The utilization of ultrasonic NDE data with the SAFER finite element based code for the estimation of remaining life of a steam turbine rotor

Uncertainty exists concerning the defect size in ultrasonic NDE (nondestructive evaluation) data recorded by amplitude-based systems conducting a radial beam boresonic test on a steam turbine rotor. Five different approaches to modifying the EFBH (equivalent flat bottom hole diameter) values found in the raw data are investigated. Three conservative approaches are found to lead to reasonable results from the fracture mechanics analysis. A nonconservative treatment of the NDE data is found to lead to the prediction of immediate failures. Both deterministic and probabilistic fracture calculations are performed by EPRI-developed SAFER (stress and fracture evaluation of rotors) and PERL computer programs, respectively