Development of the diagnostics algorithms of the water chemistry conditions at the nuclear power plant second circuit

Abstract

Based on the investigations, it was found that the maintenance quality of water-chemistry conditions (WCC) of secondary circuit of nuclear power plant WWER-1000 is evaluated using such indicators as the rate of corrosion of structural materials, the amount of deposits on the inner surfaces of equipment and the amount of liquid waste that can cause damage to the environment.

To minimize the performance by listed indicators now it is used a data support, such as pH, electrical conductivity, concentration of corrective additives within the established norms. But only support of values of WCC quality indicators makes it impossible to completely eliminate the occurrence of corrosion processes and the formation of deposits of impurities in the second circuit.

Therefore, it is set the task to develop a strategy management that will minimize corrosion rate of the secondary circuit equipment and the number of deposits on the surfaces of process equipment for WCC optimal control.

In this paper it is analyzed the causes of accidents at nuclear power plants and the principles of decision making by operational staff during these accidents. Special attention was paid to development of basic diagnostics of WCC algorithm that will reduce errors of decision making by operational staff.

As a result of researches it is developed a complex of logic models for the evaluation of violations of WCC maintenance. Based on the decisions obtained by logical model, the authors developed a strategy to control the formation of appropriate control actions that will reduce the degree of corrosion damage to construction materials of equipment and, as a result, avoid emergency modes of power plants.