Nuclear power provided 10% of the world's electricity. In Ontario Nuclear provides the base electrical load on the grid. Nuclear power is very unique. It is able to release a tremendous amount of power if it is not controlled properly. There is three objectives that are required to be meet at all times when running a Nuclear power plant. These are called the three C’s. The three C’s are Control, Cool and Contain. The nuclear reaction in a power plant is required to be controlled, at all times. This is completed by maintaining the nuclear fission reaction in the reactor. The Nuclear fission reaction releases radioactivity. This radioactivity needs to be contained in the reactor and not released in the environment, at any cost. The reactor is required to be cooled at all times. This report will provide a basis on controlling the heat on a nuclear reactor. This design of the Instrumentation and Control of the Heat Transport System for a CANDU REACTOR, will be discussed in detail in this report. The Heat transport system is responsible to maintain the coolant mass balance of the nuclear power plant. The main control goal is to stabilize the water level at a reference value and to suppress the effect of various disturbances.