Triggered Steam Explosions with the Corium Melts of Various Compositions in a Two-Dimensional Interaction Vessel in the TROI Facility

SIMMER-III Analyses of Local Fuel-Coolant Interactions in a Simulated Molten Fuel Pool: Effect of Coolant Quantity

“…Nevertheless, it seems that, for all the runs calculated, the obtained values are varying over a comparatively narrow range (20∼27%), which perhaps demonstrates again that the cooling effect induced by the remaining unevaporated water should be rather limited. Further, it is also confirmable that, possibly due to the distinct difference involved in experimental conditions (e.g., material and temperature difference and interaction mechanism (steam explosion or nonsteam explosion) as well as interaction mode (FI or CI)), whatever the water volume is, the calculated values are much higher than the reported results in several FI-mode investigations [12,13,32]. To further understand the difference between FI and CI modes, more calculations over a variety of parametric conditions are being planned.…”

“…where 0 and 1 are the initial and maximum pressures of the cover gas, respectively; 0 , 1 , and are the volumes of cover gas corresponding to 0 , 1 , and , respectively; and is the ratio of specific heats. By assuming a one-dimensional acceleration of an inertial mass (melt slug), can be estimated as [13,32]…”

“…where ther is the total thermal energy used for the interaction. Although, in the past FI-mode investigations, it is more common to calculate ther from the exothermic (melt) side [12,13,32], in our earlier experimental study, regarding the CI-mode FCI [16], due to the unknown mass of melt involved in the interaction, based on energy conservation, the ther , which is actually the maximum thermal energy absorbable by water, has been tentatively employed for analyses:…”

“…Unfortunately, it is instructive to note that, over the past decades, although extensive studies (e.g., CCM [10], KROTOS [11], FARO [12], and TROI [13]), with an emphasis on ascertaining the mechanisms of steam explosion and debris bed formation in a FCI, have been conducted, most of them were performed in a fuel-injection (FI) mode, namely, by injecting or pouring melt into a coolant pool, while the knowledge and data gained from a coolant-injection (CI) mode has not been accumulated sufficiently, especially in a scenario where a certain amount of liquid coolant is entrapped within a larger melt pool. Park et al [14] and Sibamoto et al [15] are the few representative authors that independently performed their investigations in a CI mode within various situations (such as energetic or nonenergetic conditions).…”

The challenge of modeling fuel–coolant interaction: Part II – Steam explosion

“…The water height was about 1 m. The experiment has then a 1-dimensional geometry with no lateral venting of the pressure wave as it can be the case in e.g. TROI (Kim et al, 2011) or FARO tests. The propagation of the pressure wave can then easily be measured.…”