Commonwealth Fusion makes a physics case for its 400 MW reactor

It is inevitable that some parts of the device will be exposed to radiation and possibly fusion plasma. The inner walls of the reactor will be protected by tungsten, which will reduce material erosion. Currently, the vacuum cleaner is designed to be replaced every year for up to two years. The papers note that this flexibility will allow them to make further changes even after the ARC is built. In order to do this, the entire tokamak must be split in half to be repaired.

Restlessness

The two main concerns with ARC operations are problems that have been around for a while to combine: how to deal with magnetic instability, and how to deal with helium ash and magnetically evasive materials.

Some of the latter are only controlled by a reset that takes place every 15 minutes, which drains the chamber and adds new oil. But during the work, this will be controlled by what is called a divertera place where magnetic fields are created to allow other substances to escape from prison.

“In order to increase the mixing power of the ARC and avoid the erosion of the target material in the plasma, we will need to lose more energy that passes through the closed surface, and introduce impurities such as argon or neon to obtain interference,” one of the papers says. “Divertor detachment must be combined with a high-performance plasma, as well as a steady negative flow to keep the helium ash in the core.”

The models they use predict that the system will maintain enough energy on the diverter to spit out enough helium ash to not interfere with the fusion process. But this prediction should be tested with caution.

Magnetic instability can cause a rapid loss of plasma, which can lead to large particles hitting the walls of the reactor. Tungsten reduces damage and protects sensitive equipment, but it will erode, and the removed tungsten can remain in the chamber and contaminate other systems.