LIGHT WATER REACTOR Meaning and
Definition
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A light water reactor (LWR) is a type of nuclear power reactor that employs ordinary water as both the coolant and the moderator for generating thermal energy in the form of heat. It is the most common and extensively used type of nuclear reactor globally. In an LWR, ordinary water, with naturally occurring hydrogen and oxygen atoms, is utilized to carry away the heat generated by the nuclear fission reactions occurring within the reactor core.
The term "light water" differentiates the use of regular water from heavy water, which contains a higher proportion of deuterium, a heavy isotope of hydrogen. The light water in an LWR not only cools the reactor but serves the crucial role of slowing down, or moderating, the speed of neutrons released during the fission process. By moderating the neutrons, the water enables a chain reaction, sustaining the nuclear reactions and releasing more energy.
Light water reactors can be further classified into pressurized water reactors (PWR) and boiling water reactors (BWR). In a PWR, water acts as both the coolant and the moderator, whereas in a BWR, water serves as the coolant that directly boils to produce steam, which powers a turbine to produce electricity.
Due to their outstanding safety record and efficiency, light water reactors remain the primary source of nuclear power generation worldwide. They are known for their ability to produce significant amounts of heat energy while minimizing the risks associated with radioactive materials and reactor operations, making them an essential component of many countries' energy generation infrastructure.
