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According to modern normative documents, the loading of postulated cracks in reactor vessels and standard specimens during crack resistance tests has a number of differences, namely: biaxiality of certain load configurations on the crack faces can change during non-isothermal, nonmonotonic processes under emergency modes of thermal shock, while crack front have a semi-elliptical shape of with relative depth ratio of 0.1–0.15. These factors prompt the development of an experimental technique to study crack resistance on non-standard type specimens. Cross-shaped (cruciform) bending specimens with a semi-elliptic surface crack and a through linear short crack, as well as model strip specimens with similar cracks in previous tests, were designed and studied for their static fracture strength. A method for monitoring fatigue crack initiation on a cross-shaped specimen by changes in its suppleness has been proposed. Evolution of semi-elliptic crack front shape at its initiation from a surface stress raiser under cyclic bending load has been investigated and the possibility of obtaining fatigue semi-elliptic crack of a certain configuration close to the postulated, according to the normative documents of cracks was shown. On the basis of test results, it was established that at temperature 20°C for 15Kh2NMFA-A steel, the standard conditions of a plane deformation in the used specimens were not satisfied, leading to the overestimated values of crack resistance since the steel ductile-brittle transition temperature T0 (according to the Master-curve) was much lower. It was shown that the obtained increase in crack resistance under equal-axial bending is comparable with literature sources for the conditions of large-scale yielding with uniaxial loading. [ABSTRACT FROM AUTHOR]