June 6, 2024 • 42 mins
Daniel and Kelly talk about whether planes could be powered by nuclear reactors and whether that would be a bad idea, or a very bad idea.
See omnystudio.com/listener for privacy information.
Mark as Played
Transcript
Episode Transcript
Available transcripts are automatically generated. Complete accuracy is not guaranteed.
Speaker 1 (00:00):
Hey, everyone, A quick note to let you know that
our preschool science TV show on PBS Kids called Eleanor
Wonders Why just launched its second season. It's a show
about curiosity and exploration and learning to use science to
find your own answers to questions or Hey. And I
created the show a few years ago, and the second
season has just premiered. We're so excited to share this
(00:23):
new batch of stories and adventures. Check it out on
PBS Kids. Eleanor Wonders Why. Hey, Kelly, do your kids
like to fly?
Speaker 2 (00:38):
Yeah, they do, particularly my oldest. They were a little
bit scared at first, but I was explaining to them
that likes flying on a plane is probably safer than
driving in a car, and I eventually convinced them it's
safe and now they just enjoy it.
Speaker 1 (00:51):
Hmmm, you convince them it's safe?
Speaker 2 (00:53):
Huh, Daniel, what does that mean? Flying? Flying is safe?
But have you figured out a way to make it unsafe?
Speaker 1 (01:02):
I mean, current airplane technology is mostly pretty safe, but
there are some pretty cool ideas out there.
Speaker 2 (01:09):
Okay, wait, safe and boring as you described to current planes.
I feel like that's what you're going for. That's what
you want with planes.
Speaker 1 (01:18):
I guess so. But I bet your kids want a
ride at a new experimental crazy plane that involve nuclear power,
don't they?
Speaker 2 (01:26):
I bet they won't because they're not going to hear
about it, And I'm about letting you hear my kids.
Speaker 1 (01:46):
Hi. I'm Daniel. I'm a particle physicist and a professor
at UC Irvine, and I want to bring the fun
into Kelly's kids' lives.
Speaker 2 (01:53):
I'm Kelly water Smith. I'm adjoned at Rice University, and
I think flying should be boring and safe.
Speaker 1 (02:01):
But what if we have crazy new ideas for how
to get big heavy stuff into the air.
Speaker 2 (02:06):
Dream a little, Kelly.
Speaker 1 (02:12):
That's not why I had kids, That's why other people
had kids.
Speaker 2 (02:19):
Not sure you understand people in their motivations very well, Daniel.
Speaker 1 (02:23):
That's probably true, And my goal here is not to
explain people and their motivations, but the universe. So welcome
to the podcast Daniel and Jorge explain the Universe production
of iHeartRadio, in which we do just that. We try
to explain everything that's out there in the universe to you,
the fundamental laws of reality, the nature of space and time,
and how we can use our understanding of that, to
(02:45):
bend reality to our will, to make it do cool.
Stuff might fly tons and tons of metal through the
air across the ocean totally safely.
Speaker 2 (02:54):
Yes, safely, cool and safe because cool is safe kids.
Speaker 1 (03:00):
But we're also interested in pushing the boundaries of what
can be done. Every time we learn something new about
the universe, we wonder, how can we use this to
improve our lives? How can we use this to make
life more exciting? What new kind of gizmo or what's
it can this allow us to create that might change
the very nature of what it's like to be a
living human in this universe.
Speaker 2 (03:21):
I begrudgingly agree.
Speaker 1 (03:24):
And of course, the last century has given us lots
of new insights into the nature of reality at the
microscopic level. Zooming in past atoms, we've discovered all sorts
of new rules for how the universe works, rules that
are counterintuitive, that disagree with our classical intuition for how
things operate. This new realm of quantum mechanics has opened
up lots of crazy new opportunities and dangers for all
(03:48):
sorts of humanity. Atomic weapons, atomic power, atomic devastation, and
of course potential for nuclear winter. All sorts of consequences
for doing.
Speaker 2 (03:56):
Physics, all kinds of reasons for my kids to not
listening podcast. Do we talk about Project Plowshare at all?
Speaker 1 (04:05):
I can't remember what is Project Plowshare? Tell me.
Speaker 2 (04:08):
Project Plowshare was a US project to try to use
nuclear weapons for like cool good stuff, like making bays
by blowing up land so that you can have a
little area where you can bring ships inside close to
land at some point. And we had a bunch of
projects where we set off nuclear weapons for like funzies
and building stuff that we thought might be nice. But
(04:29):
of course, you know, being with the US's history, we
often did it in ways that were not amenable to
the desires of the people who lived in that area,
and eventually we stopped doing this, thankfully. But Russia or
the Soviet Union had a similar program. And if you
look up Lake Chaign, I think that's how you pronounce
it Chigan. I don't know. Anyway. They've got a lake
(04:52):
and it's perfectly circular, and that's because it was created
by a nuclear weapon exploding, and then some poor person
had to swim across it like convince everyone, no, it's safe,
this is cool.
Speaker 1 (05:02):
Cool, Wow, terraforming with nuclear weapons. That's just terrifying. But
there was an era after the discovery of atomic power
when people felt like this could change lots of different
aspects of our lives. Our nuclear knowledge could wiggle its
fingers into all sorts of aspects of everyday life. And
of course we know now that we have nuclear power plants,
(05:25):
and there are nuclear powered chips and nuclear powered submarines.
But today we want to explore another question, which is
why nuclear power hasn't made inroads into the skies. And
so on today's podcast, we'll be asking the question why
don't we have nuclear powered airplanes?
Speaker 2 (05:47):
Well? Should we see what the audience thinks.
Speaker 1 (05:50):
This is a fascinating question, and so as usual, we
went out into our list of volunteers to see what
people thought about having a nuclear reactor on board an airplane.
If you'd like to participate in this segment of the podcast,
please don't be shy. Write to me two questions at
Daniel and Jorge dot com. We will set you up
with random physics questions in your inbox every week. Everybody's welcome.
(06:13):
So before you hear these answers, think to yourself, how
do you feel about having a nuclear reactor on board
your airplane. Here's what people had to say.
Speaker 3 (06:22):
Well, we are too far from having electric powered planes,
but if we use water and eating them up with
nuclear reactor and use it as a propellant, then it
could be. But that would require enormous amount of water
to be stored, so it's not very likely.
Speaker 1 (06:38):
But maybe in the future.
Speaker 4 (06:41):
I'd say no, because they're quite heavy, I think, and
I think they need to be called down quite a lot.
So I know in nuclear submarines they use the sea
walls to cool down the reactor, so I don't know
what is heavy. And unless it was a very very
big airplane with nobody on board and nothing on board
other than a nuclear reactor, i'd say no.
Speaker 5 (07:04):
Well, I wouldn't fly on it. I mean, a nuclear
reactor is typically just a heat engine, steam engine, or
just creating heat like on the Mars Rovers. So to
have enough energy to continuously power an airplane would need
it to be enormous, and then I don't think you
could put it on the airplane, So probably not. But
since you're asking, maybe.
Speaker 6 (07:26):
Let's see, the biggest airplanes can carry about four hundred
or five hundred tons, so I would say, if you
could make one that's light enough, I would say, yes,
they put them in submarines, So yes, I.
Speaker 2 (07:39):
Thought these answers were really good. To be honest, heavy
wasn't the main concern that I had in mind when
you sent the title of this episode to me. My
thought was I wouldn't want to ride that close to
a nuclear reactor. But then I thought, oh, well they
do it on submarines, is probably okay. So then after
deciding that that concern wasn't big one, I thought, well,
(08:01):
probably I don't want nuclear material flying over my head.
When sometimes airplanes don't come down in the safest ways,
you wouldn't want them to drop their nuclear material and
spread it across earth. But this the most common thing
that the audience said was that this is too heavy
to work on planes. Were they on the right track.
Speaker 1 (08:21):
That's definitely an issue, and it's actually all entangled because
one of the reasons that submarines can be saved is
that they have lots of shielding because they don't have
to worry about weight, and so these questions of safety
and shielding are all connected.
Speaker 2 (08:36):
Excellent, good job, audience. So my first thought here is
that planes seem to be doing just fine, But of
course it would be really nice if planes were using
cleaner energy sources, and nuclear power is a good energy
source if you're trying to cut down on greenhouse gases.
(08:57):
So let's talk about the pros first. They assume that's
one of the pros. So why else might you want
nuclear powered aircraft.
Speaker 1 (09:05):
The whole idea for nuclear power aircraft comes out of
World War II. Of course, that's when nuclear powers invented,
and maybe the primary motivation was to make airplanes that
could fly for longer without needing to refuel. And World
War Two, a lot of our strategic decisions were based
on needing to refuel. You had these bombers and you
wanted to drop bombs on enemy territory, and those bombers
(09:27):
needed gas, and that limited how far they could fly,
and in many missions the bombers came back with just
like fumes. It really limited the reach of these bombers,
And so people were thinking, could we develop airplanes that
ran on nuclear power that could fly for much much
longer because nuclear fuel is so much denser. So, for example,
submarines can operate for a very very long time without refueling.
(09:51):
Same with nuclear powered aircraft carriers. These things can sometimes
go decades without refueling, except.
Speaker 2 (09:58):
The humans who ride them would need to refuel by
sleeping at night. But I guess, I guess you could
have a number of pilots circulate or you know, taking
turns that you could keep going. But like those bombers,
aren't the figure something like one in four didn't return
on each run. Think of the amount of nuclear material
that would be falling to Earth with these bombers as
(10:21):
they got shot down. But all right, we're probably going
to talk about that in the con section. I'm guessing so,
but you know me, I always get hung up on
the cons. Okay, so let's spok about more pros.
Speaker 1 (10:30):
That's definitely an issue. But if your goal is to
have airplanes that could like fly all over the world
and drop bombs on any target without needing to refuel,
or without needing to worry about like tricky aerial refueling
maneuvers which make new and the refueling plane very vulnerable
to enemy aircraft, or without needing to like buy territory
(10:51):
in foreign countries for refueling bases. Did you know, for example,
the United States tried to buy Greenland from Denmark even
before Trump offered. They wanted to refueling in Greenland, and
they offered one hundred million dollars in gold to Denmark
for Greenland, and Denmark said, no, thanks, We'll keep Greenland.
Speaker 2 (11:09):
And we did this so that we could refuel there.
That was our main purpose.
Speaker 1 (11:13):
Yeah, Greenland is very strategic location between the US and
the Soviet Union. Absolutely. Yeah.
Speaker 2 (11:18):
Did we try Iceland next, maybe for less money?
Speaker 1 (11:24):
And then Island was offended. They're like, what we're not
as value is Greenland? Are you guys crazy? Yeah? Hence
the Cold War very chilly. But the idea was basically
try to get airplanes that could fly longer, right, And
the concept there, the physics underneath it is that nuclear
fuel is so much more dense. Like if you think
about how much energy is stored in uranium versus how
(11:47):
much energy is stored in like diesel, it's really just
enormous like diesel, and gas has more energy than coal,
or more energy than like you know, animal fat or whatever.
But just by a few factors, uranium has seventy six
million megadewles of energy per kilo of uranium, whereas gas
(12:07):
has forty six megadels. So the energy density uranium is
a million times that of diesel.
Speaker 2 (12:13):
Oh my gosh, that's incredible. Okay, so this is an
amazing power source. Tell us about subs and why it
works so well in submarines.
Speaker 1 (12:23):
Yeah, this is something that works very very well for
submarines and the newest generation of submarines. They never need
to refuel like they think. These subs will last for
like fifty years, and the fuel will also last for
fifty years. You'd like, just build the sub, you build
the fuel in, and you never refuel it because it's
so energy dense. It's amazing.
Speaker 2 (12:42):
That's incredible.
Speaker 1 (12:43):
So they have these miniaturized reactors and they're powered by uranium,
and you know, there's fission that happens there and the
fission releases heat that heats water, which produces steam, which
turns a turbine which then directly turns the ship's propeller.
Often in land based nuclear power. The turbine then spins
a generator which makes electricity. You put it on the grid,
(13:04):
but there's no need here to generate electricity. You can
just directly have that turbine spin the ship's propeller. And
the cool thing is this is much quieter than a
diesel engine, and there's no pistons, for example, And so
if you're trying to run quiet underwater, that having a
nuclear powered submarine that never needs to come up to
refuel is quite the advantage from a military point of view.
Speaker 2 (13:25):
That is pretty incredible. Is the US the only country
that has these? I'm going to guess that the Soviet
Union also came up with this, and so Russia has
it too.
Speaker 1 (13:34):
Absolutely, the Soviets have them, and we've had them for decades.
Speaker 2 (13:37):
They're not the Soviets anymore.
Speaker 1 (13:42):
The Soviets had them. The Russians now have them, of course,
But this is something which is decades old. It was
nineteen sixty when we had the first submerged circumnavigation of
the globe, like the first time a submarine went around
the globe without surfacing. That's just like a decade and
a half after the whole invention of nuclear power.
Speaker 2 (14:01):
Wow, that's incredible.
Speaker 1 (14:03):
Yeah, And a few decades later we had more nuclear
reactors in ships than there were on land producing electric power. So,
like the military has really been into this idea for
a long time because they're like not refueling and they're
like the quietness of these reactors, and frankly, probably because
they don't also care as much about the potential disasters
(14:23):
and the ecological impact.
Speaker 2 (14:26):
And why is that? Is it because the bottom of
the ocean is sort of desolate and it doesn't even
if a sub crashes, most of the material stays in
one spot, so the you know, devastation and the problems
are sort of limited. Or why do why would you
not care about the ecological Well, I.
Speaker 1 (14:43):
Don't want to speak to the motivations of the military person,
but you know you're developing weapons anyway that are causing
huge destruction, right Your goal is destruction, So like gentleness
about the territory, I mean, I guess it must always
be second or a third concern. But you're also right that,
like submarine that crashes underwater, water is a pretty good
(15:03):
shield from radiation. And so unless that uranium then leaks
out and like spreads into ocean currents, the actual radiation
from the crash site is pretty limited to that location
because water is an excellent shield.
Speaker 2 (15:16):
Okay, that's good, all right, So we use a lot
of these underwater. I happen to also know that they're
very helpful in space, So where have they been used
in space?
Speaker 1 (15:25):
Vivin used underwater, they're also used on the surface. The
US Navy eleven carriers are all nuclear powered. Some of
these things have two some of them have eight separate
reactor units. So, like maritime nuclear power very well established.
But you're right, we also use nuclear power in space.
Some of the rovers that we have sent to other
planets use nuclear power. They don't have nuclear reactors in
(15:49):
the same way that these subs do in the sense
that they have controlled fission reactions. Instead, they use another
kind of nuclear power, where there's uncontrolled decay that essentially
leads to heating more like a nuclear battery. These used
plutonium and they worked for like ten to fifteen years,
providing a gentle source of heat which is then converted
into the electricity to run some of these rovers like
(16:10):
Curiosity and Perseverance. So we definitely have nuclear powered craft underwater,
on the surface and in space.
Speaker 2 (16:18):
Well, we also have little nuclear reactors in some satellites.
We don't do it so regularly anymore. The US had
snapped ten A, which we sent up and it did
okay for a little while. Then it failed and we
boosted it to a graveyard orbit. So that didn't go
super well for us, and I think maybe it's leaking
a little nuclear material woops. And then the Soviets actually
(16:40):
sent up something like thirty three nuclear powered satellites and
they use these because they wanted to go kind of
lower for like surveillance purposes, and they were low enough
that they were starting to hit like atmosphere particles, so
solar panels would have slowed them down. So the nuclear
reactors allowed them to go for a long time without
the solar panels which would slow them down, and that
(17:01):
went okay most of the time. They didn't always spread
nuclear material across Canada, so that's good. There's just that
one time.
Speaker 1 (17:13):
You get one freebie, right, I mean, I'm sure Canada
is cool with that one time.
Speaker 2 (17:17):
There's a lot of Canada, and like a lot of
it's not being used for other stuff. Maybe.
Speaker 1 (17:22):
Wow, you're pretty cavalier about safety when it's not your
kids involved, Kelly. You know Canadians have kids also, you
understand how that works.
Speaker 2 (17:31):
I am so sorry Canadians. I was joking and I
shouldn't have I shouldn't have done it, all right, So
we've talked about the various places that we find nuclear reactors.
Let's take a break and you know, shield our houses
against the radioactive material that might come falling down on
us at some point in the future. And we'll talk
about engine concepts next, and we're back, all right. So
(18:08):
we've talked about the various ways nuclear power has been
used in things like submarines and satellites and rovers and
of course nuclear power plants. Let's talk about some engine
concepts for how you might be able to make this
stuff work in an airplane.
Speaker 1 (18:23):
Yeah, it's really fun to think about how you might
actually power an airplane using a nuclear reactor, because the
basic concept that works underwater is to have it directly
spin a propeller. But those propellers can spin fairly slowly
and still power the ship. But an airplanes, of course,
we have jet engines, and so people have explored lots
of different ways to make a nuclear powered aircraft. But
(18:46):
the leading idea I think is a nuclear jet engine.
Speaker 2 (18:50):
Ooh sounds epic.
Speaker 1 (18:51):
Yeah, So to review the way a jet engine works
in general, is essentially your burning fuel. Jet fuel essentially
some fossil fuel to heat the air, and that expands
through a turbine into a propelling nozzle to provide thrust.
So the goal of the fuel, the reason you need fuel,
the reason we have jet fuel in airplanes is to
(19:12):
heat a bunch of air which then expands, and that
expansion gives you thrust. So the core idea of a
nuclear power jet engine is just to replace the source
of heat. And so because fission produces heat, right, it
produces these energetic particles, people thought, well, let's just use
fission to directly heat the air instead of having the
diesel fuel do that job.
Speaker 2 (19:33):
And then the air is just whatever air is surrounding
the airplane in the sky. Or are you like putting
some gas in there that gets heated.
Speaker 5 (19:42):
No.
Speaker 1 (19:43):
That's one of the cool things about a jet airplane
is that as it's flying through the air, it's pulling
air in, compressing it, and then expanding it with the heat.
And that's how the whole jet engine runs. That's why
jets don't work so well at low speeds because they
require this influx of air into the compressor oka And so.
Speaker 2 (19:58):
Then would fission be able to heat it up even
more like better than the other methods, so you could
go even faster. Or the point is just that it
can heat for longer because it burns slowly.
Speaker 1 (20:08):
Yeah, the idea is just that it can heat for
longer that the fuel is much more dense. And that's
also an attractive feature of nuclear power jets because you'd
like to be able to lower your weight in the air.
Right when the seven forty seven takes off or a
cross country trip, it's carrying enormous amounts of fuel. Some
of that fuel is just in order to provide the
thrust to carry the rest of the fuel. It's like
(20:30):
the whole rocket equation problem in miniature. And so if
you could figure out a way to make your fuel less,
then you can lighten the whole weight of the aircraft
and then need less fuel. Yeah.
Speaker 2 (20:39):
So okay, So at the beginning of the show, the
listeners said that they thought the problem was weight, but
it sounds like you were saying that's not the problem. Actually,
this could be a less heavy way to fly.
Speaker 1 (20:50):
Weight is definitely an issue, and we're going to talk
about like the shielding and the reactor itself being quite heavy.
But in terms of the fuel, there is a wind
and so we're going to keep track of the weight
accounting in terms of the fuel volume and weight. Nuclear
power winds. When it comes to the actual equipment involved,
you're going to see it's an overall loss, but you know,
there's something in the wind category there. And so people
(21:13):
have actually people and so people have actually built these things.
They have prototypes. You can go to the Idaho National Lab.
They have a couple of these set up that you
can actually see. They built them in the fifties and
they tested them, and there's sort of two different models there.
One is a direct air cycle, where the air comes
in from the compressor, goes directly into the nuclear core.
(21:34):
That air gets heated up by the nuclear power plant
and then emitted. That's very powerful, but the problem is
the air that comes out also kind of radioactive.
Speaker 2 (21:43):
That's a problem, and so if.
Speaker 1 (21:45):
You're like flying regularly back and forth across your own
country and you're spewing radiation and that's you know, bad.
So they developed a second model, an indirect air cycle,
where you basically have two different loops. You have the
air that comes in and then it gets heated by
something which has been heated by the nuclear reactor. So
for example, the nuclear actor doesn't directly heat the air.
(22:06):
It might heat like liquid metal in pipes, or very
high pressure water, which is then getting radioactive, but it's
not getting sprayed out the back of the jet engine. Instead,
it's just heating up the air. So you're sort of
shielding the air from the radioactivity by having this indirect
loop of liquid metal or high pressure water.
Speaker 2 (22:24):
That sounds more complex but better.
Speaker 1 (22:27):
Yeah, exactly, you're not killing your own people. But now
you have to have this extra machinery and you have
to hope that your high pressure liquid metal doesn't explode.
You have to monitor that, so it becomes more complicated,
which is the downside of it, But the basic idea works,
like in principle, you can have a nuclear powered jet engine.
Speaker 2 (22:45):
Oh, I don't think I would want that flying over
my home. What are what are some of our other options?
Speaker 1 (22:52):
So instead of having a jet engine, you could also
have a nuclear powered thermal rocket, so a chemical rocket,
the thing that like the set Urn and five used
to get off the surface of the Earth. You have
some chemical reaction which creates expansion and gives your propellants
basically momentum out the back. Right, This is the way
a rocket engine works. Well, you could imagine a nuclear
powered version of that where the heat comes from the
(23:14):
nuclear reaction and that flies off some propellants, and that
those propellants are then pumped through the core to heat
up something. So it's sort of similar to the jet
engine concept. You're using the nuclear reactor to heat something
and then that is expanding and flying out the back,
but we call this a thermal rocket instead of a
jet engine because you also don't have this compression cycle.
Speaker 2 (23:35):
Is this what project Orion was all about.
Speaker 1 (23:37):
Project Oryon was actually blowing up nuclear bombs behind it,
So it's sort of similar. It's sort of similar and
much more awesome and impossible, but.
Speaker 2 (23:50):
Awesome if you're like not living on the planet where
they're trying it out, maybe.
Speaker 1 (23:53):
But yeah, awesome sense Like if you see it, you're like,
oh my gosh. Wow.
Speaker 2 (24:01):
So this is a more delicate approach, yeah, exactly.
Speaker 1 (24:05):
The third approach is to think about action generating electrical
power and then using that electrical power to run like
an electrical engine. So you sort of separate the two components.
You have the nuclear planet on board, it's running, it's
producing steam that's turning a turbine that's running a generator
that's producing electrical power. Then you're feeding the electrical power
to like a turboprop engine, So the engine and the
(24:27):
power generation are separate.
Speaker 2 (24:29):
So do you have a sense for out of these
three methods, which one is like the best. So they
differ in complexity, they differ in pollution or you know
how bad they are for the environment below, they probably
differ in how much power they produce for a given
amount of nuclear material. Is there like a favorite amongst
people who are excited about these ideas?
Speaker 1 (24:50):
I think the jet engine is definitely the leading idea.
People like jets. Jets can go really fast, they work
really well on airplanes. People have actually built prototypes of
this that it can work. So the jet engine is
definitely the leading concept.
Speaker 2 (25:04):
All right, So we've talked about the different ways to
make this work. We've talked about the pros. You know
why you would want to use nuclear power for an airplane,
But we all know that Kelly's the wet blanket around here.
So I'm excited for us to move on to the cons.
What are the reasons why this idea that sounds bad
to me is bad?
Speaker 1 (25:25):
So many reasons. Let's start with the practical ones, and
that's the issue of weight, right, So reactors can be big,
and they can becumbersome. This has been mostly solved. People
have made miniature versions of reactors, like to put on
a submarine or to put several of them independent reactors
onto a big aircraft carrier, so you can make the
(25:46):
reactor fairly miniature. Physicists are really good at figuring that
kind of stuff out. What's very hard to miniaturize, though,
is the shielding. Like on a boat, a submarine, or
an aircraft carrier, you can have lots of layers of steel,
not a big deal, right, but on an airplane that
really costs you. And so it's possible to miniaturize the
reactor itself and reduce the weight there, but the shielding
(26:08):
is always going to be an issue. You want to
put a lot of heavy atoms between you and the
source of radiation, and a lot of heavy atoms are
always just going to be heavy.
Speaker 2 (26:17):
So you had said that what was it like, gas
was something like fifty mega jeles per kilogram and uranium
was almost like eighty thousand. So even with that massive
increase in the amount of power that you get that
that doesn't do enough to even nearly offset the shielding.
(26:38):
Is that is that the message here.
Speaker 1 (26:40):
Yeah, exactly. You either need a lot of shielding or
you need to not worry about your crew. And there
was actually a time where people talked about only having
crew that were like past child bearing age or had
a terminal disease. Anyway, people seriously talked about this kind
of stuff, like the documents from the Cold War are crazy.
Speaker 2 (27:00):
Gonna die anyway, fly on our plane. You always wanted
to be a pilot, right, Crid.
Speaker 1 (27:06):
And basically every step you take to make these things
more safe makes them impractical because now they're too heavy.
So not just the shielding but also the cooling systems. Right,
you want to generate this heat, but you also don't
want to overheat the rest of the airplane, and you
want to have devices in place to protect yourself against
meltdowns and all sorts of other issues, and so all
these cooling systems and safety systems and all that shielding
(27:29):
just gets heavy.
Speaker 2 (27:30):
And I think perhaps the biggest dagger in this idea
to me is that if something goes wrong and you crash,
you spread nuclear material across a large area problems, which
is a problem.
Speaker 1 (27:43):
Yes, poisoning the earth bad for sure, and it's definitely
something people think about also when we go into space
with nuclear power, Like every time we launch a rover
with a blob of plutonium in it, we worry, like,
is this going to be the time it blows up
in the atmosphere and then spreads that plutonium on our planet.
It's a risk every time they do it, and so
they worry about it. But those are pretty rare launches.
Speaker 2 (28:05):
Oh you mean is this going to be the second time?
Speaker 1 (28:07):
Yes, exactly, the next time.
Speaker 2 (28:10):
The next time, yes.
Speaker 1 (28:11):
But if you're talking about regularly flying bombers or even
commercial airplanes around the world with nuclear power, then you're
constantly taking that risk, and you know, crashes happen and
they kill people, and you don't want to then compound
the dangers and the consequences by also poisoning the planet.
Speaker 2 (28:28):
Well, especially if these planes are being used as like
weapons of war or surveillance things, and you know other
countries might specifically be trying to shoot them down. That
seems bad. Yeah, although maybe a country won't shoot down
your spyplane if they know that they're going to be
like contaminating their land with radioactive waste. So, oh, you
have forgot that in the pro section, Daniel.
Speaker 1 (28:49):
It's like the poison pill. But you know, realistically and
maybe sadly, if you ask me, like, why aren't their
nuclear powered airplanes right now? I don't think that's the reason.
I think the reason we don't have nuclear powered airplanes
or not because they aren't safe or they would kill
your crew. I think that people would make those compromises
if they thought it was good for our military or
(29:10):
our strategic situation. The reason I think is actually just strategic,
that nuclear powered bombers are no longer the quiver we
thought we needed in our arsenal is that.
Speaker 2 (29:21):
Because satellites are so good, we can just buy from there,
or or yeah, why I.
Speaker 1 (29:25):
Think the reason is that you don't need nuclear bombers.
You don't really need bombers anymore. I mean, we have ICBMs,
we can deliver nuclear weapons from the planes of Montana
without putting any humans in the air, And we have
nuclear powered submarines which can sneak around the oceans and
send nuclear weapons to anywhere on Earth very quietly. So
you don't really need nuclear powered bombers to stay aloft
(29:48):
for twenty four hours anymore. We can already bomb people
with impunity. Oh yay, And I think that's probably the
reason we don't have it. All these other concer earns
are reasonable, and it makes it impractical and it makes
it unsafe. But I think because it's not strategically valuable,
it is probably why we don't actually have them.
Speaker 2 (30:09):
I guess we should all be glad that we have
ICBMs instead.
Speaker 1 (30:13):
I suppose. But of course, the US spent billions and
billions of dollars and more than a decade trying to
build nuclear powered airplanes, and they actually flew airplanes with
reactors on board.
Speaker 2 (30:26):
Were these jet engine reactors like you were talking about.
Speaker 1 (30:28):
No, we've never actually flown an airplane that was powered
by the reactor, but they did fly airplanes that had
reactors on them.
Speaker 2 (30:36):
All right, let's take a break and then you can
tell us more about that. Okay, So now we're back.
So you said that a plane has flown with a
nuclear reactor on it. Was that plane just transporting the
(30:59):
reactor from one place to another? Or Yeah? Why would
you want to carry nuclear material with you on a plane.
Speaker 1 (31:07):
You don't pack nuclear material every time you take a flight, Kelly.
Speaker 2 (31:10):
Not yet. But if it was strategically valuable, maybe I.
Speaker 1 (31:13):
Want, Yes, you might exactly. Now, this was like the
first step in the US's exploratory project to build nuclear
power aircraft. They thought, well, first let's try to fly
an airplane with a reactor on board. Study the shielding issues,
the safety issues. Can we actually get this thing working
and operating in the environment of an airplane before we
actually try to connect the reactor to the engines. So
(31:36):
in the fifties they had this project using a modified
B thirty six bomber with a working nuclear reactor on board.
So you have your standard jet engines flying this airplane,
but in the center you have a miniaturized reactor designed
specifically for flight.
Speaker 2 (31:51):
Wow, okay, and so this comports with your even if
it's hard, we'd do it if it were strategic. Because
this was what decade were they trying this in the fifties.
I'm going to assume that in the fifties they had
enough shielding. Is is that true? Or were they able
to do this because they you know, four went shielding
for this experiment.
Speaker 1 (32:11):
Well both, Actually they put a lot of shielding. So
this is like an eighteen ton reactor producing one megawatt,
and they had it in this special version of the
aircraft where the humans would live in this little pod,
this like special cockpit that was super shielded. If twelve
tons of lead and rubber that the humans would get
in and the rest of the airplane would just be
(32:32):
like totally irradiated. And this little pod had like windows
in it that were like twelve inches thick and pockets
of water to protect them, but still there was a
lot of radiation even though they were shielded. It was
well above anything you would consider safe for the pilots.
Speaker 2 (32:48):
Oh yikes. And if you ever need to do any
work on the body of the plane, any technician who's
working on it is going to be getting your radiated.
Speaker 1 (32:56):
Right, yeah, exactly. The whole thing is going to be
a disaster. And you know, for the project, they only
recruited pilots above child bearing age because they basically knew
that they were killing these people.
Speaker 2 (33:06):
Oh my goodness, you know, us people above child bearing
age are still valuable. Just throwing that out there.
Speaker 1 (33:15):
It's kind of amazing how they treated these things, like
they knew that there were potential disasters, and they actually
tried to plan for them. Like, so, this thing took
flight in the fifties. They made forty six flights with
this bomber, and every time they did, they also flew
it with a special extra bomber that had specially trained
paratroopers that if this plane crash, the paratroopers would jump
(33:35):
out of the airplane, paratroop down to the crash site
and seal it off. They were like nuclear trained paratroopers
to help try and contain a disaster.
Speaker 2 (33:44):
Were they all also above child bearing age?
Speaker 1 (33:49):
Yes, and they all wore lead underwear.
Speaker 2 (33:51):
Oh good, good plan, although it's too late, I guess.
But so when they were flying over the Southwest, were
they I guess specifically trying to fly over portions of
the southward but are not populated, like those paratroopers aren't
going to be helpful if it lands in Phoenix.
Speaker 1 (34:07):
You know, I hope so. I don't have any details
to back that up, but I certainly hope they do.
But you know, this thing was airborne over the Southwest
forty six times in the fifties, so they definitely took
a risk.
Speaker 2 (34:19):
Did it ever crash?
Speaker 1 (34:20):
This one never did crash, but they tried to estimate
what would happen if it did crash. They created some
situations where they like put a fuel rod into a
burning jet engine in Idaho. So they did these experiments
and this is pretty bad. Those experiments ended up like
releasing quite a bit of caesium one thirty seven into
the air above Idaho. Yeah, it's pretty bad. And they
(34:43):
called this test operation Wiener Roast because they used because
they used a bunch of live cattle at varying distances
to help measure the effects of the radiation.
Speaker 2 (34:55):
Wow, I mean they clearly should have been using doxins
little Wiener dogs. So I was I was soffing because
that was really a missed opportunity.
Speaker 1 (35:06):
But you have just pissed off a lot of dog
owners out there, Kelly, I'm sure I have.
Speaker 2 (35:12):
That's right.
Speaker 1 (35:14):
So this is like a real government program.
Speaker 4 (35:16):
You know.
Speaker 1 (35:16):
They invested a lot of money into this program, billions
of dollars, decades of research to try to make this
thing happen. And they got as far as flying airplanes
around with nuclear reactors on board.
Speaker 2 (35:27):
That's that's pretty far, just to confirm, we've never flown
anything that was actually powered by the nuclear power source, right,
It's just been sort of carried along like the.
Speaker 1 (35:37):
First exactly, we got as far as airplanes with nuclear
reactors on board and then on the ground nuclear powered
jet engines that never flew, but we never put them
together into an airplane that was powered by a nuclear reactor.
Speaker 2 (35:52):
Okay, so there's always a Soviet equivalent to these sorts
of things. So did the Soviet Union have a similar project?
Speaker 1 (36:01):
Of course they did. In the fifties, the Soviet Union
had a project to fly one of their enormous TU twenties.
If you haven't seen a picture of one of these things,
this is like a really incredibly huge bomber with this
really elegant swept wing design, and they were working on
a similar project. Details are a little bit sketchy, and
part of the information is a little confusing because in
(36:22):
the fifties there was an article in Aviation Week that
turns out to have been mostly filled with false information,
claiming that the Soviets were already testing a nuclear airplane
that was powered by nuclear power. It turned out to
be misinformation, but you know, it kept the US program
going for a few more years. But the Soviets ended
up coming to the same conclusion we did, which is
(36:44):
that there's a huge radiation hazard to the crew, and
the crash risks were significant, and so they abandoned the
projects right around the same time we did.
Speaker 2 (36:53):
Presumably they also had ICBMs and stuff, and so they
had the same capabilities without the technology just like did
right or were they behind on ICBMs.
Speaker 1 (37:02):
No, that's exactly right, And so in the early sixties
both programs were abandoned because people realized that nuclear powered
submarines and ICBMs filled the strategic need in a much
simpler way than nuclear powered aircraft.
Speaker 2 (37:15):
All right, So does that mean that both Russia and
the US, like no country on Earth right now was
working on this program because we all have better ways
to do this? Is that right?
Speaker 1 (37:25):
Yes? And no no country on Earth that we know
of is trying to fly an atomic powered aircraft with
people on it. But the Russians claim to be working
on and have developed, a nuclear powered cruise missile. A
cruise missile is basically like an unmanned aircraft. It can fly,
it can loiter, it can turn. It's not just like
(37:46):
ballistic You're not just like throwing a bomb. It has
like engines and it can steer, et cetera. And the
idea of a nuclear powered cruise missile is still kind
of attractive because it would have basically unlimited range. This
thing could take off, fly around the Earth a couple
of times. You could even like hang out for a while,
like doing loops, you know, take the long path over
(38:07):
the North Pole or something. And so Russia claims to
be working on this thing. It's called the SSC x nine,
and in October twenty twenty three, Putin claimed that they
tested it successfully, though a lot of people are pretty skeptical.
Speaker 2 (38:21):
Yeah, I mean, that guy always tells the truth. So
so slam dunk we got. We've got to believe it. Huh.
Do you really need a cruise missile that can like
circle the world four times? Why not just like know
where you're going to shoot it off, and shoot it
off from one spot using another fuel source and just
(38:42):
get there right away.
Speaker 1 (38:44):
Yeah, a lot of these Russian modern weapons programs seem
kind of bombastic and unnecessary. Like he's also talking about
his supersonic missiles. It's like, you know, do you really
need supersonic missiles? Are there really an advantage to that? I
think a lot of this stuff might just be pr
I think and wants to advertise to the Russians that
their military is cutting edge, that they have advantages over
(39:06):
the West, et cetera, et cetera. So analysts that I've
read suggest that a lot of this is just for
internal propaganda, not actually military strategy.
Speaker 2 (39:15):
I can believe that, all right, So let's bottom line this.
Give me the summary the take home points for the
nuclear plane story.
Speaker 1 (39:23):
So, a nuclear powered airplane is possible. Physics says you
can do it. You put a reactor on board. We
have the techniques, We've proven that you can build a
nuclear powered jet engine. Problem is the way it becomes
very impractical. If you want your crew to survive, then
you've got to shield them from the nuclear reactor, and
that's going to make your plane very, very heavy. In addition,
(39:45):
the crash risks are significant. So it's possible, but dangerous
and kind of impractical at this point, and not really
necessary anymore because we have other weapons that fill the
strategic niche that originally motivated the idea of nuclear power aircraft.
So really the only remaining reason to do it is like, ooh,
it kind of sounds cool.
Speaker 2 (40:06):
Oh, so if I'd got my kids all excited about
flying on one of these nuclear powered airplanes, you're telling
me I'd have to let them down by saying, oh, Daniel,
got you excited about something that isn't really gonna happen.
It's not strategically helpful. Sorry, Kid one and Kid two,
they'd be very disappointed.
Speaker 1 (40:23):
Yeah, exactly. And so unless you're like a nuclear nerd
who likes to think about nuclear power powering everything and
new ways to do stuff, and you want to have
like a nuclear toaster on your kitchen, there's not really
a good reason that even considered nuclear power airplanes.
Speaker 2 (40:36):
I mean, is this a material science question, like if
we can find a much much much better shield that's light,
then suddenly this all becomes a better idea or does
such a thing not exist?
Speaker 1 (40:46):
From the physics point of view, Really, shielding is just
about having enough high z atoms between you and the source.
So it's hard to imagine how you're going to do
that without a lot of high zy atoms, which are
pretty heavy. So unless you come up with a new
way to do nuclear power which doesn't produce the same
kind of radiation, like, for example, if you had a
mini fusion reactor or a fusion reactors don't have the
(41:09):
same kind of radioactive output, So a fusion powered airplane
that might be possible but first we have to get
fusion to work like on the ground before we can
get it to work in the air.
Speaker 2 (41:21):
Well, that's a big ask. We've been saying we're pretty
close for fifty years.
Speaker 1 (41:24):
But exactly.
Speaker 2 (41:27):
But there are some pretty cool companies doing some cool work,
So hopefully we get that eventually.
Speaker 1 (41:31):
Yeah, and maybe eventually they'll develop fusion and then they'll
miniaturize it, and maybe we'll have fusion powered airplanes. Because
also the fuel for fusion is just hydrogen, and so
it's not as dangerous, So a crashed fusion powered airplane
wouldn't be any more dangerous than a crash diesel powered airplane.
Speaker 2 (41:47):
Safe is cool. I like it.
Speaker 1 (41:51):
All right. And so while it's fascinating to think about
how discoveries in physics can change our world, allowing us
to create devastating weapons and also sources of clean energy,
they don't always necessarily translate to changes in technology that
affects our daily life. Sometimes the old ways are better.
Speaker 4 (42:11):
Yay.
Speaker 1 (42:12):
Thanks very much for joining us today, everybody, and thank
you Kelly for taking this trip on a nuclear powered podcast.
Speaker 2 (42:19):
Thank you for having me. It's been a blast as always.
Speaker 1 (42:22):
All right, tune in next time. For more science and curiosity,
come find us on social media, where we answer questions
and post videos. We're on Twitter, This Org, Instant and
now TikTok. Thanks for listening and remember that Daniel and
Jorge Explain the Universe is a production of iHeartRadio. For
(42:43):
more podcasts from iHeartRadio, visit the iHeartRadio app, Apple Podcasts,
or wherever you listen to your favorite shows.
Hey, everyone, A quick note to let you know that
our preschool science TV show on PBS Kids called Eleanor
Wonders Why just launched its second season. It's a show
about curiosity and exploration and learning to use science to
find your own answers to questions or Hey. And I
created the show a few years ago, and the second
season has just premiered. We're so excited to share this
(00:23):
new batch of stories and adventures. Check it out on
PBS Kids. Eleanor Wonders Why. Hey, Kelly, do your kids
like to fly?
Speaker 2 (00:38):
Yeah, they do, particularly my oldest. They were a little
bit scared at first, but I was explaining to them
that likes flying on a plane is probably safer than
driving in a car, and I eventually convinced them it's
safe and now they just enjoy it.
Speaker 1 (00:51):
Hmmm, you convince them it's safe?
Speaker 2 (00:53):
Huh, Daniel, what does that mean? Flying? Flying is safe?
But have you figured out a way to make it unsafe?
Speaker 1 (01:02):
I mean, current airplane technology is mostly pretty safe, but
there are some pretty cool ideas out there.
Speaker 2 (01:09):
Okay, wait, safe and boring as you described to current planes.
I feel like that's what you're going for. That's what
you want with planes.
Speaker 1 (01:18):
I guess so. But I bet your kids want a
ride at a new experimental crazy plane that involve nuclear power,
don't they?
Speaker 2 (01:26):
I bet they won't because they're not going to hear
about it, And I'm about letting you hear my kids.
Speaker 1 (01:46):
Hi. I'm Daniel. I'm a particle physicist and a professor
at UC Irvine, and I want to bring the fun
into Kelly's kids' lives.
Speaker 2 (01:53):
I'm Kelly water Smith. I'm adjoned at Rice University, and
I think flying should be boring and safe.
Speaker 1 (02:01):
But what if we have crazy new ideas for how
to get big heavy stuff into the air.
Speaker 2 (02:06):
Dream a little, Kelly.
Speaker 1 (02:12):
That's not why I had kids, That's why other people
had kids.
Speaker 2 (02:19):
Not sure you understand people in their motivations very well, Daniel.
Speaker 1 (02:23):
That's probably true, And my goal here is not to
explain people and their motivations, but the universe. So welcome
to the podcast Daniel and Jorge explain the Universe production
of iHeartRadio, in which we do just that. We try
to explain everything that's out there in the universe to you,
the fundamental laws of reality, the nature of space and time,
and how we can use our understanding of that, to
(02:45):
bend reality to our will, to make it do cool.
Stuff might fly tons and tons of metal through the
air across the ocean totally safely.
Speaker 2 (02:54):
Yes, safely, cool and safe because cool is safe kids.
Speaker 1 (03:00):
But we're also interested in pushing the boundaries of what
can be done. Every time we learn something new about
the universe, we wonder, how can we use this to
improve our lives? How can we use this to make
life more exciting? What new kind of gizmo or what's
it can this allow us to create that might change
the very nature of what it's like to be a
living human in this universe.
Speaker 2 (03:21):
I begrudgingly agree.
Speaker 1 (03:24):
And of course, the last century has given us lots
of new insights into the nature of reality at the
microscopic level. Zooming in past atoms, we've discovered all sorts
of new rules for how the universe works, rules that
are counterintuitive, that disagree with our classical intuition for how
things operate. This new realm of quantum mechanics has opened
up lots of crazy new opportunities and dangers for all
(03:48):
sorts of humanity. Atomic weapons, atomic power, atomic devastation, and
of course potential for nuclear winter. All sorts of consequences
for doing.
Speaker 2 (03:56):
Physics, all kinds of reasons for my kids to not
listening podcast. Do we talk about Project Plowshare at all?
Speaker 1 (04:05):
I can't remember what is Project Plowshare? Tell me.
Speaker 2 (04:08):
Project Plowshare was a US project to try to use
nuclear weapons for like cool good stuff, like making bays
by blowing up land so that you can have a
little area where you can bring ships inside close to
land at some point. And we had a bunch of
projects where we set off nuclear weapons for like funzies
and building stuff that we thought might be nice. But
(04:29):
of course, you know, being with the US's history, we
often did it in ways that were not amenable to
the desires of the people who lived in that area,
and eventually we stopped doing this, thankfully. But Russia or
the Soviet Union had a similar program. And if you
look up Lake Chaign, I think that's how you pronounce
it Chigan. I don't know. Anyway. They've got a lake
(04:52):
and it's perfectly circular, and that's because it was created
by a nuclear weapon exploding, and then some poor person
had to swim across it like convince everyone, no, it's safe,
this is cool.
Speaker 1 (05:02):
Cool, Wow, terraforming with nuclear weapons. That's just terrifying. But
there was an era after the discovery of atomic power
when people felt like this could change lots of different
aspects of our lives. Our nuclear knowledge could wiggle its
fingers into all sorts of aspects of everyday life. And
of course we know now that we have nuclear power plants,
(05:25):
and there are nuclear powered chips and nuclear powered submarines.
But today we want to explore another question, which is
why nuclear power hasn't made inroads into the skies. And
so on today's podcast, we'll be asking the question why
don't we have nuclear powered airplanes?
Speaker 2 (05:47):
Well? Should we see what the audience thinks.
Speaker 1 (05:50):
This is a fascinating question, and so as usual, we
went out into our list of volunteers to see what
people thought about having a nuclear reactor on board an airplane.
If you'd like to participate in this segment of the podcast,
please don't be shy. Write to me two questions at
Daniel and Jorge dot com. We will set you up
with random physics questions in your inbox every week. Everybody's welcome.
(06:13):
So before you hear these answers, think to yourself, how
do you feel about having a nuclear reactor on board
your airplane. Here's what people had to say.
Speaker 3 (06:22):
Well, we are too far from having electric powered planes,
but if we use water and eating them up with
nuclear reactor and use it as a propellant, then it
could be. But that would require enormous amount of water
to be stored, so it's not very likely.
Speaker 1 (06:38):
But maybe in the future.
Speaker 4 (06:41):
I'd say no, because they're quite heavy, I think, and
I think they need to be called down quite a lot.
So I know in nuclear submarines they use the sea
walls to cool down the reactor, so I don't know
what is heavy. And unless it was a very very
big airplane with nobody on board and nothing on board
other than a nuclear reactor, i'd say no.
Speaker 5 (07:04):
Well, I wouldn't fly on it. I mean, a nuclear
reactor is typically just a heat engine, steam engine, or
just creating heat like on the Mars Rovers. So to
have enough energy to continuously power an airplane would need
it to be enormous, and then I don't think you
could put it on the airplane, So probably not. But
since you're asking, maybe.
Speaker 6 (07:26):
Let's see, the biggest airplanes can carry about four hundred
or five hundred tons, so I would say, if you
could make one that's light enough, I would say, yes,
they put them in submarines, So yes, I.
Speaker 2 (07:39):
Thought these answers were really good. To be honest, heavy
wasn't the main concern that I had in mind when
you sent the title of this episode to me. My
thought was I wouldn't want to ride that close to
a nuclear reactor. But then I thought, oh, well they
do it on submarines, is probably okay. So then after
deciding that that concern wasn't big one, I thought, well,
(08:01):
probably I don't want nuclear material flying over my head.
When sometimes airplanes don't come down in the safest ways,
you wouldn't want them to drop their nuclear material and
spread it across earth. But this the most common thing
that the audience said was that this is too heavy
to work on planes. Were they on the right track.
Speaker 1 (08:21):
That's definitely an issue, and it's actually all entangled because
one of the reasons that submarines can be saved is
that they have lots of shielding because they don't have
to worry about weight, and so these questions of safety
and shielding are all connected.
Speaker 2 (08:36):
Excellent, good job, audience. So my first thought here is
that planes seem to be doing just fine, But of
course it would be really nice if planes were using
cleaner energy sources, and nuclear power is a good energy
source if you're trying to cut down on greenhouse gases.
(08:57):
So let's talk about the pros first. They assume that's
one of the pros. So why else might you want
nuclear powered aircraft.
Speaker 1 (09:05):
The whole idea for nuclear power aircraft comes out of
World War II. Of course, that's when nuclear powers invented,
and maybe the primary motivation was to make airplanes that
could fly for longer without needing to refuel. And World
War Two, a lot of our strategic decisions were based
on needing to refuel. You had these bombers and you
wanted to drop bombs on enemy territory, and those bombers
(09:27):
needed gas, and that limited how far they could fly,
and in many missions the bombers came back with just
like fumes. It really limited the reach of these bombers,
And so people were thinking, could we develop airplanes that
ran on nuclear power that could fly for much much
longer because nuclear fuel is so much denser. So, for example,
submarines can operate for a very very long time without refueling.
(09:51):
Same with nuclear powered aircraft carriers. These things can sometimes
go decades without refueling, except.
Speaker 2 (09:58):
The humans who ride them would need to refuel by
sleeping at night. But I guess, I guess you could
have a number of pilots circulate or you know, taking
turns that you could keep going. But like those bombers,
aren't the figure something like one in four didn't return
on each run. Think of the amount of nuclear material
that would be falling to Earth with these bombers as
(10:21):
they got shot down. But all right, we're probably going
to talk about that in the con section. I'm guessing so,
but you know me, I always get hung up on
the cons. Okay, so let's spok about more pros.
Speaker 1 (10:30):
That's definitely an issue. But if your goal is to
have airplanes that could like fly all over the world
and drop bombs on any target without needing to refuel,
or without needing to worry about like tricky aerial refueling
maneuvers which make new and the refueling plane very vulnerable
to enemy aircraft, or without needing to like buy territory
(10:51):
in foreign countries for refueling bases. Did you know, for example,
the United States tried to buy Greenland from Denmark even
before Trump offered. They wanted to refueling in Greenland, and
they offered one hundred million dollars in gold to Denmark
for Greenland, and Denmark said, no, thanks, We'll keep Greenland.
Speaker 2 (11:09):
And we did this so that we could refuel there.
That was our main purpose.
Speaker 1 (11:13):
Yeah, Greenland is very strategic location between the US and
the Soviet Union. Absolutely. Yeah.
Speaker 2 (11:18):
Did we try Iceland next, maybe for less money?
Speaker 1 (11:24):
And then Island was offended. They're like, what we're not
as value is Greenland? Are you guys crazy? Yeah? Hence
the Cold War very chilly. But the idea was basically
try to get airplanes that could fly longer, right, And
the concept there, the physics underneath it is that nuclear
fuel is so much more dense. Like if you think
about how much energy is stored in uranium versus how
(11:47):
much energy is stored in like diesel, it's really just
enormous like diesel, and gas has more energy than coal,
or more energy than like you know, animal fat or whatever.
But just by a few factors, uranium has seventy six
million megadewles of energy per kilo of uranium, whereas gas
(12:07):
has forty six megadels. So the energy density uranium is
a million times that of diesel.
Speaker 2 (12:13):
Oh my gosh, that's incredible. Okay, so this is an
amazing power source. Tell us about subs and why it
works so well in submarines.
Speaker 1 (12:23):
Yeah, this is something that works very very well for
submarines and the newest generation of submarines. They never need
to refuel like they think. These subs will last for
like fifty years, and the fuel will also last for
fifty years. You'd like, just build the sub, you build
the fuel in, and you never refuel it because it's
so energy dense. It's amazing.
Speaker 2 (12:42):
That's incredible.
Speaker 1 (12:43):
So they have these miniaturized reactors and they're powered by uranium,
and you know, there's fission that happens there and the
fission releases heat that heats water, which produces steam, which
turns a turbine which then directly turns the ship's propeller.
Often in land based nuclear power. The turbine then spins
a generator which makes electricity. You put it on the grid,
(13:04):
but there's no need here to generate electricity. You can
just directly have that turbine spin the ship's propeller. And
the cool thing is this is much quieter than a
diesel engine, and there's no pistons, for example, And so
if you're trying to run quiet underwater, that having a
nuclear powered submarine that never needs to come up to
refuel is quite the advantage from a military point of view.
Speaker 2 (13:25):
That is pretty incredible. Is the US the only country
that has these? I'm going to guess that the Soviet
Union also came up with this, and so Russia has
it too.
Speaker 1 (13:34):
Absolutely, the Soviets have them, and we've had them for decades.
Speaker 2 (13:37):
They're not the Soviets anymore.
Speaker 1 (13:42):
The Soviets had them. The Russians now have them, of course,
But this is something which is decades old. It was
nineteen sixty when we had the first submerged circumnavigation of
the globe, like the first time a submarine went around
the globe without surfacing. That's just like a decade and
a half after the whole invention of nuclear power.
Speaker 2 (14:01):
Wow, that's incredible.
Speaker 1 (14:03):
Yeah, And a few decades later we had more nuclear
reactors in ships than there were on land producing electric power. So,
like the military has really been into this idea for
a long time because they're like not refueling and they're
like the quietness of these reactors, and frankly, probably because
they don't also care as much about the potential disasters
(14:23):
and the ecological impact.
Speaker 2 (14:26):
And why is that? Is it because the bottom of
the ocean is sort of desolate and it doesn't even
if a sub crashes, most of the material stays in
one spot, so the you know, devastation and the problems
are sort of limited. Or why do why would you
not care about the ecological Well, I.
Speaker 1 (14:43):
Don't want to speak to the motivations of the military person,
but you know you're developing weapons anyway that are causing
huge destruction, right Your goal is destruction, So like gentleness
about the territory, I mean, I guess it must always
be second or a third concern. But you're also right that,
like submarine that crashes underwater, water is a pretty good
(15:03):
shield from radiation. And so unless that uranium then leaks
out and like spreads into ocean currents, the actual radiation
from the crash site is pretty limited to that location
because water is an excellent shield.
Speaker 2 (15:16):
Okay, that's good, all right, So we use a lot
of these underwater. I happen to also know that they're
very helpful in space, So where have they been used
in space?
Speaker 1 (15:25):
Vivin used underwater, they're also used on the surface. The
US Navy eleven carriers are all nuclear powered. Some of
these things have two some of them have eight separate
reactor units. So, like maritime nuclear power very well established.
But you're right, we also use nuclear power in space.
Some of the rovers that we have sent to other
planets use nuclear power. They don't have nuclear reactors in
(15:49):
the same way that these subs do in the sense
that they have controlled fission reactions. Instead, they use another
kind of nuclear power, where there's uncontrolled decay that essentially
leads to heating more like a nuclear battery. These used
plutonium and they worked for like ten to fifteen years,
providing a gentle source of heat which is then converted
into the electricity to run some of these rovers like
(16:10):
Curiosity and Perseverance. So we definitely have nuclear powered craft underwater,
on the surface and in space.
Speaker 2 (16:18):
Well, we also have little nuclear reactors in some satellites.
We don't do it so regularly anymore. The US had
snapped ten A, which we sent up and it did
okay for a little while. Then it failed and we
boosted it to a graveyard orbit. So that didn't go
super well for us, and I think maybe it's leaking
a little nuclear material woops. And then the Soviets actually
(16:40):
sent up something like thirty three nuclear powered satellites and
they use these because they wanted to go kind of
lower for like surveillance purposes, and they were low enough
that they were starting to hit like atmosphere particles, so
solar panels would have slowed them down. So the nuclear
reactors allowed them to go for a long time without
the solar panels which would slow them down, and that
(17:01):
went okay most of the time. They didn't always spread
nuclear material across Canada, so that's good. There's just that
one time.
Speaker 1 (17:13):
You get one freebie, right, I mean, I'm sure Canada
is cool with that one time.
Speaker 2 (17:17):
There's a lot of Canada, and like a lot of
it's not being used for other stuff. Maybe.
Speaker 1 (17:22):
Wow, you're pretty cavalier about safety when it's not your
kids involved, Kelly. You know Canadians have kids also, you
understand how that works.
Speaker 2 (17:31):
I am so sorry Canadians. I was joking and I
shouldn't have I shouldn't have done it, all right, So
we've talked about the various places that we find nuclear reactors.
Let's take a break and you know, shield our houses
against the radioactive material that might come falling down on
us at some point in the future. And we'll talk
about engine concepts next, and we're back, all right. So
(18:08):
we've talked about the various ways nuclear power has been
used in things like submarines and satellites and rovers and
of course nuclear power plants. Let's talk about some engine
concepts for how you might be able to make this
stuff work in an airplane.
Speaker 1 (18:23):
Yeah, it's really fun to think about how you might
actually power an airplane using a nuclear reactor, because the
basic concept that works underwater is to have it directly
spin a propeller. But those propellers can spin fairly slowly
and still power the ship. But an airplanes, of course,
we have jet engines, and so people have explored lots
of different ways to make a nuclear powered aircraft. But
(18:46):
the leading idea I think is a nuclear jet engine.
Speaker 2 (18:50):
Ooh sounds epic.
Speaker 1 (18:51):
Yeah, So to review the way a jet engine works
in general, is essentially your burning fuel. Jet fuel essentially
some fossil fuel to heat the air, and that expands
through a turbine into a propelling nozzle to provide thrust.
So the goal of the fuel, the reason you need fuel,
the reason we have jet fuel in airplanes is to
(19:12):
heat a bunch of air which then expands, and that
expansion gives you thrust. So the core idea of a
nuclear power jet engine is just to replace the source
of heat. And so because fission produces heat, right, it
produces these energetic particles, people thought, well, let's just use
fission to directly heat the air instead of having the
diesel fuel do that job.
Speaker 2 (19:33):
And then the air is just whatever air is surrounding
the airplane in the sky. Or are you like putting
some gas in there that gets heated.
Speaker 5 (19:42):
No.
Speaker 1 (19:43):
That's one of the cool things about a jet airplane
is that as it's flying through the air, it's pulling
air in, compressing it, and then expanding it with the heat.
And that's how the whole jet engine runs. That's why
jets don't work so well at low speeds because they
require this influx of air into the compressor oka And so.
Speaker 2 (19:58):
Then would fission be able to heat it up even
more like better than the other methods, so you could
go even faster. Or the point is just that it
can heat for longer because it burns slowly.
Speaker 1 (20:08):
Yeah, the idea is just that it can heat for
longer that the fuel is much more dense. And that's
also an attractive feature of nuclear power jets because you'd
like to be able to lower your weight in the air.
Right when the seven forty seven takes off or a
cross country trip, it's carrying enormous amounts of fuel. Some
of that fuel is just in order to provide the
thrust to carry the rest of the fuel. It's like
(20:30):
the whole rocket equation problem in miniature. And so if
you could figure out a way to make your fuel less,
then you can lighten the whole weight of the aircraft
and then need less fuel. Yeah.
Speaker 2 (20:39):
So okay, So at the beginning of the show, the
listeners said that they thought the problem was weight, but
it sounds like you were saying that's not the problem. Actually,
this could be a less heavy way to fly.
Speaker 1 (20:50):
Weight is definitely an issue, and we're going to talk
about like the shielding and the reactor itself being quite heavy.
But in terms of the fuel, there is a wind
and so we're going to keep track of the weight
accounting in terms of the fuel volume and weight. Nuclear
power winds. When it comes to the actual equipment involved,
you're going to see it's an overall loss, but you know,
there's something in the wind category there. And so people
(21:13):
have actually people and so people have actually built these things.
They have prototypes. You can go to the Idaho National Lab.
They have a couple of these set up that you
can actually see. They built them in the fifties and
they tested them, and there's sort of two different models there.
One is a direct air cycle, where the air comes
in from the compressor, goes directly into the nuclear core.
(21:34):
That air gets heated up by the nuclear power plant
and then emitted. That's very powerful, but the problem is
the air that comes out also kind of radioactive.
Speaker 2 (21:43):
That's a problem, and so if.
Speaker 1 (21:45):
You're like flying regularly back and forth across your own
country and you're spewing radiation and that's you know, bad.
So they developed a second model, an indirect air cycle,
where you basically have two different loops. You have the
air that comes in and then it gets heated by
something which has been heated by the nuclear reactor. So
for example, the nuclear actor doesn't directly heat the air.
(22:06):
It might heat like liquid metal in pipes, or very
high pressure water, which is then getting radioactive, but it's
not getting sprayed out the back of the jet engine. Instead,
it's just heating up the air. So you're sort of
shielding the air from the radioactivity by having this indirect
loop of liquid metal or high pressure water.
Speaker 2 (22:24):
That sounds more complex but better.
Speaker 1 (22:27):
Yeah, exactly, you're not killing your own people. But now
you have to have this extra machinery and you have
to hope that your high pressure liquid metal doesn't explode.
You have to monitor that, so it becomes more complicated,
which is the downside of it, But the basic idea works,
like in principle, you can have a nuclear powered jet engine.
Speaker 2 (22:45):
Oh, I don't think I would want that flying over
my home. What are what are some of our other options?
Speaker 1 (22:52):
So instead of having a jet engine, you could also
have a nuclear powered thermal rocket, so a chemical rocket,
the thing that like the set Urn and five used
to get off the surface of the Earth. You have
some chemical reaction which creates expansion and gives your propellants
basically momentum out the back. Right, This is the way
a rocket engine works. Well, you could imagine a nuclear
powered version of that where the heat comes from the
(23:14):
nuclear reaction and that flies off some propellants, and that
those propellants are then pumped through the core to heat
up something. So it's sort of similar to the jet
engine concept. You're using the nuclear reactor to heat something
and then that is expanding and flying out the back,
but we call this a thermal rocket instead of a
jet engine because you also don't have this compression cycle.
Speaker 2 (23:35):
Is this what project Orion was all about.
Speaker 1 (23:37):
Project Oryon was actually blowing up nuclear bombs behind it,
So it's sort of similar. It's sort of similar and
much more awesome and impossible, but.
Speaker 2 (23:50):
Awesome if you're like not living on the planet where
they're trying it out, maybe.
Speaker 1 (23:53):
But yeah, awesome sense Like if you see it, you're like,
oh my gosh. Wow.
Speaker 2 (24:01):
So this is a more delicate approach, yeah, exactly.
Speaker 1 (24:05):
The third approach is to think about action generating electrical
power and then using that electrical power to run like
an electrical engine. So you sort of separate the two components.
You have the nuclear planet on board, it's running, it's
producing steam that's turning a turbine that's running a generator
that's producing electrical power. Then you're feeding the electrical power
to like a turboprop engine, So the engine and the
(24:27):
power generation are separate.
Speaker 2 (24:29):
So do you have a sense for out of these
three methods, which one is like the best. So they
differ in complexity, they differ in pollution or you know
how bad they are for the environment below, they probably
differ in how much power they produce for a given
amount of nuclear material. Is there like a favorite amongst
people who are excited about these ideas?
Speaker 1 (24:50):
I think the jet engine is definitely the leading idea.
People like jets. Jets can go really fast, they work
really well on airplanes. People have actually built prototypes of
this that it can work. So the jet engine is
definitely the leading concept.
Speaker 2 (25:04):
All right, So we've talked about the different ways to
make this work. We've talked about the pros. You know
why you would want to use nuclear power for an airplane,
But we all know that Kelly's the wet blanket around here.
So I'm excited for us to move on to the cons.
What are the reasons why this idea that sounds bad
to me is bad?
Speaker 1 (25:25):
So many reasons. Let's start with the practical ones, and
that's the issue of weight, right, So reactors can be big,
and they can becumbersome. This has been mostly solved. People
have made miniature versions of reactors, like to put on
a submarine or to put several of them independent reactors
onto a big aircraft carrier, so you can make the
(25:46):
reactor fairly miniature. Physicists are really good at figuring that
kind of stuff out. What's very hard to miniaturize, though,
is the shielding. Like on a boat, a submarine, or
an aircraft carrier, you can have lots of layers of steel,
not a big deal, right, but on an airplane that
really costs you. And so it's possible to miniaturize the
reactor itself and reduce the weight there, but the shielding
(26:08):
is always going to be an issue. You want to
put a lot of heavy atoms between you and the
source of radiation, and a lot of heavy atoms are
always just going to be heavy.
Speaker 2 (26:17):
So you had said that what was it like, gas
was something like fifty mega jeles per kilogram and uranium
was almost like eighty thousand. So even with that massive
increase in the amount of power that you get that
that doesn't do enough to even nearly offset the shielding.
(26:38):
Is that is that the message here.
Speaker 1 (26:40):
Yeah, exactly. You either need a lot of shielding or
you need to not worry about your crew. And there
was actually a time where people talked about only having
crew that were like past child bearing age or had
a terminal disease. Anyway, people seriously talked about this kind
of stuff, like the documents from the Cold War are crazy.
Speaker 2 (27:00):
Gonna die anyway, fly on our plane. You always wanted
to be a pilot, right, Crid.
Speaker 1 (27:06):
And basically every step you take to make these things
more safe makes them impractical because now they're too heavy.
So not just the shielding but also the cooling systems. Right,
you want to generate this heat, but you also don't
want to overheat the rest of the airplane, and you
want to have devices in place to protect yourself against
meltdowns and all sorts of other issues, and so all
these cooling systems and safety systems and all that shielding
(27:29):
just gets heavy.
Speaker 2 (27:30):
And I think perhaps the biggest dagger in this idea
to me is that if something goes wrong and you crash,
you spread nuclear material across a large area problems, which
is a problem.
Speaker 1 (27:43):
Yes, poisoning the earth bad for sure, and it's definitely
something people think about also when we go into space
with nuclear power, Like every time we launch a rover
with a blob of plutonium in it, we worry, like,
is this going to be the time it blows up
in the atmosphere and then spreads that plutonium on our planet.
It's a risk every time they do it, and so
they worry about it. But those are pretty rare launches.
Speaker 2 (28:05):
Oh you mean is this going to be the second time?
Speaker 1 (28:07):
Yes, exactly, the next time.
Speaker 2 (28:10):
The next time, yes.
Speaker 1 (28:11):
But if you're talking about regularly flying bombers or even
commercial airplanes around the world with nuclear power, then you're
constantly taking that risk, and you know, crashes happen and
they kill people, and you don't want to then compound
the dangers and the consequences by also poisoning the planet.
Speaker 2 (28:28):
Well, especially if these planes are being used as like
weapons of war or surveillance things, and you know other
countries might specifically be trying to shoot them down. That
seems bad. Yeah, although maybe a country won't shoot down
your spyplane if they know that they're going to be
like contaminating their land with radioactive waste. So, oh, you
have forgot that in the pro section, Daniel.
Speaker 1 (28:49):
It's like the poison pill. But you know, realistically and
maybe sadly, if you ask me, like, why aren't their
nuclear powered airplanes right now? I don't think that's the reason.
I think the reason we don't have nuclear powered airplanes
or not because they aren't safe or they would kill
your crew. I think that people would make those compromises
if they thought it was good for our military or
(29:10):
our strategic situation. The reason I think is actually just strategic,
that nuclear powered bombers are no longer the quiver we
thought we needed in our arsenal is that.
Speaker 2 (29:21):
Because satellites are so good, we can just buy from there,
or or yeah, why I.
Speaker 1 (29:25):
Think the reason is that you don't need nuclear bombers.
You don't really need bombers anymore. I mean, we have ICBMs,
we can deliver nuclear weapons from the planes of Montana
without putting any humans in the air, And we have
nuclear powered submarines which can sneak around the oceans and
send nuclear weapons to anywhere on Earth very quietly. So
you don't really need nuclear powered bombers to stay aloft
(29:48):
for twenty four hours anymore. We can already bomb people
with impunity. Oh yay, And I think that's probably the
reason we don't have it. All these other concer earns
are reasonable, and it makes it impractical and it makes
it unsafe. But I think because it's not strategically valuable,
it is probably why we don't actually have them.
Speaker 2 (30:09):
I guess we should all be glad that we have
ICBMs instead.
Speaker 1 (30:13):
I suppose. But of course, the US spent billions and
billions of dollars and more than a decade trying to
build nuclear powered airplanes, and they actually flew airplanes with
reactors on board.
Speaker 2 (30:26):
Were these jet engine reactors like you were talking about.
Speaker 1 (30:28):
No, we've never actually flown an airplane that was powered
by the reactor, but they did fly airplanes that had
reactors on them.
Speaker 2 (30:36):
All right, let's take a break and then you can
tell us more about that. Okay, So now we're back.
So you said that a plane has flown with a
nuclear reactor on it. Was that plane just transporting the
(30:59):
reactor from one place to another? Or Yeah? Why would
you want to carry nuclear material with you on a plane.
Speaker 1 (31:07):
You don't pack nuclear material every time you take a flight, Kelly.
Speaker 2 (31:10):
Not yet. But if it was strategically valuable, maybe I.
Speaker 1 (31:13):
Want, Yes, you might exactly. Now, this was like the
first step in the US's exploratory project to build nuclear
power aircraft. They thought, well, first let's try to fly
an airplane with a reactor on board. Study the shielding issues,
the safety issues. Can we actually get this thing working
and operating in the environment of an airplane before we
actually try to connect the reactor to the engines. So
(31:36):
in the fifties they had this project using a modified
B thirty six bomber with a working nuclear reactor on board.
So you have your standard jet engines flying this airplane,
but in the center you have a miniaturized reactor designed
specifically for flight.
Speaker 2 (31:51):
Wow, okay, and so this comports with your even if
it's hard, we'd do it if it were strategic. Because
this was what decade were they trying this in the fifties.
I'm going to assume that in the fifties they had
enough shielding. Is is that true? Or were they able
to do this because they you know, four went shielding
for this experiment.
Speaker 1 (32:11):
Well both, Actually they put a lot of shielding. So
this is like an eighteen ton reactor producing one megawatt,
and they had it in this special version of the
aircraft where the humans would live in this little pod,
this like special cockpit that was super shielded. If twelve
tons of lead and rubber that the humans would get
in and the rest of the airplane would just be
(32:32):
like totally irradiated. And this little pod had like windows
in it that were like twelve inches thick and pockets
of water to protect them, but still there was a
lot of radiation even though they were shielded. It was
well above anything you would consider safe for the pilots.
Speaker 2 (32:48):
Oh yikes. And if you ever need to do any
work on the body of the plane, any technician who's
working on it is going to be getting your radiated.
Speaker 1 (32:56):
Right, yeah, exactly. The whole thing is going to be
a disaster. And you know, for the project, they only
recruited pilots above child bearing age because they basically knew
that they were killing these people.
Speaker 2 (33:06):
Oh my goodness, you know, us people above child bearing
age are still valuable. Just throwing that out there.
Speaker 1 (33:15):
It's kind of amazing how they treated these things, like
they knew that there were potential disasters, and they actually
tried to plan for them. Like, so, this thing took
flight in the fifties. They made forty six flights with
this bomber, and every time they did, they also flew
it with a special extra bomber that had specially trained
paratroopers that if this plane crash, the paratroopers would jump
(33:35):
out of the airplane, paratroop down to the crash site
and seal it off. They were like nuclear trained paratroopers
to help try and contain a disaster.
Speaker 2 (33:44):
Were they all also above child bearing age?
Speaker 1 (33:49):
Yes, and they all wore lead underwear.
Speaker 2 (33:51):
Oh good, good plan, although it's too late, I guess.
But so when they were flying over the Southwest, were
they I guess specifically trying to fly over portions of
the southward but are not populated, like those paratroopers aren't
going to be helpful if it lands in Phoenix.
Speaker 1 (34:07):
You know, I hope so. I don't have any details
to back that up, but I certainly hope they do.
But you know, this thing was airborne over the Southwest
forty six times in the fifties, so they definitely took
a risk.
Speaker 2 (34:19):
Did it ever crash?
Speaker 1 (34:20):
This one never did crash, but they tried to estimate
what would happen if it did crash. They created some
situations where they like put a fuel rod into a
burning jet engine in Idaho. So they did these experiments
and this is pretty bad. Those experiments ended up like
releasing quite a bit of caesium one thirty seven into
the air above Idaho. Yeah, it's pretty bad. And they
(34:43):
called this test operation Wiener Roast because they used because
they used a bunch of live cattle at varying distances
to help measure the effects of the radiation.
Speaker 2 (34:55):
Wow, I mean they clearly should have been using doxins
little Wiener dogs. So I was I was soffing because
that was really a missed opportunity.
Speaker 1 (35:06):
But you have just pissed off a lot of dog
owners out there, Kelly, I'm sure I have.
Speaker 2 (35:12):
That's right.
Speaker 1 (35:14):
So this is like a real government program.
Speaker 4 (35:16):
You know.
Speaker 1 (35:16):
They invested a lot of money into this program, billions
of dollars, decades of research to try to make this
thing happen. And they got as far as flying airplanes
around with nuclear reactors on board.
Speaker 2 (35:27):
That's that's pretty far, just to confirm, we've never flown
anything that was actually powered by the nuclear power source, right,
It's just been sort of carried along like the.
Speaker 1 (35:37):
First exactly, we got as far as airplanes with nuclear
reactors on board and then on the ground nuclear powered
jet engines that never flew, but we never put them
together into an airplane that was powered by a nuclear reactor.
Speaker 2 (35:52):
Okay, so there's always a Soviet equivalent to these sorts
of things. So did the Soviet Union have a similar project?
Speaker 1 (36:01):
Of course they did. In the fifties, the Soviet Union
had a project to fly one of their enormous TU twenties.
If you haven't seen a picture of one of these things,
this is like a really incredibly huge bomber with this
really elegant swept wing design, and they were working on
a similar project. Details are a little bit sketchy, and
part of the information is a little confusing because in
(36:22):
the fifties there was an article in Aviation Week that
turns out to have been mostly filled with false information,
claiming that the Soviets were already testing a nuclear airplane
that was powered by nuclear power. It turned out to
be misinformation, but you know, it kept the US program
going for a few more years. But the Soviets ended
up coming to the same conclusion we did, which is
(36:44):
that there's a huge radiation hazard to the crew, and
the crash risks were significant, and so they abandoned the
projects right around the same time we did.
Speaker 2 (36:53):
Presumably they also had ICBMs and stuff, and so they
had the same capabilities without the technology just like did
right or were they behind on ICBMs.
Speaker 1 (37:02):
No, that's exactly right, And so in the early sixties
both programs were abandoned because people realized that nuclear powered
submarines and ICBMs filled the strategic need in a much
simpler way than nuclear powered aircraft.
Speaker 2 (37:15):
All right, So does that mean that both Russia and
the US, like no country on Earth right now was
working on this program because we all have better ways
to do this? Is that right?
Speaker 1 (37:25):
Yes? And no no country on Earth that we know
of is trying to fly an atomic powered aircraft with
people on it. But the Russians claim to be working
on and have developed, a nuclear powered cruise missile. A
cruise missile is basically like an unmanned aircraft. It can fly,
it can loiter, it can turn. It's not just like
(37:46):
ballistic You're not just like throwing a bomb. It has
like engines and it can steer, et cetera. And the
idea of a nuclear powered cruise missile is still kind
of attractive because it would have basically unlimited range. This
thing could take off, fly around the Earth a couple
of times. You could even like hang out for a while,
like doing loops, you know, take the long path over
(38:07):
the North Pole or something. And so Russia claims to
be working on this thing. It's called the SSC x nine,
and in October twenty twenty three, Putin claimed that they
tested it successfully, though a lot of people are pretty skeptical.
Speaker 2 (38:21):
Yeah, I mean, that guy always tells the truth. So
so slam dunk we got. We've got to believe it. Huh.
Do you really need a cruise missile that can like
circle the world four times? Why not just like know
where you're going to shoot it off, and shoot it
off from one spot using another fuel source and just
(38:42):
get there right away.
Speaker 1 (38:44):
Yeah, a lot of these Russian modern weapons programs seem
kind of bombastic and unnecessary. Like he's also talking about
his supersonic missiles. It's like, you know, do you really
need supersonic missiles? Are there really an advantage to that? I
think a lot of this stuff might just be pr
I think and wants to advertise to the Russians that
their military is cutting edge, that they have advantages over
(39:06):
the West, et cetera, et cetera. So analysts that I've
read suggest that a lot of this is just for
internal propaganda, not actually military strategy.
Speaker 2 (39:15):
I can believe that, all right, So let's bottom line this.
Give me the summary the take home points for the
nuclear plane story.
Speaker 1 (39:23):
So, a nuclear powered airplane is possible. Physics says you
can do it. You put a reactor on board. We
have the techniques, We've proven that you can build a
nuclear powered jet engine. Problem is the way it becomes
very impractical. If you want your crew to survive, then
you've got to shield them from the nuclear reactor, and
that's going to make your plane very, very heavy. In addition,
(39:45):
the crash risks are significant. So it's possible, but dangerous
and kind of impractical at this point, and not really
necessary anymore because we have other weapons that fill the
strategic niche that originally motivated the idea of nuclear power aircraft.
So really the only remaining reason to do it is like, ooh,
it kind of sounds cool.
Speaker 2 (40:06):
Oh, so if I'd got my kids all excited about
flying on one of these nuclear powered airplanes, you're telling
me I'd have to let them down by saying, oh, Daniel,
got you excited about something that isn't really gonna happen.
It's not strategically helpful. Sorry, Kid one and Kid two,
they'd be very disappointed.
Speaker 1 (40:23):
Yeah, exactly. And so unless you're like a nuclear nerd
who likes to think about nuclear power powering everything and
new ways to do stuff, and you want to have
like a nuclear toaster on your kitchen, there's not really
a good reason that even considered nuclear power airplanes.
Speaker 2 (40:36):
I mean, is this a material science question, like if
we can find a much much much better shield that's light,
then suddenly this all becomes a better idea or does
such a thing not exist?
Speaker 1 (40:46):
From the physics point of view, Really, shielding is just
about having enough high z atoms between you and the source.
So it's hard to imagine how you're going to do
that without a lot of high zy atoms, which are
pretty heavy. So unless you come up with a new
way to do nuclear power which doesn't produce the same
kind of radiation, like, for example, if you had a
mini fusion reactor or a fusion reactors don't have the
(41:09):
same kind of radioactive output, So a fusion powered airplane
that might be possible but first we have to get
fusion to work like on the ground before we can
get it to work in the air.
Speaker 2 (41:21):
Well, that's a big ask. We've been saying we're pretty
close for fifty years.
Speaker 1 (41:24):
But exactly.
Speaker 2 (41:27):
But there are some pretty cool companies doing some cool work,
So hopefully we get that eventually.
Speaker 1 (41:31):
Yeah, and maybe eventually they'll develop fusion and then they'll
miniaturize it, and maybe we'll have fusion powered airplanes. Because
also the fuel for fusion is just hydrogen, and so
it's not as dangerous, So a crashed fusion powered airplane
wouldn't be any more dangerous than a crash diesel powered airplane.
Speaker 2 (41:47):
Safe is cool. I like it.
Speaker 1 (41:51):
All right. And so while it's fascinating to think about
how discoveries in physics can change our world, allowing us
to create devastating weapons and also sources of clean energy,
they don't always necessarily translate to changes in technology that
affects our daily life. Sometimes the old ways are better.
Speaker 4 (42:11):
Yay.
Speaker 1 (42:12):
Thanks very much for joining us today, everybody, and thank
you Kelly for taking this trip on a nuclear powered podcast.
Speaker 2 (42:19):
Thank you for having me. It's been a blast as always.
Speaker 1 (42:22):
All right, tune in next time. For more science and curiosity,
come find us on social media, where we answer questions
and post videos. We're on Twitter, This Org, Instant and
now TikTok. Thanks for listening and remember that Daniel and
Jorge Explain the Universe is a production of iHeartRadio. For
(42:43):
more podcasts from iHeartRadio, visit the iHeartRadio app, Apple Podcasts,
or wherever you listen to your favorite shows.
Hosts And Creators
Daniel Whiteson
Kelly Weinersmith
Popular Podcasts
40s and Free Agents: NFL Draft Season
Daniel Jeremiah of Move the Sticks and Gregg Rosenthal of NFL Daily join forces to break down every team's needs this offseason.
Dateline NBC
Current and classic episodes, featuring compelling true-crime mysteries, powerful documentaries and in-depth investigations. Follow now to get the latest episodes of Dateline NBC completely free, or subscribe to Dateline Premium for ad-free listening and exclusive bonus content: DatelinePremium.com
The Bobby Bones Show
Listen to 'The Bobby Bones Show' by downloading the daily full replay.