Nuclear engineering

Reactor design, criticality, delayed neutrons, and radiation shielding

What is nuclear engineering?

Nuclear engineering applies the nuclear physics covered in the Nuclear Physics article to practical technology — most prominently nuclear power plants, but also medical radiation equipment, nuclear-powered ships, and radiation safety systems.

How a nuclear power plant generates electricity

A nuclear power plant generates electricity fundamentally the same way most power plants do: heat boils water into steam, and that steam spins a turbine connected to a generator. The difference is the heat source — instead of burning fuel, a nuclear reactor generates heat from controlled nuclear fission (introduced in the Nuclear Physics article), splitting uranium atoms in a sustained, carefully controlled chain reaction.

Controlling the chain reaction

A nuclear reactor must carefully control its fission chain reaction, since fission releases neutrons that can trigger further fission in nearby uranium atoms. Control rods, made of materials that absorb neutrons, can be inserted or withdrawn to precisely control how many neutrons are available to sustain the reaction, letting operators increase, decrease, or completely stop the reaction as needed.

Reactor safety

Nuclear engineering places enormous emphasis on safety, using multiple independent, redundant safety systems specifically designed so that no single equipment failure or operator error can lead to a serious accident. This includes systems to shut down the chain reaction automatically if something goes wrong, and systems to keep the reactor cool even after it has been shut down, since nuclear fuel continues generating some heat for a period even after the main chain reaction stops.

Why nuclear engineering matters

Nuclear engineering provides a significant source of electricity generation that produces no direct carbon dioxide emissions during operation, and nuclear technology also underlies important medical applications, including radiation therapy for cancer treatment and diagnostic imaging using radioactive tracers.