AN ASSESSMENT OF THE RISKS ASSOCIATED WITH CONTINUED OPERATION OF A SUPERHEATER SECONDARY OUTLET HEADER

摘要

A superheater secondary outlet header, with pronounced creep damage in stub weld regions, presents a risk of catastrophic failure during continued operation. An integrity review was performed, which considered the following aspects: Internationally recorded catastrophic failure incidents of similar components; experience on stable damage leading to leaks and header retirement; statistical distributions of damage locations indicating areas of highest damage prevalence; microstructural degradation of the particular header and fracture mechanics (LEFM) assessment of critical crack size requirements for catastrophic failure for the particular header. The paper, comprising literature review, FEA analysis, and fracture mechanics assessment, has shown that world-wide incidence of catastrophic failures of superheater secondary outlet headers has been very low and that the majority of risk locations on the header in question present low risks to catastrophic failure.