Natural circulation stable operation device based on nuclear thermal coupling simulation and control method

The invention discloses a natural circulation stable operation device based on nuclear thermal coupling simulation and a control method. The device comprises a reactor simulation body, a steam generator simulation body, a main pump simulation body and a voltage stabilizer. The voltage stabilizer is used for stabilizing voltage in a loop; the reactor simulation body is used for simulating a heat source of which the power is automatically adjusted according to the coolant temperature of a loop so as to realize stable operation of natural circulation; the steam generator simulation body is used for simulating a cold source; the main pump simulation body is used for driving the coolant to circulate in the starting process of the test device; and the coolant is driven by the gravity difference of the cold and hot fluid in the pipeline to flow in the pipeline so as to realize natural circulation. According to the embodiment of the invention, in the natural circulation operation mode, the reactivity change is calcul