[1G16-19] Severe Accident Analysis/Experiment

[1G16] Improvement of JASMINE code for evaluation of molten debris coolability in containment vessel

*Toshionori Matsumoto¹, Yuzuru Iwasawa¹, Ryuhei Kawabe¹, Kohei Ajima¹, Tomoyuki Sugiyama¹, Yu Maruyama¹ (1. JAEA)

Keywords:Severe accident, JASMINE, Agglomeration, Melt spreading, Debris coolability in containment vessel

To perform the evaluation of the effectiveness of precautionary water injection into the containment vessel as the mitigation/prevention of MCCI during severe accident, the debris thickness and the contact surface area between molten core and concrete base mat are important parameters. We have improved models in JASMINE code relating with the phenomena such as jet breakup and melt spreading on the floor to estimate these parameters. Analyses of DEFOR-A tests demonstrated that the state of the code is appropriate to predict the mass fraction of agglomerated debris. The models for crust formation at the tip of spreading and stopping of the spreading using the tensile strength of the crust have also been implemented and the code reproduced PULiMS test results.