0:00:00.656,0:00:02.959
Well, I have a big announcement to make today,

0:00:02.959,0:00:05.132
and I'm really excited about this.

0:00:05.132,0:00:07.460
And this may be a little bit of a surprise

0:00:07.460,0:00:10.714
to many of you who know my research

0:00:10.714,0:00:12.869
and what I've done well.

0:00:12.869,0:00:16.273
I've really tried to solve some big problems:

0:00:16.273,0:00:18.740
counterterrorism, nuclear terrorism,

0:00:18.740,0:00:22.388
and health care and diagnosing and treating cancer,

0:00:22.388,0:00:24.852
but I started thinking about all these problems,

0:00:24.852,0:00:29.412
and I realized that the really biggest problem we face,

0:00:29.412,0:00:31.660
what all these other problems come down to,

0:00:31.660,0:00:35.302
is energy, is electricity, the flow of electrons.

0:00:35.302,0:00:38.421
And I decided that I was going to set out

0:00:38.421,0:00:41.803
to try to solve this problem.

0:00:41.803,0:00:45.775
And this probably is not what you're expecting.

0:00:45.775,0:00:47.427
You're probably expecting me to come up here

0:00:47.427,0:00:49.006
and talk about fusion,

0:00:49.006,0:00:50.986
because that's what I've done most of my life.

0:00:50.986,0:00:54.252
But this is actually a talk about, okay --

0:00:54.252,0:00:56.876
(Laughter) —

0:00:56.876,0:00:59.843
but this is actually a talk about fission.

0:00:59.843,0:01:01.369
It's about perfecting something old,

0:01:01.369,0:01:04.019
and bringing something old into the 21st century.

0:01:04.019,0:01:08.644
Let's talk a little bit about how nuclear fission works.

0:01:08.644,0:01:10.388
In a nuclear power plant, you have

0:01:10.388,0:01:13.036
a big pot of water that's under high pressure,

0:01:13.036,0:01:14.554
and you have some fuel rods,

0:01:14.554,0:01:16.923
and these fuel rods are encased in zirconium,

0:01:16.923,0:01:19.793
and they're little pellets of uranium dioxide fuel,

0:01:19.793,0:01:23.949
and a fission reaction is controlled and maintained at a proper level,

0:01:23.949,0:01:27.100
and that reaction heats up water,

0:01:27.100,0:01:29.925
the water turns to steam, steam turns the turbine,

0:01:29.925,0:01:31.855
and you produce electricity from it.

0:01:31.855,0:01:34.635
This is the same way we've been producing electricity,

0:01:34.635,0:01:38.100
the steam turbine idea, for 100 years,

0:01:38.100,0:01:41.121
and nuclear was a really big advancement

0:01:41.121,0:01:42.701
in a way to heat the water,

0:01:42.701,0:01:47.156
but you still boil water and that turns to steam and turns the turbine.

0:01:47.156,0:01:50.972
And I thought, you know, is this the best way to do it?

0:01:50.972,0:01:53.772
Is fission kind of played out,

0:01:53.772,0:01:56.627
or is there something left to innovate here?

0:01:56.627,0:01:59.212
And I realized that I had hit upon something

0:01:59.212,0:02:03.516
that I think has this huge potential to change the world.

0:02:03.516,0:02:07.007
And this is what it is.

0:02:07.007,0:02:09.612
This is a small modular reactor.

0:02:09.612,0:02:14.316
So it's not as big as the reactor you see in the diagram here.

0:02:14.316,0:02:16.719
This is between 50 and 100 megawatts.

0:02:16.719,0:02:18.340
But that's a ton of power.

0:02:18.340,0:02:21.789
That's between, say at an average use,

0:02:21.789,0:02:26.930
that's maybe 25,000 to 100,000 homes could run off that.

0:02:26.930,0:02:29.508
Now the really interesting thing about these reactors

0:02:29.508,0:02:31.633
is they're built in a factory.

0:02:31.633,0:02:33.596
So they're modular reactors that are built

0:02:33.596,0:02:35.941
essentially on an assembly line,

0:02:35.941,0:02:38.100
and they're trucked anywhere in the world,

0:02:38.100,0:02:40.411
you plop them down, and they produce electricity.

0:02:40.411,0:02:43.853
This region right here is the reactor.

0:02:43.853,0:02:46.164
And this is buried below ground, which is really important.

0:02:46.164,0:02:48.877
For someone who's done a lot of counterterrorism work,

0:02:48.877,0:02:51.573
I can't extol to you

0:02:51.573,0:02:54.358
how great having something buried below the ground is

0:02:54.358,0:02:58.397
for proliferation and security concerns.

0:02:58.397,0:03:01.910
And inside this reactor is a molten salt,

0:03:01.910,0:03:04.688
so anybody who's a fan of thorium,

0:03:04.688,0:03:06.014
they're going to be really excited about this,

0:03:06.014,0:03:11.096
because these reactors happen to be really good

0:03:11.096,0:03:13.680
at breeding and burning the thorium fuel cycle,

0:03:13.680,0:03:15.731
uranium-233.

0:03:15.731,0:03:18.301
But I'm not really concerned about the fuel.

0:03:18.301,0:03:21.525
You can run these off -- they're really hungry,

0:03:21.525,0:03:24.957
they really like down-blended weapons pits,

0:03:24.957,0:03:27.821
so that's highly enriched uranium and weapons-grade plutonium

0:03:27.821,0:03:28.854
that's been down-blended.

0:03:28.854,0:03:32.246
It's made into a grade where it's not usable for a nuclear weapon,

0:03:32.246,0:03:35.397
but they love this stuff.

0:03:35.397,0:03:37.180
And we have a lot of it sitting around,

0:03:37.180,0:03:38.822
because this is a big problem.

0:03:38.822,0:03:40.939
You know, in the Cold War, we built up this huge arsenal

0:03:40.939,0:03:43.279
of nuclear weapons, and that was great,

0:03:43.279,0:03:45.734
and we don't need them anymore,

0:03:45.734,0:03:49.078
and what are we doing with all the waste, essentially?

0:03:49.078,0:03:51.493
What are we doing with all the pits of those nuclear weapons?

0:03:51.493,0:03:53.394
Well, we're securing them, and it would be great

0:03:53.394,0:03:55.138
if we could burn them, eat them up,

0:03:55.138,0:03:57.139
and this reactor loves this stuff.

0:03:57.139,0:04:00.161
So it's a molten salt reactor. It has a core,

0:04:00.161,0:04:03.935
and it has a heat exchanger from the hot salt,

0:04:03.935,0:04:08.005
the radioactive salt, to a cold salt which isn't radioactive.

0:04:08.005,0:04:10.652
It's still thermally hot but it's not radioactive.

0:04:10.652,0:04:12.432
And then that's a heat exchanger

0:04:12.432,0:04:15.725
to what makes this design really, really interesting,

0:04:15.725,0:04:18.733
and that's a heat exchanger to a gas.

0:04:18.733,0:04:21.277
So going back to what I was saying before about all power

0:04:21.277,0:04:24.270
being produced -- well, other than photovoltaic --

0:04:24.270,0:04:28.168
being produced by this boiling of steam and turning a turbine,

0:04:28.168,0:04:30.688
that's actually not that efficient, and in fact,

0:04:30.688,0:04:33.064
in a nuclear power plant like this,

0:04:33.064,0:04:37.872
it's only roughly 30 to 35 percent efficient.

0:04:37.872,0:04:40.409
That's how much thermal energy the reactor's putting out

0:04:40.409,0:04:42.062
to how much electricity it's producing.

0:04:42.062,0:04:44.987
And the reason the efficiencies are so low is these reactors

0:04:44.987,0:04:46.693
operate at pretty low temperature.

0:04:46.693,0:04:48.448
They operate anywhere from, you know,

0:04:48.448,0:04:52.141
maybe 200 to 300 degrees Celsius.

0:04:52.141,0:04:56.140
And these reactors run at 600 to 700 degrees Celsius,

0:04:56.140,0:04:58.845
which means the higher the temperature you go to,

0:04:58.845,0:05:01.741
thermodynamics tells you that you will have higher efficiencies.

0:05:01.741,0:05:05.415
And this reactor doesn't use water. It uses gas,

0:05:05.415,0:05:07.893
so supercritical CO2 or helium,

0:05:07.893,0:05:09.334
and that goes into a turbine,

0:05:09.334,0:05:11.195
and this is called the Brayton cycle.

0:05:11.195,0:05:13.669
This is the thermodynamic cycle that produces electricity,

0:05:13.669,0:05:16.099
and this makes this almost 50 percent efficient,

0:05:16.099,0:05:18.989
between 45 and 50 percent efficiency.

0:05:18.989,0:05:20.660
And I'm really excited about this,

0:05:20.660,0:05:23.173
because it's a very compact core.

0:05:23.173,0:05:27.309
Molten salt reactors are very compact by nature,

0:05:27.309,0:05:30.614
but what's also great is you get a lot more electricity out

0:05:30.614,0:05:33.359
for how much uranium you're fissioning,

0:05:33.359,0:05:35.438
not to mention the fact that these burn up.

0:05:35.438,0:05:37.030
Their burn-up is much higher.

0:05:37.030,0:05:39.008
So for a given amount of fuel you put in the reactor,

0:05:39.008,0:05:41.364
a lot more of it's being used.

0:05:41.364,0:05:44.549
And the problem with a traditional nuclear power plant like this

0:05:44.549,0:05:48.821
is, you've got these rods that are clad in zirconium,

0:05:48.821,0:05:51.550
and inside them are uranium dioxide fuel pellets.

0:05:51.550,0:05:53.724
Well, uranium dioxide's a ceramic,

0:05:53.724,0:05:56.940
and ceramic doesn't like releasing what's inside of it.

0:05:56.940,0:05:59.241
So you have what's called the xenon pit,

0:05:59.241,0:06:01.345
and so some of these fission products love neutrons.

0:06:01.345,0:06:02.592
They love the neutrons that are going on

0:06:02.592,0:06:04.992
and helping this reaction take place.

0:06:04.992,0:06:07.968
And they eat them up, which means that, combined with

0:06:07.968,0:06:10.205
the fact that the cladding doesn't last very long,

0:06:10.205,0:06:11.919
you can only run one of these reactors

0:06:11.919,0:06:16.447
for roughly, say, 18 months without refueling it.

0:06:16.447,0:06:21.038
So these reactors run for 30 years without refueling,

0:06:21.038,0:06:23.758
which is, in my opinion, very, very amazing,

0:06:23.758,0:06:25.711
because it means it's a sealed system.

0:06:25.711,0:06:28.582
No refueling means you can seal them up

0:06:28.582,0:06:31.495
and they're not going to be a proliferation risk,

0:06:31.495,0:06:33.766
and they're not going to have

0:06:33.766,0:06:36.270
either nuclear material or radiological material

0:06:36.270,0:06:38.582
proliferated from their cores.

0:06:38.582,0:06:41.646
But let's go back to safety, because everybody

0:06:41.646,0:06:45.424
after Fukushima had to reassess the safety of nuclear,

0:06:45.424,0:06:47.974
and one of the things when I set out to design a power reactor

0:06:47.974,0:06:51.526
was it had to be passively and intrinsically safe,

0:06:51.526,0:06:54.005
and I'm really excited about this reactor

0:06:54.005,0:06:56.334
for essentially two reasons.

0:06:56.334,0:06:59.278
One, it doesn't operate at high pressure.

0:06:59.278,0:07:02.519
So traditional reactors like a pressurized water reactor

0:07:02.519,0:07:04.951
or boiling water reactor, they're very, very hot water

0:07:04.951,0:07:08.358
at very high pressures, and this means, essentially,

0:07:08.358,0:07:11.222
in the event of an accident, if you had any kind of breach

0:07:11.222,0:07:14.263
of this stainless steel pressure vessel,

0:07:14.263,0:07:16.535
the coolant would leave the core.

0:07:16.535,0:07:19.574
These reactors operate at essentially atmospheric pressure,

0:07:19.574,0:07:23.480
so there's no inclination for the fission products

0:07:23.480,0:07:26.052
to leave the reactor in the event of an accident.

0:07:26.052,0:07:28.370
Also, they operate at high temperatures,

0:07:28.370,0:07:31.249
and the fuel is molten, so they can't melt down,

0:07:31.249,0:07:35.827
but in the event that the reactor ever went out of tolerances,

0:07:35.827,0:07:38.137
or you lost off-site power in the case

0:07:38.137,0:07:41.327
of something like Fukushima, there's a dump tank.

0:07:41.327,0:07:45.798
Because your fuel is liquid, and it's combined with your coolant,

0:07:45.798,0:07:48.169
you could actually just drain the core

0:07:48.169,0:07:50.350
into what's called a sub-critical setting,

0:07:50.350,0:07:52.304
basically a tank underneath the reactor

0:07:52.304,0:07:54.264
that has some neutrons absorbers.

0:07:54.264,0:07:58.054
And this is really important, because the reaction stops.

0:07:58.054,0:08:00.718
In this kind of reactor, you can't do that.

0:08:00.718,0:08:04.199
The fuel, like I said, is ceramic inside zirconium fuel rods,

0:08:04.199,0:08:07.190
and in the event of an accident in one of these type of reactors,

0:08:07.190,0:08:09.327
Fukushima and Three Mile Island --

0:08:09.327,0:08:12.222
looking back at Three Mile Island, we didn't really see this for a while —

0:08:12.222,0:08:15.708
but these zirconium claddings on these fuel rods,

0:08:15.708,0:08:18.537
what happens is, when they see high pressure water,

0:08:18.537,0:08:21.094
steam, in an oxidizing environment,

0:08:21.094,0:08:23.166
they'll actually produce hydrogen,

0:08:23.166,0:08:26.094
and that hydrogen has this explosive capability

0:08:26.094,0:08:28.304
to release fission products.

0:08:28.304,0:08:30.518
So the core of this reactor, since it's not under pressure

0:08:30.518,0:08:32.782
and it doesn't have this chemical reactivity,

0:08:32.782,0:08:36.256
means that there's no inclination for the fission products

0:08:36.256,0:08:37.990
to leave this reactor.

0:08:37.990,0:08:40.255
So even in the event of an accident,

0:08:40.255,0:08:43.973
yeah, the reactor may be toast, which is, you know,

0:08:43.973,0:08:45.632
sorry for the power company,

0:08:45.632,0:08:47.732
but we're not going to contaminate large quantities of land.

0:08:47.732,0:08:51.744
So I really think that in the, say,

0:08:51.744,0:08:53.872
20 years it's going to take us to get fusion

0:08:53.872,0:08:56.092
and make fusion a reality,

0:08:56.092,0:08:58.673
this could be the source of energy

0:08:58.673,0:09:01.347
that provides carbon-free electricity.

0:09:01.347,0:09:03.005
Carbon-free electricity.

0:09:03.005,0:09:06.350
And it's an amazing technology because

0:09:06.350,0:09:09.180
not only does it combat climate change,

0:09:09.180,0:09:10.684
but it's an innovation.

0:09:10.684,0:09:13.751
It's a way to bring power to the developing world,

0:09:13.751,0:09:16.230
because it's produced in a factory and it's cheap.

0:09:16.230,0:09:18.366
You can put them anywhere in the world you want to.

0:09:18.366,0:09:21.622
And maybe something else.

0:09:21.622,0:09:24.143
As a kid, I was obsessed with space.

0:09:24.143,0:09:26.886
Well, I was obsessed with nuclear science too, to a point,

0:09:26.886,0:09:29.286
but before that I was obsessed with space,

0:09:29.286,0:09:31.197
and I was really excited about, you know,

0:09:31.197,0:09:33.071
being an astronaut and designing rockets,

0:09:33.071,0:09:35.157
which was something that was always exciting to me.

0:09:35.157,0:09:38.563
But I think I get to come back to this,

0:09:38.563,0:09:41.864
because imagine having a compact reactor in a rocket

0:09:41.864,0:09:44.694
that produces 50 to 100 megawatts.

0:09:44.694,0:09:47.971
That is the rocket designer's dream.

0:09:47.971,0:09:51.702
That's someone who is designing a habitat on another planet's dream.

0:09:51.702,0:09:53.706
Not only do you have 50 to 100 megawatts

0:09:53.706,0:09:58.119
to power whatever you want to provide propulsion to get you there,

0:09:58.119,0:09:59.518
but you have power once you get there.

0:09:59.518,0:10:03.039
You know, rocket designers who use solar panels

0:10:03.039,0:10:05.998
or fuel cells, I mean a few watts or kilowatts --

0:10:05.998,0:10:07.591
wow, that's a lot of power.

0:10:07.591,0:10:10.036
I mean, now we're talking about 100 megawatts.

0:10:10.036,0:10:11.209
That's a ton of power.

0:10:11.209,0:10:13.496
That could power a Martian community.

0:10:13.496,0:10:15.093
That could power a rocket there.

0:10:15.093,0:10:17.800
And so I hope that

0:10:17.800,0:10:19.921
maybe I'll have an opportunity to kind of explore

0:10:19.921,0:10:24.588
my rocketry passion at the same time that I explore my nuclear passion.

0:10:24.588,0:10:27.578
And people say, "Oh, well, you've launched this thing,

0:10:27.578,0:10:30.142
and it's radioactive, into space, and what about accidents?"

0:10:30.142,0:10:33.175
But we launch plutonium batteries all the time.

0:10:33.175,0:10:35.294
Everybody was really excited about Curiosity,

0:10:35.294,0:10:37.895
and that had this big plutonium battery on board

0:10:37.895,0:10:40.014
that has plutonium-238,

0:10:40.014,0:10:42.414
which actually has a higher specific activity

0:10:42.414,0:10:46.158
than the low-enriched uranium fuel of these molten salt reactors,

0:10:46.158,0:10:49.661
which means that the effects would be negligible,

0:10:49.661,0:10:51.113
because you launch it cold,

0:10:51.113,0:10:54.824
and when it gets into space is where you actually activate this reactor.

0:10:54.824,0:10:56.132
So I'm really excited.

0:10:56.132,0:10:58.669
I think that I've designed this reactor here

0:10:58.669,0:11:02.574
that can be an innovative source of energy,

0:11:02.574,0:11:06.255
provide power for all kinds of neat scientific applications,

0:11:06.255,0:11:08.783
and I'm really prepared to do this.

0:11:08.783,0:11:11.550
I graduated high school in May, and --

0:11:11.550,0:11:15.698
(Laughter) (Applause) —

0:11:15.698,0:11:17.749
I graduated high school in May,

0:11:17.749,0:11:20.589
and I decided that I was going to start up a company

0:11:20.589,0:11:22.957
to commercialize these technologies that I've developed,

0:11:22.957,0:11:25.814
these revolutionary detectors for scanning cargo containers

0:11:25.814,0:11:28.094
and these systems to produce medical isotopes,

0:11:28.094,0:11:31.542
but I want to do this, and I've slowly been building up

0:11:31.542,0:11:33.795
a team of some of the most incredible people

0:11:33.795,0:11:35.982
I've ever had the chance to work with,

0:11:35.982,0:11:38.744
and I'm really prepared to make this a reality.

0:11:38.744,0:11:41.841
And I think, I think, that looking at the technology,

0:11:41.841,0:11:47.191
this will be cheaper than or the same price as natural gas,

0:11:47.191,0:11:48.991
and you don't have to refuel it for 30 years,

0:11:48.991,0:11:51.718
which is an advantage for the developing world.

0:11:51.718,0:11:54.840
And I'll just say one more maybe philosophical thing

0:11:54.840,0:11:56.769
to end with, which is weird for a scientist.

0:11:56.769,0:11:59.263
But I think there's something really poetic

0:11:59.263,0:12:03.062
about using nuclear power to propel us to the stars,

0:12:03.062,0:12:05.817
because the stars are giant fusion reactors.

0:12:05.817,0:12:08.158
They're giant nuclear cauldrons in the sky.

0:12:08.158,0:12:11.555
The energy that I'm able to talk to you today,

0:12:11.555,0:12:13.650
while it was converted to chemical energy in my food,

0:12:13.650,0:12:16.838
originally came from a nuclear reaction,

0:12:16.838,0:12:19.614
and so there's something poetic about, in my opinion,

0:12:19.614,0:12:22.583
perfecting nuclear fission

0:12:22.583,0:12:26.302
and using it as a future source of innovative energy.

0:12:26.302,0:12:28.253
So thank you guys.

0:12:28.253,0:12:33.238
(Applause)