CANDU stands for "Canada Deuterium Uranium" and refers to a type of nuclear reactor designed in Canada. It uses heavy water (deuterium oxide) as a moderator and coolant, allowing it to utilize natural uranium as fuel. This design enables efficient energy production while minimizing the need for enriched uranium. CANDU reactors are known for their safety features and flexibility in fuel use, including the ability to use recycled nuclear fuel. They are widely used in Canada and have been exported to several countries, contributing to global nuclear energy generation and research in nuclear technology.