Investigations on steam explosion phenomena with FARO and TROI experiments

In this paper, we have numerically simulated the steam explosion behaviour observed in FARO L-33 and TROI-13 tests using the code COMETA. The main objective was to understand effects of various parameters on the dynamic pressure profile generated during the melt-water interactions. The FARO L-33 geometry and operating conditions were different from the TROI-13 tests. While a strong pressure spike was observed in TROI-13, a relatively mild pressure rise was observed in the FARO L-33 test. Hence, we conducted parametric studies by changing some parameters and their effects on the dynamic pressure profile were studied. It was found that the hydrogen concentration and the fragmented drop size are the two parameters which play key roles on the pressure spike and the pressure profile. The water depth and melt superheat also found to have similar effects on the dynamic pressure profile. Then, we simulated the TROI operating conditions in FARO geometry and studied the pressure profile after triggering was activated. It was found that, a smaller hydrogen concentration and larger melt superheat as in TROI, could produce a stronger pressure rise in FARO geometry. (author)