Modeling of in-vessel gap cooling and its validation against LAVA, ALPHA, and LMP200 experiments

摘要: Abstract The gap cooling phenomenon is a key issue to explain why the 19 tons of melt retained in RPV lower head TMI accident did not significantly damage vessel. This study developed model for and was validated against several experiments with 30 kg, 50 kg, 70 kg Al2O3 (LAVA ALPHA experiments), 220 kg 360 kg Al2O3 + Fe (LMP200 experiments). To estimate thermal behavior vessel during cooling, we modeled heat transfer from crust removal by water penetrating gap. size which determines flow rate evaluated considering interaction between water; Inverse-Leidenfrost effect, fracture crust, deformations In addition, three-regime widely used analyze quenching applied simplify calculation compared boiling curve previous studies. A sensitivity discretization dimension showed that 1D can substitute 2D analyzing experiments. From study, node time step were proposed as 3 mm 0.1 s obtain converged results. Through extensive validation large-scaled mass experiments) well small-scaled 30, 50 kg introduced correction factors account uncertainties degree local contacts reactor effect solidified debris penetration on CCFL. We found out current predicted peak temperatures times error ranges −15 ~ 15% −50 ~ 70%, respectively. Finally, other codes.