CFD - ANALYSIS OF THE THERMAL AND HUMIDITY STATE OF THE NEW SAFE CONFINEMENT AT THE CNPP BASED ON OPERATIONAL DATA

Abstract

For the first time, modeling of the non-stationary thermal and humidity conditions of the New Safe Confinement (NSC) at the Chernobyl Nuclear Power Plant was conducted (based on the development of the author's work [1]) using monthly operational data (temperature, humidity, and fan flow rates) within the NSC volume, taking into account changing climatic conditions (temperature, humidity, wind speed, and direction) over the course of a month. Additionally, the operation of special dehumidification units to maintain air humidity within the circular space (CS) of the NSC (with a volume of approximately 1 million m3) at no more than 40% over a 100-year period was considered. Operational temperature and humidity values at 8 local points at the inlet of the recirculation circuits in the CS were used to determine the temperatures and humidity at the outlet of the dehumidification units through 16 supply pipes of dehumidified and heated air with specified flow rates into the CS volume. These temperatures and humidity levels from the dehumidification units were achieved by minimizing the quadratic criterion of matching model and operational values at the aforementioned 8 local points for all 677-time moments, allowing for detailed three-dimensional non-stationary temperature and humidity fields throughout the CS volume. An analysis of these fields over a period of 28 days revealed humidity values exceeding 40% in areas where humidity sensors were absent. It was demonstrated that such exceedances could be addressed by including specific recirculation circuits. Thus, it is shown that only with the help of such models and continuous acquisition of operational data, it is possible to control temperature and humidity variations over time throughout the CS volume, which is the objective of this work. The possibility of using the models to prevent humidity values from exceeding 40% through optimal control of the NSC's humidity conditions using dehumidification units is considered.