This paper justifies the necessity for detailed analysis and forecasting of the associated gas-dynamic, thermal and radiation state of the Shelter Object (OS) of the New Safe Confinement (NSC), as well as its moisture state, which determines the 100-year life time of the supporting structures in the NSC annular space. To analyze and predict these processes, a three-dimensional computer CFD (Computational Fluid Dynamic) model was developed, which allowed to test the performance of the NSC ventilation system under various climatic conditions and ventilation equipment failures. Examples are given of applying the model to the analysis of the distribution of radioactive aerosols leaving the OS into the main volume of the NSC and the environment both during the NSC commissioning period and during operation. The possibilities of using the developed model as part of the ongoing monitoring of detailed analysis and forecasting of the gas-dynamic, thermal, humidity and radiation state of the NSC are considered. CFD model «Shelter» object and NSC. One of the methods for analyzing and prediction the behavior of processes within an «Shelter» object is computer CFD modeling (Computational Fluid Dynamics), which makes it possible to predict the distribution of temperatures, humidity, air velocities and other values, such as concentrations of impurities or phases. A set of methodological and software approaches and technologies were applied which allowed the model to take into account main physical processes and features of the structure and geometry of the NSC and the «Shelter» object for analysis, prediction and monitoring of humidity and radioactive aerosol distribution processes in the «Shelter» object and the NSC. Approach to radioactive aerosol modeling. Radioactive aerosols in the model are presented as one of the phases of a multiphase medium, taking into account the processes of their transfer with air streams, due to diffusion, including turbulent, RA emissions from the central hall of the Shelter and their gradual subsidence under the action of gravity. As a result, the developed model can be included in the permanent monitoring system of the NSC and the «Shelter» object as a socalled “digital twin NSC”, which allows the NSC to analyze and predict its state and refine the operational parameters in various normal and abnormal situations throughout the life of the NSC.
Keywords: new safe confinement, thermal, humidity, radiation state, CFD modeling, state monitoring
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