Speaker 1: Brought to you by the reinvented two thousand twelve Camray.
Speaker 1: It's ready. Are you get in touch with technology? With
Speaker 1: tech Stuff from how stuff works dot com. Hello again, everyone,
Speaker 1: Welcome to tech Stuff. My name is Chris Poulette and
Speaker 1: I am an editor at how stuff works dot com.
Speaker 1: Sitting across from me as always a senior writer, Jonathan Strickland.
Speaker 1: Hey there, Okay, I think we'll probably be a little
Speaker 1: subdued for those those of you who are long term fans.
Speaker 1: A few weeks ago we recorded an episode of tech
Speaker 1: Stuff because of a seismic event in christ Church, New Zealand.
Speaker 1: Yet uh did a lot of damage, but hadn't resulted
Speaker 1: in a lot of human costs. Since then, of course, um,
Speaker 1: you know, we've had the earthquake in Japan nine point
Speaker 1: oh earthquake um, which, if you remember in the Seismology podcast,
Speaker 1: each each number in the Richter scale is ten times
Speaker 1: greater in intensity than the previous number, So a two
Speaker 1: is ten times more intense than a one. So nine
Speaker 1: is an incredibly intense earthquake. What's what's interesting about that too?
Speaker 1: Just as a note, um, I understand that that was
Speaker 1: actually an aftershock of a six point two I believe
Speaker 1: magnitude earthquake. It was in the sixes. Yeah, it can
Speaker 1: sound kind of unusual to some of us that an
Speaker 1: aftershock would actually be more powerful than the initial earthquake.
Speaker 1: But you just have to remember those those plates that
Speaker 1: we talked about in the Seismology podcast are the pressure
Speaker 1: is incredible. There's nothing else like it on Earth really
Speaker 1: where uh and if if those plates slip against each other,
Speaker 1: then your you can get a pretty massive earthquake or
Speaker 1: an aftershock. So um, of course, we we touched on
Speaker 1: how earthquakes are measured, the different devices have been used
Speaker 1: to measure them in the past. Um. And uh, you know,
Speaker 1: of course in Japan there were the earthquakes and aftershocks
Speaker 1: in the tsunami that followed, resulting in a lot of
Speaker 1: property damage and loss of life. We're still not sure
Speaker 1: at this point how many people are gone. No, it's
Speaker 1: a tragedy that is definitely on a on a huge scale.
Speaker 1: We just don't know the extent of that yet. And um,
Speaker 1: although no one has really asked about this yet, we're
Speaker 1: kind of thinking that maybe people would want to know
Speaker 1: about the other major news event that has gone along
Speaker 1: with that, which was the the nuclear power plant that
Speaker 1: has suffered catastrophic failures as the result of the earthquake. UM,
Speaker 1: and we thought it might be interesting to talk about
Speaker 1: how nuclear power plants work, and then we'll we'll go
Speaker 1: into exactly what the problem is in Japan. Yeah, with this, frankly,
Speaker 1: this could be a marathon episode. We could talk about
Speaker 1: nuclear power plants for hours because they are very involved.
Speaker 1: So we decided to stick primarily to the general type
Speaker 1: of nuclear power plant being used in question, but also
Speaker 1: some of the others that have had major problems in
Speaker 1: the past, notably the Chernobyl reactor and the one in
Speaker 1: Three Mile Island in in the United States. So let's
Speaker 1: talk first about what a nuclear reactor is and how
Speaker 1: it generates power. Uh, of course, it's using a nuclear process, right,
Speaker 1: It's using decay. Really, it's we're talking about controlling the
Speaker 1: decay of of uranium. Really, it's when you compare it
Speaker 1: to a coal power plant, um, and you and you
Speaker 1: take the very very basics together, this type of nuclear
Speaker 1: power plant is almost exactly the same type. You're using
Speaker 1: a new clear reaction to generate heat as you would
Speaker 1: for a coal fired power plant, right, exactly, you would
Speaker 1: you would burn coal to generate heat in a coal plant? So, yeah,
Speaker 1: same thing, you're trying to use heat to generate electricity.
Speaker 1: You use that to to generate steam. The steam turns
Speaker 1: a turbine and a generator, which generates electricity. It's it's
Speaker 1: the nuclear reaction that makes it so very different from
Speaker 1: the coal plants that. Yeah, And you might ask, well,
Speaker 1: why would you want to use nuclear power in the
Speaker 1: first place. Well, there's several reasons. One is that, unlike coal,
Speaker 1: it doesn't produce uh, greenhouse gases. That's right, right, So
Speaker 1: when you burn coal, you're going to generate greenhouse gases
Speaker 1: and essentially carbon dioxide being chief among them, and uh
Speaker 1: and that can contribute to lots of environmental problems. So
Speaker 1: in some ways, nuclear power, at least from a greenhouse
Speaker 1: gas perspective, is greener than coal technology. Also, you don't
Speaker 1: need as much fuel to generate power as you would
Speaker 1: with coal. It's it's actually an incredible skin you could
Speaker 1: be talking about, you know, a few pounds of uranium
Speaker 1: versus tons and tons and tons of coal. Yes, it
Speaker 1: wasn't that long ago that the uh, those of us
Speaker 1: in the United States were talking about the coal mine
Speaker 1: the coal miners who are trapped in West Virginia. UM.
Speaker 1: And of course people start talking about the pros and
Speaker 1: cons of coal. Now of course we're talking about the
Speaker 1: pros and cons of of nuclear energy. UM. But yes,
Speaker 1: it requires far less uh um raw material to generate
Speaker 1: the nuclear reaction as it would for the coal fired
Speaker 1: power plants. Now, so you're you're talking about material where
Speaker 1: you don't need as much. You aren't genering greenhouse gases UM,
Speaker 1: and you can create an intense amount of heat very
Speaker 1: pretty simply in the grand scheme of things. But there
Speaker 1: are a lot of concerns around nuclear power as well.
Speaker 1: For one, I mean, we're talking about radioactive material, and
Speaker 1: radioactive material that is harmful to human Yes, it's not
Speaker 1: just you know, lots of things radiate energy, and not
Speaker 1: all of that energy is harmful. Yes. Just the other
Speaker 1: night I was watching, uh the CBS news report on
Speaker 1: radio activity, and a lot of people in the United
Speaker 1: States have been concerned that, first of all, the governments
Speaker 1: of Japan and the United States aren't being truthful with
Speaker 1: the amount of radiation being leaked in the atmosphere as
Speaker 1: a result of the explosions that took place at the
Speaker 1: plant in Japan. UM. But they were One of the
Speaker 1: things that I think was interesting was they took a
Speaker 1: Geiger counter around to several different They were basically walking
Speaker 1: around New York City with a Geiger counter, and they
Speaker 1: went to the middle of the park and turned it
Speaker 1: on and it was picking up readings of radio activity.
Speaker 1: And they walked over to granite, a granite monument as
Speaker 1: a matter of fact, and UH and and took the
Speaker 1: Geiger counter. A geiger counter, by the way, as a
Speaker 1: device that measures radioactivity. You hear clicking sounds and it
Speaker 1: has a needle. One of the UH. I think of
Speaker 1: it as an old style, but really I guess it's not.
Speaker 1: With the needle and it shows you roughly how much
Speaker 1: radioactivity is being gendered. And granted is naturally radioactive, and
Speaker 1: I didn't know that now. Of course, you can't take
Speaker 1: just anything UM and throw it in a nuclear reactor
Speaker 1: and have it react. You have to use a very
Speaker 1: special UM type of material. Because to generate a nuclear
Speaker 1: reaction UM, you're splitting an atom, use a stray neutron
Speaker 1: to UH break apart the nucleus of another atom. And
Speaker 1: and some some elements are more likely to be are
Speaker 1: are are easier to do that with than others. You
Speaker 1: need something that's called fistle if you're using a effission
Speaker 1: reaction as the one as these reactors do. Fusion power
Speaker 1: right now is kind of beyond us as far as
Speaker 1: it takes more energy to create a fusion reaction than
Speaker 1: we get back, I'll of it. But there is a
Speaker 1: lot of hope that in the future fusion will become
Speaker 1: the the power source for nuclear facilities. The Sun generates
Speaker 1: energy through fusion, not fission, so uh yeah, we haven't
Speaker 1: we haven't gotten there yet, but there are a lot
Speaker 1: of very very smart people working on ways to create
Speaker 1: fusion power plants, and it's quite a bit of research
Speaker 1: on on these things from Britannica. I like to to
Speaker 1: use that, of course as one of my sources. Um
Speaker 1: and uranium two thirty five, according to Britannica, is the
Speaker 1: only naturally occurring fistle material that's in a ready state
Speaker 1: to be to be split apart this way. Um, there
Speaker 1: are other, uh different kinds of materials. We're we're talking
Speaker 1: about the nucleides um. Somebody probably correct my pronunciation. I
Speaker 1: think that's right, but those some of them basically as
Speaker 1: long as the atoms are in an excited state. Uh,
Speaker 1: they can be um. When they're hit with a slow
Speaker 1: moving neutron, you can you can break them apart. Uranium
Speaker 1: two thirty five to thirty three, plutonium two thirty nine
Speaker 1: and two forty one um Plutonium two thirty nine. You
Speaker 1: actually create with your uranium two thirty eight and then
Speaker 1: you bombard it with neutrons. Yeah, materials that are fertile,
Speaker 1: uh can be that if you are different kinds of
Speaker 1: materials that if you add an extra neutron, you can
Speaker 1: they can become fiztle. Uh. Those are thorium two thirty two,
Speaker 1: uranium two thirty eight, and plutonium two forty um. So
Speaker 1: these are very complex atoms and heavy atoms and very
Speaker 1: heavy atoms and um. There are are the kinds of
Speaker 1: materials required to be used in a in a core
Speaker 1: of a nuclear reactor, and uranium two thirty five will
Speaker 1: break apart naturally decays over time. But but that's not
Speaker 1: the You know, you want to have a controlled and
Speaker 1: a controlled reaction in order to be able to generate power,
Speaker 1: and you want to be able to do it at
Speaker 1: a good time scale. Because we're uh, we don't have
Speaker 1: thousands of years to generate electricity. So with the uranium
Speaker 1: two thirty five, you actually would bombard it with neutrons
Speaker 1: in order to uh to speed up that reaction. Now,
Speaker 1: what that will do is that the the atom splits apart,
Speaker 1: it generates a lot of energy in the form of
Speaker 1: heat and radiation. The radiation comes in the forms of
Speaker 1: gamma radiation, beta radiation, and alpha radiation. Uh So, gamma
Speaker 1: radiation is a form of electromagnetic radiation UM. In fact,
Speaker 1: there are two major kinds of radiation. Electromagnetic radiation, which
Speaker 1: is some form of light. Uh it's it's photon radiation UM.
Speaker 1: That may not be visible light, but it is. It
Speaker 1: falls under the photon radiation. Then you have particulate radiation,
Speaker 1: which is when you're talking about an unstable uh atom
Speaker 1: particle shoots off essentially from the the atom. And uh
Speaker 1: So with alpha radiation uh uh or well, I'll start
Speaker 1: with beta radiation. With beta radiation, you've got electrons being released. Right,
Speaker 1: alpha radiation, it's protons and neutrons being released. Now, protons
Speaker 1: and neutrons are much much much larger in comparison to electrons,
Speaker 1: and they move slower than electrons do. So alpha radiation,
Speaker 1: you get the protons and neutron splitting off. That's a
Speaker 1: particulate radiation that moves slowly. It can actually depending upon you,
Speaker 1: know how how you're being exposed to it. Your skin
Speaker 1: can sometimes block alpha radiation just because your skin is
Speaker 1: thick enough where it's the particles are not moving at
Speaker 1: a speed sufficient to be able to penetrate the skin. Um.
Speaker 1: The beta radiation is different because those electrons are very
Speaker 1: tiny and they're moving really really fast and uh, and
Speaker 1: this is the sort of radiation that the sort of
Speaker 1: particular radiation that can actually cause pretty nasty deep tissue
Speaker 1: damage if it hit to you. And then of course
Speaker 1: gamma radiation is really really high energy electro magnetic radiation,
Speaker 1: and that stuff is serious business. Uh. You know, gamma
Speaker 1: radiation can cause lots of problems in both immediate acute
Speaker 1: problems and chronic problems over time. So why would you
Speaker 1: want to use this, Well, it's because it gives off
Speaker 1: this this amount of energy, this this kind of intense energy.
Speaker 1: It's really good at converting water into steam. So if
Speaker 1: you can control this reaction, uh and generate the right
Speaker 1: amount of heat, you're going to generate a lot of
Speaker 1: steam that's going to move through the system and eventually
Speaker 1: turn the turbine which is going to uh provide the
Speaker 1: power to the generator, and then you you create power
Speaker 1: for the power grid. And some countries rely very heavily
Speaker 1: on nuclear power to create to to supplement their power grid.
Speaker 1: Countries like like France, it's nearly seventy of their power
Speaker 1: that comes from nuclear power. In the United States, it's
Speaker 1: more like it's funny because there are two, um, two
Speaker 1: different things to consider that you might not consider with
Speaker 1: some of the other forms of electricity generation. Here UM
Speaker 1: atomic reactions are deal with probability UM and they deal
Speaker 1: with chain reactions. UM. I remember watching in one of
Speaker 1: my science classes a long long time ago an experiment
Speaker 1: that they did where they had set up we're not
Speaker 1: an experiment, but an an illustration. They had a plexiglass
Speaker 1: or clear plastic box and across the floor of it,
Speaker 1: the entire floor was covered with mouse traps set mouse traps.
Speaker 1: Each mouse trap had two ping pong balls on top
Speaker 1: of it and everything was still. So this is the
Speaker 1: normal state of the atoms that's supposed to represent the
Speaker 1: normal state of the atoms inside the fuel. UM. And
Speaker 1: then there was a small hole at the top of
Speaker 1: the box, and the person said, Okay, this is what
Speaker 1: happens when you add the neutron. The stray neutron is
Speaker 1: another ping pong ball in this illustration, and the person
Speaker 1: dropped the ping pong ball into into the box, and
Speaker 1: of course it hit one of the mouse traps, setting
Speaker 1: it off. The other two ping pong balls representing neutrons again, uh,
Speaker 1: jumped up from the mouse trap in different directions, and
Speaker 1: each of those set off more mouse traps, and each
Speaker 1: of those set off more mouse traps. Exponential growth. Yes. Now,
Speaker 1: of course in the nuclear fuel uh, you know, in
Speaker 1: that particular illustration ended and very quickly within a matter
Speaker 1: of you know, probably two or three seconds, because they
Speaker 1: were you know, forty mouse traps or something like that.
Speaker 1: In nuclear fuel, this continues on UM, but they have
Speaker 1: to control that. They have to look at the probability
Speaker 1: that a neutron will continue, that there will still be
Speaker 1: stray neutrons able to generate more heat energy release UM.
Speaker 1: So when they want to what they call a slightly
Speaker 1: super critical uh level of reaction, because there's that means
Speaker 1: that there is more more than one fission per neutron
Speaker 1: so you're you're you don't want it to be a
Speaker 1: little bit. You don't want to be underneath that. When
Speaker 1: it gets subcritical, that's when there are a few there
Speaker 1: are fewer neutrons available to make the nuclear reactions, which
Speaker 1: means that you would actually have to pour more power
Speaker 1: into the system to to shoot more neutrons into it
Speaker 1: in order to generate power. And of course, you know,
Speaker 1: the whole goal here is to make it as efficient
Speaker 1: as possible when you're generating electricity. Otherwise you're actually consuming
Speaker 1: far more power than you are able to convert into electricity. Yes,
Speaker 1: when it's one spare neutron to a reaction, that's or
Speaker 1: to a nucleus of another atom, that's critical. That literally,
Speaker 1: that is what they call critical, and that's the reactive
Speaker 1: state of the the reactor core um. From what I understand,
Speaker 1: they do want it to be slightly super critical, but
Speaker 1: only lightly, and so controlling the reaction is very important,
Speaker 1: and it's done in a number of different ways. Sure,
Speaker 1: let's talk a little bit about the way the fuel
Speaker 1: is put together and then we can talk about how
Speaker 1: that control happens. Yeah, I think that that would be
Speaker 1: excellent because that is a big part of how they
Speaker 1: control the reaction. Yeah, so, so the uranium is enriched
Speaker 1: with uranium two thirty five right now for a nuclear facility,
Speaker 1: I was gonna say, we should might maybe explain what
Speaker 1: that means, because uranium two thirty five is naturally reactive,
Speaker 1: but there's only so much of you two thirty five
Speaker 1: found in a chunk of uranium. So enriched uranium is
Speaker 1: basically they've added more uranium two thirty five to the
Speaker 1: uranium overall to make it, to make it more reactive
Speaker 1: so they can use it as nuclear fuel. And so
Speaker 1: for UH, you have to for for fuel for a
Speaker 1: nuclear power plant, you need to have added enough you
Speaker 1: two thirty five, So it's got two to you two
Speaker 1: thirty five and the overall fuel now you two thirty
Speaker 1: five is the same element that you're going to find
Speaker 1: in UH in nuclear weapons. But nuclear weapons require a
Speaker 1: much higher percentage of you two thirty five to thirty
Speaker 1: five within the uranium in order for it to be
Speaker 1: weapons grade. So that's a pretty easy way to tell
Speaker 1: if someone's making weapons grade uranium is you measure how
Speaker 1: how the percentage of you to to thirty five in
Speaker 1: the fuel itself. If you've been following the news and
Speaker 1: you've seen pieces on where some countries are concerned about
Speaker 1: Iran enriching uranium. This is why you can enrich uranium
Speaker 1: for a nuclear power program, or it can also be
Speaker 1: used in weapons. Right, So if you're enriching beyond that
Speaker 1: two to three percent, then that's a good indicator that
Speaker 1: you're looking at something more uh dangerous than the nuclear
Speaker 1: power plant. So the what the bits of uranium are
Speaker 1: actually formed into what what is called pellets, and they're
Speaker 1: about an inch long. They're about the diameter of a dime.
Speaker 1: So you can think it's kind of like a cylinder
Speaker 1: right now. These pellets are stacked together to form rods.
Speaker 1: Yes they are. They are contained within a metal rod, yes, yes,
Speaker 1: so yeah, you can think of like a there's like
Speaker 1: a sheath, a metal sheath, and these uranium pellets are
Speaker 1: stacked within that sheath. Now, these rods are then grouped
Speaker 1: together into a collection called a bundle. And if if
Speaker 1: that's all it was, if that's all you had and
Speaker 1: then you started introducing neutrons into it, you would have
Speaker 1: no way to to modify to moderate that at all.
Speaker 1: It would just the reaction would would increase and increase
Speaker 1: until either you would spent all the fuel or you
Speaker 1: had had a melt down. And meltdown essentially is when
Speaker 1: the fuel itself gets so hot that it melts um.
Speaker 1: So in order to control this, they have control rods.
Speaker 1: And control rods are made of material that are that
Speaker 1: absorbs neutrons, because as we were talking about, you know
Speaker 1: these neutrons that that fly off and hit uranium two five,
Speaker 1: that's what initializes this reaction. So if you have material
Speaker 1: that absorbs neutrons, it's like taking you know, you're you're
Speaker 1: you're putting the brakes on things, and the control rods
Speaker 1: tend to be you can you can insert them either
Speaker 1: all the way down where they are going to control
Speaker 1: the reaction as much as possible, keeping in mind that
Speaker 1: there's still some decay heat that's going on here. It's
Speaker 1: not like it's not like you immediately switch it off.
Speaker 1: It's just slowing it down to the point where you
Speaker 1: call it a nuclear shut down, but there's still heat.
Speaker 1: Or you can raise them all the way up and
Speaker 1: then just let the UH reaction go to full full blast.
Speaker 1: Cadmium and boron are two elements that are very good
Speaker 1: at absorbing stray neutrons, and you may have heard about
Speaker 1: born being introduced into the Japanese facility along with sea water.
Speaker 1: We'll talk about that in a minute too, um, but
Speaker 1: those are those are also uh, those are useful because
Speaker 1: they're basically fighting over who gets the stray neutrons and
Speaker 1: that just slows everything down and helps right keep it
Speaker 1: under control. Now, inside this nuclear reactor, you also have
Speaker 1: to have coolant because and actually the coolant is what
Speaker 1: heats up to go and then usually you have a
Speaker 1: you have a coolant that then runs through another system
Speaker 1: that will heat up water and the water becomes steam
Speaker 1: and that's what drives the turbine. Some nuclear power plants,
Speaker 1: and these are the ones that are kind of particularly dangerous,
Speaker 1: have the coolant system also driving the turbine, which means
Speaker 1: that you have radioactive material pushing that turbine because the
Speaker 1: coolant that encounters the actual rods is going to pick
Speaker 1: up radioactive material itself, will become radioactive. It's gonna have
Speaker 1: radioacti particles running through that cooling system. So most of
Speaker 1: these cooling systems are are self contained and they do
Speaker 1: not cross over into the water system that drives the turbine.
Speaker 1: They just they just you can think of it as
Speaker 1: it runs up against the water system, and the heat
Speaker 1: from the cooling system is what generates the steam in
Speaker 1: the water system. Um. So, but you have to have that.
Speaker 1: If you don't have that again, the uh, the core
Speaker 1: can reach a temperature that's so high that the uranium
Speaker 1: begins to melt. And there there's a lot of scary
Speaker 1: guesswork as to what would happen if you had a
Speaker 1: true meltdown, like a full on meltdown to the point
Speaker 1: where we're not really sure if the material would get
Speaker 1: so hot, like the reaction would continue to a point
Speaker 1: where it would just burn right through the reactor. Um
Speaker 1: that's a theoretical possibility, although we haven't actually seen that
Speaker 1: happen in real life yet, Thank goodness us that's true. Well,
Speaker 1: the the movie The China Syndrome is about that, and
Speaker 1: I think most scientists would probably tell you that that's
Speaker 1: a bit hysterical for what might actually happen. Uh. The
Speaker 1: the premise being that the core melts down, the fuel
Speaker 1: is melting, and it melts all the way through the
Speaker 1: center of the Earth again, from the United States to China,
Speaker 1: all the way through the the Earth that might be
Speaker 1: a little I think that's probably I mean, I'm not
Speaker 1: a scientist obviously, but I think that's a little extreme.
Speaker 1: I would definitely call that the worst case scenario. Yeah,
Speaker 1: I don't I don't know that it could actually go
Speaker 1: that far. But yes, that that is an exaggeration of
Speaker 1: what Jonathan's talking about, the idea that it would melt
Speaker 1: through the reactor. So the the problems that we could
Speaker 1: conceivably face with a nuclear power plant would involve something
Speaker 1: going wrong with the ability to insert or remove the
Speaker 1: control rods, really to insert them, because because if they're
Speaker 1: stuck there, all you really have is a dead nuclear
Speaker 1: power plan. And yes, that is terrible and that it's
Speaker 1: gonna cost billions of dollars to fix, but it doesn't
Speaker 1: pose an immediate threat to the surrounding area. UM. You
Speaker 1: also have the problem with if if the water system,
Speaker 1: if the cooling system is UH in any way compromised,
Speaker 1: then you have the chance of the nuclear reactor overheating,
Speaker 1: which unfortunately we have seen happen before, and that can
Speaker 1: cause UH massive problems down the line. Now, what happened
Speaker 1: with Japan is that the earthquake actually did not UH
Speaker 1: did not damage the reactors to the point where they
Speaker 1: were inoperable. In fact, what happened was that the control
Speaker 1: rods descended, as they should have in that instance to
Speaker 1: control that reaction. But again there's decay heat. It's not
Speaker 1: like it can shut it off immediately. It's just that
Speaker 1: the reaction is no longer continuing, right, but still generating heat. Right. UM.
Speaker 1: Another thing to consider with regard to the Japanese reactor
Speaker 1: is that, uh, there were containment devices set up. When
Speaker 1: you build a nuclear power plant like this, this light
Speaker 1: water plant, UM, it is ideal to build a containment
Speaker 1: area around the reactor course. UM. This is usually made
Speaker 1: with concrete, UH, very thick concrete in the case of
Speaker 1: the Japanese plant, UM, which for has has so far
Speaker 1: as of the time we're talking right now, prevented a
Speaker 1: major release of radiation. UM. The problem comes from what
Speaker 1: happens with spent nuclear fuel, which to this point we
Speaker 1: haven't mentioned. At some point, when the fuel becomes subcritical
Speaker 1: and it cannot continue producing a nuclear reaction sufficient enough
Speaker 1: to continue the the electrical output of the plant, UM,
Speaker 1: they're going to want the people running the plan are
Speaker 1: going to run and replace it with fresh fuel. This
Speaker 1: can take weeks. Usually they do maintenance on the plant
Speaker 1: at the same time, because it's a good time the
Speaker 1: plant shut down. So what they'll do is they'll remove
Speaker 1: the bundle of rods and replace it with new rods
Speaker 1: of with fresh fuel. But what do you do with
Speaker 1: the old rods. That's the tricky part because the old
Speaker 1: rods are very hot and they are very very radioactive. Yeah,
Speaker 1: it's just like it like Chris was saying, it's kind
Speaker 1: of like, you know, it's just that they're not generating
Speaker 1: the amount of energy necessary to run the plant, but
Speaker 1: they're still generating tons of like of energy and not
Speaker 1: really tons. Don't write me and um, the they are
Speaker 1: very much dangerous to people and here's eventually they will
Speaker 1: be inert. But but eventually I'm talking like ten thousand years. Yes,
Speaker 1: we can't wait around that long. And because they're generating
Speaker 1: so much heat and so much radioactivity, they tend to
Speaker 1: corrode pretty much any container you put them in. This
Speaker 1: is one of the aside from the potential for an accident. Uh,
Speaker 1: this is one of the things that can that makes
Speaker 1: nuclear power so controversial, is that this is the flip
Speaker 1: side of the green coin. Yes, Storing the nuclear fuel,
Speaker 1: the spent nuclear fuel is very, very difficult. Uh. Nobody
Speaker 1: wants nuclear fuel in their backyard. Um, and there's not
Speaker 1: even there's not a good answer for that. Storing it
Speaker 1: in caves is one solution. The question is whether or
Speaker 1: not people will go in there. Um. You know, a
Speaker 1: thousand years down the road is still very radioactive. Um.
Speaker 1: You could say, well, why don't we shoot it off
Speaker 1: into space. Well, that's fine, except there's the potential for
Speaker 1: an accident. Rockets are not foolproof, and if you have
Speaker 1: an accident with the rocket, there's the potential that radioactive
Speaker 1: waste could be scattered across the roth's atmosphere in that again,
Speaker 1: is something that no one wants to happen. So one
Speaker 1: of the first things they do when they remove the
Speaker 1: fuel from what I understand from the reactor core, is
Speaker 1: they put it in a containment pool. Water, as it
Speaker 1: turns out, is a natural shield against radioactivity. Uh. Not
Speaker 1: only is it cooling the very very hot rods with
Speaker 1: the nuclear fuel inside, but it also is shield doing
Speaker 1: some shielding against radioactivity. Well in the Japanese plant, when
Speaker 1: the power was shut off, ironically enough, Uh, the water
Speaker 1: began to evaporate. It was boiling off. And that's the
Speaker 1: problem is that there when there's no more water surrounding
Speaker 1: the spent fuel. It wasn't the reactor cores, it was
Speaker 1: this the spent fuel. Uh, and the reaction is allowed
Speaker 1: to continue that generates hydrogen when the hydrogen is explosive. Yeah,
Speaker 1: it's It's a process called thermolysis. It's when heat turns
Speaker 1: water into hydrogen and oxygen breaks up the molecules into
Speaker 1: their into their component atoms, and you can you can
Speaker 1: do the same thing with electricity, that's electrolysis. So it's
Speaker 1: the same sort of thing. It's just you pour enough
Speaker 1: energy into a molecule and you can break those molecular bonds.
Speaker 1: And that's exactly what happened. Hydrogen built up. But before
Speaker 1: we get to the hydrogen problem, I should also mention
Speaker 1: there were a lot of fail safe procedures in place
Speaker 1: at the Japanese plant. It's none of the Japanese were
Speaker 1: not doing due diligence with safety. It's just that was
Speaker 1: the perfect set of terrible situations for this to happen.
Speaker 1: And it and it from what I understand, not to
Speaker 1: interrupt him, um, from what I understand, the plant was
Speaker 1: intended to survive and eight plus UH point Richter scale earthquake. Yeah,
Speaker 1: it was the tsunami that really hit them. Because here's
Speaker 1: what happens. They lost power from the power grid, well
Speaker 1: the power plant had and they need power to pump
Speaker 1: water through the system in where to keep it cool.
Speaker 1: So the pumps run on electricity. So they switched to
Speaker 1: their diesel generators. But then the tsunami hit and the
Speaker 1: diesel generators were not above the tsunami levels, so they
Speaker 1: were flooded and could no longer work. They also had
Speaker 1: battery power, but the battery power was only meant to
Speaker 1: last you know, I think it like a day, because
Speaker 1: the idea was that, well, we won't be without power
Speaker 1: for longer than that. But they could not get supplemental
Speaker 1: power in place to uh to cover the gap between
Speaker 1: the battery power and when they could get some other
Speaker 1: form online. And so the water stopped pumping and the
Speaker 1: temperature kept building and the hydrogen built up. Um and
Speaker 1: hydrogen is incredibly flammable. It's explosive, and there was the
Speaker 1: hydrogen collected at the top of the facility. UH. Something
Speaker 1: set it off and there was that's what that big
Speaker 1: explosion was when we first you know, and there's been
Speaker 1: a uh, there's been other ones since then, but that
Speaker 1: initial explosion, people were worried that the reactor had exploded.
Speaker 1: That's not what happened. It was the pocket of hydrogen
Speaker 1: that it exploded. And as uh, if you've been through
Speaker 1: a certain level of science, of course we have some
Speaker 1: younger listeners. The three things that you need for fire
Speaker 1: are you know, heat, a source of fuel, and air,
Speaker 1: and you would certainly have that with very hot fuel rods,
Speaker 1: air in the in the area, and then you know
Speaker 1: the source of hydrogen. So um, it was a very
Speaker 1: dangerous situation. Now uh people have said, uh, you know,
Speaker 1: this is going to be another Chernobyl. But Chernobyl was
Speaker 1: a different situation. They did not have any containment in place,
Speaker 1: or what they did have some containment that it was
Speaker 1: not designed to prevent the kind of release that that occurred.
Speaker 1: Chernobyl was interesting. So when we're talking containment, like Chris
Speaker 1: was saying, you're talking about a very thick concrete liner,
Speaker 1: usually there's a steel a steel like you can call
Speaker 1: it like a furnace, I guess, but it's a steel
Speaker 1: container that is lined with concrete, and then you have
Speaker 1: a big concrete building around that, so you've got two
Speaker 1: barriers of concrete and a barrier of steel in order
Speaker 1: to contain the nuclear reactions. Chernobyl only had the basic container,
Speaker 1: did not have a secondary container, so if there were
Speaker 1: a failure, then there you have much more chance of
Speaker 1: nuclear fallout. And in fact, the Chernobyl incident happened ironically
Speaker 1: during a procedure where they were trying to test out
Speaker 1: a safety feature because what Chernobyl was going to have
Speaker 1: was having some similar issues to the japan facility and
Speaker 1: that Chernobyl um they were worried about what would happen
Speaker 1: if power were lost, If they lost power from the
Speaker 1: power grid and they can no longer pump water through
Speaker 1: their system, so they uh they had these diesel backups,
Speaker 1: but the diesel backups would would not really kick in
Speaker 1: until about a minute after the initial power loss, and
Speaker 1: that minute is a long time for these nuclear reactions
Speaker 1: to go unchecked, right with no water cooling them down.
Speaker 1: So one of the things that we're looking at doing
Speaker 1: was using the turbine as it slowed down to generate
Speaker 1: enough electricity to keep the pumps running for that one minute.
Speaker 1: Before the diesel backups could kick in, and they were
Speaker 1: running a test and it was like the perfect set again,
Speaker 1: a perfect set of situations going wrong for that test
Speaker 1: to fail. There was a power spike, and then while
Speaker 1: they were trying to react to the initial power spike,
Speaker 1: there was a second power spike, and that's when you
Speaker 1: had another explosion and release of steam and nuclear steam,
Speaker 1: and then there was the terrible fallout that happened in
Speaker 1: a huge radius around your noble Belarus in particular was
Speaker 1: hit really really hard by that radio and it was UH.
Speaker 1: And there there are levels of nuclear disaster. We give
Speaker 1: them a numeric UH assignment for how bad it is,
Speaker 1: and it goes from one to seven. Chernobyl was a
Speaker 1: seven three mile island which happened in the United States
Speaker 1: nineteen seventy nine. That was a five, and the Japan
Speaker 1: incident right now is is listed as six. Of course,
Speaker 1: that can change over time and things get worse. Um
Speaker 1: hopefully it will not so, but yeah, because Chernobyl was
Speaker 1: was not as protective as it needed to be. That's
Speaker 1: why the it was ended up being a seven. Like
Speaker 1: if it had had the right protections in place, it
Speaker 1: may still have been a terrible, terrible accident, but it
Speaker 1: may not have been as bad as it turned out
Speaker 1: to be. Three Mile Island was interesting and that uh,
Speaker 1: it was a combination of user error and mechanical failure.
Speaker 1: There was a valve that was open, and then the
Speaker 1: power to the valve was shut off, which normally would
Speaker 1: mean the valve would close. The valve would only open
Speaker 1: when powered. There's a mechanical failure. The valve did not close,
Speaker 1: and because um the indicator on the console said that
Speaker 1: there was no longer power going to that valve, all
Speaker 1: the operators assumed that the valve was closed, but their
Speaker 1: readings were showing that the pressure and temperature were off,
Speaker 1: like the pressure and temperature of the core should not
Speaker 1: have been what it was. Well, the reason why there
Speaker 1: was a problem was because the water was boiling off
Speaker 1: and there was this open valve and so there was
Speaker 1: an open you know, the pressure was not building the
Speaker 1: right way. But it took hours for them to figure
Speaker 1: out what the problem was. Actually, there was a shift change,
Speaker 1: and it was when someone from the new shift was
Speaker 1: looking at the problem that they figured it out. And
Speaker 1: then by then the scare had really hit. Unfortunately, Three
Speaker 1: Mile Island wasn't as bad as it could have been.
Speaker 1: There was no There was only I think there's a
Speaker 1: partial melt down, which was scary, but it could have
Speaker 1: been so much worse if someone had not picked up
Speaker 1: on that mistake. Now as far as Japan goes, Uh,
Speaker 1: we talked about the boron uh and the seawater. Well,
Speaker 1: dumping seawater into the reactor is pretty much a last
Speaker 1: step because the seawater is going to ruin that reactor.
Speaker 1: You're not gonna be able to use it again. Um.
Speaker 1: And the boron is there to help absorb those neutrons,
Speaker 1: like Chris was saying. Yes. Another another one of the
Speaker 1: problems that they were mentioning on the news yesterday as
Speaker 1: that the day we're recording this is that Um there
Speaker 1: they are currently this. This will show you probably when
Speaker 1: we're recording this. Uh. They were talking about the pumps
Speaker 1: that are in place. They wanted to be able to
Speaker 1: restart them. They've had trouble doing that and they're going
Speaker 1: to have more trouble doing that now. Uh. They're hoping
Speaker 1: to again as at the time we're recording, to restore
Speaker 1: electricity to the plant so that they can go ahead
Speaker 1: and shut the pumps back on. But for the reactors
Speaker 1: UH in which they have introduced seawater, this is an
Speaker 1: issue because the seawater also clogs those pumps, so it
Speaker 1: is going to be even more difficult for them to
Speaker 1: contain the situations in those damaged reactors UH today than
Speaker 1: it would have been a few days ago when the
Speaker 1: problem was first getting out of hand. Yeah, the issue
Speaker 1: was just that if they did not introduce the seawater,
Speaker 1: there was there was an increased danger of a meltdown because,
Speaker 1: like we said, this temperature just keeps on going. It's
Speaker 1: not even with the control rods in place, which the
Speaker 1: system did do UM, it does not eliminate that heat.
Speaker 1: You have to be able to circulate the coolant through
Speaker 1: there in order to to maintain the temperature. And UM,
Speaker 1: because there was no way to circulate the coolant, they
Speaker 1: had a choice either they introduced the seawater and boron
Speaker 1: into the reactor core, or they take a chance on
Speaker 1: a meltdown. And and clearly the second option is not
Speaker 1: one that anyone wants to take. That that is not
Speaker 1: an option, right. So there's a lot of concern actually
Speaker 1: that this this UH will really set Japan back quite
Speaker 1: a bit because they are very reliant on nuclear power
Speaker 1: and that um losing this facility, which it's quite possible
Speaker 1: that they will lose at least, uh more than half
Speaker 1: of the reactors in this facility, that it will really
Speaker 1: impact their ability to create electricity. And the quake in
Speaker 1: general has really um, I mean, it seems it seems
Speaker 1: weird to say this because there are so many more
Speaker 1: important tragedies that are connected to the quake, But the
Speaker 1: quake itself could actually set back everything from electronics to computers,
Speaker 1: just because so much of it is manufactured in Japan
Speaker 1: and those manufacturing facilities were damaged in in the quake.
Speaker 1: That that's true. Um, Even places that weren't directly hit
Speaker 1: by the tsunami are still suffering problems. Um. And from
Speaker 1: what I understand, the majority of flash memory used in
Speaker 1: all kinds of electronic devices cell phones, smartphones, tablets, MP
Speaker 1: three players, and all kinds of other things, the majority
Speaker 1: of it comes from Japan. Uh So this is likely
Speaker 1: to u to cause problems in the supply chain and
Speaker 1: disrupt um electronics manufacturers the world over. And of course,
Speaker 1: you know, those those people who who weren't directly hit
Speaker 1: probably would like to get back to work. But this
Speaker 1: is going to be difficult for them to be able
Speaker 1: to move on and and do things that they want
Speaker 1: to do again. You know, even even people who weren't
Speaker 1: directly affected by uh, you know, losing their homes and
Speaker 1: losing friends and loved ones. Um, you know, this is
Speaker 1: this is difficult for for them as well. It's a
Speaker 1: major catastrophe. It's all. It's I was gonna say it's
Speaker 1: almost unimaginable to me, but no, I think I have
Speaker 1: to say it's unimaginable. I I cannot comprehend the level
Speaker 1: of catastrophe this is. I mean, I see the pictures,
Speaker 1: and I see the video, and I hear the testimonials
Speaker 1: and it's all heartbreaking. But it's just there's I can't
Speaker 1: grasp it. It's beyond my ability. Um, and guys, I
Speaker 1: want to say this before we before we start wrapping up.
Speaker 1: We have some amazing articles on how stuff works dot Com,
Speaker 1: about nuclear reactors, about radiation, and about the Japanese crisis.
Speaker 1: There's how nuclear power works, how Japan's nuclear crisis works,
Speaker 1: how radiation works. These articles are fantastic. I read through
Speaker 1: all of them in prep for this UH, this podcast
Speaker 1: and the writing on these are amazing. I mean, you
Speaker 1: get the Marshall brain and Robert Lamb and uh and
Speaker 1: and Deborah Ront's all did fantastic jobs. And my hat
Speaker 1: is off to them because they took a very complex,
Speaker 1: dense subject and they broke it down in a really
Speaker 1: understandable way. So if you want to learn more, I
Speaker 1: highly recommend you check them out. Yeah. There there are
Speaker 1: so many other types of uh nuclear energy to the
Speaker 1: haven't touched on and talk anything about, uh some of
Speaker 1: the other new technologies that people are trying out now, um,
Speaker 1: one of them being the pebble bed reactor that they're
Speaker 1: starting to roll out in China, which, from what I understand,
Speaker 1: maybe to some degree safer there's less chance of something
Speaker 1: like a meltdown occurring because it uses a different method
Speaker 1: of nuclear reaction, and that might be maybe we can
Speaker 1: look at that again when when this uh these issues
Speaker 1: aren't so fresh and we can uh uh you know,
Speaker 1: look at some of those. And I'm also interested in personally,
Speaker 1: and something that I read about and wired um a
Speaker 1: couple of years ago now or maybe about a year
Speaker 1: and a half ago, thorium using thorium, which is not
Speaker 1: nearly as radioactive as uranium. Of course it will carry
Speaker 1: for some people, probably for a lot of people, the
Speaker 1: stigma of being labeled nuclear energy. But from what I understand,
Speaker 1: you can hold the piece of thorium in your hand
Speaker 1: and you should not suffer any ill effects because it's
Speaker 1: not the same kind of it's not as radioactive as
Speaker 1: as uranium or plutonium, and can be used on a
Speaker 1: smaller scale with uh, you know, the possibility. Like I said,
Speaker 1: I'm only reading this, but it doesn't look like there's
Speaker 1: nearly the possibility of uh, the kind of disaster that
Speaker 1: we're talking about here. So there might be other kinds
Speaker 1: of technologies that will use in the future that can
Speaker 1: still harness the power of the atom without being so
Speaker 1: dangerous in the event of an act of you know,
Speaker 1: a nature event like this. And I imagine that this,
Speaker 1: this disaster will definitely make countries around the world rethink
Speaker 1: their their approach to nuclear power. Well, that's already that's
Speaker 1: already happening in the United States. President Obama has ordered
Speaker 1: um a look at all the nuclear reactors currently in
Speaker 1: service to to just as a check up to see
Speaker 1: how they're doing. Germany, I think has taken all of
Speaker 1: theirs offline, um with the idea that they will evaluate
Speaker 1: their safety. There were bills in many countries or laws
Speaker 1: already passed to extend the life of aging nuclear reactors
Speaker 1: that from one understand, are being rescinded one by one
Speaker 1: as people are rethinking the possibility that older reactors and
Speaker 1: this the reactor in Japan was older too. Yeah. Um so,
Speaker 1: I mean there you know, as as we complain about
Speaker 1: very often, technology changes very quickly and it's hard for
Speaker 1: us to keep track of It's also changing in the
Speaker 1: nuclear industry as well, and there are new safe safety
Speaker 1: measures that might be implemented in a in a new
Speaker 1: reactor that wouldn't have been implemented in the nineties, seventies
Speaker 1: and eighties. It's just the question of will it be
Speaker 1: politically feasible to implement nuclear power, because uh, it's one
Speaker 1: thing to to tell people that safety measures have improved
Speaker 1: and that, uh that we've learned lessons from these events
Speaker 1: that we can, um we can implement in the future.
Speaker 1: But there's it's such an emotional issue and uh it
Speaker 1: has it does have problems. I mean, the nuclear waste
Speaker 1: is still a very very big and uh, there's not
Speaker 1: an easy solution to that, and as long as those
Speaker 1: still exist, I think we're going to see increased resistance
Speaker 1: to implementation of nuclear power, which I mean that's gonna
Speaker 1: be very frustrating for some people, although you have to
Speaker 1: admit that, um that the we've seen examples of things
Speaker 1: going wrong, and sometimes it's because people did not react
Speaker 1: the right way, and sometimes it's just that the perfect
Speaker 1: set of circumstances hit in order for something to go
Speaker 1: terribly wrong. And you know, there there is the argument
Speaker 1: you could make that the likelihood of that happening is low,
Speaker 1: but there's also the argument of any likelihood is too much, right.
Speaker 1: So it'll be interesting to see where the future of
Speaker 1: nuclear power goes. It'll be interesting for me to see
Speaker 1: if the the projects that are trying to make breakthroughs
Speaker 1: infusion power suffer as a result, because that is another
Speaker 1: form of nuclear energy, and uh, it's a frame form
Speaker 1: of nuclear energy. It's not the same as vision at all.
Speaker 1: But it could very well be that just because it
Speaker 1: has that association, that these programs could start to lose funding.
Speaker 1: So we'll have to keep our eyes open see what happens. Uh.
Speaker 1: Our thoughts go out to everyone in Japan. And all
Speaker 1: those who are affected by this disaster. And it's absolutely
Speaker 1: a tragic event. And uh and we really feel for
Speaker 1: you guys. Um, if you guys want to talk to
Speaker 1: us about nuclear power, if you have your own thoughts
Speaker 1: you would like to share, please do so. You can
Speaker 1: contact us on Twitter and Facebook. That handle is tech
Speaker 1: Stuff hs W, or you can write us an email.
Speaker 1: That email addresses tech stuff at how stuff works dot com.
Speaker 1: Chris and I will talk to you again really soon.
Speaker 1: For more on this and thousands of other topics. Is
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