How Does Nuclear Fission Create Energy?
Most commonly, uranium-235 is bombarded with a neutron, causing the atom to split into two lighter atoms, simultaneously releasing two or three neutrons and approximately 200 MeV (million electron volts) of energy. The process continues on its own in a self-sustaining chain reaction, whereby the two neutrons produced from the initial reaction collide with uranium-235, and so on and so forth, until all of the uranium-235 atoms are used up. As the chain reaction progresses, the number of neutrons produced increases exponentially. The heat energy produced by the exothermic reaction is used to heat water into steam. The steam then powers a turbine, which spins a generator to produce electrical power.
One pound of highly-enriched uranium produces about as much energy as one million gallons of gasoline!
One pound of highly-enriched uranium produces about as much energy as one million gallons of gasoline!
The Nuclear Reactor
Nuclear reactors consist of an outer containment shell surrounding a reactor vessel. Uranium fuel rods within the reactor are interspersed between control rods, which can slow or accelerate the reaction depending on how they are placed within the core. The fuel tubes in the reactor are separated by water, which slows the collisions to ensure that the fission reaction occurs at the appropriate speed.
Commercial nuclear power plants have one of two nuclear reactor types:
Commercial nuclear power plants have one of two nuclear reactor types:
Boiling Water Reactor
The water surrounding the nuclear fuel is boiled and heated to steam directly within the nuclear reactor vessel. This steam is brought to power the turbine, which converts it into electricity, and unused steam is condensed into water and recycled again in the heating process.
Pressurized Water Reactor
The water surrounding the nuclear fuel rods is heated, but is kept under pressure to prevent it from boiling. The hot water is then pumped into a steam generator, and the heat from the water is used to boil a second, separate supply of water until it is heated to steam. This steam is brought to power the turbine, which converts it into electricity, and unused steam is condensed into water and recycled again in the heating process.
The water surrounding the nuclear fuel rods is heated, but is kept under pressure to prevent it from boiling. The hot water is then pumped into a steam generator, and the heat from the water is used to boil a second, separate supply of water until it is heated to steam. This steam is brought to power the turbine, which converts it into electricity, and unused steam is condensed into water and recycled again in the heating process.