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How a Nuclear Reactor Power Plant Works

Most power plants utilize the same basic method for producing electricity. Steam is produced and is then used to turn a turbine which produces the electricity. The only thing that makes a nuclear power plant unique is the method it uses to produce the steam. Instead of burning a fossil fuel it utilizes the tremendous amount of energy released when atoms undergo fission. Let's take a closer look at the primary components of a nuclear power plant. As illustrated to the right, these components include: (1) fuel assemblies ( also called fuel rods); (2) control rods; (3) moderator (not illustrated); (4)reactor vessel (the kidney shaped object); (5) containment building structure; (6)turbine/generator and (7) cooling towers (not illustrated). Now let's take a closer look at what some of the components are responsible for.

  • Fuel Rods: These metal containers hold the individual fuel pellets. Each rod holds approximately 500 enriched uranium fuel pellets. Keep in mind that each pellet is a cylinder about 3 cm long with a width about the size of a pencil. Each fuel pellet is capable of producing the same amount of energy as 1,780 pounds of coal or 149 gallons of oil or 17,000 cubic feet of natural gas!
  • Control Rods: These are metallic rods (capable of absorbing neutrons) which can be lowered or raised between the fuel rods. Their job is to slow down or speed up the nuclear reaction. They accomplish this by controlling the number of free neutrons running around in the reactor vessel. (Remember it is the slow moving neutrons which are responsible for the nucleus being split (fission)). To slow down the reaction the rods are lowered and absorb the neutrons. If the reactor is moving to slow the rods are raised, thus increasing the number of free neutrons.
  • Moderator: This material (sometimes "heavy water" is responsible for slowing down the neutrons. In order for fission to occur the neutrons have to be slow moving. Fast neutrons will not be absorbed by the enriched uranium.

 

Illustration of A Nuclear Reactor and its' Components

 

 


Second Illustration of Reactor and Turbine