Tokamak Fusion Reactor
>> What is a Tokamak
Unlike most nuclear reactors, a Tokamak is designed for the process of fusion rather than fission. Meaning that instead of producing energy by splitting large atoms (like Uranium), the reactor creates energy by putting together small atoms. This is the same process through which the sun creates energy.
To create fusion, the atoms are required to be at extreme temperatures, so extreme that electrons are ripped off the nucleus. Because of the extreme temperature, the fuel becomes plasma, which is the only state of matter in which fusion is possible. The plasma is suspended through magnetic confinement to prevent it from touching the reactor and damaging it.
Tokamaks were invented in the former USSR by scientists in the late 60s. The word itself can be translated to a Russian acronym that stands for the toroidal chamber with magnetic coils. As the name implies, the reactor takes a toroidal shape and is surrounded by magnetic coils.
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>> How does it Work
There are various steps to controlling a Tokamak reactor. Since it is an incredibly complex procedure, I've broken it down into three main parts: plasma production, confinement, and electricity generation.
Plasma Production
To produce energy, a tokamak uses deuterium and tritium fuel to create helium.
In order to get the fuel to a state of plasma, changing magnetic fields act on the gaseous fuel after it is in the reaction chamber.
The magnetic fields agitate the atoms which collide violently with each other making some electrons separate from the nucleus. This intensely heats up the fuel.
These electrically charged atoms are what the plasma is made out of.
Confinement
The toroidal chamber is vacuum sealed to optimize the fusion reaction.
Because the plasma reaches temperatures hotter than the surface of the sun if it were to touch the surface of the reactor the whole system would be ruined.
The solution to that problem was using magnetic confinement to levitate the plasma away from the walls. Since the plasma is composed of charged atoms by using large magnets, scientists were able to control the plasma with electric and magnetic fields
The main magnets of a Tokamak are the toroidal field magnets, poloidal field magnets, and the central solenoid.
Electricity Generation
The electricity generation portion of the process is very similar to that of a nuclear fission power plant. there is a heat exchange between the walls of the reactor and a water system. That primary water system then undergoes another heat exchange with a secondary water system.
The water on the secondary water system becomes steam and that steam then spins a turbine, thus generating electricity.
>> The ITER Project
What Is It?
ITER is nothing short of the biggest experimental Nuclear Fusion reactor in the world. The reactor will weigh over 23,000 tonnes and be able to store over 830 cubic meters of plasma.
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Where is it?
The construction site for ITER is Saint-Paul-lès-Durance, in souther France. Although the reactor is being put together there its components are being produced all over the world by its member states.
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Why is ITER being built?
The main goal of the Iter is to once and for all prove the feasibility of self-sustaining large-scale fusion. When the project is complete, it will be the first-ever to have a net force.
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How much power will it generate?
The reactor is designed to output ten times its energy input, that is, for every 50 MW input to the reactor, it will produce 500 MW. Current projections indicate that ITER will be able to produce 500 MW every 400 to 600 seconds.
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How much will it cost? Who is funding it?
Current price estimates say that the project will wind up costing is members $22 billion, though this figure is disputed by the US Department of energy. The price is being split by the seven members of the project: the European Union, China, the United States, Russia, Korea, Japan, and India.
This is a picture of where the Tokamak reactor will be placed. The white tower at the centre of the pit is where the central solenoid will be once assembly is complete.,
This is a picture of the ITER assembly site in Saint-Paul-lès-Durance, France
>> Videos
Here is a quick video talking about tokamaks and how they work