Rolled tungsten (W) was sequentially exposed to nitrogen (N) and deuterium (D) plasma at different surface temperatures to investigate the influence of N pre-irradiation on D retention and surface blistering of W. Surface imaging revealed that significant amounts of blisters are formed after D exposure at 230 and 370 K. However, no blisters were found in the case of 520 K D exposure. In addition, N pre-irradiation increases the areal density of blisters, in particular that of small blisters. This effect becomes more significant for 500 K N exposure compared with 300 K N exposure. D depth profiles show that N pre-irradiation leads to an increase of the D concentration in the near surface. Thermal desorption spectra show that only one main desorption peak appears for the case of 230/520 K, while two peaks are found for 370 K D exposure. Though N pre-irradiation does not change the deuterium desorption peak positions, it slightly changes the total D retention. These phenomena indicate a temperature dependence of the effect of N pre-irradiation on the D behavior in W.
Effect of D on the evolution of radiation damage in W during high temperature annealing