Neutron radiation damage in tungsten single crystals

Tungsten single crystals were neutron irradiated to exposures of 0·46, 2·4, 4·0 and 7·3×1019 nvt (E> 1 Mev) and examined by transmission electron microscopy. Defect clusters, observed after 2·4×1019 nvt, increased in size and concentration with increasing neutron exposure. One specimen irradiated to 7·3×1019 nvt was subsequently annealed for one hour at 1090°c in argon. The defect cluster density was substantially reduced and some loops were produced. Neither the loops nor the defect clusters were analysed, but are presumed to be interstitial in nature.