Decision support algorithms for managing the water-chemical regime of a nuclear power plant

The study examines a set of indicators characterizing the conditions for implementing the water-chemical regime of the secondary circuit in domestic nuclear power plants equipped with VVER-440 / VVER-1000 water-water energetic reactors. The presented research results are intended for use in software complexes for personnel training, specifically computer simulators. The reliable operation of nuclear power plants in any country depends on the proper functioning of all plant systems and the qualification of personnel. The study aims to assess the impact of deviations in the water-chemical regime and to develop decision-making algorithms for operational personnel managing the water-chemical regime. As part of the computer simulators for training operational personnel, structural and parametric identification of mathematical models for the time-dependent performance indicators of the water-chemical regime was carried out. The modeling primarily focused on the channels "concentration of specific agents (hydrazine hydrate, morpholine) vs concentration of impurities (iron compounds, etc.) in the coolant", as these are closely associated with the corrosion processes of pipelines, primary, and auxiliary equipment in the secondary circuit of nuclear power plants. The study included modeling conditions for violations of the water-chemical regime in the secondary circuit using indicators such as electrical conductivity, mass concentration of oxygen, mass concentration of copper, and mass concentration of sodium. Experimental-statistical validation of the models was conducted, demonstrating that the developed mathematical models adequately describe the analyzed processes. Based on the obtained mathematical descriptions (a family of mathematical models in the form of ordinary differential equations), computer models were constructed. These models enable personnel to predict changes in the performance indicators of the investigated processes over time. Non-stationary process computer models for the water-chemical regime of the secondary circuit in nuclear power plants with VVER-1000 reactors, developed through the identification of extensive industrial data, facilitate the integration of new subsystems for modeling coolant composition management regimes into the computer simulator for operator training.