Validation of New Friction Model for Dryout Heat Flux in Ex-Vessel Porous Debris Bed in the Multi-Dimensional Configurations

In the severe accident of a light water reactor (LWR) with water filled reactor cavity as a part of the accident management measures, the ex-vessel corium debris bed would be formed with the settled corium particles due to the breakup in water rather than a continuous molten phase. However, if the debris bed is not cooled effectively, the debris bed may re-melt and leads to the molten core-concrete interaction (MCCI). Many researchers worked on two-phase friction model in porous media to predict DHF. We, recently argued the necessity of friction model modifications especially at high void fraction conditions and suggested the modification of the previous drag force models by proposing channel and annular regime inside the porous media and for interfacial friction modeling in it. The modifications showed reasonable agreement with one dimensional pressure drop and dryout heat flux experimental database. Therefore, the purpose of this work is to examine the validity of the proposed model in the multidimensional configurations. The multi-dimensional CFD simulation of dryout in porous beds has been conducted to test applicability of proposed two phase friction drag models in porous media in our previous work. In overall, the proposed model shows reasonable agreement to the COOLOCE experimental results. The cone shape porous bed case showed more deviation from the experimental data compared with other shapes. The comparison of dryout location with the experimental result indicated that it would be caused by the limitation of measurement point in the experiment.