Cost optimal reliability based inspection and replacement planning of piping subjected to CO2 corrosion

A methodology for cost optimal reliability based inspection and replacement planning of piping subjected to CO2 corrosion is described. Both initial ( design phase) and in-service planning are dealt with. The methodology is ba sed on the application of methods for structural reliability analysis withi n the framework of Bayesian decision theory. The planning problem is formul ated as an optimization problem where the expected lifetime costs are minim ized with a constraint on the minimum acceptable reliability level. The opt imization parameters are the number of inspections in the expected lifetime , the inspection times and methods. In the design phase the nominal design wall thickness is also treated as an optimization parameter. The most impor tant benefits gained through the application of the methodology are consist ent evaluation of the consequences of different inspection and replacement plans, consistent incorporation and handling of uncertainties, and consiste nt updating of inspection and replacement plans based on inspection results . The latter is achieved through application of Bayesian statistics for upd ating in combination with structural reliability methods. (C) 1999 Elsevier Science Ltd. All rights reserved.