Analysis of Unsteady Behaviour of Natural Circulation Helium Loop

This paper deals with the one-dimensional unsteady fluid flow model of the natural circulation loop. The presented model represents the experimental facility Helium Loop STU which is the physical model of an emergency coolant system of a nuclear reactor. The governing equations are solved according both Euler and Lagrange approaches on two parallel computational grids. Linearization of equations and semi-implicit discretization scheme are used to enhance the algorithm effectiveness. The simulation results were compared to experimental data. The model can be considered as high-accurate in comparison with experimental data (relative error 1.14÷1.15 % at specified time interval).