Updated measure of radiation damage exposure

Two previous correlations of the change in ductile-to-brittle transition temperature of A302B steel with neutron exposure have been supplemented by an updated correlation that employs newer cross-section information for neutron spectral calculations and for analyzing monitor activations. An International Atomic Energy Agency specialists' recommended damage model for secondary displacements and an improved treatment of energy transfer to primary knock-on atoms due to neutron inelastic scattering have also been used. Consistent application of the previous and updated correlations at the inner edge of a typical pressurized water reactor vessel results in no significant differences in anticipated change in transition temperature