A method for estimating the residual lifetime of selected primary circuit facilities. Fundamentals

A procedure is proposed for estimating the residual lifetime of primary circuit facilities. The procedure comprises the following steps: (i) acquisition and analysis of data from design, manufacturing and assembling documentation; (ii) analysis of results of in-service inspections; (iii) operational history; (iv) evaluation of fatigue damage and fracture mechanics parameters; (v) assessment of materials condition (degradation); (vi) prediction of facility integrity till the end of lifetime or till the next inspection; (vii) suggestions for activities to follow; (viii) setting up a plan for the next in-service inspection; and (ix) repeated estimate of the residual lifetime of the facility. The approach to the evaluation of the reactor pressure vessel, steam generators, pressurizer, and primary circuit is outlined. (J.B.). 1 tab., 2 refs