Deuterium Removal Efficiency in Tungsten as a Function of Hydrogen Ion Beam Fluence and Temperature

Establishment of effective tritium removal method was one of important issues for the development of fusion reactor from the view of fuel recycle and safe operation. The deuterium (D) removal efficiency in tungsten (W) by energetic hydrogen (H) ions under room temperature and baking under 623 K were studied by thermal desorption spectroscopy (TDS). Iron (Fe) damaged W with various damage level by 6 MeV Fe2+ was adopted to simulate neutron irradiation damages. To understand the D removal behavior, the desorption of D2 was measured in-situ by a quadrupole mass spectrometer (QMS) during H2+ implantation and baking. The in-situ results showed that the desorption of D2 started after H2+ implantation and became slowly with the increment of H2+ implantation time. After H2+ implantation, part of D trapped by dislocation loops, vacancy clusters and voids could be removed by hydrogen isotope exchange. However, the removal efficiency by hydrogen isotope exchange decrease obviously as the presence of irradiation damages. The D trapped by dislocation loops and vacancy clusters can be removed by baking with high efficiency. It is worth to note that the D trapped by voids cannot be removed by baking leading to the lower D removal efficiency for W with high damage level.