Weibull statistical models of K_(Ic)/K_(Ia) fracture toughness databases for pressure vessel steels with an application to pressurized thermal shock assessments of nuclear reactor pressure vessels

摘要

This paper presents new statistical representations of recently fracture toughness K_(Ic) and K_(Ia) databases for pressure steels. These models were developed by the Heavy Section Steel Technology program at Oak Ridge National Laboratory in support of the current effort by the U.S. Nuclear Regulatory Commission to update its regulatory guidance for pressurized-thermal-shock (PTS) transients in nuclear reactor pressure vessels. The Weibull distribution, with two of its parameters calculated by the Method of Moments point-estimation technique, forms the basis for the new statistical models. An application of the new K_(Ic)/K_(Ia) models, as implemented in the FAVOR probabilistic fracture mechanics computer program, is also presented for three PTS transients.