The local approach to fracture is applied to analysis of the influence of fabrication and operation history on the safety margins for fracture of a pressurized water reactor vessel with an underclad reheat crack in the belt line, subjected to a severe pressurized thermal shock (PTS) transient at end-of-life. The elastoplastic analysis begins with numerical simulation of the manufacturing of the belt-line cladding, then continues with the creation of the crack during stress relief heat treatment, proof testing, loading-to-operating conditions, and, finally, occurrence of the pressurized thermal shock. Computation of the behavior of laboratory specimens at the temperature occurring at the crack tips at maximum load during the PTS transient makes it possible to translate the results obtained in terms of cleavage or tearing damage values, respectively, into the scales of the conventional K_I and J toughness parameters. This analysis, which accounts for all effects of the vessel fabrication, and the operation history, discloses much larger safety margins than the conventional analysis presently used for vessel integrity assessments.