To mitigate severe accidents in nuclear reactors, the present research sheds light on the melt-coolability behavior of corium with hypothetical experiments that have been performed at two different nozzle diameters under bottom flooding conditions. In this research, a simulant material CaO-Fe2O3 powder mixture was melted and poured into the test section that was embedded in the test facility (using a bottom pouring furnace instead of a tiltable furnace). Then, from the bottom of the melt pool, water was flooded through a nozzle at a pressure of 0.70 bar and a water flow rate of 12 liters per minute. Because of the interaction between the water and melt, the melt quenched and converted into fine porous debris, and the temperature history was recorded using 12 K-type thermocouples connected to a data acquisition system. The average quenching time and porosity of the debris were affected by variations in the nozzle diameter. This research will help in understanding real core-melt accidents that generally occur in nuclear power plants.

The role of simulant materials becomes necessary for the predictive study of the nuclear severe accident phenomena due to its similarity with corium (a liquid form of UO2 and steel). Since simulant material is eco-friendly and has similar properties to corium, it has been widely used in the research field of severe accident management. In this study, material CaO-Fe2O3 a non-eutectic binary mixture is considered for characterization purpose to address the thermophysical properties at different compositional ratios. The CaO-Fe2O3 powder mixture was prepared in mortar for 40 minutes manually to form a homogeneous mixture and then cylindrical pellets prepared at five different ratios with the help of the phase diagram. Further, these pellets were heat-treated at 1200°C for three hours soaking time to address its thermal stability in a programmable electric furnace. Finally, pellets ground into powder form manually for further characterization. Initially, the weight loss analysis was reported by measurement of dimensions of pellets before and after heat treatment. The thermal properties, phase analysis, and morphological studies have been carried out through DSC, XRD and FE-SEM in laboratory and results were discussed in the context of the property of ideal simulant materials used for the study of nuclear severe accidents. The melting point of all the samples were found stable (1200°C-1230°C) and values of activation energy and specific heat were well synchronized between with and without heat-treated samples. Dislocation density of samples increases significantly with increasing the proportion value of calcium oxide after heat treatment.

In severe accident management, the integrity of the containment structure is a key point to focus the study related to severe accident scenarios that need knowledge of thermo-physical properties of material composition. In the present nuclear accident scenario, nuclear severe accident management is one of the challenging tasks to mitigate the phenomena occurring inside the reactor pressure vessel (RPV). Numerous studies have been done in the past to predict the severe accident phenomena and tried to explore the incidence by using different prototype and non-prototype (simulant) materials. In this context, an initial effort has been made to study the actual phenomena during an accident scenario with non-prototype material CaO-Fe2O3. Initially, the present work involved the study of the material CaO-Fe2O3 powder for thermo-physical property analysis and later, the study will be carried out via melt cool ability of this material in a hypothetical nuclear reactor for analysis and mitigation of nuclear severe accident phenomena. The non-eutectic binary powder mixture of CaO and Fe2O3 has prepared manually by mixing in a mortar for 40 minutes in the ratio of 21:79 by wt. % (21C79F; C refers to CaO and F refers to Fe2O3) which has been confirmed by the phase diagram. Further, pallets were prepared of the non-eutectic binary mixture and heat-treated at 1000°C, 1100°C, and 1200°C for 3 hours in a programmable furnace. The powder form of heat-treated pellets was characterized to analyze thermophysical properties and to validate as a simulant material (non-prototype) used for the predictive study of a nuclear severe accident. The thermal properties, phase analysis, and morphological studies of the CaO-Fe2O3 (21:79 by wt. %) have been reported in the current research work and analyzed accordingly.

In present study, the effect of Air-quenching on the properties of CaO-Fe2O3 (22:78 by wt. %) powder mixture and CaO-B2O3 (30:70 by wt. %) powder mixture was discussed. These materials are used in the nuclear industry as simulant material to study the melt coolability behavior. This study was carried out in order to development of CaO-Fe2O3 as a simulant material. The CaO-Fe2O3 and CaO-B2O3 powder mixture are melted in the Bottom pouring electric furnace then quenched in air. The quenched material have characterized through Field Emission Scanning Electron Microscopy (FE-SEM) with Energy-Dispersive X-Ray Spectroscopy (EDS), X-Ray Diffraction analysis (XRD), and Differential Scanning Calorimetry (DSC) analysis. The FE-SEM was used to study the morphology of the material after air quenching. The particles size analysis of air quenched material was performed macroscopically. The elemental analysis was carried out through the Electron Diffraction Spectroscopy. XRD analysis was carried out to determine the phases after air quenching. The density and porosity of these materials also have been calculated using Archimedes principle.

The simulant materials play important role in the melt coolability experiments to understand the actual scenarios of core melt accidents in the field of nuclear reactor. Simulant materials are generally oxide/ceramics materials which have the properties similar to the properties of corium (mixture of UO2 , ZrO2 , Zr alloy, Fe, Ni and Cr etc.). This work was carried out to determine the thermo-physical properties of CaO-Fe2O3 binary mixtures of different ratio of CaO and Fe2O3 (23C77F, 26C74F, 29C71F, 32CF68 and 35C65F; here the ratio is in the wt% and C for CaO and F for Fe2O3 ) and compare the properties of CaO-Fe2O3 with the properties of corium. It was observed that the thermo-physical properties of CaO-Fe2O3 binary mixture are close to the properties of corium, so it can be said that this material is simulant material. In this research work, thermal behavior of CaO-Fe2O3 was also carried out using differential scanning calorimetry (DSC). The simulant material CaO-Fe2O3 can be used in the melt coolability experiment to understand the phenomena that happened during the core melt accidents in the nuclear reactor.

Abstract In present paper a study has been carried out to analyze the thermophysical properties and microstructural behavior of CaO.Fe2O3.A binary eutectic sample material is taken in the ratio of 22:78 by Wt. % in mixed powder form prepared manually. The sample powder is heat-treated at 950°C, 1050°C, and 1150°C for three hour holding time in programmable furnace. Further, the characterization is done with the help of different characterization technique like DSC, XRD, TGA to analyze its thermophysical properties and microstructural changes. This studies became necessary to analyze and interpret the data collected from prototype material found from nuclear severe accident occurred in the past. As heat transfer phenomena plays the crucial role in nuclear severe accident due to high temperature gradient developed inside the reactor vessel. Hence a non-prototype material is needed to study about heat transfer phenomena and in context of this study the material CaO.Fe2O3 is being considered. This study bears the first stage to validate the given material is simulant material. In the current study, heat absorbed, phase analysis, unit cell volume, melting point, crystallite size, dislocation density, and weight loss have been reported and analyzed.

In the field of nuclear reactor, corium simulant material is used in the melt-coolability experiments to simulate the phenomena of core melt accident. Corium simulant materials are material which have thermo-physical properties (density, melting point, specific heat capacity, thermal conductivity, and thermal diffusivity) similar or close to the properties of corium. In this research work, two studies were performed. The first study was determined thermo-physical properties of CaO-Fe2O3 (26:74 by wt.%) binary mixture and compared these properties with the properties of corium and other simulant materials. The thermo-physical properties of CaO-Fe2O3 (26:74 by wt.%) binary mixture was found close to the properties of corium. It is confirmed that the material CaO-Fe2O3 (26:74 by wt.%) binary mixture is corium simulant material, so it may be used in the melt-coolability experiments to simulate the phenomena of nuclear severe accident. In the second part of study, the study of influence of heat treatment temperature (1000 , 1100 , and 1200 ) for one-hour soaking on density, morphology, phases, melting point, specific heat capacity, heat of fusion, activation energy of CaO-Fe2O3 (26:74 by wt.%) binary mixture was carried out. This study was carried out in order to develop of CaO-Fe2O3 (26:74 by wt.%) binary mixture and to know thermal stability of the material CaO-Fe2O3 (26:74 by wt.%) binary mixture at higher temperature. It is observed that the morphology, phases, thermal properties was altered with variation in the heat treatment temperature (1000 , 1100 , and 1200 ) for one-hour soaking time.

In present study, the effect of soaking time on morphology, phases, and thermo-physical properties of CaO-Fe2O3 (26:74 by wt%) powder mixture at constant heat treatment temperature (HTT) 1100 degrees C was discussed. This study was carried out to know thermal stability of the material at higher heat treatment temperature for different soaking time 1 h, 2 h, and 3 h. In the nuclear field, melt-coolability experiments perform with using simulant material. The material CaO-Fe2O3 (26:74 by wt%) may also be use as simulant material in the melt-coolability experiments to know the quenching behaviour of the material to stabilize and terminate the severe accident. In this study, the material CaO-Fe2O3 was characterized by using different characterization techniques. The pellets of CaO-Fe2O3 powder mixture were prepared by using hydraulic pressure machine with a load of 2.5 ton. These pellets were heat treated at constant heat treatment temperature (1100 degrees C) for different soaking time 1 h, 2 h, and 3 h. After heat treatment, the pellets were characterized through Field Emission-Scanning Electron Microscopy (FE-SEM) with Energy-Dispersive X-Ray Spectroscopy (EDS) to study the morphology and element of the material. X-Ray Diffraction analysis (XRD) was carried to find the phases of the material, crystallite size, dislocation density and micro strain in the material. Differential Scanning Calorimetry (DSC) analysis was done to know the thermal behaviour of the material. The morphology, phases, thermal properties and dimensions of CaO-Fe2O3 were changed with changing the soaking time. (C) 2019 Elsevier Ltd. All rights reserved.

A numerical investigation has been carried out to characterize both single and multiphase hydrodynamics in a continuous casting mold under the influence of a superimposed magnetic field. Three-dimensional single- and two-phase magnetohydrodynamic flow and turbulence models have been developed for numerical simulation. The computational model results are in agreement with the plant experimental measurements. In a single phase paradigm, with a functional variation in applied magnetic field distributions, the results have been shown for both conducting and non-conducting media. On the other hand, for multiphase flow, based on the actual magnetic field measurement values at the plant, simulations have been carried out at a representative 6L/min argon flow rate. Overall, the superimposed magnetic field is observed to subdue the flow velocity magnitude and the distribution of turbulence intensity in the continuous casting mold. A similar phenomenon has also been noticed for multiphase flows.