Question 8: Nuclear power plant use nuclear fission reaction to generate steam to run steam-turbine generator. How does the nuclear reaction produce heat?
In a nuclear power plant, controlled fission reaction produces the heat. U235 or Pu239 (or both) is used for fission. Small pieces of U235 are spread in a material called moderator.
Neutron is directed to fall on the uranium which starts the fission reaction with the emission of three fast moving neutrons. These neutrons strike the moderator to slow down to be prepared for another strike with the fuel (uranium) for further fissions. When the neutrons slows down by the collisions with the moderator, they transfer their K.E to the moderator which appears as heat.
This heat is removed from the moderator through the coolant, sometimes called heat exchanger. This not only cools the moderator to avoid any accidents but also water is converted to hot steam. The steam is directed to run a turbine. The turbine runs an electric generator to produce electricity.
So the energy produced in the fission reaction in a nuclear power plant is converted to steam which runs a generator through a turbine to produce electricity.