[en] On performing various over-power ramp experiments in the R2 test reactor at Studsvik, Sweden, observations of certain phenomena associated with the PCI/SCC failure occurence have been made. These observations concern primarily the occasional appearance of so-called power spikes, the response of the rod elongation detector to the failure event, and to some extent the formation of incipient cracks on the inside surface of the Zircaloy cladding. Failure of the cladding of a fuel rod during a ramp test is usually indicated by the release of activity to the cooling water. The moment of the crack penetration is more accurately determined by the observation of a power spike and probably also by a contraction of the cladding tube