There many technical changes which will have to be overcome for fusion to: 1. Produce long term stable plasma. SPARC should demonstrate this. Commonwealth Fus

There many technical changes which will have to be overcome for fusion to: 1. Produce long term stable plasma. SPARC should demonstrate this. Commonwealth Fusion Systems are confident that with the magnet properties of SPARC and the conservative parameters of the SPARC plasma they can demonstrate this. 2. Produce the prototype of a fusion power plant, the ARC reactor. Commonwealth Fusion Systems has to scale up the SPARC reactor. They have to not only design, but also build and test, reactor vessel which would allow useful heat recovery and tritium breeding. Tritium is hydrogen, very small molecule that has tendency do leak through smallest cracks. It can also cause hydrogen embrittlement. 3. Produce energy from fusion on commercial scale and at competitive prices. Reactor vessel is exposed to very strong magnetic field and as result large forces. The neutrons produced from D-T plasma have energy about 13 MeV and they cause faster material degradation than in fission power plants. It's possible that frequent replacements of the reactor vessel will be needed. The reactor vessel is neutron activated low-level radioactive waste, which has to be properly disposed of. The beryllium used in some designs is quite rare (world's annual production of beryllium is 220 tons). All this issues affect the economy of fusion power plant. I confident that all this non-trivial material and engineering changes will be solved and commercial fusion power plants will exist in 50-100 years. For quick introduction I recommend watching: "International Colloquia #26: Fusion Reactor First Wall Cooling" https://www.youtube.com/watch?v=bHJyoqDO0zw https://www.youtube.com/watch?v=bHJyoqDO0zw