Methodology of evaluation of the residual lifetime of reactor pressure vessels and their internals (principal procedure)

A general procedure is suggested for setting up a methodology to assess the residual lifetime of a reactor pressure vessel and its internals, based on elastic or elasto-plastic fracture mechanics methods. The following aspects were taken into account: evaluation of the residual lifetime with a 'calculation defect'; evaluation of the residual lifetime with the existing defects; evaluation of the 'fatigue lifetime'; and evaluation of the 'corrosion-mechanical lifetime'. The general procedure consists of the following steps: (1) compilation and analysis of data extracted from the design, manufacturing and installation documentation; (2) analysis of the results of inspections; (3) overview of the operation history; (4) evaluation of the fatigue damage and fracture mechanics parameters; (5) evaluation of the condition (degradation) of the materials; (6) evaluation of the integrity of the facility till the end of its lifetime/the next inspection; (7) proposal for subsequent provisions; (8) setting up a plan of the next inspection; and (9) repeated assessment of the residual lifetime of the facility. (P.A.). 7 figs., 15 refs