Evaluation of jet breakup length with a CFD code under steam generation condition in a pre-flooded cavity

• Published in: Nuclear engineering and technology Vol. 55; no. 7; pp. 2498 - 2503
• Main Authors: Eom, Jeong-Hyeon, Tak, Gi-Young, Ra, In-Sik, Nguyen, Huu Tiep, Jeong, Hae-Yong
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-07-2023; Elsevier; 한국원자력학회
• Subjects: Computational fluid dynamics; Ex-vessel phenomena; Fuel-coolant interaction; Jet breakup length; Severe accident; 원자력공학; Fuel-coolant interaction; Ex-vessel phenomena; Severe accident; Computational fluid dynamics; Jet breakup length
• ISSN: 1738-5733; 2234-358X
• DOI: 10.1016/j.net.2023.04.020

When the reactor vessel is penetrated in a severe accident of light water reactor, the molten fuel-coolant interaction including the jet breakup occurs and the jet breakup length becomes one of the important parameters. Most numerical studies on jet breakup process have been carried out using dedicated computer codes. Some researchers are trying to apply commercial CFD codes to their investigations on comprehensive jet breakup process. However, the complexity of the phenomena limits the CFD application only to hydrodynamic aspects. In the present study, numerical analysis of jet breakup under vapor generation is pursued using the STAR-CCM + code. The obtained CFD prediction of the MATE09 experiment shows jet breakup progression patterns consistent to the images taken in the experiment. Further, the predicted positions of leading head, which determine the jet breakup length, are in good agreement with the MATE 09 data. The investigation of hydrodynamic effects on the jet breakup with higher jet velocity results in a stronger shear force and earlier jet breakup process even though there exists the vapor pocket around the corium jet. In future studies, the effect of vapor intensity on the jet breakup length would be investigated further by changing other parameters.