Nuclear power plant

A nuclear power plant converts energy from controlled nuclear fission into electrical energy. A nuclear reactor produces heat; a coolant carries it to the working cycle; a turbine drives an electrical generator. A pressurized water reactor transfers heat to a separate steam circuit, whereas a boiling water reactor generates steam in the reactor vessel.^[ref]

If thermal input is $P_{\mathrm{th}}$ and conversion efficiency is $\eta$, gross electrical output is approximately $\eta P_{\mathrm{th}}$; the remaining thermal power must be rejected. The plant also needs its own electrical supply, so gross output differs from net export. After the chain reaction stops, decay heat still requires removal.