Latest / Daniel and Kelly’s Extraordinary Universe / Why don't we have nuclear powered airplanes?

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Why don't we have nuclear powered airplanes? · Daniel and Kelly’s Extraordinary Universe

• 0:00
  Speaker 1: Hey, everyone, A quick note to let you know that
• 0:02
  Speaker 1: our preschool science TV show on PBS Kids called Eleanor
• 0:06
  Speaker 1: Wonders Why just launched its second season. It's a show
• 0:10
  Speaker 1: about curiosity and exploration and learning to use science to
• 0:14
  Speaker 1: find your own answers to questions or Hey. And I
• 0:17
  Speaker 1: created the show a few years ago, and the second
• 0:19
  Speaker 1: season has just premiered. We're so excited to share this
• 0:23
  Speaker 1: new batch of stories and adventures. Check it out on
• 0:25
  Speaker 1: PBS Kids. Eleanor Wonders Why. Hey, Kelly, do your kids
• 0:37
  Speaker 1: like to fly?
• 0:38
  Speaker 2: Yeah, they do, particularly my oldest. They were a little
• 0:42
  Speaker 2: bit scared at first, but I was explaining to them
• 0:45
  Speaker 2: that likes flying on a plane is probably safer than
• 0:48
  Speaker 2: driving in a car, and I eventually convinced them it's
• 0:50
  Speaker 2: safe and now they just enjoy it.
• 0:51
  Speaker 1: Hmmm, you convince them it's safe?
• 0:53
  Speaker 2: Huh, Daniel, what does that mean? Flying? Flying is safe?
• 0:59
  Speaker 2: But have you figured out a way to make it unsafe?
• 1:02
  Speaker 1: I mean, current airplane technology is mostly pretty safe, but
• 1:06
  Speaker 1: there are some pretty cool ideas out there.
• 1:09
  Speaker 2: Okay, wait, safe and boring as you described to current planes.
• 1:14
  Speaker 2: I feel like that's what you're going for. That's what
• 1:17
  Speaker 2: you want with planes.
• 1:18
  Speaker 1: I guess so. But I bet your kids want a
• 1:20
  Speaker 1: ride at a new experimental crazy plane that involve nuclear power,
• 1:25
  Speaker 1: don't they?
• 1:26
  Speaker 2: I bet they won't because they're not going to hear
• 1:28
  Speaker 2: about it, And I'm about letting you hear my kids.
• 1:46
  Speaker 1: Hi. I'm Daniel. I'm a particle physicist and a professor
• 1:49
  Speaker 1: at UC Irvine, and I want to bring the fun
• 1:51
  Speaker 1: into Kelly's kids' lives.
• 1:53
  Speaker 2: I'm Kelly water Smith. I'm adjoned at Rice University, and
• 1:58
  Speaker 2: I think flying should be boring and safe.
• 2:01
  Speaker 1: But what if we have crazy new ideas for how
• 2:03
  Speaker 1: to get big heavy stuff into the air.
• 2:06
  Speaker 2: Dream a little, Kelly.
• 2:12
  Speaker 1: That's not why I had kids, That's why other people
• 2:14
  Speaker 1: had kids.
• 2:19
  Speaker 2: Not sure you understand people in their motivations very well, Daniel.
• 2:23
  Speaker 1: That's probably true, And my goal here is not to
• 2:25
  Speaker 1: explain people and their motivations, but the universe. So welcome
• 2:30
  Speaker 1: to the podcast Daniel and Jorge explain the Universe production
• 2:33
  Speaker 1: of iHeartRadio, in which we do just that. We try
• 2:36
  Speaker 1: to explain everything that's out there in the universe to you,
• 2:39
  Speaker 1: the fundamental laws of reality, the nature of space and time,
• 2:42
  Speaker 1: and how we can use our understanding of that, to
• 2:45
  Speaker 1: bend reality to our will, to make it do cool.
• 2:48
  Speaker 1: Stuff might fly tons and tons of metal through the
• 2:51
  Speaker 1: air across the ocean totally safely.
• 2:54
  Speaker 2: Yes, safely, cool and safe because cool is safe kids.
• 3:00
  Speaker 1: But we're also interested in pushing the boundaries of what
• 3:03
  Speaker 1: can be done. Every time we learn something new about
• 3:05
  Speaker 1: the universe, we wonder, how can we use this to
• 3:07
  Speaker 1: improve our lives? How can we use this to make
• 3:10
  Speaker 1: life more exciting? What new kind of gizmo or what's
• 3:14
  Speaker 1: it can this allow us to create that might change
• 3:16
  Speaker 1: the very nature of what it's like to be a
• 3:19
  Speaker 1: living human in this universe.
• 3:21
  Speaker 2: I begrudgingly agree.
• 3:24
  Speaker 1: And of course, the last century has given us lots
• 3:26
  Speaker 1: of new insights into the nature of reality at the
• 3:29
  Speaker 1: microscopic level. Zooming in past atoms, we've discovered all sorts
• 3:33
  Speaker 1: of new rules for how the universe works, rules that
• 3:36
  Speaker 1: are counterintuitive, that disagree with our classical intuition for how
• 3:40
  Speaker 1: things operate. This new realm of quantum mechanics has opened
• 3:44
  Speaker 1: up lots of crazy new opportunities and dangers for all
• 3:48
  Speaker 1: sorts of humanity. Atomic weapons, atomic power, atomic devastation, and
• 3:52
  Speaker 1: of course potential for nuclear winter. All sorts of consequences
• 3:56
  Speaker 1: for doing.
• 3:56
  Speaker 2: Physics, all kinds of reasons for my kids to not
• 3:59
  Speaker 2: listening podcast. Do we talk about Project Plowshare at all?
• 4:05
  Speaker 1: I can't remember what is Project Plowshare? Tell me.
• 4:08
  Speaker 2: Project Plowshare was a US project to try to use
• 4:10
  Speaker 2: nuclear weapons for like cool good stuff, like making bays
• 4:14
  Speaker 2: by blowing up land so that you can have a
• 4:16
  Speaker 2: little area where you can bring ships inside close to
• 4:19
  Speaker 2: land at some point. And we had a bunch of
• 4:22
  Speaker 2: projects where we set off nuclear weapons for like funzies
• 4:25
  Speaker 2: and building stuff that we thought might be nice. But
• 4:29
  Speaker 2: of course, you know, being with the US's history, we
• 4:32
  Speaker 2: often did it in ways that were not amenable to
• 4:36
  Speaker 2: the desires of the people who lived in that area,
• 4:39
  Speaker 2: and eventually we stopped doing this, thankfully. But Russia or
• 4:43
  Speaker 2: the Soviet Union had a similar program. And if you
• 4:45
  Speaker 2: look up Lake Chaign, I think that's how you pronounce
• 4:48
  Speaker 2: it Chigan. I don't know. Anyway. They've got a lake
• 4:52
  Speaker 2: and it's perfectly circular, and that's because it was created
• 4:55
  Speaker 2: by a nuclear weapon exploding, and then some poor person
• 4:58
  Speaker 2: had to swim across it like convince everyone, no, it's safe,
• 5:01
  Speaker 2: this is cool.
• 5:02
  Speaker 1: Cool, Wow, terraforming with nuclear weapons. That's just terrifying. But
• 5:10
  Speaker 1: there was an era after the discovery of atomic power
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  Speaker 1: when people felt like this could change lots of different
• 5:16
  Speaker 1: aspects of our lives. Our nuclear knowledge could wiggle its
• 5:19
  Speaker 1: fingers into all sorts of aspects of everyday life. And
• 5:22
  Speaker 1: of course we know now that we have nuclear power plants,
• 5:25
  Speaker 1: and there are nuclear powered chips and nuclear powered submarines.
• 5:29
  Speaker 1: But today we want to explore another question, which is
• 5:31
  Speaker 1: why nuclear power hasn't made inroads into the skies. And
• 5:36
  Speaker 1: so on today's podcast, we'll be asking the question why
• 5:44
  Speaker 1: don't we have nuclear powered airplanes?
• 5:47
  Speaker 2: Well? Should we see what the audience thinks.
• 5:50
  Speaker 1: This is a fascinating question, and so as usual, we
• 5:52
  Speaker 1: went out into our list of volunteers to see what
• 5:55
  Speaker 1: people thought about having a nuclear reactor on board an airplane.
• 6:00
  Speaker 1: If you'd like to participate in this segment of the podcast,
• 6:02
  Speaker 1: please don't be shy. Write to me two questions at
• 6:05
  Speaker 1: Daniel and Jorge dot com. We will set you up
• 6:08
  Speaker 1: with random physics questions in your inbox every week. Everybody's welcome.
• 6:13
  Speaker 1: So before you hear these answers, think to yourself, how
• 6:16
  Speaker 1: do you feel about having a nuclear reactor on board
• 6:19
  Speaker 1: your airplane. Here's what people had to say.
• 6:22
  Speaker 3: Well, we are too far from having electric powered planes,
• 6:26
  Speaker 3: but if we use water and eating them up with
• 6:29
  Speaker 3: nuclear reactor and use it as a propellant, then it
• 6:33
  Speaker 3: could be. But that would require enormous amount of water
• 6:35
  Speaker 3: to be stored, so it's not very likely.
• 6:38
  Speaker 1: But maybe in the future.
• 6:41
  Speaker 4: I'd say no, because they're quite heavy, I think, and
• 6:45
  Speaker 4: I think they need to be called down quite a lot.
• 6:48
  Speaker 4: So I know in nuclear submarines they use the sea
• 6:52
  Speaker 4: walls to cool down the reactor, so I don't know
• 6:54
  Speaker 4: what is heavy. And unless it was a very very
• 6:57
  Speaker 4: big airplane with nobody on board and nothing on board
• 7:00
  Speaker 4: other than a nuclear reactor, i'd say no.
• 7:04
  Speaker 5: Well, I wouldn't fly on it. I mean, a nuclear
• 7:06
  Speaker 5: reactor is typically just a heat engine, steam engine, or
• 7:10
  Speaker 5: just creating heat like on the Mars Rovers. So to
• 7:14
  Speaker 5: have enough energy to continuously power an airplane would need
• 7:17
  Speaker 5: it to be enormous, and then I don't think you
• 7:20
  Speaker 5: could put it on the airplane, So probably not. But
• 7:23
  Speaker 5: since you're asking, maybe.
• 7:26
  Speaker 6: Let's see, the biggest airplanes can carry about four hundred
• 7:30
  Speaker 6: or five hundred tons, so I would say, if you
• 7:33
  Speaker 6: could make one that's light enough, I would say, yes,
• 7:36
  Speaker 6: they put them in submarines, So yes, I.
• 7:39
  Speaker 2: Thought these answers were really good. To be honest, heavy
• 7:42
  Speaker 2: wasn't the main concern that I had in mind when
• 7:45
  Speaker 2: you sent the title of this episode to me. My
• 7:49
  Speaker 2: thought was I wouldn't want to ride that close to
• 7:52
  Speaker 2: a nuclear reactor. But then I thought, oh, well they
• 7:54
  Speaker 2: do it on submarines, is probably okay. So then after
• 7:58
  Speaker 2: deciding that that concern wasn't big one, I thought, well,
• 8:01
  Speaker 2: probably I don't want nuclear material flying over my head.
• 8:04
  Speaker 2: When sometimes airplanes don't come down in the safest ways,
• 8:08
  Speaker 2: you wouldn't want them to drop their nuclear material and
• 8:12
  Speaker 2: spread it across earth. But this the most common thing
• 8:15
  Speaker 2: that the audience said was that this is too heavy
• 8:18
  Speaker 2: to work on planes. Were they on the right track.
• 8:21
  Speaker 1: That's definitely an issue, and it's actually all entangled because
• 8:25
  Speaker 1: one of the reasons that submarines can be saved is
• 8:27
  Speaker 1: that they have lots of shielding because they don't have
• 8:29
  Speaker 1: to worry about weight, and so these questions of safety
• 8:33
  Speaker 1: and shielding are all connected.
• 8:36
  Speaker 2: Excellent, good job, audience. So my first thought here is
• 8:41
  Speaker 2: that planes seem to be doing just fine, But of
• 8:45
  Speaker 2: course it would be really nice if planes were using
• 8:48
  Speaker 2: cleaner energy sources, and nuclear power is a good energy
• 8:54
  Speaker 2: source if you're trying to cut down on greenhouse gases.
• 8:57
  Speaker 2: So let's talk about the pros first. They assume that's
• 9:00
  Speaker 2: one of the pros. So why else might you want
• 9:03
  Speaker 2: nuclear powered aircraft.
• 9:05
  Speaker 1: The whole idea for nuclear power aircraft comes out of
• 9:08
  Speaker 1: World War II. Of course, that's when nuclear powers invented,
• 9:11
  Speaker 1: and maybe the primary motivation was to make airplanes that
• 9:14
  Speaker 1: could fly for longer without needing to refuel. And World
• 9:18
  Speaker 1: War Two, a lot of our strategic decisions were based
• 9:20
  Speaker 1: on needing to refuel. You had these bombers and you
• 9:23
  Speaker 1: wanted to drop bombs on enemy territory, and those bombers
• 9:27
  Speaker 1: needed gas, and that limited how far they could fly,
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  Speaker 1: and in many missions the bombers came back with just
• 9:33
  Speaker 1: like fumes. It really limited the reach of these bombers,
• 9:37
  Speaker 1: And so people were thinking, could we develop airplanes that
• 9:39
  Speaker 1: ran on nuclear power that could fly for much much
• 9:43
  Speaker 1: longer because nuclear fuel is so much denser. So, for example,
• 9:46
  Speaker 1: submarines can operate for a very very long time without refueling.
• 9:51
  Speaker 1: Same with nuclear powered aircraft carriers. These things can sometimes
• 9:54
  Speaker 1: go decades without refueling, except.
• 9:58
  Speaker 2: The humans who ride them would need to refuel by
• 10:02
  Speaker 2: sleeping at night. But I guess, I guess you could
• 10:05
  Speaker 2: have a number of pilots circulate or you know, taking
• 10:08
  Speaker 2: turns that you could keep going. But like those bombers,
• 10:11
  Speaker 2: aren't the figure something like one in four didn't return
• 10:14
  Speaker 2: on each run. Think of the amount of nuclear material
• 10:17
  Speaker 2: that would be falling to Earth with these bombers as
• 10:21
  Speaker 2: they got shot down. But all right, we're probably going
• 10:23
  Speaker 2: to talk about that in the con section. I'm guessing so,
• 10:26
  Speaker 2: but you know me, I always get hung up on
• 10:28
  Speaker 2: the cons. Okay, so let's spok about more pros.
• 10:30
  Speaker 1: That's definitely an issue. But if your goal is to
• 10:33
  Speaker 1: have airplanes that could like fly all over the world
• 10:35
  Speaker 1: and drop bombs on any target without needing to refuel,
• 10:39
  Speaker 1: or without needing to worry about like tricky aerial refueling
• 10:43
  Speaker 1: maneuvers which make new and the refueling plane very vulnerable
• 10:46
  Speaker 1: to enemy aircraft, or without needing to like buy territory
• 10:51
  Speaker 1: in foreign countries for refueling bases. Did you know, for example,
• 10:54
  Speaker 1: the United States tried to buy Greenland from Denmark even
• 10:57
  Speaker 1: before Trump offered. They wanted to refueling in Greenland, and
• 11:01
  Speaker 1: they offered one hundred million dollars in gold to Denmark
• 11:04
  Speaker 1: for Greenland, and Denmark said, no, thanks, We'll keep Greenland.
• 11:09
  Speaker 2: And we did this so that we could refuel there.
• 11:11
  Speaker 2: That was our main purpose.
• 11:13
  Speaker 1: Yeah, Greenland is very strategic location between the US and
• 11:16
  Speaker 1: the Soviet Union. Absolutely. Yeah.
• 11:18
  Speaker 2: Did we try Iceland next, maybe for less money?
• 11:24
  Speaker 1: And then Island was offended. They're like, what we're not
• 11:26
  Speaker 1: as value is Greenland? Are you guys crazy? Yeah? Hence
• 11:31
  Speaker 1: the Cold War very chilly. But the idea was basically
• 11:34
  Speaker 1: try to get airplanes that could fly longer, right, And
• 11:37
  Speaker 1: the concept there, the physics underneath it is that nuclear
• 11:40
  Speaker 1: fuel is so much more dense. Like if you think
• 11:43
  Speaker 1: about how much energy is stored in uranium versus how
• 11:47
  Speaker 1: much energy is stored in like diesel, it's really just
• 11:50
  Speaker 1: enormous like diesel, and gas has more energy than coal,
• 11:55
  Speaker 1: or more energy than like you know, animal fat or whatever.
• 11:58
  Speaker 1: But just by a few factors, uranium has seventy six
• 12:02
  Speaker 1: million megadewles of energy per kilo of uranium, whereas gas
• 12:07
  Speaker 1: has forty six megadels. So the energy density uranium is
• 12:11
  Speaker 1: a million times that of diesel.
• 12:13
  Speaker 2: Oh my gosh, that's incredible. Okay, so this is an
• 12:16
  Speaker 2: amazing power source. Tell us about subs and why it
• 12:20
  Speaker 2: works so well in submarines.
• 12:23
  Speaker 1: Yeah, this is something that works very very well for
• 12:25
  Speaker 1: submarines and the newest generation of submarines. They never need
• 12:29
  Speaker 1: to refuel like they think. These subs will last for
• 12:31
  Speaker 1: like fifty years, and the fuel will also last for
• 12:34
  Speaker 1: fifty years. You'd like, just build the sub, you build
• 12:37
  Speaker 1: the fuel in, and you never refuel it because it's
• 12:40
  Speaker 1: so energy dense. It's amazing.
• 12:42
  Speaker 2: That's incredible.
• 12:43
  Speaker 1: So they have these miniaturized reactors and they're powered by uranium,
• 12:47
  Speaker 1: and you know, there's fission that happens there and the
• 12:49
  Speaker 1: fission releases heat that heats water, which produces steam, which
• 12:54
  Speaker 1: turns a turbine which then directly turns the ship's propeller.
• 12:58
  Speaker 1: Often in land based nuclear power. The turbine then spins
• 13:01
  Speaker 1: a generator which makes electricity. You put it on the grid,
• 13:04
  Speaker 1: but there's no need here to generate electricity. You can
• 13:06
  Speaker 1: just directly have that turbine spin the ship's propeller. And
• 13:10
  Speaker 1: the cool thing is this is much quieter than a
• 13:12
  Speaker 1: diesel engine, and there's no pistons, for example, And so
• 13:15
  Speaker 1: if you're trying to run quiet underwater, that having a
• 13:19
  Speaker 1: nuclear powered submarine that never needs to come up to
• 13:21
  Speaker 1: refuel is quite the advantage from a military point of view.
• 13:25
  Speaker 2: That is pretty incredible. Is the US the only country
• 13:29
  Speaker 2: that has these? I'm going to guess that the Soviet
• 13:31
  Speaker 2: Union also came up with this, and so Russia has
• 13:33
  Speaker 2: it too.
• 13:34
  Speaker 1: Absolutely, the Soviets have them, and we've had them for decades.
• 13:37
  Speaker 2: They're not the Soviets anymore.
• 13:42
  Speaker 1: The Soviets had them. The Russians now have them, of course,
• 13:45
  Speaker 1: But this is something which is decades old. It was
• 13:48
  Speaker 1: nineteen sixty when we had the first submerged circumnavigation of
• 13:52
  Speaker 1: the globe, like the first time a submarine went around
• 13:55
  Speaker 1: the globe without surfacing. That's just like a decade and
• 13:58
  Speaker 1: a half after the whole invention of nuclear power.
• 14:01
  Speaker 2: Wow, that's incredible.
• 14:03
  Speaker 1: Yeah, And a few decades later we had more nuclear
• 14:06
  Speaker 1: reactors in ships than there were on land producing electric power. So,
• 14:11
  Speaker 1: like the military has really been into this idea for
• 14:14
  Speaker 1: a long time because they're like not refueling and they're
• 14:17
  Speaker 1: like the quietness of these reactors, and frankly, probably because
• 14:20
  Speaker 1: they don't also care as much about the potential disasters
• 14:23
  Speaker 1: and the ecological impact.
• 14:26
  Speaker 2: And why is that? Is it because the bottom of
• 14:28
  Speaker 2: the ocean is sort of desolate and it doesn't even
• 14:31
  Speaker 2: if a sub crashes, most of the material stays in
• 14:34
  Speaker 2: one spot, so the you know, devastation and the problems
• 14:37
  Speaker 2: are sort of limited. Or why do why would you
• 14:40
  Speaker 2: not care about the ecological Well, I.
• 14:43
  Speaker 1: Don't want to speak to the motivations of the military person,
• 14:47
  Speaker 1: but you know you're developing weapons anyway that are causing
• 14:50
  Speaker 1: huge destruction, right Your goal is destruction, So like gentleness
• 14:54
  Speaker 1: about the territory, I mean, I guess it must always
• 14:57
  Speaker 1: be second or a third concern. But you're also right that,
• 14:59
  Speaker 1: like submarine that crashes underwater, water is a pretty good
• 15:03
  Speaker 1: shield from radiation. And so unless that uranium then leaks
• 15:07
  Speaker 1: out and like spreads into ocean currents, the actual radiation
• 15:11
  Speaker 1: from the crash site is pretty limited to that location
• 15:14
  Speaker 1: because water is an excellent shield.
• 15:16
  Speaker 2: Okay, that's good, all right, So we use a lot
• 15:19
  Speaker 2: of these underwater. I happen to also know that they're
• 15:21
  Speaker 2: very helpful in space, So where have they been used
• 15:24
  Speaker 2: in space?
• 15:25
  Speaker 1: Vivin used underwater, they're also used on the surface. The
• 15:28
  Speaker 1: US Navy eleven carriers are all nuclear powered. Some of
• 15:32
  Speaker 1: these things have two some of them have eight separate
• 15:35
  Speaker 1: reactor units. So, like maritime nuclear power very well established.
• 15:40
  Speaker 1: But you're right, we also use nuclear power in space.
• 15:43
  Speaker 1: Some of the rovers that we have sent to other
• 15:45
  Speaker 1: planets use nuclear power. They don't have nuclear reactors in
• 15:49
  Speaker 1: the same way that these subs do in the sense
• 15:51
  Speaker 1: that they have controlled fission reactions. Instead, they use another
• 15:55
  Speaker 1: kind of nuclear power, where there's uncontrolled decay that essentially
• 15:58
  Speaker 1: leads to heating more like a nuclear battery. These used
• 16:02
  Speaker 1: plutonium and they worked for like ten to fifteen years,
• 16:05
  Speaker 1: providing a gentle source of heat which is then converted
• 16:07
  Speaker 1: into the electricity to run some of these rovers like
• 16:10
  Speaker 1: Curiosity and Perseverance. So we definitely have nuclear powered craft underwater,
• 16:15
  Speaker 1: on the surface and in space.
• 16:18
  Speaker 2: Well, we also have little nuclear reactors in some satellites.
• 16:21
  Speaker 2: We don't do it so regularly anymore. The US had
• 16:24
  Speaker 2: snapped ten A, which we sent up and it did
• 16:27
  Speaker 2: okay for a little while. Then it failed and we
• 16:30
  Speaker 2: boosted it to a graveyard orbit. So that didn't go
• 16:33
  Speaker 2: super well for us, and I think maybe it's leaking
• 16:36
  Speaker 2: a little nuclear material woops. And then the Soviets actually
• 16:40
  Speaker 2: sent up something like thirty three nuclear powered satellites and
• 16:44
  Speaker 2: they use these because they wanted to go kind of
• 16:47
  Speaker 2: lower for like surveillance purposes, and they were low enough
• 16:50
  Speaker 2: that they were starting to hit like atmosphere particles, so
• 16:53
  Speaker 2: solar panels would have slowed them down. So the nuclear
• 16:56
  Speaker 2: reactors allowed them to go for a long time without
• 16:58
  Speaker 2: the solar panels which would slow them down, and that
• 17:01
  Speaker 2: went okay most of the time. They didn't always spread
• 17:04
  Speaker 2: nuclear material across Canada, so that's good. There's just that
• 17:10
  Speaker 2: one time.
• 17:13
  Speaker 1: You get one freebie, right, I mean, I'm sure Canada
• 17:15
  Speaker 1: is cool with that one time.
• 17:17
  Speaker 2: There's a lot of Canada, and like a lot of
• 17:19
  Speaker 2: it's not being used for other stuff. Maybe.
• 17:22
  Speaker 1: Wow, you're pretty cavalier about safety when it's not your
• 17:25
  Speaker 1: kids involved, Kelly. You know Canadians have kids also, you
• 17:29
  Speaker 1: understand how that works.
• 17:31
  Speaker 2: I am so sorry Canadians. I was joking and I
• 17:34
  Speaker 2: shouldn't have I shouldn't have done it, all right, So
• 17:38
  Speaker 2: we've talked about the various places that we find nuclear reactors.
• 17:42
  Speaker 2: Let's take a break and you know, shield our houses
• 17:46
  Speaker 2: against the radioactive material that might come falling down on
• 17:49
  Speaker 2: us at some point in the future. And we'll talk
• 17:51
  Speaker 2: about engine concepts next, and we're back, all right. So
• 18:08
  Speaker 2: we've talked about the various ways nuclear power has been
• 18:11
  Speaker 2: used in things like submarines and satellites and rovers and
• 18:16
  Speaker 2: of course nuclear power plants. Let's talk about some engine
• 18:19
  Speaker 2: concepts for how you might be able to make this
• 18:21
  Speaker 2: stuff work in an airplane.
• 18:23
  Speaker 1: Yeah, it's really fun to think about how you might
• 18:26
  Speaker 1: actually power an airplane using a nuclear reactor, because the
• 18:30
  Speaker 1: basic concept that works underwater is to have it directly
• 18:34
  Speaker 1: spin a propeller. But those propellers can spin fairly slowly
• 18:38
  Speaker 1: and still power the ship. But an airplanes, of course,
• 18:40
  Speaker 1: we have jet engines, and so people have explored lots
• 18:43
  Speaker 1: of different ways to make a nuclear powered aircraft. But
• 18:46
  Speaker 1: the leading idea I think is a nuclear jet engine.
• 18:50
  Speaker 2: Ooh sounds epic.
• 18:51
  Speaker 1: Yeah, So to review the way a jet engine works
• 18:55
  Speaker 1: in general, is essentially your burning fuel. Jet fuel essentially
• 18:58
  Speaker 1: some fossil fuel to heat the air, and that expands
• 19:02
  Speaker 1: through a turbine into a propelling nozzle to provide thrust.
• 19:06
  Speaker 1: So the goal of the fuel, the reason you need fuel,
• 19:09
  Speaker 1: the reason we have jet fuel in airplanes is to
• 19:12
  Speaker 1: heat a bunch of air which then expands, and that
• 19:14
  Speaker 1: expansion gives you thrust. So the core idea of a
• 19:18
  Speaker 1: nuclear power jet engine is just to replace the source
• 19:21
  Speaker 1: of heat. And so because fission produces heat, right, it
• 19:25
  Speaker 1: produces these energetic particles, people thought, well, let's just use
• 19:28
  Speaker 1: fission to directly heat the air instead of having the
• 19:31
  Speaker 1: diesel fuel do that job.
• 19:33
  Speaker 2: And then the air is just whatever air is surrounding
• 19:36
  Speaker 2: the airplane in the sky. Or are you like putting
• 19:40
  Speaker 2: some gas in there that gets heated.
• 19:42
  Speaker 5: No.
• 19:43
  Speaker 1: That's one of the cool things about a jet airplane
• 19:45
  Speaker 1: is that as it's flying through the air, it's pulling
• 19:47
  Speaker 1: air in, compressing it, and then expanding it with the heat.
• 19:51
  Speaker 1: And that's how the whole jet engine runs. That's why
• 19:53
  Speaker 1: jets don't work so well at low speeds because they
• 19:55
  Speaker 1: require this influx of air into the compressor oka And so.
• 19:58
  Speaker 2: Then would fission be able to heat it up even
• 20:01
  Speaker 2: more like better than the other methods, so you could
• 20:03
  Speaker 2: go even faster. Or the point is just that it
• 20:05
  Speaker 2: can heat for longer because it burns slowly.
• 20:08
  Speaker 1: Yeah, the idea is just that it can heat for
• 20:10
  Speaker 1: longer that the fuel is much more dense. And that's
• 20:14
  Speaker 1: also an attractive feature of nuclear power jets because you'd
• 20:17
  Speaker 1: like to be able to lower your weight in the air.
• 20:20
  Speaker 1: Right when the seven forty seven takes off or a
• 20:22
  Speaker 1: cross country trip, it's carrying enormous amounts of fuel. Some
• 20:26
  Speaker 1: of that fuel is just in order to provide the
• 20:28
  Speaker 1: thrust to carry the rest of the fuel. It's like
• 20:30
  Speaker 1: the whole rocket equation problem in miniature. And so if
• 20:33
  Speaker 1: you could figure out a way to make your fuel less,
• 20:36
  Speaker 1: then you can lighten the whole weight of the aircraft
• 20:38
  Speaker 1: and then need less fuel. Yeah.
• 20:39
  Speaker 2: So okay, So at the beginning of the show, the
• 20:41
  Speaker 2: listeners said that they thought the problem was weight, but
• 20:45
  Speaker 2: it sounds like you were saying that's not the problem. Actually,
• 20:47
  Speaker 2: this could be a less heavy way to fly.
• 20:50
  Speaker 1: Weight is definitely an issue, and we're going to talk
• 20:52
  Speaker 1: about like the shielding and the reactor itself being quite heavy.
• 20:56
  Speaker 1: But in terms of the fuel, there is a wind
• 20:58
  Speaker 1: and so we're going to keep track of the weight
• 21:00
  Speaker 1: accounting in terms of the fuel volume and weight. Nuclear
• 21:03
  Speaker 1: power winds. When it comes to the actual equipment involved,
• 21:06
  Speaker 1: you're going to see it's an overall loss, but you know,
• 21:08
  Speaker 1: there's something in the wind category there. And so people
• 21:13
  Speaker 1: have actually people and so people have actually built these things.
• 21:17
  Speaker 1: They have prototypes. You can go to the Idaho National Lab.
• 21:20
  Speaker 1: They have a couple of these set up that you
• 21:22
  Speaker 1: can actually see. They built them in the fifties and
• 21:25
  Speaker 1: they tested them, and there's sort of two different models there.
• 21:28
  Speaker 1: One is a direct air cycle, where the air comes
• 21:31
  Speaker 1: in from the compressor, goes directly into the nuclear core.
• 21:34
  Speaker 1: That air gets heated up by the nuclear power plant
• 21:37
  Speaker 1: and then emitted. That's very powerful, but the problem is
• 21:40
  Speaker 1: the air that comes out also kind of radioactive.
• 21:43
  Speaker 2: That's a problem, and so if.
• 21:45
  Speaker 1: You're like flying regularly back and forth across your own
• 21:48
  Speaker 1: country and you're spewing radiation and that's you know, bad.
• 21:52
  Speaker 1: So they developed a second model, an indirect air cycle,
• 21:55
  Speaker 1: where you basically have two different loops. You have the
• 21:58
  Speaker 1: air that comes in and then it gets heated by
• 22:00
  Speaker 1: something which has been heated by the nuclear reactor. So
• 22:03
  Speaker 1: for example, the nuclear actor doesn't directly heat the air.
• 22:06
  Speaker 1: It might heat like liquid metal in pipes, or very
• 22:09
  Speaker 1: high pressure water, which is then getting radioactive, but it's
• 22:12
  Speaker 1: not getting sprayed out the back of the jet engine. Instead,
• 22:15
  Speaker 1: it's just heating up the air. So you're sort of
• 22:17
  Speaker 1: shielding the air from the radioactivity by having this indirect
• 22:21
  Speaker 1: loop of liquid metal or high pressure water.
• 22:24
  Speaker 2: That sounds more complex but better.
• 22:27
  Speaker 1: Yeah, exactly, you're not killing your own people. But now
• 22:29
  Speaker 1: you have to have this extra machinery and you have
• 22:31
  Speaker 1: to hope that your high pressure liquid metal doesn't explode.
• 22:34
  Speaker 1: You have to monitor that, so it becomes more complicated,
• 22:37
  Speaker 1: which is the downside of it, But the basic idea works,
• 22:40
  Speaker 1: like in principle, you can have a nuclear powered jet engine.
• 22:45
  Speaker 2: Oh, I don't think I would want that flying over
• 22:48
  Speaker 2: my home. What are what are some of our other options?
• 22:52
  Speaker 1: So instead of having a jet engine, you could also
• 22:54
  Speaker 1: have a nuclear powered thermal rocket, so a chemical rocket,
• 22:59
  Speaker 1: the thing that like the set Urn and five used
• 23:01
  Speaker 1: to get off the surface of the Earth. You have
• 23:03
  Speaker 1: some chemical reaction which creates expansion and gives your propellants
• 23:06
  Speaker 1: basically momentum out the back. Right, This is the way
• 23:09
  Speaker 1: a rocket engine works. Well, you could imagine a nuclear
• 23:12
  Speaker 1: powered version of that where the heat comes from the
• 23:14
  Speaker 1: nuclear reaction and that flies off some propellants, and that
• 23:18
  Speaker 1: those propellants are then pumped through the core to heat
• 23:21
  Speaker 1: up something. So it's sort of similar to the jet
• 23:24
  Speaker 1: engine concept. You're using the nuclear reactor to heat something
• 23:27
  Speaker 1: and then that is expanding and flying out the back,
• 23:29
  Speaker 1: but we call this a thermal rocket instead of a
• 23:32
  Speaker 1: jet engine because you also don't have this compression cycle.
• 23:35
  Speaker 2: Is this what project Orion was all about.
• 23:37
  Speaker 1: Project Oryon was actually blowing up nuclear bombs behind it,
• 23:41
  Speaker 1: So it's sort of similar. It's sort of similar and
• 23:44
  Speaker 1: much more awesome and impossible, but.
• 23:50
  Speaker 2: Awesome if you're like not living on the planet where
• 23:52
  Speaker 2: they're trying it out, maybe.
• 23:53
  Speaker 1: But yeah, awesome sense Like if you see it, you're like,
• 23:57
  Speaker 1: oh my gosh. Wow.
• 24:01
  Speaker 2: So this is a more delicate approach, yeah, exactly.
• 24:05
  Speaker 1: The third approach is to think about action generating electrical
• 24:08
  Speaker 1: power and then using that electrical power to run like
• 24:10
  Speaker 1: an electrical engine. So you sort of separate the two components.
• 24:14
  Speaker 1: You have the nuclear planet on board, it's running, it's
• 24:17
  Speaker 1: producing steam that's turning a turbine that's running a generator
• 24:21
  Speaker 1: that's producing electrical power. Then you're feeding the electrical power
• 24:24
  Speaker 1: to like a turboprop engine, So the engine and the
• 24:27
  Speaker 1: power generation are separate.
• 24:29
  Speaker 2: So do you have a sense for out of these
• 24:31
  Speaker 2: three methods, which one is like the best. So they
• 24:34
  Speaker 2: differ in complexity, they differ in pollution or you know
• 24:38
  Speaker 2: how bad they are for the environment below, they probably
• 24:42
  Speaker 2: differ in how much power they produce for a given
• 24:44
  Speaker 2: amount of nuclear material. Is there like a favorite amongst
• 24:48
  Speaker 2: people who are excited about these ideas?
• 24:50
  Speaker 1: I think the jet engine is definitely the leading idea.
• 24:53
  Speaker 1: People like jets. Jets can go really fast, they work
• 24:56
  Speaker 1: really well on airplanes. People have actually built prototypes of
• 24:59
  Speaker 1: this that it can work. So the jet engine is
• 25:02
  Speaker 1: definitely the leading concept.
• 25:04
  Speaker 2: All right, So we've talked about the different ways to
• 25:06
  Speaker 2: make this work. We've talked about the pros. You know
• 25:09
  Speaker 2: why you would want to use nuclear power for an airplane,
• 25:13
  Speaker 2: But we all know that Kelly's the wet blanket around here.
• 25:15
  Speaker 2: So I'm excited for us to move on to the cons.
• 25:20
  Speaker 2: What are the reasons why this idea that sounds bad
• 25:22
  Speaker 2: to me is bad?
• 25:25
  Speaker 1: So many reasons. Let's start with the practical ones, and
• 25:28
  Speaker 1: that's the issue of weight, right, So reactors can be big,
• 25:32
  Speaker 1: and they can becumbersome. This has been mostly solved. People
• 25:36
  Speaker 1: have made miniature versions of reactors, like to put on
• 25:39
  Speaker 1: a submarine or to put several of them independent reactors
• 25:43
  Speaker 1: onto a big aircraft carrier, so you can make the
• 25:46
  Speaker 1: reactor fairly miniature. Physicists are really good at figuring that
• 25:49
  Speaker 1: kind of stuff out. What's very hard to miniaturize, though,
• 25:52
  Speaker 1: is the shielding. Like on a boat, a submarine, or
• 25:55
  Speaker 1: an aircraft carrier, you can have lots of layers of steel,
• 25:58
  Speaker 1: not a big deal, right, but on an airplane that
• 26:01
  Speaker 1: really costs you. And so it's possible to miniaturize the
• 26:05
  Speaker 1: reactor itself and reduce the weight there, but the shielding
• 26:08
  Speaker 1: is always going to be an issue. You want to
• 26:10
  Speaker 1: put a lot of heavy atoms between you and the
• 26:13
  Speaker 1: source of radiation, and a lot of heavy atoms are
• 26:16
  Speaker 1: always just going to be heavy.
• 26:17
  Speaker 2: So you had said that what was it like, gas
• 26:21
  Speaker 2: was something like fifty mega jeles per kilogram and uranium
• 26:27
  Speaker 2: was almost like eighty thousand. So even with that massive
• 26:32
  Speaker 2: increase in the amount of power that you get that
• 26:34
  Speaker 2: that doesn't do enough to even nearly offset the shielding.
• 26:38
  Speaker 2: Is that is that the message here.
• 26:40
  Speaker 1: Yeah, exactly. You either need a lot of shielding or
• 26:43
  Speaker 1: you need to not worry about your crew. And there
• 26:46
  Speaker 1: was actually a time where people talked about only having
• 26:49
  Speaker 1: crew that were like past child bearing age or had
• 26:52
  Speaker 1: a terminal disease. Anyway, people seriously talked about this kind
• 26:56
  Speaker 1: of stuff, like the documents from the Cold War are crazy.
• 27:00
  Speaker 2: Gonna die anyway, fly on our plane. You always wanted
• 27:03
  Speaker 2: to be a pilot, right, Crid.
• 27:06
  Speaker 1: And basically every step you take to make these things
• 27:09
  Speaker 1: more safe makes them impractical because now they're too heavy.
• 27:12
  Speaker 1: So not just the shielding but also the cooling systems. Right,
• 27:15
  Speaker 1: you want to generate this heat, but you also don't
• 27:17
  Speaker 1: want to overheat the rest of the airplane, and you
• 27:20
  Speaker 1: want to have devices in place to protect yourself against
• 27:22
  Speaker 1: meltdowns and all sorts of other issues, and so all
• 27:26
  Speaker 1: these cooling systems and safety systems and all that shielding
• 27:29
  Speaker 1: just gets heavy.
• 27:30
  Speaker 2: And I think perhaps the biggest dagger in this idea
• 27:35
  Speaker 2: to me is that if something goes wrong and you crash,
• 27:38
  Speaker 2: you spread nuclear material across a large area problems, which
• 27:42
  Speaker 2: is a problem.
• 27:43
  Speaker 1: Yes, poisoning the earth bad for sure, and it's definitely
• 27:46
  Speaker 1: something people think about also when we go into space
• 27:49
  Speaker 1: with nuclear power, Like every time we launch a rover
• 27:52
  Speaker 1: with a blob of plutonium in it, we worry, like,
• 27:55
  Speaker 1: is this going to be the time it blows up
• 27:56
  Speaker 1: in the atmosphere and then spreads that plutonium on our planet.
• 28:01
  Speaker 1: It's a risk every time they do it, and so
• 28:02
  Speaker 1: they worry about it. But those are pretty rare launches.
• 28:05
  Speaker 2: Oh you mean is this going to be the second time?
• 28:07
  Speaker 1: Yes, exactly, the next time.
• 28:10
  Speaker 2: The next time, yes.
• 28:11
  Speaker 1: But if you're talking about regularly flying bombers or even
• 28:14
  Speaker 1: commercial airplanes around the world with nuclear power, then you're
• 28:18
  Speaker 1: constantly taking that risk, and you know, crashes happen and
• 28:21
  Speaker 1: they kill people, and you don't want to then compound
• 28:24
  Speaker 1: the dangers and the consequences by also poisoning the planet.
• 28:28
  Speaker 2: Well, especially if these planes are being used as like
• 28:30
  Speaker 2: weapons of war or surveillance things, and you know other
• 28:34
  Speaker 2: countries might specifically be trying to shoot them down. That
• 28:37
  Speaker 2: seems bad. Yeah, although maybe a country won't shoot down
• 28:41
  Speaker 2: your spyplane if they know that they're going to be
• 28:42
  Speaker 2: like contaminating their land with radioactive waste. So, oh, you
• 28:46
  Speaker 2: have forgot that in the pro section, Daniel.
• 28:49
  Speaker 1: It's like the poison pill. But you know, realistically and
• 28:51
  Speaker 1: maybe sadly, if you ask me, like, why aren't their
• 28:54
  Speaker 1: nuclear powered airplanes right now? I don't think that's the reason.
• 28:58
  Speaker 1: I think the reason we don't have nuclear powered airplanes
• 29:01
  Speaker 1: or not because they aren't safe or they would kill
• 29:04
  Speaker 1: your crew. I think that people would make those compromises
• 29:07
  Speaker 1: if they thought it was good for our military or
• 29:10
  Speaker 1: our strategic situation. The reason I think is actually just strategic,
• 29:15
  Speaker 1: that nuclear powered bombers are no longer the quiver we
• 29:18
  Speaker 1: thought we needed in our arsenal is that.
• 29:21
  Speaker 2: Because satellites are so good, we can just buy from there,
• 29:24
  Speaker 2: or or yeah, why I.
• 29:25
  Speaker 1: Think the reason is that you don't need nuclear bombers.
• 29:28
  Speaker 1: You don't really need bombers anymore. I mean, we have ICBMs,
• 29:31
  Speaker 1: we can deliver nuclear weapons from the planes of Montana
• 29:35
  Speaker 1: without putting any humans in the air, And we have
• 29:38
  Speaker 1: nuclear powered submarines which can sneak around the oceans and
• 29:42
  Speaker 1: send nuclear weapons to anywhere on Earth very quietly. So
• 29:45
  Speaker 1: you don't really need nuclear powered bombers to stay aloft
• 29:48
  Speaker 1: for twenty four hours anymore. We can already bomb people
• 29:52
  Speaker 1: with impunity. Oh yay, And I think that's probably the
• 29:57
  Speaker 1: reason we don't have it. All these other concer earns
• 30:00
  Speaker 1: are reasonable, and it makes it impractical and it makes
• 30:03
  Speaker 1: it unsafe. But I think because it's not strategically valuable,
• 30:07
  Speaker 1: it is probably why we don't actually have them.
• 30:09
  Speaker 2: I guess we should all be glad that we have
• 30:11
  Speaker 2: ICBMs instead.
• 30:13
  Speaker 1: I suppose. But of course, the US spent billions and
• 30:17
  Speaker 1: billions of dollars and more than a decade trying to
• 30:20
  Speaker 1: build nuclear powered airplanes, and they actually flew airplanes with
• 30:24
  Speaker 1: reactors on board.
• 30:26
  Speaker 2: Were these jet engine reactors like you were talking about.
• 30:28
  Speaker 1: No, we've never actually flown an airplane that was powered
• 30:31
  Speaker 1: by the reactor, but they did fly airplanes that had
• 30:35
  Speaker 1: reactors on them.
• 30:36
  Speaker 2: All right, let's take a break and then you can
• 30:37
  Speaker 2: tell us more about that. Okay, So now we're back.
• 30:52
  Speaker 2: So you said that a plane has flown with a
• 30:55
  Speaker 2: nuclear reactor on it. Was that plane just transporting the
• 30:59
  Speaker 2: reactor from one place to another? Or Yeah? Why would
• 31:02
  Speaker 2: you want to carry nuclear material with you on a plane.
• 31:07
  Speaker 1: You don't pack nuclear material every time you take a flight, Kelly.
• 31:10
  Speaker 2: Not yet. But if it was strategically valuable, maybe I.
• 31:13
  Speaker 1: Want, Yes, you might exactly. Now, this was like the
• 31:16
  Speaker 1: first step in the US's exploratory project to build nuclear
• 31:20
  Speaker 1: power aircraft. They thought, well, first let's try to fly
• 31:23
  Speaker 1: an airplane with a reactor on board. Study the shielding issues,
• 31:27
  Speaker 1: the safety issues. Can we actually get this thing working
• 31:29
  Speaker 1: and operating in the environment of an airplane before we
• 31:33
  Speaker 1: actually try to connect the reactor to the engines. So
• 31:36
  Speaker 1: in the fifties they had this project using a modified
• 31:39
  Speaker 1: B thirty six bomber with a working nuclear reactor on board.
• 31:44
  Speaker 1: So you have your standard jet engines flying this airplane,
• 31:47
  Speaker 1: but in the center you have a miniaturized reactor designed
• 31:49
  Speaker 1: specifically for flight.
• 31:51
  Speaker 2: Wow, okay, and so this comports with your even if
• 31:55
  Speaker 2: it's hard, we'd do it if it were strategic. Because
• 31:57
  Speaker 2: this was what decade were they trying this in the fifties.
• 32:01
  Speaker 2: I'm going to assume that in the fifties they had
• 32:03
  Speaker 2: enough shielding. Is is that true? Or were they able
• 32:06
  Speaker 2: to do this because they you know, four went shielding
• 32:09
  Speaker 2: for this experiment.
• 32:11
  Speaker 1: Well both, Actually they put a lot of shielding. So
• 32:15
  Speaker 1: this is like an eighteen ton reactor producing one megawatt,
• 32:19
  Speaker 1: and they had it in this special version of the
• 32:20
  Speaker 1: aircraft where the humans would live in this little pod,
• 32:23
  Speaker 1: this like special cockpit that was super shielded. If twelve
• 32:27
  Speaker 1: tons of lead and rubber that the humans would get
• 32:30
  Speaker 1: in and the rest of the airplane would just be
• 32:32
  Speaker 1: like totally irradiated. And this little pod had like windows
• 32:36
  Speaker 1: in it that were like twelve inches thick and pockets
• 32:38
  Speaker 1: of water to protect them, but still there was a
• 32:41
  Speaker 1: lot of radiation even though they were shielded. It was
• 32:45
  Speaker 1: well above anything you would consider safe for the pilots.
• 32:48
  Speaker 2: Oh yikes. And if you ever need to do any
• 32:50
  Speaker 2: work on the body of the plane, any technician who's
• 32:53
  Speaker 2: working on it is going to be getting your radiated.
• 32:56
  Speaker 1: Right, yeah, exactly. The whole thing is going to be
• 32:58
  Speaker 1: a disaster. And you know, for the project, they only
• 33:01
  Speaker 1: recruited pilots above child bearing age because they basically knew
• 33:04
  Speaker 1: that they were killing these people.
• 33:06
  Speaker 2: Oh my goodness, you know, us people above child bearing
• 33:09
  Speaker 2: age are still valuable. Just throwing that out there.
• 33:15
  Speaker 1: It's kind of amazing how they treated these things, like
• 33:17
  Speaker 1: they knew that there were potential disasters, and they actually
• 33:20
  Speaker 1: tried to plan for them. Like, so, this thing took
• 33:22
  Speaker 1: flight in the fifties. They made forty six flights with
• 33:25
  Speaker 1: this bomber, and every time they did, they also flew
• 33:29
  Speaker 1: it with a special extra bomber that had specially trained
• 33:32
  Speaker 1: paratroopers that if this plane crash, the paratroopers would jump
• 33:35
  Speaker 1: out of the airplane, paratroop down to the crash site
• 33:38
  Speaker 1: and seal it off. They were like nuclear trained paratroopers
• 33:42
  Speaker 1: to help try and contain a disaster.
• 33:44
  Speaker 2: Were they all also above child bearing age?
• 33:49
  Speaker 1: Yes, and they all wore lead underwear.
• 33:51
  Speaker 2: Oh good, good plan, although it's too late, I guess.
• 33:54
  Speaker 2: But so when they were flying over the Southwest, were
• 33:57
  Speaker 2: they I guess specifically trying to fly over portions of
• 33:59
  Speaker 2: the southward but are not populated, like those paratroopers aren't
• 34:03
  Speaker 2: going to be helpful if it lands in Phoenix.
• 34:07
  Speaker 1: You know, I hope so. I don't have any details
• 34:09
  Speaker 1: to back that up, but I certainly hope they do.
• 34:11
  Speaker 1: But you know, this thing was airborne over the Southwest
• 34:14
  Speaker 1: forty six times in the fifties, so they definitely took
• 34:18
  Speaker 1: a risk.
• 34:19
  Speaker 2: Did it ever crash?
• 34:20
  Speaker 1: This one never did crash, but they tried to estimate
• 34:23
  Speaker 1: what would happen if it did crash. They created some
• 34:26
  Speaker 1: situations where they like put a fuel rod into a
• 34:29
  Speaker 1: burning jet engine in Idaho. So they did these experiments
• 34:33
  Speaker 1: and this is pretty bad. Those experiments ended up like
• 34:36
  Speaker 1: releasing quite a bit of caesium one thirty seven into
• 34:39
  Speaker 1: the air above Idaho. Yeah, it's pretty bad. And they
• 34:43
  Speaker 1: called this test operation Wiener Roast because they used because
• 34:48
  Speaker 1: they used a bunch of live cattle at varying distances
• 34:52
  Speaker 1: to help measure the effects of the radiation.
• 34:55
  Speaker 2: Wow, I mean they clearly should have been using doxins
• 35:00
  Speaker 2: little Wiener dogs. So I was I was soffing because
• 35:04
  Speaker 2: that was really a missed opportunity.
• 35:06
  Speaker 1: But you have just pissed off a lot of dog
• 35:08
  Speaker 1: owners out there, Kelly, I'm sure I have.
• 35:12
  Speaker 2: That's right.
• 35:14
  Speaker 1: So this is like a real government program.
• 35:16
  Speaker 4: You know.
• 35:16
  Speaker 1: They invested a lot of money into this program, billions
• 35:19
  Speaker 1: of dollars, decades of research to try to make this
• 35:22
  Speaker 1: thing happen. And they got as far as flying airplanes
• 35:24
  Speaker 1: around with nuclear reactors on board.
• 35:27
  Speaker 2: That's that's pretty far, just to confirm, we've never flown
• 35:30
  Speaker 2: anything that was actually powered by the nuclear power source, right,
• 35:35
  Speaker 2: It's just been sort of carried along like the.
• 35:37
  Speaker 1: First exactly, we got as far as airplanes with nuclear
• 35:41
  Speaker 1: reactors on board and then on the ground nuclear powered
• 35:45
  Speaker 1: jet engines that never flew, but we never put them
• 35:49
  Speaker 1: together into an airplane that was powered by a nuclear reactor.
• 35:52
  Speaker 2: Okay, so there's always a Soviet equivalent to these sorts
• 35:56
  Speaker 2: of things. So did the Soviet Union have a similar project?
• 36:01
  Speaker 1: Of course they did. In the fifties, the Soviet Union
• 36:03
  Speaker 1: had a project to fly one of their enormous TU twenties.
• 36:07
  Speaker 1: If you haven't seen a picture of one of these things,
• 36:09
  Speaker 1: this is like a really incredibly huge bomber with this
• 36:13
  Speaker 1: really elegant swept wing design, and they were working on
• 36:16
  Speaker 1: a similar project. Details are a little bit sketchy, and
• 36:19
  Speaker 1: part of the information is a little confusing because in
• 36:22
  Speaker 1: the fifties there was an article in Aviation Week that
• 36:26
  Speaker 1: turns out to have been mostly filled with false information,
• 36:29
  Speaker 1: claiming that the Soviets were already testing a nuclear airplane
• 36:33
  Speaker 1: that was powered by nuclear power. It turned out to
• 36:36
  Speaker 1: be misinformation, but you know, it kept the US program
• 36:39
  Speaker 1: going for a few more years. But the Soviets ended
• 36:41
  Speaker 1: up coming to the same conclusion we did, which is
• 36:44
  Speaker 1: that there's a huge radiation hazard to the crew, and
• 36:47
  Speaker 1: the crash risks were significant, and so they abandoned the
• 36:51
  Speaker 1: projects right around the same time we did.
• 36:53
  Speaker 2: Presumably they also had ICBMs and stuff, and so they
• 36:56
  Speaker 2: had the same capabilities without the technology just like did
• 37:00
  Speaker 2: right or were they behind on ICBMs.
• 37:02
  Speaker 1: No, that's exactly right, And so in the early sixties
• 37:05
  Speaker 1: both programs were abandoned because people realized that nuclear powered
• 37:09
  Speaker 1: submarines and ICBMs filled the strategic need in a much
• 37:13
  Speaker 1: simpler way than nuclear powered aircraft.
• 37:15
  Speaker 2: All right, So does that mean that both Russia and
• 37:19
  Speaker 2: the US, like no country on Earth right now was
• 37:22
  Speaker 2: working on this program because we all have better ways
• 37:24
  Speaker 2: to do this? Is that right?
• 37:25
  Speaker 1: Yes? And no no country on Earth that we know
• 37:28
  Speaker 1: of is trying to fly an atomic powered aircraft with
• 37:32
  Speaker 1: people on it. But the Russians claim to be working
• 37:35
  Speaker 1: on and have developed, a nuclear powered cruise missile. A
• 37:39
  Speaker 1: cruise missile is basically like an unmanned aircraft. It can fly,
• 37:43
  Speaker 1: it can loiter, it can turn. It's not just like
• 37:46
  Speaker 1: ballistic You're not just like throwing a bomb. It has
• 37:49
  Speaker 1: like engines and it can steer, et cetera. And the
• 37:52
  Speaker 1: idea of a nuclear powered cruise missile is still kind
• 37:55
  Speaker 1: of attractive because it would have basically unlimited range. This
• 37:58
  Speaker 1: thing could take off, fly around the Earth a couple
• 38:01
  Speaker 1: of times. You could even like hang out for a while,
• 38:03
  Speaker 1: like doing loops, you know, take the long path over
• 38:07
  Speaker 1: the North Pole or something. And so Russia claims to
• 38:10
  Speaker 1: be working on this thing. It's called the SSC x nine,
• 38:14
  Speaker 1: and in October twenty twenty three, Putin claimed that they
• 38:17
  Speaker 1: tested it successfully, though a lot of people are pretty skeptical.
• 38:21
  Speaker 2: Yeah, I mean, that guy always tells the truth. So
• 38:26
  Speaker 2: so slam dunk we got. We've got to believe it. Huh.
• 38:33
  Speaker 2: Do you really need a cruise missile that can like
• 38:36
  Speaker 2: circle the world four times? Why not just like know
• 38:38
  Speaker 2: where you're going to shoot it off, and shoot it
• 38:40
  Speaker 2: off from one spot using another fuel source and just
• 38:42
  Speaker 2: get there right away.
• 38:44
  Speaker 1: Yeah, a lot of these Russian modern weapons programs seem
• 38:47
  Speaker 1: kind of bombastic and unnecessary. Like he's also talking about
• 38:51
  Speaker 1: his supersonic missiles. It's like, you know, do you really
• 38:53
  Speaker 1: need supersonic missiles? Are there really an advantage to that? I
• 38:56
  Speaker 1: think a lot of this stuff might just be pr
• 38:59
  Speaker 1: I think and wants to advertise to the Russians that
• 39:03
  Speaker 1: their military is cutting edge, that they have advantages over
• 39:06
  Speaker 1: the West, et cetera, et cetera. So analysts that I've
• 39:09
  Speaker 1: read suggest that a lot of this is just for
• 39:11
  Speaker 1: internal propaganda, not actually military strategy.
• 39:15
  Speaker 2: I can believe that, all right, So let's bottom line this.
• 39:19
  Speaker 2: Give me the summary the take home points for the
• 39:22
  Speaker 2: nuclear plane story.
• 39:23
  Speaker 1: So, a nuclear powered airplane is possible. Physics says you
• 39:27
  Speaker 1: can do it. You put a reactor on board. We
• 39:29
  Speaker 1: have the techniques, We've proven that you can build a
• 39:32
  Speaker 1: nuclear powered jet engine. Problem is the way it becomes
• 39:36
  Speaker 1: very impractical. If you want your crew to survive, then
• 39:40
  Speaker 1: you've got to shield them from the nuclear reactor, and
• 39:42
  Speaker 1: that's going to make your plane very, very heavy. In addition,
• 39:45
  Speaker 1: the crash risks are significant. So it's possible, but dangerous
• 39:50
  Speaker 1: and kind of impractical at this point, and not really
• 39:54
  Speaker 1: necessary anymore because we have other weapons that fill the
• 39:57
  Speaker 1: strategic niche that originally motivated the idea of nuclear power aircraft.
• 40:02
  Speaker 1: So really the only remaining reason to do it is like, ooh,
• 40:05
  Speaker 1: it kind of sounds cool.
• 40:06
  Speaker 2: Oh, so if I'd got my kids all excited about
• 40:09
  Speaker 2: flying on one of these nuclear powered airplanes, you're telling
• 40:12
  Speaker 2: me I'd have to let them down by saying, oh, Daniel,
• 40:14
  Speaker 2: got you excited about something that isn't really gonna happen.
• 40:17
  Speaker 2: It's not strategically helpful. Sorry, Kid one and Kid two,
• 40:21
  Speaker 2: they'd be very disappointed.
• 40:23
  Speaker 1: Yeah, exactly. And so unless you're like a nuclear nerd
• 40:26
  Speaker 1: who likes to think about nuclear power powering everything and
• 40:29
  Speaker 1: new ways to do stuff, and you want to have
• 40:30
  Speaker 1: like a nuclear toaster on your kitchen, there's not really
• 40:33
  Speaker 1: a good reason that even considered nuclear power airplanes.
• 40:36
  Speaker 2: I mean, is this a material science question, like if
• 40:39
  Speaker 2: we can find a much much much better shield that's light,
• 40:42
  Speaker 2: then suddenly this all becomes a better idea or does
• 40:44
  Speaker 2: such a thing not exist?
• 40:46
  Speaker 1: From the physics point of view, Really, shielding is just
• 40:48
  Speaker 1: about having enough high z atoms between you and the source.
• 40:53
  Speaker 1: So it's hard to imagine how you're going to do
• 40:55
  Speaker 1: that without a lot of high zy atoms, which are
• 40:57
  Speaker 1: pretty heavy. So unless you come up with a new
• 41:00
  Speaker 1: way to do nuclear power which doesn't produce the same
• 41:03
  Speaker 1: kind of radiation, like, for example, if you had a
• 41:06
  Speaker 1: mini fusion reactor or a fusion reactors don't have the
• 41:09
  Speaker 1: same kind of radioactive output, So a fusion powered airplane
• 41:13
  Speaker 1: that might be possible but first we have to get
• 41:15
  Speaker 1: fusion to work like on the ground before we can
• 41:18
  Speaker 1: get it to work in the air.
• 41:21
  Speaker 2: Well, that's a big ask. We've been saying we're pretty
• 41:23
  Speaker 2: close for fifty years.
• 41:24
  Speaker 1: But exactly.
• 41:27
  Speaker 2: But there are some pretty cool companies doing some cool work,
• 41:30
  Speaker 2: So hopefully we get that eventually.
• 41:31
  Speaker 1: Yeah, and maybe eventually they'll develop fusion and then they'll
• 41:34
  Speaker 1: miniaturize it, and maybe we'll have fusion powered airplanes. Because
• 41:37
  Speaker 1: also the fuel for fusion is just hydrogen, and so
• 41:40
  Speaker 1: it's not as dangerous, So a crashed fusion powered airplane
• 41:44
  Speaker 1: wouldn't be any more dangerous than a crash diesel powered airplane.
• 41:47
  Speaker 2: Safe is cool. I like it.
• 41:51
  Speaker 1: All right. And so while it's fascinating to think about
• 41:54
  Speaker 1: how discoveries in physics can change our world, allowing us
• 41:58
  Speaker 1: to create devastating weapons and also sources of clean energy,
• 42:03
  Speaker 1: they don't always necessarily translate to changes in technology that
• 42:07
  Speaker 1: affects our daily life. Sometimes the old ways are better.
• 42:11
  Speaker 4: Yay.
• 42:12
  Speaker 1: Thanks very much for joining us today, everybody, and thank
• 42:14
  Speaker 1: you Kelly for taking this trip on a nuclear powered podcast.
• 42:19
  Speaker 2: Thank you for having me. It's been a blast as always.
• 42:22
  Speaker 1: All right, tune in next time. For more science and curiosity,
• 42:29
  Speaker 1: come find us on social media, where we answer questions
• 42:32
  Speaker 1: and post videos. We're on Twitter, This Org, Instant and
• 42:36
  Speaker 1: now TikTok. Thanks for listening and remember that Daniel and
• 42:39
  Speaker 1: Jorge Explain the Universe is a production of iHeartRadio. For
• 42:43
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• 42:48
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