Blocking of annihilation of Frenkel pairs by He atoms

Abstract

The results of DFT modelling of blocking the annihilation of Frenkel pairs at small distances between vacancy and self interstitial atom is performed in application to “subthreshold” radiation defects formation in W. It is shown that even at small distances sufficient for spontaneous annihilation of the Frenkel pair, He atoms can suppress the annihilation near the surface. In some cases an additional vacancy can appear close to the surface thus increasing the radiation damage. It is concluded that He impurities can be an additional reason for subthreshold” radiation damage.