High Quality Content by WIKIPEDIA articles! The Light Water Reactor Sustainability Program is a U.S. government research and development program. It is directed by the United States Department of Energy and is aimed at performing research and compiling data necessary to qualify for licenses to extend the life of America`s current 104 electricity generating nuclear power plants beyond 60 years of life. Practically all of the commercial electric-generating nuclear power plants currently in the United States are light water reactor (LWR) plants, meaning they use ordinary (light) water as a moderator and coolant simultaneously.