Analyses of in-pile experiments by an analysis code on initiating phase of core disruptive accident in sodium cooled fast reactors, 4 Analysis of EFM1 test

Imaizumi, Yuya ; Fukano, Yoshitaka  

The test result of EFM1 in the CABRI in-pile experiment which was conducted as an internationally collaborated project was analyzed by SAS4A code. The code was developed for the analysis of initiation phase of core disruptive accident. In the EFM1 test, transient overpower was imposed after the cladding melting and coolant boiling which was due to the previously imposed loss of flow. The behavior of large relocation and refreezing of the molten fuel which was caused by the heating peak after the fuel melting was one of the important point in the analysis. As a result, good agreements were observed between the results of experiment and analysis such as timings of coolant boiling, extension of boiling area and behavior of molten fuel motion.