Why Nuclear Power Plants are used as a Base Load Plants

The similarity between the Conventional power plants such as thermal plants and the Nuclear power plant is the way in which the power is tapped. In thermal power plants heat is produced by burning the coal in the boiler (Reactor) and in nuclear power plant the heat is produced by the nuclear fission process. Then after tapping the heat all the process remain almost same. 

However in thermal power plant the Reactor follows the Turbine, means when the power demand varies over a period of time the impact was seen in the turbine  and generator speed in the power plant. When the power demand increases turbine and generator speed slowly reduces and in order to compensate that the fuel intake increases. But in Nuclear Power Plant Turbine follows the Reactor, means depends on the Reactor power level the heat is produced so is the power generated by the plant irrespective of the load demand. This happen because in Nuclear Power Plant Safety is the main issue rather than producing the electricity. So, it is not advisable to operate the reactor based on the load demand which results in reactor trips. When the reactor trips many problems arises like the problems in starting the reactor and thermal stesses which consumes the life of the reactor and cooling the reactor. So it is very much require to operate the Nuclear Reactor from Tripping. So Nuclear Power Plants Connected to the Grids generally operate as a Base Load Plants.