The heat generated by nuclear fission is used to produce steam which drives turbines to generate electricity.

The hot water or steam produced in the reactor core transfers thermal energy to a secondary circuit, often via a heat exchanger. This steam then spins turbines connected to electric generators. This process converts nuclear energy into electrical energy, providing a large portion of the world's low-carbon electricity. Different reactor designs, like pressurized water reactors and boiling water reactors, achieve this steam generation in slightly different ways.