Verification of the WWER-1200 reactor dynamic model consisting of one-fuel unit adjacent to two coolant units

As modern control systems engineering imposes limits on mathematical models of control objects, further development, and verification of the mathematical models suitable for power control system synthesis of nuclear power facilities is an ongoing problem. This article deals with the low-order dynamics model with lumped parameters of the Russian-designed pressurized water reactor, as well as its verification with experimental data from the full-size simulator of the WWER – 1200 nuclear reactor within two tests related to changing the position of Group 12 of CPS CR and changing the inlet coolant temperature. This model was created as a MATLAB S-function lv.2 model because of its capability to handle any type of signal.  Within this approach, the equation describing the coolant heating process is represented as a «two well-stirred tanks in series» model. The article demonstrates the upside of the given approach in comparison with the conventional approach, where the average temperature of the coolant is determined as an arithmetic mean of inlet and outlet coolant temperatures, respectively, on the basis of the test with a sudden change of the reactor inlet coolant temperature. In the frequency domain, the authors carry out stability analyses of the given model in a state-space form in relation to different external disturbances. Conclusions about the suitability of the given model as a fifth-order control object for parametric synthesis of a controller for the power control system of a nuclear power facility are drawn.

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