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  • this episode was made possible by Wicks, and we'll tell you more about them later in the episode.

  • Today we're going inside a nuclear reactor, and not just any reactor but the reactor that is used to make the rare isotopes of elements like Vicky, Liam, California the ones that are so important for synthesizing the super heavy elements.

  • So this is an old reactor, and the reason why this reactor is here is because a gentleman named Glenn Seaboard, he had a lot of work at Berkeley Labs, and he had a vision of practicing that work on these heavy elements.

  • But he didn't have a great supply.

  • And we can look forward with the hope that nuclear energy will become the servant of all men everywhere.

  • He pushed the Atomic Energy Commission through the fifties, pushed, pushed, pushed and finally, of course, he won the Nobel Prize for chemistry 1951.

  • You get a little bit of credibility on dhe.

  • He finally made some progress in the late fifties 1958 and time again is the commission said, Yeah, we want to do this.

  • We want to build a reactor to produce heavy elements for you to do your chemistry.

  • And so the commission looked around the country at the time, and at that time in the late fifties, there was a lot happening with nuclear reactors, lot of drawings, lot of designs being put on paper, particularly here in Oak Ridge.

  • America's atomic city at Oak Ridge, Tennessee, has been open to the public, and even the opening was by atomic energy.

  • Watch that tape.

  • Oh, crates had the only school that was specifically designed for reactor engineering.

  • It was called the Oak Ridge Reactor Engineering School and this gentleman who's on the wall, Dick Shepperton, has a plaque up here.

  • He was a student in that school at that time, and he'd come up with a concept.

  • And the commissioner of the Atomic Energy Commission saw this concept and said, And I think this is the one.

  • Plenty.

  • Seaborg needed a nuclear reactor with a high neutron flux so that he could get the elements to study Up.

  • Till then, he had gone to the sites where they had been nuclear tests and looked among the rubble for traces of these elements.

  • And obviously this is not very environmentally friendly, and there's a limit to the number of nuclear tests that can be done.

  • And people are not very interested in doing a test just to make some exotic elements.

  • In 1960 they broke ground on this site, and then they put the reactor building in and put the reactor in, and they were up and running by 1965.

  • So for the 1st 20 years of operation, we produced these heavy isotope small quantities.

  • But we produced a very regularly.

  • We operated very regularly and we operated often, meaning the total number of days we operated over the year was very, very large of 75%.

  • Now we operate much, much less about 50% of the year.

  • We actually operate, and our mission has shifted over the decades.

  • Now our mission is neutron scattering, condensed matter physics.

  • But we still have a nice top component.

  • We still make isotopes.

  • So we got a big window.

  • This is our bay.

  • Our reactor is actually to the right side of the pool.

  • The yellow bridge has a damn underneath.

  • And that Well, that doesn't have a damn.

  • Today, I can see the dam is out of the dam is actually moved to the left.

  • We're currently shut down for an outage.

  • And, uh but the reactor is in the pool on the right kind of you seethe stairway going down.

  • That stairway goes down to, ah, platform basically grading So we can lower that when we have the damn in place.

  • We can lower that pool when we can actually walk down there and perform maintenance and repairs in the pool is the reactor vessel were a pressurized reactor.

  • So we have, ah, very sizable pressure vessel And then the reactor core is actually inside of that vessel.

  • The vessel itself is, um it's eight feet across.

  • So what?

  • Two and 1/2 meters.

  • But the core inside of the reactors where all the action happens.

  • This reactor is designed to produce neutrons, not to produce power.

  • It's not trying to make electricity like, say, Chernobyl reactor Waas.

  • So it's small on dhe.

  • It produces the neutrons at the very high rate and then it burns out quite quickly.

  • Each reactor core only lasts that its proper operating power about 25 days less than a month.

  • The reason we pressurize it is to increase the boiling point of water.

  • So that we can cool without boiling our reactor because we produce an enormous amount of heat along with an enormous amount of neutrons.

  • What's the liquid in the pool?

  • Plain water just out of the tap?

  • What he purified a slightly diminished realized.

  • There are still some minerals in it, but we do to mineral eyes it water is all for cooling.

  • All we're trying to do is remove heat.

  • We produce a huge number of neutrons in ways that we can explain.

  • A 1,000,000 billion neutrons 10 to the 15th neutrons.

  • Every second hit a square centimeter that's just one square centimeter.

  • It's a huge number of nutrients, so the pool water is separate from the water that's inside the pressure vessel and the pool.

  • Water remains at about 100 degrees Fahrenheit.

  • The water inside the vessel starts out at about 120 degrees Fahrenheit.

  • As it passes down through our reactor core, it raises about 36 degrees Fahrenheit, exits at about 156 degrees Fahrenheit way, way below boiling.

  • This is good for US power reactors.

  • They want to generate steam, but we don't want steam.

  • Steam would be bad for us we would like our water to be liquid.

  • It's blue because there's so much metal in there.

  • It really isn't blue.

  • We get that question often, but it's pretty, but it's not like there's an additive.

  • So this is a mock up of our fuel.

  • Our fuel is different.

  • Power reactor, you know, uses fuel rods.

  • We use fuel plates, but they're arranged in a very strange arrangement for compared to other research reactors, even our fuel is is placed in these plates.

  • That Aaron here.

  • These air curved plates.

  • And we basically have to fuel elements.

  • An outer element in an inter element.

  • This part in here, which has rods these air not fuel rods, thes air target rods.

  • This area is our area.

  • Very high neutron flux.

  • So this is the business end of our reactor for making isotopes when we make California to 50 to which you may have learned about next door or Berkeley, um, to 49 way Make it in here in the fox trap.

  • The main point of the reactor is that have a tube in the middle in which you put your samples in fairly long, thin, essentially metal test tubes to be radiated and neutrons were important because these heavy elements could be formed by bombarding lighter elements with neutrons.

  • These fuel elements are mostly aluminum.

  • But inside of these fuel plates is uranium.

  • So we have, uh, you We use you 308 which is uranium oxide.

  • And, uh, it's sandwiched in between two aluminum plates.

  • So we basically protect the uranium, but allow it to cool or effectively by having these very small channels to force the water through.

  • And that's why we raised temperature from 1 20 to 1 56 it all All that heat transfer happens through these plates, so the plates themselves are about 24 inches, but we call the fuel meat.

  • Uranium is really about 20 inches.

  • Talk about 20 inches of fuel meat, and, uh, and the rest is aluminum.

  • Our fuel, actually, the uranium comes from the Y 12 national security complex, and we get our uranium for free.

  • However, the free part is metal chunks, and we can't use metal chunks in our fuel.

  • So we have to pay to have our uranium converted to you 308 oxide.

  • So why 12 does that?

  • They converted to an oxide, and then our fuel is actually fabricated at B W X T Technologies, which is in Lynchburg, Virginia.

  • They are the ones that take that you 308 and they blend it with aluminum powder, and they form these compacts.

  • Basically the U three wait and the aluminum are blended together.

  • It press it into these compacts.

  • These compacts are then put into this aluminum picture frame.

  • So now you can envision there's uranium.

  • There's aluminum in this, in the middle section's here, and this is just all aluminum, and then we sandwich that with aluminum plate.

  • Then we take that plate and we roll it out.

  • Then what they do is they form it into this shape, and this is a unique shape.

  • This shape is called on in veloute shape.

  • What makes that shape unique?

  • It's the Onley geometric shape that you can stack around a circle and maintain a constant water gap thickness.

  • You can't do that with a circle.

  • You can't do it with anything else.

  • It's it's and this in veloute shape.

  • So here on this dummy version, I'm looking at these air representing to feel that uranium, these like this'll pretty fluted area.

  • Yep, yep.

  • Both these fluted areas are where the uranium is.

  • That's where we generate all of our power, our overheat, all of our neutrons.

  • And how you making sure that most of the neutrons go to the center where you want.

  • I assume you want them to go to the center more than the outside.

  • Well, you can't really control that.

  • However, that's the that's the amazing part of this unique design that Dix Everton came up with is this flux trap.

  • He called it a trap, but it's really just a high concentration.

  • There's no such thing as trapped can't travel neutron.

  • But you can create a high density of neutrons, and that's basically what this does.

  • However, those neutrons do go outward to.

  • In fact, we look at this mock up.

  • This gives us a more complete picture of the of the reactor core.

  • So we have our flux trap that we saw over there.

  • We have our fuel.

  • We have a small region called our control region, and then we have a reflector region.

  • So these are all annular regions, our reflector region.

  • This is necessary for the reactor toe work, and so is our control region.

  • The reflector is made of brilliant and brilliant is a unique material.

  • It's unique Nu tronic Lee because when a neutron hits brilliant on average about two and 1/2 new neutrons are made from that they're lower energy than the ones that came in and hit it.

  • But so you get two and 1/2 neutrons, Some of those neutrons go back into the fuel and cause that fuel division Maur and you build up this population of neutrons, some of them can be used for experiments that are out here in the corps in the Reflector that you just let your district We've got this great neutral environment.

  • Scientists like What else can we chuck it in there to see what happens?

  • So, in fact, out here, what we generally make these days is we make plutonium to 38 for NASA.

  • So we start with Neptune IAM to 37 we irradiate those Neptune IAM target for three of our operating cycles, which is about 25 days.

  • So 75 days of irradiation and we convert about 10% of that Neptune Ian to 37 2 plutonium to 38.

  • Then we take it to the hot cells next door that you just visited.

  • They extract that they ship it out to Los Alamos, and eventually it ends up in radio thermal electric generators.

  • RTGs, for example, like the Monets on Mars Rover curiosity or the one that's going to be on March 2020 road between the cool and the reflector, there are plates containing the element you rope him one of the rare earths you roped him in.

  • This context is a very efficient absorber of neutrons.

  • So it stops the neutrons from the core getting to the reflector, and the control plates are in two parts so that you can move one up and one down and adjust the size of the gap between them.

  • So when you're ready to go, everything is assembled.

  • The reactor is in its case, in water for the cooling, and everything is shielded.

  • Then remotely, you can pull these control plates apart on the outer one moves up and the other one moves down, and we create a window of communication between the fuel and the reflector.

  • So the new drones can communicate, and we build up that population of neutrons and then we finally go critical, then what we'll do is for the remainder.

  • However long it takes, it takes 23 days, 25 days, 27 days.

  • We pull these plates apart until they're all the way out.

  • Once they're completely out and we can't maintain 85 megawatts, we shut it down.

  • But at any point, if you if you shut the window with the whole thing, would go out with it turns off what's going on in the center where those robes.

  • So those targets we do produce other ice steps.

  • We make nickel 63.

  • We make Cellini, um, 75.

  • We make a California to 52 then we also make some of these other elements the like the Berkeley, um, to 49.

  • What are the rods typically made of, Or does that depend on what you're trying to achieve?

  • It depends on what you're trying to achieve.

  • But most of the targets most of the components in the reactor and especially the targets are have ah have a capsule housing made of aluminum.

  • Most targets are made of aluminum, and then they have some material interest inside.

  • In the case of plutonium like I discussed Neptune to 37.

  • In the case of California to 52 we start with heavy curium which might be curious to 46 to 48 for selenium 75.

  • We have slain him 74 targets, so we generally want most.

  • Most of the processes are to capture new drones to get to the next isotope.

  • We are fairly full, but we have a regular routine set of radiations that we do particularly for I still production.

  • But we also do a lot of materials radiations testing in here.

  • We have a lot of materials for material science in that core.

  • It's one of these.

  • It lasts for 25 days.

  • When we take it out, we put a brand new one in each one of these is about 1.8 million U.

  • S.

  • Dollars, and it lasts for 25 days.

  • And then what happens?

  • Is it refit door that goes in the bin?

  • So what happens is so, as I said, we're in an outage.

  • This is a temporary just little cap to cover, so we don't drop things in their This'd our vessel head.

  • This is the part that's about eight feet in diameter.

  • This is the grading.

  • You can see that you can actually walk down the steps to get to.

  • Not a lot to see here because we're not operating.

  • Usually when we're operating, you could see a blue glow.

  • You get the shrink off radiation glow.

  • So you slide the court today.

  • Yes.

  • So it's actually quite deep down in there.

  • So we use very long tools attached to things, and the operators rolled a bridge over, and then they can lower the fuel down into the core locations.

  • That always an exciting day for you guys.

  • That is, Everyone come out and watch and go.

  • We're starting a new wonder.

  • Is it like just routine?

  • Now?

  • I will say it's fairly routine now.

  • Putting it in taking it out is more exciting.

  • But generally that happens overnight, so not a lot of people come out overnight.

  • But when you take it out, you take out elements that look like, uh, you get the nice Shirin cough glow.

  • We don't have a lot of them right now that are glowing.

  • Um, but and actually I don't really see many glowing.

  • Usually, we would have these would be glowing that they've been out for quite a while.

  • We had a long outage, so they've had time to decay, said these air out ones cooling down these air, old ones cooling down.

  • They always stay underwater, and they stay in this center section the pool for maybe two or three years.

  • And then eventually they go over to these racks, which are three tier, so we can hold a lot of elements over here.

  • And then eventually they get shipped to Savannah River site, where Savannah River site will dissolve them and extract out the good remaining material and recycle that into a program that supposedly makes power reactor fuel not very familiar with the program.

  • How do you get to stuff out that you've just made, like, you know, all that, all those cool isotopes that everyone's dying to get their hands on?

  • How do you get them out of there off the core and all those surrounding little cylinders?

  • So that's that is a challenge, and I will say that is what our operators do, um, with long tools.

  • It's like a laparoscopic surgery to get these out, so it would be nice and you look at the top of this and you see these plugs and holes, those plugs and holes initially, you think, Oh, those line up with the holes that are on top of the reflector But they don't.

  • The reflector is actually only about this diameter.

  • Everything we do has to go through this one hatch.

  • So they're working down there and they're going around things with these long tools.

  • It's arduous.

  • It's difficult, but they they're very talented at it.

  • So it is difficult to get things out.

  • But we do.

  • We do it routinely every cycle, and then they literally take them and they just keep them underwater.

  • They drag them across to the other side of the pool, and then we can weaken, store them.

  • We can put them in shipping casks, and then we can ship them over to the hot cells or wherever they're gonna go fuel elements.

  • While they're not producing neutrons or many neutrons, they're still producing a tremendous amount of gamma radiation.

  • So we use thes.

  • We have developed a small canister that can go down into that flux trap area and weaken, fill that canister, weaken stream, water or electricity, or whatever we want into that canister.

  • We can do high intensity gamma radiation.

  • These are control plates.

  • You can see that.

  • I described the two cylinders.

  • Okay, that was a little bit of a stretch.

  • They are two cylinders, but the inner cylinder is one contiguous cylinder.

  • The outer cylinder is actually made up of four plates and you can see one of these plates here on the window sill.

  • That's Ah, an example of a control plate.

  • These air very difficult to fabricate.

  • They take a tremendous amount of time.

  • They're very expensive.

  • Remember these have your opium oxide inside is a meat and, uh, they take two years to fabricate a set like this.

  • So media shipments, we can actually back a truck in here, and it comes right over to this area where these gray squares are on.

  • We can use the big crane and bring the big shipping cask and set it down.

  • The shipping cast for California 2 52 targets is quite large.

  • It's a nine foot diameter sphere that they painted white and call the cue ball.

  • It weighs 25 tons, so it's not.

  • It's not insignificant, and it can get set onto a truck.

  • Very exciting.

  • when the ship California and plutonium targets are shipped in the same in the same caste.

  • I was really impressed that they're using this reactor for all sorts of different experiments, not just making the new elements.

  • They also have Beem lines coming out from the reactor generating beams of neutrons.

  • The reactor core is that way.

  • The beam.

  • You can see the red lines designate three beam lines.

  • There's actually 1/4 1 on the far right.

  • It doesn't get a red line.

  • So we have four beam lines that come down, and they actually get split even further because we have more than four instruments out here.

  • So these large tanks air called sands tanks.

  • Small angle, neutron scattering thanks.

  • They get evacuated.

  • There's a detector plate, a large one meter square detector played inside, and they can use the beams of neutrons for what's it called Newt's On the fraction which will allow you to do all sorts of interesting experiments.

  • The one that really excited me was that you can take a diesel engine like for a car, and you can image the fuel being squirted into the engine block by shining neutrons through the block.

  • of a running engine.

  • And because the fuel contains hydrogen atoms, which absorb neutrons strongly, you can see this jet a fuel going into names and when it's running without disturbing any of the workings of the engine, Have you seen our new periodic videos website yet?

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  • Australian servicemen and scientist played a big part in the operation, which included the construction of the tower, the tower that vanished instantly when the atomic weapon was exploded on it.

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原子炉の中 (Inside a Nuclear Reactor)

  • 5 1
    林宜悉 に公開 2021 年 01 月 14 日
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