[en] The surface crack embedded in the clad layer of a reactor pressure vessel (RPV) has been identified as a critical safety assessment condition relative to the pressurized thermal shock accident scenario. This project was initiated to determine the severity of such cracks experimentally. It is the first study to investigate irradiated, clad vessel steel, and to identify the material property and stress conditions in the local region of the crack that are significant to the analysis. Bend bar tests provided the experimental simulation of the subject RPV surface crack. This report covers analysis techniques used and presents the findings indicated by the experimental results for irradiated and unirradiated materials. 13 refs., 13 figs., 2 tabs