steel sleeve was cleaned also, coated with soap, and then they would put this can in there. They would stick it down in the bath with the can opened—the top—reheat it. Then just before they brought over the fuel elements, they would submerge it.
Then they would stick these coated fuel elements down inside, and somebody else had a cap that has been cleaned, they'd push that down on top of that. They were then taken over to a quench tank and quenched in water, so they wouldn't stay there long enough to melt through the aluminum. So you'd have a good aluminum structure, and that's bonded. And you'd have aluminum, you'd have the AlSi, you'd have the coating of the bronze on the uranium, and you’d have uranium. That was your layer.
When they came out of the quench tank, they took them to a radiograph machine and they would measure off the distance they wanted that cap to be. They could see the uranium. They would measure off, say, it's a half inch, say, and they would make a mark. They would machine that end off down to that mark. Then they put a weld on it to cover up that braze, the AlSi, and mix it with aluminum, so you wouldn't have a porous—brazes are kind of porous, you wouldn't want metal uranium to get down to water contact that would cover up that braze. So that would have a nice welding, and that was a heliarc welding.
They had to make sure there wasn't a bunch of voids in the braze—the metal. They went through something called a frost test. And a frost test, they dipped these fuel elements down into a bath of acenaphthene, which is in carbon tetrachloride. They brought these out, the acenaphthene would coat this fuel, this core, this fuel element, they would coat it, and it looked frosty when it dried. Then they sent that coated fuel element through a duction coil. When the duction coil would add heat to the outside in the aluminum, if there was a void in that bonding layer, you’d get a silver spot. And they called this a frost test. They have a nice spot, and everything else is frosty. So if they'd look at that, if it was a spot there that was shiny, they would reject the fuel element.
If it passed that test, they went to a nitric acid solution to take off—well, before that they had to go through a degreaser, would take off the excess frost. Then they would wash it nitric acid. Rhey went through a weld inspection, and they looked it all over. Then they went through an autoclave, which simulated the reactor, to make sure there wasn't any holes anywhere in the weld bead or any place else. If the water got in to the uranium, it would possibly blow up and you would have a failure in the autoclave instead of the reactor. And that's where they would want those. Not out in the reactor. And then the last thing they did was, they took an X-ray of the weld bead and checked it for voids. And then after that was done, they made a final kind of final inspection, put them in shipping containers and then set them out to the 100 Areas. That's the process, basic process of the triple dip process.
After that we went into other processes. We had to change the length from eight to four when one person said, “The process tubes distorted because the graphite had changed.” And so they solved the growth of the distortion. They stayed at four inches for a few years, then went to six and back to eight. Later on in years we had a lot of six inches, but they were different kind of fuel elements. They had higher enrichment.
When we first started out, we had nothing but natural uranium, .71 % U-235, which is the reactive part. When they started getting some enriched uranium, they upgraded ours to .95. So most of our fuel elements were .95 in later years. And then we had some 1.25 for target elements and some 2.1 enriched for making tritium [inaudible]. So we had ways of enriching but that was later on, after the Manhattan process. Anything else?
How long did it take to make all the fuel elements?
Weakley: It took them quite a while to get a good first batch out. I think it was in something like in June they started really canning, June of '44. And they got the first load, it took them—and then all this business about the whiz- bang and whatnot and trying to develop—it took them a while to get down to the process was safe enough that they would say, “We’ll put these in the reactor.” I think they were out there in about September, they got full load for B Reactor, for instance, which was the first one loaded up.
They did a lot of recycling. Now the cleaning—to recycle a fuel that's a reject, and I'm sure they did, they had a lot of rejects at that time. They would take the fuel element, they had to dissolve the aluminum off and sodium hydroxide or caustic. Then they had this compound layer, which was a copper-tin-uranium compound layer. And they used hydrofluosilicic acid which is a kind of an odd one. That would dissolve off the bonding layer. Then they would put it back through the process of nitric acid, inspect it, and put it back through the process, the core. So they would use those over again. Course, the aluminum's gone.
What percent were bad?
Weakley: Well, it took them quite a while. A hundred percent for several months, until they got the process going. Oh, there was a lot of work out there before they got going. There was a lot of concern whether they were going to have enough fuel, a good fuel, to load the reactor. And they solved this by putting the triple dip process. And there was some frantic work out there I understand. Most of those people that worked on that are gone. But I heard, you know, talking to some of them in old days about the process. Lou Turner worked on it, but he worked at it back East and they didn't come up with that process. It was done here.
What is an autoclave?
Weakley: An autoclave is a steam autoclave that came up with the temperatures and the pressures to simulate—an autoclave is to simulate the reactor. They put up steam at actually a little bit higher temperature than they're going to have in the reactor. And if there's any failure, like a little crack or a pinhole through the cladding, that steam would get through and react with the uranium and blow up. I mean, it would actually just disintegrate. Usually you end up with, all you have is a little bit of aluminum, and all the uranium is in the bottom or is uranium oxide.
That's what they don't want to have out in the reactor. They rather have it down here, so it wouldn't cost you that much. And you clean it up, cleanup the reactor, auto—you know, it’s mess out there to clean up. Here you clean up the autoclave and you're ready to go again. Get the uranium oxide out and recycle.
So it was a big cast iron furnace?
Weakley: It was a very big. They put about five baskets, and then it was probably twelve foot deep and would go down into the floor. And it was with steam, high pressure steam. And it set in there for hours, several hours, until they got up to temperature. They'd bring them out, cool them off and then inspect them. Once in a while there'd be a small hole and there’d just be a bulge on the side. Most of the time it just disintegrated the whole—all the uranium, it'd be gone. But that was just to protect the reactors.
Did they try various cladding materials?
Weakley: Aluminum was picked because it's commercially available. They didn't have zircalloy-2 at that time, it wasn't even available. And so that was the cheapest and less cross section material they had. It had to be commercially available. And it worked. It essentially was two-S aluminum.
Later on they had twelve, fourteen alloy, which was kind of an iron control. Then they went to M3 at 388, I think it was. That had a little bit of nickel iron in it for the corrosion of the aluminum itself. Now, they controlled the corrosion of aluminum by controlling out by the 100 Areas, the water treatment. They would treat the water so that it wouldn't attack the aluminum quite so bad. That's where the sodium dichromate came in. You probably heard about it when you talked about the reactor. That was to control the corrosion of aluminum cadmium.
Characterize what was going on at that time and what the atmosphere was like.
Weakley: Well, we kept making improvements as we went for years. Right up to the very end, even when I was in N Reactor fuel, we tried to make improvements for increasing the production, increasing the quality, throughout. We had to. That was just the way it was, a way of life.
We would change the process. We went from the triple dip to the lead dip process. We were able to do that because we heat treated the fuel elements in bare form before they got in to the—didn’t need a triple dip bath and they didn't need that bronze bath as up in the beta phase. Because everything was in the alpha phase then. Like right around—less than 660, about 590. So we were able to can everything in the alpha. Then you could make a larger fuel element, because there was some distortion when you beta heat treated. So you have a little bit more uranium per foot in the reactor. That would up your yield. Then they kept changing the power of the reactors, up and up and up and up, the temperature.
Can you explain the beta and alpha phase?
Weakley: The alpha phase is up to 660, you got an alpha phase. An orthorhombic, very complicated crystalline structure. You heated that, as I said, two directions it would expand and one of them would shrink. And when you extruded, those grains are all oriented. If you did not heat treat that, that would blow the cap off in the reactor. Either blow the cap off or it would punch holes out the side like a cucumber. It was a pickle, you know, out of cucumbers—out the side. And so they had to put it up into the next phase, which is the beta phase, and then would quench it back down, and that randomized the grains.
And if you went far above 770, you're in the gamma phase and that's the phase that they like to extrude in, because it was easy extruding, like extruding toothpaste, almost, compared to back in alpha. Alpha they rolled. They rolled them in alpha, but they extruded them in the gamma phase.
So you had to have it at a certain temperature?
Weakley: Only above 770 and below the 1130, which is the melting point. In between there was the gamma phase. Somewhere in there, you would do the extrusion.
Can you describe the extrusion presses?
Weakley: Those were done back—well, we had a few small ones here. Extrusion press, they have a billet and it goes down through a die till you come out to the size of, say, an inch and a half. Which is the rod you want to machine down to 1.4. So you go through a die to end up with a 1200 pound billet. You end up with a 1200 pound rod that is several feet long, you know, twenty feet long or eighteen or whatever it happened to be. And it was that simple.
Now they took all these rod ends—they’d have rod ends and machining chips. The rod ends would be re-melded into chips, like Lou explained, were compacted and then they were sent back to the re-meld plant in 314, and goes back in and put in and melded up again with derbies from the green salt part. Then re-melded and then extruded again, or sent off site for rolling. We didn't have the rolling part here, we sent most of those off site for the alpha rolling. But they did do the gamma extrusion here for a while. Now in 1952, practically all that metal working was done at Fernald in Ohio. Everything was done then back there.
The Manhattan Project was done partly at Hanford and partly—?
Weakley: Most of it was done here for the gamma extrusion. If they wanted to roll it, that they sent it off to some other outfit and they rolled it for them. But most of it was gamma extrusion. They did a little bit of both. And they both worked.
Can you discuss the pyrophoric quality of uranium and how that effected the machining of it?
Weakley: The chips would catch on fire. Usually you had water and, you know, water-solvent oil sprayed on them, but you had to watch that. You had to watch that all the way from there on. Because you didn't want to have a fire that shut you down. But we controlled it, mainly by just submersion under cooling water, which had water-soluble oil in it usually. And that would smother it down and control it.
We had very few fires; they had no fires that would shut us down. But we did have a little chip fires from the machining, they had to. No way you could get around that. And later on, many years later, when you got into the zircalloy-2, that was pyrophoric and you had to watch zircalloy-2 from burning, too, because zirconium will burn also in fine form. But the uranium, that was the first thing that impressed me was those fires going in those lathes. I walked through and, huh, you know [chuckle]. But they just sort of smothered them out with the excess cooling water.
Could you say uranium is very pyrophoric?
Weakley: Oh, yes, it is. Oh, yeah. Uranium is very pyrophoric, and we had to watch the—you didn't want the fires going. Especially the fine [uranium]. The finer it is, the more pyrophoric it is. If you have a real fine powder, it'll catch on fire spontaneously. But a chip is a little bit harder. You have to have really the action of the heat of the machining it to get it to start.
Can you tell us about Du Pont and how they laid out specifications for the fuel rods?
Weakley: Well B Reactor and the other old reactors were fixed as far as the size of the tubes. The size of the tubes then said how—and then how they had to have much water—the size of the fuel element, which is about 1.4 inches in diameter, in that range and the length. Now those were the process that they gave them, that they had to work with. And they had have, of course we talked about, they had to be clad in aluminum because that's the only really commercial thing they had available at that time that would really work and low cross-section. They could not have any high cross-section materials around.
Everything that went out to that reactor practically was checked in the test reactor in 305 Building, to make sure they didn't have impurities such as boron or something like that that was high cross section elements. And as I said before, all of our fuel rods, that one fuel core was checked in the reactor to make sure something hadn't got in accidentally and contaminated the uranium with a high cross section material. And boron was one of the biggest ones, of course, they had to worry about.
But they had to make that fuel element and to protect it from the water and it had to be bonded, etcetera. They tried a number of different things. One of them was zinc and that didn't work. Then they finally the AlSi process came up, and that did work. And as Lou Turner was saying, they were trying things back at the same time in Chicago, trying to come up with a method of bonding that. It was developed here finally.
Was the fact that some the rolled and some they extruded an example of this?
Weakley: They did not extrude them in the beta, they extruded them in the gamma. And they rolled them in the alpha. It was easier, because it was easier to roll something in the alpha phase and it's easier to extrude it in the gamma phase. They did not try to work that in the beta phase because you only have 660 to 770, which is too short a range to work in. You'd be going back and forth. That's where you went in and heated it to change the structure, so it wouldn't deform in the reactor. When you got done canning, in the canning process.
They tried both?
Weakley: Well, they were trying both, yeah, right. They used a lot of gamma extrusion out there when they first started in 314 Building. Later on they went to alpha; that was off-site. And then when they went to Frenald, they went to the alpha rolling process. But then at that time, they also changed and they heat-treated the cores before they came to Hanford. The cores were heat-treated by themselves back up and then back down, and we didn't have to do that. That's why they changed the process from “triple-dip” to what they call “lead-dip.” That cut out the part—made the canning line much simpler.
They only had two canning pots, a lead-dip covered with AlSi and it was less than 660, and then a canning pot. And so it was a lot easier and it didn't grow. The uranium didn't change shape and so you had more uranium per foot than you had before, because you make the diameter of the uranium a little bit better than you waited for the distortion of going into the beta phase. And so that's one of the advantage of why we switched, but that was not until the early ‘50s. Long after the Du Pont.
How many lines did they have at once?
Weakley: When I came there, like I said, I think there was about two and then shortly after that we end up with six canning lines—had an expansion. But that was primarily when we went to change of process to lead-dip. We had six lead-dip processes going. That was early in the ‘50s, and we put out 6,000 fuel elements a day in the lead-dip process, because we had six canning lines, and you got a 1,000 per, so it was a two-shift operation. That's maximum.
Back before that, we didn't have that many reactors, we didn't have the K reactors, and we didn't have some of the other ones that weren't built yet. And that was the maximum. But that was lead-dip process. Triple-dip—there wasn't that many. Like I said, there were about two canning lines. It was slower. I was there during the transition when we were going from triple-dip to lead-dip.
During the Manhattan Project, were they able to keep up with the demand for new fuel elements?
Weakley: They had trouble at first, and then they got in the swing of things and they had no problem of keeping up with the production.
How'd they get the slugs from the 300 Area to 100 Areas?
Weakley: Well, they didn't send the slugs out. They sent the fuel elements out in cans. The slugs were the bare ones. They were shipped out in boxes, in shipping containers in a truck. And they shipped those out in a truck, had spacers in there. They shipped them vertical and filled up a semi-truck and out they'd go. Then they'd unload them and bring the empty boxes back and they'd fill them up again. I don't remember how many, 100 and some I think in one box. But they were just little pigeon holes set in there. They wouldn't hit each other.
Was there any concern about criticality?
Weakley: Not on this enriched uranium. There was no criticality of problems in shipping [laughter].
A question was brought up: is there a problem with criticality in shipping these uranium fuels out? No. There's no criticality problem, unless you had a reactor wrapped around it and it's hard to get one of those in—that there's a lot of tons—so we had no critical problems in shipping fuel elements to the 100 Areas in shipping boxes. You'd have to have very highly enriched product to have any criticality problem in shipping out to the 200 Area, or 100 Areas. And you'd have to have space, you'd have to have moderators and so on to make it critical and you’d have to have tons of it, in the early days. If you have highly enriched then you'd have to worry about criticality, but we did not have that in the early days.
What was the composition of the fuel elements?
Weakley: The only thing we had when we started with the Manhattan Project was natural uranium and it's only got .71% U-235, which is what goes critical. So there's no way you can get that stuff to go critical without putting a reactor around it. After they started getting some enriched uranium in from Oak Ridge, then we went up to .95 was our standard. That still you could not get that critical. We had a few elements up to 1.25 and 2.1 for when they have target elements going in and out in some of the reactors, to make tritium and to make some of the other isotopes that they wanted for their space programs and whatnot. But even that stuff you could not get critical in that form.
We had some elements that were high-enriched aluminum elements that were taken out there in the ‘50s and ‘60s. Those you watched a little bit closer because they were essentially bomb-grade U-235 in aluminum alloy form. We did watch those closer and you could get those—but they were shipped out usually separate in small quantities.
People seem to wonder if that much uranium in one place will go critical?
Weakley: No. It will not go critical if you put all this uranium in one place, unless you have a reactor around it to control it and space it and moderate it. You got to moderate it with the graphite.
What were some of the PPE requirements for handling the uranium?
Weakley: What's a PPE [Personal Protection Equipment]?
What were guys dressed in that were handling and shipping the uranium?
Weakley: The operators normally wore coveralls in our area. They really didn't worry too much about uranium except to wash it off. It wasn't like something that's highly contaminated like say tritium or plutonium of anything like that. So those people had white coveralls on usually, and they would change them back in the changing rooms and that was about it. I wore a lab coat most of the time, but it wasn't that much problem with uranium because it's un-irradiated.
Now back in the machining areas, they had step-off pads and whatnot to keep the people, you know, from getting contaminated and taking it home and whatnot kind of thing. And they would check them out in some certain areas like machining area; make sure you weren't getting your hair contaminated of something like that, but it wasn't that bad. They just make them take a shower. It wasn't like being out in the 200 Areas where you have high plutonium or something like that. Uranium wasn't considered that much of a hazard at that time.
There was a big difference between handing uranium before and after irradiation?
Weakley: Oh, yes. After irradiation, yes, it's highly radioactive. After irradiation, then you have all these other byproducts, these high intensity gamma radiation, beta radiation. Uranium is alpha. Alpha you can stop on a sheet of paper. Your skin stops it. It isn't like something with a gamma or a beta. We didn't get into much of that, fortunately. That’s why we had hands on: you could pick it up, the bare uranium, but most of the time they wore gloves. But if you picked it up, the bare uranium, you still wouldn't get irradiated because your skin would stop it, the alpha.
What kind of monitoring was done on your exposure?
Weakley: They had monitors there in the building and the people had step-off pads where they could check their hands. When they came out of these places where they have machining, you know, they'd check and make sure they weren't packing it off around the building. And they have shoe covers on that they would take off. Oh yeah, and then they had the monitors there. But it's not like in the 200 Areas, where you had plutonium, which is poisonous to your system more than uranium.
What was impressive about the Manhattan Project?
Weakley: Well, the whole thing. By getting it out in time to stop the war, before we lose all the people, soldiers. If we hadn't had the Manhattan Project, we would have lost, I don't know, hundreds of thousands, maybe a million men trying to get the war over.
And then we got into the Cold War, and that was a race to develop the hydrogen bomb and other bombs. You look back at those old B Reactor and the old reactors and you wonder, those people really had to have insight to build something like that that would work the first time. From that little old reactor that they—“pile” as they call it in Chicago, with a little bit of uranium oxide and very little uranium metal, and say “Hey, this works.” And then to scale it up to the old reactors was phenomenal. Once they had the old reactors going, then the step up to the next reactor phase, like the K's and then the N Reactor, was just a matter of development. Little bit easier step.