A thermal reactor is a type of nuclear reactor that uses thermal neutrons to sustain a nuclear chain reaction. These reactors typically use materials like uranium or plutonium as fuel, which undergo fission when struck by slow-moving neutrons. The heat generated from this process is used to produce steam, which drives turbines to generate electricity. In thermal reactors, the neutron moderation is crucial, as it slows down the neutrons to increase the likelihood of fission. Common moderators include water, graphite, and heavy water. Thermal reactors are widely used in commercial power generation due to their efficiency and relatively straightforward design.