Effect of periodic deuterium ion irradiation on deuterium retention and blistering in Tungsten

Highlights: • The effects of the irradiation cycles on D behavior in W materials were investigated. • At 573 K, D retention decreased with increasing the number of irradiation cycles. • At 643 K, D retention was similar between continuous and periodic irradiation. • Blisters densities decreased with increasing irradiation cycles at 573 K case. - Abstract: The effect of periodic irradiation on Deuterium (D) retention and blistering in Tungsten (W) was investigated. W samples were exposed to D plasma at a fixed fluence while varying the irradiation cycle number (1-shot, 2-shots and 3-shots). Exposure energy and flux were ∼50 eV and ∼1 × 10²² D m⁻² s⁻¹, respectively. Sample temperatures were 537 K and 643 K. At 573 K, D retention and blister density decreased with increasing number of irradiation cycle. In contrast at 643 K, D retention showed no dependence on number of irradiation cycle. Therefore, sample temperature during irradiation is an important parameter in comparing the results of continuous and periodic irradiation, especially in studies involving extremely-high-flux (>10²⁴ D m⁻² s⁻¹) irradiation and fluence dependency of D retention.