This book, prepared by NEA member country experts, contains data and analyses relevant to nuclear power plant life management and the plants' extended, longer-term operation (LTO). It addresses technical, economic and environmental aspects and provides insights into the benefits and challenges of plant life management and LTO.It will be of interest to policy makers and senior managers in the nuclear power sector and governmental bodies involved in nuclear power programme design and management. The data and information on current trends in nuclear power plant life management will be useful to researchers and analysts working in the field of nuclear energy system assessment