A weak-beam transmission electron microscopy study was carried out for matrix damage in A533B reactor pressure vessel steel produced by 3MeV Ni2+ ion irradiation up to a dose of 1dpa at 290C. The matrix damage was found to consist of small dislocation loops. The observed and analyzed dislocation loops had a Burgers vector of a<100>. The dislocation loops had a mean image size 2.5nm, and the number-density was about 1022/m3. Most of the loops were stable after thermal annealing (400C, 0.5h). This indirect evidence suggested that their nature was interstitial.

Characterization of Defect Clusters in Ion-Irradiated A533B Steel. K.Fujii, K.Fukuya: Journal of Nuclear Materials, 2005, 336[2-3], 323-30