A practical methodology devoted to pool-type phenomena simulation in safety analysis for sodium-cooled fast reactor

Accuracy and computational expenses are contradictory when performing simulation to hot plenum where multi-dimensional phenomena voice loudly in sodium-cooled fast reactor (SFR). A 2-dimensional method was preferred in light of the cylindrical shape and drive force behind significant thermal stratification phenomena during transient case. One barrier related to buoyancy effect on turbulent flux transportation has been removed before. Asymmetric arrangement of components in circumferential direction makes another difficulty to reproduce actual flow field within hot plenum of pool-type SFR. A series of special techniques for spatial discretization were implemented to restore geometry reality. Treatments about upper core structure, main heat exchanger and auxiliary heat exchanger were evaluated based on criterion of predicting well-mixed inner plenum and stratification like outer plenum. Finally, optimal model came to an 8-block partition scheme in which whole profiles of upper core structure and auxiliary heat exchanger were described. Validation was carried out through a normal state experiment on a water platform with reduced-scale structure. Agreement of relative temperature distribution demonstrated ability of this model for tackling spatial layout in pool-type SFR with the 2-dimensional library. All real-physics and efficient features indicate that this 2-dimensional methodology is an excellent tool for engineering application when designing or evaluating a new SFR concept.

Automated summary

The study focused on simulation of the hot plenum in a sodium-cooled fast reactor, proposing a 2-dimensional method to address the thermal stratification phenomena. Special techniques were implemented to restore the geometry reality, resulting in an optimal model with an 8-block partition scheme. Experimental validation demonstrated the effectiveness of the model in tackling spatial layout in pool-type SFRs.