Speaker 1: Welcome to Brainstuff from house stuff Works dot com where
Speaker 1: smart happens him Marcill Brain with today's question, how does
Speaker 1: fusion power work? And will we ever have fusion power
Speaker 1: plants anytime in the near future? If you think about it,
Speaker 1: the Earth is already powered by one fusion power plant.
Speaker 1: The Sun is a gigantic fusion reactor that creates nearly
Speaker 1: all the energy making life on Earth possible. Sunlight provides
Speaker 1: the warmth that keeps water from freezing, and sunlight let's
Speaker 1: plants create the food that makes animal life possible. What
Speaker 1: if we could take the fusion principles seen in the
Speaker 1: Sun and bring them down to Earth in a miniaturized form.
Speaker 1: If we could do that, it would be possible to
Speaker 1: generate all the electricity that humanity uses. We would not
Speaker 1: need to release any more of the carbon and pollutants
Speaker 1: generated by coal fired power plants, and we could also
Speaker 1: do away with most of the high level nuclear waste
Speaker 1: produced by traditional nuclear power plants. Scientists and engineers have
Speaker 1: been working on fusion power for decades. Why are there
Speaker 1: no fusion power plants on Earth today? It's because it
Speaker 1: is very difficult to create a mini sun on planet Earth.
Speaker 1: The temperatures involved are mind boggling. Let's look at the
Speaker 1: basic idea behind fusion to understand where the temperatures come from.
Speaker 1: Hydrogen atoms are very common on Earth. Each water molecule,
Speaker 1: for example, contains two of them. The goal of a
Speaker 1: fusion reaction is to press two hydrogen atoms together so
Speaker 1: tightly that their atomic nuclei fuse with each other to
Speaker 1: create a single helium atom. The nucleus of any hydrogen
Speaker 1: atom contains one proton. The nucleus of any helium atom
Speaker 1: contains two protons, so if you fuse the two hydrogens together,
Speaker 1: you get a helium The problem is that protons have
Speaker 1: no desire to get together because they have the same charge.
Speaker 1: They repel each other in a way that's similar to
Speaker 1: magnetic propulsion. When you try to press the north poles
Speaker 1: of two magnets together, you can feel that repulsion, which
Speaker 1: gets stronger as the two magnets get closer together. That
Speaker 1: same kind of repulsion happens when trying to press the
Speaker 1: protons of two hydrogen atoms together. One way to get
Speaker 1: hydrogen atoms diffuse into helium atoms is to use a
Speaker 1: nuclear bomb to generate the appropriate temperatures and pressures. Hydrogen bomb,
Speaker 1: also known as a fusion bomb, is a two stage weapon.
Speaker 1: The first stage is a traditional uranium powered fission bomb
Speaker 1: that explodes towards a capsule containing tritium and deuterium, which
Speaker 1: are two forms of hydrogen. The tritium and the deuterium
Speaker 1: fused together to create helium. As the helium has created
Speaker 1: a huge amount of energy is released, As we see
Speaker 1: in the sun. That energy takes the for orm of
Speaker 1: heat and light. This second stage fusion reaction that takes
Speaker 1: place inside a fusion bomb is what makes a fusion
Speaker 1: bomb so powerful. Hydrogen bombs prove that fusion is possible
Speaker 1: on Earth and extremely powerful. However, they also show how
Speaker 1: messy the process can be. The goal of fusion research
Speaker 1: is to tap into the power in a controlled way
Speaker 1: that eliminates the explosion. One technology that's been used to
Speaker 1: contain the temperatures needed for fusion is called a tokeomac.
Speaker 1: A tokomac looks like a donut shaped cavity surrounded by magnets.
Speaker 1: The magnets allow a ring of energetic hydrogen plasma to
Speaker 1: be created at the center of the hollow donut, so
Speaker 1: the plasma doesn't touch the walls of the chamber. If
Speaker 1: the plasma is heated to a hundred plus million degrees celsius,
Speaker 1: hydrogen atoms start fusing to create helium atoms. At that point,
Speaker 1: the heat of fusion keeps the plasma hot and the
Speaker 1: reaction becomes self sust daining. The extra heat produced can
Speaker 1: be converted into electricity. A second way to create a
Speaker 1: fusion reaction is to burn a little bit of fuel
Speaker 1: at a time. In this approach, powerful beams of laser
Speaker 1: light focus on a tiny capsule of hydrogen think peppercorn
Speaker 1: in size. For this capsule, the lasers provide the heat
Speaker 1: to initiate a fusion reaction, which then extinguishes itself because
Speaker 1: the amount of fuel is so small. At this point
Speaker 1: in the research process, scientists are about to build a
Speaker 1: tokemac that may be large enough to contain a real
Speaker 1: self sustaining reaction. It's called I T E R. And
Speaker 1: scientists have built and are currently testing a laser facility
Speaker 1: that may demonstrate the principles needed to build an eventual
Speaker 1: power plant. It's called the National Ignition Facility. But these
Speaker 1: are huge facilities and are extremely expensive to build, So
Speaker 1: the research process is slow and deliberate. It may be
Speaker 1: several more decades before a large, reliable fusion power plant
Speaker 1: designed emergence from all this research. For more on this
Speaker 1: and thousands of other topics, esit how stuff works dot
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