Thermal-hydraulic model of the heavy liquid metal coolant—steam-water mixture flow

Abstract

Background

Reactors with heavy liquid metal coolant (HLMC) based on a eutectic lead-bismuth alloy (Pb-Bi) require a safety justification. The latter includes the obligatory simulation of normal operating and emergency modes using thermal-hydraulic calculation codes.

Aim

To develop a one-dimensional three-field model for the joint flow of three fluids including HLMC, steam, and water for a KORSAR/LMR-based software tool numerically simulating in detail physical processes in reactor plants during inter-circuit leaks with water coolant ingress into HLMC.

Materials and methods

The KORSAR/LMR thermal-hydraulic code developed by the Alexandrov Research Institute of Technology was used for calculations; validation was performed using published experimental data of the LIFUS 5 facility.

Results and discussion

In the course of the study, we have modified the system of conservation equations, flow mode and heat exchange maps, as well as changed an approach to closing relations. The calculated pressure dynamics of the three-field model turned out to be closer to the experimental one as compared to the two-field model consisting of HLMC and steam-gas mixture.

Conclusion

A three-field one-dimensional model of the joint flow for three fluids has been developed and implemented in a new software tool based on the KORSAR/LMR computer code. This software can be used for the predictive safety analysis of reactor plants with HLMC. Model correlations can be further refined due to the expansion of the experimental base.