[3P08-13] Accident Analysis

3:30 PM - 3:45 PM JST(6:30 AM - 6:45 AM UTC)

[3P11] Evaluation on Reactor Core Degradation and Relocation at Severe Accident(9) Evaluation of molten core spreading during the TMI-2 accident

*Koji Nishida¹, Hiroaki Takanami¹, Seitaro Sakurai¹, Michio Murase¹ (1. INSS)

Keywords:

TMI-2,Severe accident,Fuel damage,Relocation,MAAP5,Core melt

In the TMI-2 accident, the core damage and relocation continued even after the core was flooded by restarting RCP. The core melt region expanded, and some of the melt materials fell to the lower plena. We evaluated the core damage, relocation, and expansion of the core melt region using MAAP5. The computed results showed that the region containing melting materials extended to the core diameter, and then a portion of the melt materials fell into the lower plenum at around 225 minutes almost the same as the time of the investigation report.