5 – You said, Tokamak ?

Here we enter in the most interesting subject !

The Tokamak is to fusion what the reactor is to fission. It is used to create electric energy by nuclear fusion.
It has been possible for us to visit it from the exterior. A giant door of 4 meters high out of 1.5 meters deep (alloy of lead and concrete) split the tokamak room from the operators.

The Tokamak :

The tokamak consists of 18 superconducting electromagnets cooled to 2 ° K. When switching on the system (to create the plasma), the ends of the magnets are at approximately 200 ° C.
They are cooled because of the magnet loses its magnetic properties when heated.

Magnets are used because it enables the plasma to not be in contact with a material: in fact, at this temperature, no material can resist, they would melt. The plasma is held in levitation using the magnets.

The surface of the plasma is 2,000 ° C and the core 150 000 000 ° C. The distance from the core of the plasma and the magnet is 70cm.
This means that the temperature gradient is the largest of the universe (given that the distance between the center of the magnet and its ends is 30cm).

In 1 meter, we have temperatures between the almost absolute zero and ten times the sun’s temperature (-271 ° C to 150,000,000 ° C).
Around the electromagnets are positioned -for controlling the flow of material and ensure a process optimal- 6 circular magnets one top above the other.

So we need energy.

To start feeding the reaction, they begin by pumping in batteries.
Then they pump to the power grid of the power plant specially constructed and used for the center. If they used the conventional power grid, they could plunge into the night throughout the south of France.

Batteries deliver 1400 amps.

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How does the Tokama works ?

The nuclear fusion :

Research in the field of fusion started along the field of fission, it means that there are great benefits to be drawn:

  • Unlimited fuel: deuterium is found in up to 33 g / m ^ 3. Tritium, radioactive element, has a lifetime of 130 years on average (ie those that existed on earth have already disintegrated), it is made with lithium, this element is available in large quantities.
  • Low waste (helium). The wastes will be neutrons that will go bump the walls. It’s going to make activation materials: make non-radioactive materials, radioactive.
  • The fusion reaction is not a chain reaction. If there’s the slightest problem, everything stops instantly and automatically.