Transient and stability analysis in single-phase natural circulation

This paper presents the mathematical modeling of single-phase natural circulation of the University of Genoaʹs rectangular loop (LOOP#1) by a computer program and using RELAP5 system code. The mass, momentum and energy conservation equations in transient form were solved numerically using the finite difference method. One-dimensional linear stability analysis was performed for the single-phase natural circulation loop and the numerical perturbation technique was used in this analysis. The Nyquist criterion was employed to find the stability map of the LOOP#1. The obtained transient results using the first order upwind scheme of the fluid temperatures in various sectors of the LOOP#1 are compared with the results obtained from the RELAP5 system code and available experimental data.