Designing a Fusion Power Plant with Superconducting Training Magnets

Fusion power has the potential to revolutionise global energy production with a reliable, low CO2 (not zero due to the use of steel, concrete etc. that typically produce CO2 during manufacture), low radioactivity power supply, that is readily available at the point of need. The ITER and SPARC reactors are already under construction, with plans to begin full-power (Qfus ≥ 10) operation in the early 2030s; proving that fusion is a viable energy source. To see wide adoption however, reactors must be made as commercially attractive as possible. Here we present superconducting pilot reactor designs that have been optimised for minimum capital cost using the PROCESS systems code. Key design choices were made using technologies that are either available now or already in development; with concentrated effort these reactors could be built on 2030-2040 timescales. We focus primarily on the reactor from this set with the lowest overall capital cost, our “preferred” reactor: a 100 MW net electricity producing tokamak with REBCO superconducting toroidal field coils and central solenoid and Nb-Ti superconducting poloidal field coils. In addition, we have investigated using ductile, remountable Nb-Ti training coils (named after the training wheels of children’s bicycles) during the commissioning phase of a reactor to remove the risk of brittle failure of the full-power magnets during this stage. Such magnets would operate at lower field, but would enable thorough machine testing. Finally, we investigate and predict how advances in magnet technologies could effect our preferred reactor design and cost, and conclude that the effects of such advances do not justify waiting yet longer before beginning detailed reactor design and construction.