WEBVTT - How does fusion power work?

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<v Speaker 1>Welcome to Brainstuff from house stuff Works dot com where

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<v Speaker 1>smart happens him Marcill Brain with today's question, how does

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<v Speaker 1>fusion power work? And will we ever have fusion power

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<v Speaker 1>plants anytime in the near future? If you think about it,

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<v Speaker 1>the Earth is already powered by one fusion power plant.

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<v Speaker 1>The Sun is a gigantic fusion reactor that creates nearly

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<v Speaker 1>all the energy making life on Earth possible. Sunlight provides

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<v Speaker 1>the warmth that keeps water from freezing, and sunlight let's

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<v Speaker 1>plants create the food that makes animal life possible. What

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<v Speaker 1>if we could take the fusion principles seen in the

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<v Speaker 1>Sun and bring them down to Earth in a miniaturized form.

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<v Speaker 1>If we could do that, it would be possible to

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<v Speaker 1>generate all the electricity that humanity uses. We would not

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<v Speaker 1>need to release any more of the carbon and pollutants

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<v Speaker 1>generated by coal fired power plants, and we could also

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<v Speaker 1>do away with most of the high level nuclear waste

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<v Speaker 1>produced by traditional nuclear power plants. Scientists and engineers have

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<v Speaker 1>been working on fusion power for decades. Why are there

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<v Speaker 1>no fusion power plants on Earth today? It's because it

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<v Speaker 1>is very difficult to create a mini sun on planet Earth.

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<v Speaker 1>The temperatures involved are mind boggling. Let's look at the

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<v Speaker 1>basic idea behind fusion to understand where the temperatures come from.

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<v Speaker 1>Hydrogen atoms are very common on Earth. Each water molecule,

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<v Speaker 1>for example, contains two of them. The goal of a

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<v Speaker 1>fusion reaction is to press two hydrogen atoms together so

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<v Speaker 1>tightly that their atomic nuclei fuse with each other to

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<v Speaker 1>create a single helium atom. The nucleus of any hydrogen

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<v Speaker 1>atom contains one proton. The nucleus of any helium atom

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<v Speaker 1>contains two protons, so if you fuse the two hydrogens together,

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<v Speaker 1>you get a helium The problem is that protons have

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<v Speaker 1>no desire to get together because they have the same charge.

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<v Speaker 1>They repel each other in a way that's similar to

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<v Speaker 1>magnetic propulsion. When you try to press the north poles

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<v Speaker 1>of two magnets together, you can feel that repulsion, which

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<v Speaker 1>gets stronger as the two magnets get closer together. That

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<v Speaker 1>same kind of repulsion happens when trying to press the

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<v Speaker 1>protons of two hydrogen atoms together. One way to get

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<v Speaker 1>hydrogen atoms diffuse into helium atoms is to use a

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<v Speaker 1>nuclear bomb to generate the appropriate temperatures and pressures. Hydrogen bomb,

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<v Speaker 1>also known as a fusion bomb, is a two stage weapon.

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<v Speaker 1>The first stage is a traditional uranium powered fission bomb

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<v Speaker 1>that explodes towards a capsule containing tritium and deuterium, which

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<v Speaker 1>are two forms of hydrogen. The tritium and the deuterium

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<v Speaker 1>fused together to create helium. As the helium has created

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<v Speaker 1>a huge amount of energy is released, As we see

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<v Speaker 1>in the sun. That energy takes the for orm of

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<v Speaker 1>heat and light. This second stage fusion reaction that takes

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<v Speaker 1>place inside a fusion bomb is what makes a fusion

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<v Speaker 1>bomb so powerful. Hydrogen bombs prove that fusion is possible

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<v Speaker 1>on Earth and extremely powerful. However, they also show how

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<v Speaker 1>messy the process can be. The goal of fusion research

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<v Speaker 1>is to tap into the power in a controlled way

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<v Speaker 1>that eliminates the explosion. One technology that's been used to

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<v Speaker 1>contain the temperatures needed for fusion is called a tokeomac.

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<v Speaker 1>A tokomac looks like a donut shaped cavity surrounded by magnets.

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<v Speaker 1>The magnets allow a ring of energetic hydrogen plasma to

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<v Speaker 1>be created at the center of the hollow donut, so

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<v Speaker 1>the plasma doesn't touch the walls of the chamber. If

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<v Speaker 1>the plasma is heated to a hundred plus million degrees celsius,

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<v Speaker 1>hydrogen atoms start fusing to create helium atoms. At that point,

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<v Speaker 1>the heat of fusion keeps the plasma hot and the

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<v Speaker 1>reaction becomes self sust daining. The extra heat produced can

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<v Speaker 1>be converted into electricity. A second way to create a

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<v Speaker 1>fusion reaction is to burn a little bit of fuel

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<v Speaker 1>at a time. In this approach, powerful beams of laser

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<v Speaker 1>light focus on a tiny capsule of hydrogen think peppercorn

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<v Speaker 1>in size. For this capsule, the lasers provide the heat

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<v Speaker 1>to initiate a fusion reaction, which then extinguishes itself because

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<v Speaker 1>the amount of fuel is so small. At this point

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<v Speaker 1>in the research process, scientists are about to build a

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<v Speaker 1>tokemac that may be large enough to contain a real

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<v Speaker 1>self sustaining reaction. It's called I T E R. And

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<v Speaker 1>scientists have built and are currently testing a laser facility

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<v Speaker 1>that may demonstrate the principles needed to build an eventual

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<v Speaker 1>power plant. It's called the National Ignition Facility. But these

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<v Speaker 1>are huge facilities and are extremely expensive to build, So

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<v Speaker 1>the research process is slow and deliberate. It may be

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<v Speaker 1>several more decades before a large, reliable fusion power plant

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<v Speaker 1>designed emergence from all this research. For more on this

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