Power uprate and life extension are ongoing concerns for nuclear power stations due to strengthened safety and regulatory requirements. While great successes have been achieved, huge costs have been reported and numerous technically challenging questions have been raised. With regard to piping, most issues concern whether relevant code requirements are reasonably met. This monograph addresses a few issues essential for achieving a consistent Design-By-Analysis in accordance with the ASME Boiler & Pressure Vessel Code: nonlinear alternative rules, fatigue, thermal ratcheting, dynamic loads, strain-based criteria, nonlinear finite element procedures, supports under combined stresses, and others. Throughout the text, the authors endeavour to seek more reliable and consistent alternatives using advanced non-linear finite element analysis. Unlike other texts on piping, this monograph is focused on commercial software and current practices for power uprate and life extension of aging nuclear power facilities.