Part 3 of 3 Parts (Please read Parts 1 and 2 first)
     Part of the plan to support the construction of the STEP reactor is the new fusion research facility that will be constructed next to the Nuclear AMRC in Rotherham. This facility will take the conceptual design for the STEP reactor and convert it into buildable components that are ready to be used in construction.
     One of the main advances in fusion research that makes the STEP design viable is the Super-X divertor. The heat involved in the fusion reaction must go somewhere. If the walls of the reactor vessel absorbed this heat, they would instantly melt. This would, of course, cause the fusion reaction to stop. To prevent this, the plasma exhaust from the fusion reaction is sent to the divertor.
    Chapman said, “Plasma exhaust is one of the key technical challenges facing fusion. Byproducts and excess heat from the plasma will need to be removed, without damaging the surrounding surfaces. We do this with an exhaust system known as a divertor. The new system we’re testing at the Mast Upgrade should reduce the heat to manageable levels, such as that found in a car engine.”
      The divertor allows the waste material that is generated during the fusion process to be removed while the reactor is operational. As the high-energy plasma particles strike the targets, their kinetic energy is transformed into heat which is then removed by various cooling methods.
     The Mast Upgrade achieved first plasma at Culham in October of 2020.
      One possible way to make the 2040 deadline more likely could be to use a section of an existing power plant. The old-power generation system could be replaced by the STEP reactor. The benefit of this approach is that the energy conversion process that generates electricity remains the same.
      Storer said, “If the decision is made to build the STEP reactor, but to utilize an existing site with an existing turbine building, then it becomes a lot more feasible to me. All that time and cost has already been sunk.”
      The main hurdle that would have to be overcome would be the interface between the new fusion reactor and the existing power plant. Unfortunately, there is no such thing as a standard coupling for power plants. On the other hand, the time and cost of constructing an entirely new power plant is certainly significant. The comparatively small size of the STEP reactor is also an advantage.
     The promise of being able to capture the power of the sun in a bottle has resulted in the investment of huge amounts of time, energy and resources in this vision of a clean, never-ending fuel source utilizing cheap and readily available isotopes for fuel. It could have been argued with justification in the 1930s that that dream of fusion power was an illusion. But now we could genuinely have commercial nuclear fusion power plants within a few decades time. Cheap non-pollution power could go a long way to solving many of the world’s major problems.