Question

In nuclear reacter what kind of energy transformation occurs

Answer 1

In most electric power plants, water is heated and converted into steam, which drives a turbine-generator to produce electricity. Fossil-fueled power plants produce heat by burning coal, oil, or natural gas. In a nuclear power plant, the fission of Uranium atoms in the reactor provides the heat to produce steam for generating electricity.

Heat is produced in a nuclear reactor when neutrons strike Uranium atoms causing them to fission in a continuous chain reaction. Control elements, which are made of materials that absorb neutrons, are placed among the fuel assemblies. When the control elements, or control rods as they are often called, are pulled out of the core, more neutrons are available and the chain reaction speeds up, producing more heat. When they are inserted into the core, more neutrons are absorbed, and the chain reaction slows or stops, reducing the heat.
Most commercial nuclear reactors use ordinary water to remove the heat created by the fission process. These are called light water reactors. The water also serves to slow down, or "moderate" the neutrons. In this type of reactor, the chain reaction will not occur without the water to serve as a moderator.