Experimental investigation of quenching behavior of simulant material CaO-Fe2O3 under bottom flooding with the effect of melt volume

Abstract

In a severe accident of a nuclear reactor, the termination and stabilization of the melt pool are necessary for the safety of the reactor. To address this issue, melt pool coolability plays a significant role in severe accident scenarios. In the context of this coolability measures, there are three major techniques i.e. top flooding, bottom flooding, and indirect cooling were used in the past and also in the present scenario to analyzed the actual phenomena occurred during a severe accident in a nuclear reactor with numerous simulant material of different composition and melt volume. This is because of extremely difficult to use the prototype material and conditions. Among the various strategy of melt coolability, it has been found that the melt coolability with the bottom flooding technique is very efficient to quench the material within a few minutes. In this regard, the present paper has involved the study of quenching phenomena of melt pool using bottom flooding at a small scale with a simulant material CaO-Fe2O3 at two different melt volume i.e. 1 l and 2 l. The simulant material is melted into an electric furnace at 1420 °C (~200 °C superheat) and poured into the test section where it has been quenched through water induction by a nozzle (12 mm) from the bottom side. Temperature history has been analyzed along the radial and axial direction of melt flow and further particle size and porosity of debris were measured. The size of debris was measured in the range of 0.4 to 40 mm although this debris was so fragile in nature. The average porosity was measured as 56% and the result was found in good agreement with literature.