A Graphite Moderated Reactor is a type of nuclear reactor that uses graphite as a moderator to slow down neutrons, making them more effective for sustaining a nuclear chain reaction. This design allows for the use of natural or low-enriched uranium as fuel, which is more abundant and less expensive than highly enriched uranium. In these reactors, the graphite helps maintain a stable reaction by absorbing some of the energy produced while allowing enough neutrons to continue the process. This type of reactor has been used in various applications, including electricity generation and research, and is known for its safety features and efficiency.