Abstract
In-Vessel Retention (IVR) is one of the primary technique to mitigate severe accidents. This enables retaining the corium inside the Reactor Pressure Vessel (RPV) through external cooling. However, it is important to assess the validity and success of this technique, though actual validation is impossible. In this work, we have developed a model of selected case study and used MATLAB 2018b to simulate it. Developed model has been tested using two sources; constant temperature source and constant heat flux. These two sources were applied at the internal surface of RPV separately and heat transfer through RPV lower plenum was monitored. Main purpose of this analysis is to obtain temperature profiles along the RPV lower plenum external surface. Results show that the technique is successful because external surface temperature is lower than melting point of RPV in both the cases discussed. Sensitivity analysis showed that external temperature can be further decreased by increasing heat transfer, which can be changed by thickness of RPV and sub-cooling of inlet water. However, both parameters have their own limitations. Results obtained through MATLAB simulations are also comparable to MELCOR1.8.5 code simulation results and both found in agreement.