Fusion Reactor Walls Degrading Faster Than Expected: Billion-Atom Calculation Reveals Anomalous Defect Spike in Tungsten

Controlled nuclear fusion is expected to become a source of virtually inexhaustible and clean energy. In tokamak-type devices, researchers heat hydrogen isotopes—deuterium and tritium—to the state of plasma at temperatures exceeding 100 million degrees Celsius. When hydrogen nuclei fuse, helium nuclei and high-energy neutrons are produced. Since neutrons lack an electric charge, magnetic fields cannot contain them. They exit the reaction zone and strike the inner wall of the vacuum chamber. The most vulnerable component of this chamber is the divertor—a unit that absorbs heat fluxes and removes byproducts of nuclear fusion reactions. In modern reactor designs, both the divertor and protective cladding are made from tungsten.…