LIVE experiment on thermal behavior of solid-liquid mixture pool in RPV lower head

Madokoro, Hiroshi  ; Gaus-Liu, X.*; Cron, T.*; Fluhrer, B.*; Stngle, R.*; Wenz, T.*; Vervoortz, M.*; Yamashita, Takuya  ; Sato, Ikken ; Mizokami, Shinya

Since the structures inside the pedestal of Fukushima Daiichi Nuclear Power Station Unit 2 are relatively intact, the temperature of fuel debris relocated from the reactor pressure vessel (RPV) to the pedestal region is estimated to be rather low; oxide components remained solid and metallic components are molten. In order to predict the RPV failure, the molten pool behavior in the lower head is a key factor. Only a few experiments, however, addresses the transient heat transfer of solid-liquid molten pool. To enrich experimental database, melting and heat transfer behavior are investigated using the LIVE facility at Karlsruhe Institute of Technology. The results showed that convective heat transfer could take place in a solid-liquid mixture pool and the thermal loads on the vessel wall shifted from bottom upwards.