cna.ca

banner image How a Nuclear Reactor Works Nuclear reactors produce heat by splitting atoms. This heat converts water into steam, which in turn turns a turbine that spins a magnet, causing electricity to flow to the grid. How a nuclear reactor produces electricity Nuclear reactors are sophisticated machines built to exacting engineering standards. Here’s an overview of how they produce electricity. [...] 1. Uranium is mined and converted into a fuel bundle. Operators load these fuel bundles into a nuclear reactor. 2. Slow-moving neutrons split apart the uranium nuclei, initiating a nuclear chain reaction. This reaction continues due to careful engineering and can be stopped at any time by personnel working at the plant. [...] 3. The neutrons released from splitting the uranium nucleus travel very quickly, near the speed of light. Slow neutrons are most effective for splitting uranium atoms. The nuclear reactor contains a special material called a moderator that slows down neutrons. While many materials can act as a moderator, Canadian reactors use special heavy water, which is H2O with the normal hydrogen replaced by a heavier form of hydrogen called deuterium. Nuclear professionals working at the reactor control

world-nuclear.org

JOIN US MEMBERS LOGIN HOME / Nuclear Essentials / How does a nuclear reactor work? Nuclear Essentials How does a nuclear reactor work? Updated Tuesday, 19 May 2026 Nuclear reactors are, fundamentally, large kettles, which are used to heat water to produce enormous amounts of low-carbon electricity. They come in different sizes and shapes, and can be powered by a variety of different fuels. [...] The Ringhals Nuclear Power Plant, home to four reactors capable of generating 20% of Sweden’s electricity demand (Image: Vattenfall) A nuclear reactor is driven by the splitting of atoms, a process called fission, where a particle (a ‘neutron’) is fired at an atom, which then fissions into two smaller atoms and some additional neutrons. Some of the neutrons that are released then hit other atoms, causing them to fission too and release more neutrons. This is called a chain reaction. [...] In order to ensure the nuclear reaction takes place at the right speed, reactors have systems that accelerate, slow or shut down the nuclear reaction, and the heat it produces. This is normally done with control rods, which typically are made out of neutron-absorbing materials such as silver and boron. Two examples of nuclear fissioning of uranium-235, the most commonly used fuel in nuclear reactors.

youtube.com

Now that we know the components of a nuclear reactor, let us understand the working of a nuclear reactor. It is usually enclosed in a shield made of thick concrete walls. It consists of a reactor core, pump and heat exchanger. The reactor core and pump are in placed in contact with the water, which is usually the heat exchanger used in reactors. Due to the enormous amount of heat released dusing nuclear fission reaction, this surrounding water gets heated up and changes to steam, which is in [...] Nuclear reactors are the modern day devices extensively used for power generation as the traditional fossil fuels, like coal, are at the breach of extinction. A nuclear reactor is the source of intense heat which is in turn used for generation of power in nuclear power station. Its mechanism is similar to that of a furnace in a steam generator; the steam is used to drive the turbines of the electric generator system. [...] A nuclear reactor consists of three crucial components: Fuel elements, moderator and control rods.

energy.gov

Funding Opportunities Breadcrumb NUCLEAR 101: How Does a Nuclear Reactor Work? Learn how boiling and pressurized light-water reactors work. Office of Nuclear Energy Fuel loaded into the core of Vogtle Unit 2 Nuclear reactors are the heart of a nuclear power plant. They contain and control nuclear chain reactions that produce heat through a physical process called fission. That heat is used to make steam that spins a turbine to create electricity. [...] More than 65% of the commercial reactors in the United States are pressurized-water reactors or PWRs. These reactors pump water into the reactor core under high pressure to prevent the water from boiling. The water in the core is heated by nuclear fission and then pumped into tubes inside a heat exchanger. Those tubes heat a separate water source to create steam. The steam then turns an electric generator to produce electricity. [...] Reactors use uranium for nuclear fuel. The uranium is processed into small ceramic pellets and stacked together into sealed metal tubes called fuel rods. Typically, more than 200 of these rods are bundled together to form a fuel assembly. A reactor core is typically made up of a couple hundred assemblies, depending on power level.

en.wikipedia.org

A nuclear reactor coolant – usually water but sometimes a gas or a liquid metal (like liquid sodium or lead) or molten salt – is circulated past the reactor core to absorb the heat that it generates. The heat is carried away from the reactor and is then used to generate steam. Most reactor systems employ a cooling system that is physically separated from the water that will be boiled to produce pressurized steam for the turbines, like the pressurized water reactor. However, in some reactors the [...] The rate of fission reactions within a reactor core can be adjusted by controlling the quantity of neutrons that are able to induce further fission events. Nuclear reactors typically employ several methods of neutron control to adjust the reactor's power output. Some of these methods arise naturally from the physics of radioactive decay and are simply accounted for during the reactor's operation, while others are mechanisms engineered into the reactor design for a distinct purpose. [...] Liquid-core reactor. A closed-loop liquid-core nuclear reactor, where the fissile material is molten uranium or uranium solution cooled by a working gas pumped in through holes in the base of the containment vessel.