Defect annealing and thermal desorption of deuterium in low dose HFIR neutron-irradiated tungsten

Abstract Three tungsten samples irradiated at High Flux Isotope Reactor at Oak Ridge National Laboratory were exposed to deuterium plasma (ion fluence of 1 × 10²⁶ m^-2) at three different temperatures (100, 200, and 500°C) in Tritium Plasma Experiment at Idaho National Laboratory. Subsequently, thermal desorption spectroscopy was performed with a ramp rate of 10°C min^-1 up to 900°C, and the samples were annealed at 900°C for 0.5 h. These procedures were repeated three times to uncover defect-annealing effects on deuterium retention. The results show that deuterium retention decreases approximately 70% for at 500°C after each annealing, and radiation damages were not annealed out completely even after the 3rd annealing. TMAP modeling revealed the trap concentration decreases approximately 80% after each annealing at 900°C for 0.5 h.