Research is aimed at solution of interdisciplinary problems in physics and mechanics of fracture of metals and structural alloys related to the effect of both micro-structural and stress strain state of metal on its ability to resist plastic deformation and fracture. Development of physical criteria of alloys` limit state in load-bearing elements of constructions and prediction of radiation life-time of RPV metal is an applied aspect of the investigation. Research methodology is related to elaboration of models of limit state of metals and alloys accounting for structural hierarchy of plastic deformation and fracture. Recently, much attention has been paid to new direction in physics of strength, which is research of atom`s deformation and fracture mechanisms of nanocrystals and peculiarities of their manifestation in 2-D (graphene) and 1-D (carbyne) crystals.