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Well, I have a big announcement to make today,

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and I'm really excited about this.

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And this may be a little bit of a surprise

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to many of you who know my research

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and what I've done well.

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I've really tried to solve some big problems:

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counterterrorism, nuclear terrorism,

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and health care and diagnosing and treating cancer,

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but I started thinking about all these problems,

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and I realized that the really biggest problem we face,

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what all these other problems come down to,

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is energy, is electricity, the flow of electrons.

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And I decided that I was going to set out

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to try to solve this problem.

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And this probably is not what you're expecting.

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You're probably expecting me to come up here

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and talk about fusion,

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because that's what I've done most of my life.

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But this is actually a talk about, okay --

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(Laughter) —

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but this is actually a talk about fission.

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It's about perfecting something old,

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and bringing something old into the 21st century.

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Let's talk a little bit about how nuclear fission works.

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In a nuclear power plant, you have

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a big pot of water that's under high pressure,

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and you have some fuel rods,

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and these fuel rods are encased in zirconium,

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and they're little pellets of uranium dioxide fuel,

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and a fission reaction is controlled and maintained at a proper level,

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and that reaction heats up water,

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the water turns to steam, steam turns the turbine,

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and you produce electricity from it.

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This is the same way we've been producing electricity,

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the steam turbine idea, for 100 years,

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and nuclear was a really big advancement

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in a way to heat the water,

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but you still boil water and that turns to steam and turns the turbine.

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And I thought, you know, is this the best way to do it?

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Is fission kind of played out,

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or is there something left to innovate here?

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And I realized that I had hit upon something

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that I think has this huge potential to change the world.

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And this is what it is.

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This is a small modular reactor.

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So it's not as big as the reactor you see in the diagram here.

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This is between 50 and 100 megawatts.

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But that's a ton of power.

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That's between, say at an average use,

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that's maybe 25,000 to 100,000 homes could run off that.

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Now the really interesting thing about these reactors

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is they're built in a factory.

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So they're modular reactors that are built

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essentially on an assembly line,

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and they're trucked anywhere in the world,

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you plop them down, and they produce electricity.

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This region right here is the reactor.

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And this is buried below ground, which is really important.

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For someone who's done a lot of counterterrorism work,

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I can't extol to you

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how great having something buried below the ground is

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for proliferation and security concerns.

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And inside this reactor is a molten salt,

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so anybody who's a fan of thorium,

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they're going to be really excited about this,

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because these reactors happen to be really good

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at breeding and burning the thorium fuel cycle,

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uranium-233.

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But I'm not really concerned about the fuel.

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You can run these off -- they're really hungry,

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they really like down-blended weapons pits,

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so that's highly enriched uranium and weapons-grade plutonium

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that's been down-blended.

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It's made into a grade where it's not usable for a nuclear weapon,

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but they love this stuff.

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And we have a lot of it sitting around,

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because this is a big problem.

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You know, in the Cold War, we built up this huge arsenal

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of nuclear weapons, and that was great,

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and we don't need them anymore,

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and what are we doing with all the waste, essentially?

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What are we doing with all the pits of those nuclear weapons?

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Well, we're securing them, and it would be great

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if we could burn them, eat them up,

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and this reactor loves this stuff.

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So it's a molten salt reactor. It has a core,

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and it has a heat exchanger from the hot salt,

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the radioactive salt, to a cold salt which isn't radioactive.

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It's still thermally hot but it's not radioactive.

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And then that's a heat exchanger

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to what makes this design really, really interesting,

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and that's a heat exchanger to a gas.

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So going back to what I was saying before about all power

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being produced -- well, other than photovoltaic --

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being produced by this boiling of steam and turning a turbine,

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that's actually not that efficient, and in fact,

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in a nuclear power plant like this,

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it's only roughly 30 to 35 percent efficient.

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That's how much thermal energy the reactor's putting out

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to how much electricity it's producing.

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And the reason the efficiencies are so low is these reactors

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operate at pretty low temperature.

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They operate anywhere from, you know,

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maybe 200 to 300 degrees Celsius.

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And these reactors run at 600 to 700 degrees Celsius,

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which means the higher the temperature you go to,

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thermodynamics tells you that you will have higher efficiencies.

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And this reactor doesn't use water. It uses gas,

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so supercritical CO2 or helium,

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and that goes into a turbine,

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and this is called the Brayton cycle.

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This is the thermodynamic cycle that produces electricity,

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and this makes this almost 50 percent efficient,

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between 45 and 50 percent efficiency.

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And I'm really excited about this,

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because it's a very compact core.

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Molten salt reactors are very compact by nature,

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but what's also great is you get a lot more electricity out

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for how much uranium you're fissioning,

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not to mention the fact that these burn up.

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Their burn-up is much higher.

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So for a given amount of fuel you put in the reactor,

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a lot more of it's being used.

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And the problem with a traditional nuclear power plant like this

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is, you've got these rods that are clad in zirconium,

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and inside them are uranium dioxide fuel pellets.

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Well, uranium dioxide's a ceramic,

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and ceramic doesn't like releasing what's inside of it.

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So you have what's called the xenon pit,

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and so some of these fission products love neutrons.

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They love the neutrons that are going on

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and helping this reaction take place.

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And they eat them up, which means that, combined with

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the fact that the cladding doesn't last very long,

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you can only run one of these reactors

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for roughly, say, 18 months without refueling it.

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So these reactors run for 30 years without refueling,

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which is, in my opinion, very, very amazing,

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because it means it's a sealed system.

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No refueling means you can seal them up

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and they're not going to be a proliferation risk,

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and they're not going to have

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either nuclear material or radiological material

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proliferated from their cores.

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But let's go back to safety, because everybody

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after Fukushima had to reassess the safety of nuclear,

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and one of the things when I set out to design a power reactor

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was it had to be passively and intrinsically safe,

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and I'm really excited about this reactor

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for essentially two reasons.

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One, it doesn't operate at high pressure.

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So traditional reactors like a pressurized water reactor

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or boiling water reactor, they're very, very hot water

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at very high pressures, and this means, essentially,

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in the event of an accident, if you had any kind of breach

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of this stainless steel pressure vessel,

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the coolant would leave the core.

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These reactors operate at essentially atmospheric pressure,

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so there's no inclination for the fission products

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to leave the reactor in the event of an accident.

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Also, they operate at high temperatures,

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and the fuel is molten, so they can't melt down,

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but in the event that the reactor ever went out of tolerances,

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or you lost off-site power in the case

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of something like Fukushima, there's a dump tank.

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Because your fuel is liquid, and it's combined with your coolant,

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you could actually just drain the core

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into what's called a sub-critical setting,

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basically a tank underneath the reactor

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that has some neutrons absorbers.

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And this is really important, because the reaction stops.

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In this kind of reactor, you can't do that.

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The fuel, like I said, is ceramic inside zirconium fuel rods,

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and in the event of an accident in one of these type of reactors,

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Fukushima and Three Mile Island --

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looking back at Three Mile Island, we didn't really see this for a while —

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but these zirconium claddings on these fuel rods,

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what happens is, when they see high pressure water,

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steam, in an oxidizing environment,

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they'll actually produce hydrogen,

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and that hydrogen has this explosive capability

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to release fission products.

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So the core of this reactor, since it's not under pressure

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and it doesn't have this chemical reactivity,

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means that there's no inclination for the fission products

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to leave this reactor.

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So even in the event of an accident,

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yeah, the reactor may be toast, which is, you know,

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sorry for the power company,

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but we're not going to contaminate large quantities of land.

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So I really think that in the, say,

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20 years it's going to take us to get fusion

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and make fusion a reality,

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this could be the source of energy

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that provides carbon-free electricity.

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Carbon-free electricity.

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And it's an amazing technology because

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not only does it combat climate change,

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but it's an innovation.

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It's a way to bring power to the developing world,

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because it's produced in a factory and it's cheap.

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You can put them anywhere in the world you want to.

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And maybe something else.

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As a kid, I was obsessed with space.

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Well, I was obsessed with nuclear science too, to a point,

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but before that I was obsessed with space,

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and I was really excited about, you know,

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being an astronaut and designing rockets,

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which was something that was always exciting to me.

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But I think I get to come back to this,

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because imagine having a compact reactor in a rocket

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that produces 50 to 100 megawatts.

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That is the rocket designer's dream.

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That's someone who is designing a habitat on another planet's dream.

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Not only do you have 50 to 100 megawatts

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to power whatever you want to provide propulsion to get you there,

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but you have power once you get there.

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You know, rocket designers who use solar panels

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or fuel cells, I mean a few watts or kilowatts --

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wow, that's a lot of power.

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I mean, now we're talking about 100 megawatts.

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That's a ton of power.

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That could power a Martian community.

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That could power a rocket there.

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And so I hope that

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maybe I'll have an opportunity to kind of explore

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my rocketry passion at the same time that I explore my nuclear passion.

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And people say, "Oh, well, you've launched this thing,

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and it's radioactive, into space, and what about accidents?"

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But we launch plutonium batteries all the time.

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Everybody was really excited about Curiosity,

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and that had this big plutonium battery on board

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that has plutonium-238,

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which actually has a higher specific activity

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than the low-enriched uranium fuel of these molten salt reactors,

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which means that the effects would be negligible,

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because you launch it cold,

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and when it gets into space is where you actually activate this reactor.

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So I'm really excited.

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I think that I've designed this reactor here

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that can be an innovative source of energy,

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provide power for all kinds of neat scientific applications,

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and I'm really prepared to do this.

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I graduated high school in May, and --

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(Laughter) (Applause) —

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I graduated high school in May,

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and I decided that I was going to start up a company

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to commercialize these technologies that I've developed,

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these revolutionary detectors for scanning cargo containers

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and these systems to produce medical isotopes,

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but I want to do this, and I've slowly been building up

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a team of some of the most incredible people

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I've ever had the chance to work with,

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and I'm really prepared to make this a reality.

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And I think, I think, that looking at the technology,

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this will be cheaper than or the same price as natural gas,

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and you don't have to refuel it for 30 years,

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which is an advantage for the developing world.

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And I'll just say one more maybe philosophical thing

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to end with, which is weird for a scientist.

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But I think there's something really poetic

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about using nuclear power to propel us to the stars,

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because the stars are giant fusion reactors.

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They're giant nuclear cauldrons in the sky.

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The energy that I'm able to talk to you today,

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while it was converted to chemical energy in my food,

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originally came from a nuclear reaction,

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and so there's something poetic about, in my opinion,

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perfecting nuclear fission

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and using it as a future source of innovative energy.

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So thank you guys.

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(Applause)