Modeling fast neutron irradiation damage accumulation in tungsten

Due to its advantageous physical properties, tungsten (W) is being considered as a candidate structural material in fusion applications. In this paper, we perform stochastic cluster dynamics calculations of irradiation damage accumulation in pure W under fast neutron spectra in up to doses of 1.5 dpa in the 400∼600◦C interval. Our calculations suggest that He bubbles and dislocation loops accumulate under fusion conditions, but not under fast fission spectra. We study the temperature dependence of swelling and find that it is maximum in the 550∼590◦C temperature range, falling precipitously above 600◦C. Swelling levels are very low, never surpassing a fraction of a percentage point. We also provide hardening estimates based on the accumulation of sessile dislocation loops under fusion conditions and show that they are moderate, ranging between 70 and 137 MPa at 400◦C.