Microstructure of fracture surfaces after radial compression of annular specimens made of cladding austenitic steel exposed to damaging dose above 100 dpa

Short-term mechanical testing of annular specimens made of a segment of the fuel element cladding irradiated in the BN-600 reactor up to damaging dose above 100 dpa has been performed. The specimens were compressed in the radial direction at different temperatures to plot experimental diagrams and analyze the stress-strain state. After testing, the fracture character and microstructure of the fracture surface were studied. It is shown that fracture of specimens at the microlevel occurs transgranularly, and the segments of fracture are observed along characteristic structural elements of cold deformed austenitic steel, along and transverse to packets of deformation twins. In general, fracture occurs with a strong deformation localization at different types of appeared defects.