Fusion systems

A fusion reactor requires many sophisticated and interconnected systems to achieve and maintain the fusion reaction and extract the energy produced. Each of these systems must function effectively and in concert with one another to achieve the conditions required.  In many cases the choices made for one system, including the materials it is made from, constrain the design and material choices for other systems, making the design and operation of a fusion reactor a highly complex and integrated engineering challenge.

The main systems include:

1. Plasma Confinement System Confining and stabilising the plasma. There are several approaches to confining the plasma.
2. Plasma Heating and/or Compression System Heating and/or compressing the plasma to the conditions needed for fusion. The systems used vary greatly depending on the confinement system chosen.
3. Magnet System For the magnetic and magneto-inertial fusion concepts, producing the required magnetic fields using coil systems and associated power supplies. In long-pulse or steady-state systems, superconducting magnets are usually used to minimise the power used to generate the high magnetic fields needed.
4. Vacuum System Maintaining the low-pressure environment required for plasma formation and minimising impurities that can cool the plasma. Usually this involves cryopumping using liquid or supercritical helium supplemented by mechanical pumping.
5. Fuel Supply System Providing the fusion fuels and managing their injection into the reactor either as gases or in the form of pellets of frozen fuel. In the case of D-T systems, the tritium needs to be bred in a lithium-containing blanket using the neutrons leaving the plasma.
6. Cooling System Removing the fusion power plus any excess heat generated by other systems in the reactor to generate exportable power, maintain structural integrity and operational safety. This requires cooling of the surfaces in contact with the plasma and radiation from it, plus (in the case of D-T fusion) the blanket.
7. Cryogenic system Delivering the required cryogenic fluids (typically helium and nitrogen) for superconducting magnets (if used) and vacuum cryopumps.
8. Power Conversion System Converting the energy released by fusion into electricity, usually using the reactor coolants to heat a secondary fluid that then drives turbines connected to generators.
9. Diagnostics and Control Systems Monitoring and controlling the plasma properties and reactor conditions in real-time, using systems including sensors, computational models and feedback loops.
10. Radiation Shielding and Safety Systems These include structural shielding and radiation monitoring systems, and protocols for safe operation and emergency responses.
11. Maintenance System Undertaking planned maintenance of systems and recovery from unplanned incidents. Remote Handling systems are generally required because of the high radiation levels.
12. Waste Management System Managing and disposing of radioactive components removed from the reactor and other byproducts produced while ensuring environmental and human safety. Remote Handling systems are generally required because of the high radiation levels.