This publication provides an overview of the latest experiences of Member States in implementing safety improvements at existing nuclear power plants. It describes in detail many of the modifications and, more generally, Member States' strategies for identifying and implementing safety improvements at their facilities. The publication aims to support practitioners in the continuous evaluation of nuclear safety at nuclear power plants. Within this publication the reader can explore a variety of technical approaches taken in retrospective assessment of safety at existing nuclear power plants and implementing safety improvements through various processes.