Analysis of the counter-flow restriction for the emergency coolant injection in case of one-phase natural circulation using ANSYS CFX

In case of a small leak of the primary circuit in a PWR plant coolant medium flows into the containment causing pressure increase and triggering reactor scram and eventually emergency coolant injection. The transport of the after-heat is assured by a one-phase or two-phase natural circulation in the coolant loops. The authors describe the CFD (computed fluid dynamics) modeling of the UPTF-TRAM A3 test concerning the counter-flow restriction for the emergency coolant injection in case of one-phase natural circulation results using the CFD code ANSYS CFX. The results of the CFD analysis agrees in large parts with the experimental results.