Home
Entrar
Registrar
Conteúdo de Aprendizagem
Loading...
Salvaging the Cold War's Sunken Nuclear Subs - Video học tiếng Anh
Praticar Escuta
Praticar Escuta
/
Video
/
SciShow
/
Salvaging the Cold War's Sunken Nuclear Subs
Salvaging the Cold War's Sunken Nuclear Subs
Selecionar modo de aprendizagem:
Ver legendas
Escolher palavra
Reescrever palavra
Highlight:
3000 Oxford Words
4000 IELTS Words
5000 Oxford Words
3000 Common Words
1000 TOEIC Words
5000 TOEFL Words
Legendas (227)
0:00
There are about 150 nuclear submarines operating today.
0:03
They spend a lot of time underwater,
0:05
but surface when they need to.
0:07
…Or at least they’re supposed to.
0:09
Sometimes subs end up permanently submerged.
0:12
After all, accidents can happen.
0:14
And this presents a bit of an issue.
0:16
A nuclear reactor isn’t a great thing
0:18
to just leave out in the wild.
0:20
So there have been some efforts to recover these
0:23
wrecks before they become a bigger problem.
0:25
But getting a nuclear reactor off the
0:27
ocean floor turns out to be kind of hard!
0:30
Here’s how scientists and engineers rescue
0:33
nuclear subs when things go very, very wrong.
0:37
[♪INTRO]
0:40
While there are a lot of nuclear submarines
0:42
in the world, the number of known nuclear
0:44
submarine wrecks is, thankfully, much lower.
0:47
The US currently has two lost nuclear subs,
0:50
the Soviet Union lost four, and the Russian Navy two,
0:53
for a grand total of eight.
0:54
So you can count them on your hands.
0:56
But still, it’s a lot when you consider all the nuclear waste on board.
1:00
A sub’s nuclear reactor is essentially a miniaturized
1:02
version of the reactors at big power plants.
1:04
It uses heat from radioactive fuel to boil water into steam.
1:08
That steam spins a turbine, which is how the propellers move.
1:11
It’s also how they get electricity.
1:13
And this isn’t the only nuclear thing on board.
1:15
In addition to the reactor, a submarine may be
1:18
carrying some spent nuclear waste as well as nuclear
1:22
weapons in the form of missiles or torpedoes.
1:25
Now, normally these are all sealed up nicely.
1:28
You can stand right next to all of them and be fine.
1:31
But, normally, the sub is not a wreck at the bottom of the ocean.
1:34
Whatever happened to sink the sub like
1:36
a fire or explosion or something can crack
1:39
open the reactor or the other equipment.
1:41
Even if the reactor does survive the incident intact,
1:44
the slow corrosion of salt water can open up that metal shell.
1:48
In any of these cases, it can result in radioactive atoms,
1:51
also known as radionuclides, being released into the water,
1:55
spreading and contaminating whatever’s nearby.
1:57
This is something we don’t really want to happen,
2:00
so different countries have been monitoring
2:02
these wrecked nuclear submarines for years.
2:04
The US monitors their two wrecks,
2:06
the Thresher and Scorpion, for example.
2:09
And Russia and nearby countries like Norway
2:11
have been monitoring the ones near them.
2:13
They send boats out to take samples of the seawater or sediment
2:16
around the wrecks to see how much radioactivity there is.
2:18
So far, the data that we have access to suggests that,
2:21
while some radionuclides are getting out from
2:24
at least a handful of these wrecks, it’s not a lot.
2:27
At least as of 2012, the Soviet submarine
2:29
known as K-27’s radiation leakage was negligible.
2:33
According to Russian research, levels of radionuclides
2:35
around another Soviet sub, K-159, are elevated,
2:39
but not enough to be of real concern right now.
2:41
And a third, K-278, leaked.
2:44
But not enough to be of huge concern to the Norwegians.
2:47
So that’s something to be thankful for. …For now.
2:50
I guess, at least.
2:52
It could still become a problem in the future, though.
2:54
Further corrosion can create new leaks.
2:56
And something could jostle the remaining nuclear
2:59
material in such a way to throw it out of control.
3:02
See, a working nuclear reactor depends on its fuel rods being
3:05
arranged in a certain shape to keep the reaction hot but not too hot.
3:09
But if, say, some part of the sub were to collapse, the fuel could get
3:14
jumbled together, start to react way too fast and get way too hot.
3:18
However unlikely, this could lead to a meltdown.
3:21
Which is bad, we don’t want one of those.
3:24
But even without a big explosion, a new crack in
3:26
the shell releasing previously radioactive stuff into
3:29
the ocean could still have significant effects.
3:31
A 2017 paper, for example, examined what would
3:33
happen if there was a big leak with the K-27.
3:36
They predicted how far currents might carry the radioactivity,
3:39
based on computer models of water and ice movement.
3:42
They also predicted how much this would affect
3:44
the environment and people living near the wreck,
3:46
based on models of the food chain and
3:49
estimates of how much seafood people eat.
3:51
Their results suggest that it could contaminate fish
3:54
in the area to the point where people who rely on
3:56
subsistence fishing may not be able to catch and eat them.
3:59
But pretty much only that population,
4:01
and it might not even be a problem for them.
4:03
But if it is, it’s thanks to phenomena known
4:05
as bioaccumulation and biomagnification.
4:08
Even though the amount of radioactive material
4:10
in the water would end up relatively small,
4:13
if little critters like fish or plankton ate it,
4:16
those radionuclides would stick around in their tissue.
4:19
That’s bioaccumulation.
4:20
Then, as creatures higher up the food chain ate those critters,
4:24
they would become radioactive, and on and on.
4:27
And because you need a lot of little fish to feed one big fish,
4:30
the higher up the food chain you go, the greater the dose ends up.
4:34
That’s biomagnification.
4:36
Even if some of the fish would technically be safe to eat,
4:38
the scare of radioactivity could still be
4:41
a disaster for fishermen in the area.
4:43
Like, if you were at the grocery store, would you eat the
4:47
fish that were caught next to the radioactive submarine?
4:50
Or would you maybe go ahead and buy the another different fish?
4:54
This isn’t a hypothetical question.
4:56
After the Fukushima nuclear disaster,
4:58
Japan suspended fishing in nearby
5:00
waters over contamination concerns.
5:02
And eventually, when they started discharging treated wastewater,
5:06
China straight-up banned fish from the area.
5:08
So we have to clean up these wrecks.
5:12
Maybe we put the EPA on the job,
5:13
or the International Atomic Energy Agency.
5:15
…Or the CIA.
5:17
We went with the CIA.
5:18
In 1968, the Soviet sub K-129 sank in the Northern Pacific Ocean.
5:23
By 1970, the CIA’s engineers had a plan to retrieve
5:26
it through a scheme called Project Azorian.
5:29
This secret six-year mission was really an effort to gain
5:32
intel on Soviet military capabilities during the Cold War,
5:36
not the US cleaning up an accident out of the goodness of their hearts.
5:40
Which is why the CIA took the helm.
5:43
Though, as a bonus, it would clear the
5:45
water of dangerous nuclear waste…
5:47
if done right.
5:48
The thing is, there was no protocol for the right way
5:51
to steal your enemy’s sunken nuclear submarine.
5:54
So CIA engineers determined that the best way to
5:58
remove this nuclear waste was to play the world’s
6:01
riskiest claw machine game, building what was
6:04
essentially a giant grabber on a ship.
6:06
And if anyone asked why this boat needed a
6:08
giant grabber out in the middle of the ocean,
6:10
the cover story was that it was a vessel for deep sea marine research.
6:14
This is going to be great for science.
6:15
Nobody ever thinks scientists are secretly CIA agents
6:18
because of stuff like this.
6:19
Unfortunately, the claw device they built for the job was just
6:22
about as effective as the claw machines that you’re familiar with.
6:25
It brought the sub about halfway up before
6:27
the sub broke apart and most of it,
6:30
including the engine room and presumably the reactor,
6:33
fell back into the depths.
6:34
The CIA retained the portion that didn’t fall.
6:37
And while they didn’t get the intelligence they wanted,
6:39
they still called it a success.
6:41
Which I disagree with.
6:43
Not the resounding success they were hoping for,
6:45
but they did also reportedly get two nuclear torpedoes,
6:49
so I guess it cleaned up some of the waste,
6:52
and also gave them some intel.
6:53
That might be the most dramatic example of a sub retrieval,
6:56
but there have been others.
6:58
In 2001, most of one Russian submarine,
7:00
the Kursk, was retrieved.
7:02
This time, they wouldn’t let it slip through their giant metal claw fingers.
7:06
They drilled holes through the hull and put grippers through the holes.
7:10
And I said most of it was retrieved because they basically
7:13
opted to avoid some of the Project Azorian troubles entirely
7:17
by not even trying to retrieve the forward section of the sub.
7:21
They had legitimate reason to be worried that it would break off and
7:24
destabilize things as they were lifting up the sub.
7:26
So they left it behind.
7:28
Sometimes it's just better
7:29
to leave your mistakes in the past.
7:31
In another rescue, an American sub called the USS Guitarro had
7:35
the “good fortune” to sink in a shipyard as it was being built.
7:39
Which is nice because probably not as many people died.
7:42
The water was shallow enough that the top
7:44
bit still stuck out of the water next to the pier.
7:47
So they could just temporarily dam the area,
7:49
then pump all the water around it out,
7:52
which let them go fix the problem and refloat it.
7:55
And right now, Russia is constructing their own specially made vessel
7:58
to recover K-27 from the Kara Sea and K-159 from the Barents Sea.
8:03
The Kara Sea is part of the Arctic Ocean,
8:05
and has already been used as a dumping ground for nuclear waste.
8:09
So the Soviets figured it was the perfect
8:10
place for a known radiation threat: K-27.
8:13
K-27 had an on-board nuclear reactor leak,
8:16
which killed nine crew members from radiation poisoning.
8:19
Thankfully, since the Russian Navy knew it was a nuclear problem,
8:22
they had the foresight to fill the reactor with
8:24
tar before sinking it so that it would be more stable.
8:29
However, that fix is only designed to last until 2032,
8:34
which is shockingly soon so,
8:36
so they're going to have to do something about it.
8:38
Researchers considered entombing the sub where it was in concrete,
8:42
but decided that the additional pressure on the reactor from all
8:44
that weight might actually raise the risk of an explosion.
8:48
So, yes, please bring that up and do something about it.
8:51
Meanwhile, the K-159 wasn’t originally
8:53
supposed to be sunk like the K-27.
8:56
But it got so rusted between decommissioning and attempted
8:59
deconstruction that it fell apart when they tried to move it.
9:02
It sank along with 800 kg of nuclear fuel.
9:06
Whoops! Just... little woopsie
9:08
K-159’s hull is too fragile to just lift it up.
9:12
And a hole in the hull rules out pumping in
9:14
air or balloons to raise it to the surface.
9:17
So the rescue team plans to have a pair of barges lower down giant,
9:22
curved grippers that get a hold of the whole thing at once.
9:26
Then they’ll lift it up enough to slide a submersible
9:29
platform underneath it for further support before bringing
9:33
the whole kit and kaboodle up to the surface.
9:35
Hopefully, they’ll be more successful than many
9:37
of our previous attempts to do this kind of thing.
9:40
Sunken nuclear submarines can’t stay on the ocean floor indefinitely.
9:43
I mean they can, but shouldn’t.
9:46
But it’s quite a challenge to remove them.
9:48
While few seem to be immediate dangers,
9:50
lost subs are still liabilities to the local environment
9:53
and the people around them.
9:54
And that’s not even considering new nuclear weapons that could
9:57
also leave nuclear reactors sitting at the bottom of the ocean.
10:00
So maybe our best scientists and engineers need to log
10:03
some hours at the local arcade with the claw machine.
10:06
This video was made possible by the Outrider Foundation,
10:09
an organization that supports multimedia storytelling
10:11
about nuclear threats and climate change.
10:14
To learn more, head to outrider.org
10:16
[♪OUTRO]
