Tungten (W) was chosen to be the divertor armor material in International Thermonuclear Experimental Reactor (ITER) and is planned to be used as a first wall material DEMO reactor concept. In a fusion reactor the plasma facing materials are bombarded with plasma components such as deuterium (D), Tritium (T) and Helium (He). The biggest safety issue comes from the fact that T is radioactive and toxic. Thus the safety limit of 700 g of T that can be accumulated in the reactor’s chamber was set for ITER. Understanding of the physical mechanisms governing the retention of T in the material is essential for safe operation of the fusion device.
The permeation, accumulation and retention of T in W are defined by the plasma exposure conditions and the microstructure of the material. Moreover, synergetic effects between He and T atoms in the material can play an important role in T retention. Molecular Dynamics (MD) simulations provide an opportunity to study the mechanisms of T retention on atomistic level at finite temperatures.