Quantitative regularities of the Zr-1%Nb alloy, Ni-Cr alloy 690 and Fr-Cr stainless steel (SS) 12X18H10T corrosion in the near-critical domain (23.5 MPa, 360…380 °C) of a circulating water coolant are searched using multi-scale calculations of the NSC KIPT Super-Critical Water (SCW) Convection Loop experiment e-irradiation environment qualifiers. The per-sample quantification of irradiation doses, temperatures, stress, and the radiolytically altered coolant chemistry was obtained. A bi-linear increase of the oxidized coupons weight gain with absorbed dose and corrodent temperature has been first revealed and described within the proposed mechanistic model approach. The origin of the experimentally found corrosion cracking of the SS sample has been attributed to the irradiation in-duced thermal-elastic hoop stress. The cracks activation threshold stress is predicted to lie between 40 and 80 MPa. An experimental technique to study the controlled stress governed corrosion in SCW under irradiation is presented.