Analysis of the dynamics and control of a Pressurized Water Reactor (PWR)

Resumo

The concerns about the advance of climate change bring the use of nuclear energy as an alternative to energy conversion technologies using fossil fuels. For a nuclear reactor to operate safely, its control must work properly to avoid nuclear accidents. Thus, the present work carries out a study that models a simple Pressurized Water Reactor (PWR) type reactor through point neutron dynamics, to understand how thermodynamic effects influence the reactivity of a nuclear reactor, which, in turn, affects the neutron density (reactor power) directly. Furthermore, it models the effect of external reactivity, which simulates the behaviour of reactivity when the control rods act to control the chain reaction.As a way of evaluating the stability of the nuclear reactor, the Bode diagram is used in two analyses: one with feedback effects and the other without feedback effects. A gain margin of around 23.6560dB is observed at a frequency of 14.9211 Hz, showing that the stability of this reactor is guaranteed through feedback, showing that the system has a great capacity to tolerate variations and uncertainties, since the profit margin found is positive. The gain margin found for the reactor without feedback tended to infinity, which shows reactor instability. The simulation found oscillations in neutron density, and this can be understood through the dynamic effects as a form of control of a nuclear reactor, since stability is found due to temperature and control rod feedback.