11:35 AM - 11:50 AM
[3F08] Fukushima-Daiichi Plant Data Analysis Focusing on Core Material Relocation to Pedestal
Estimation of core-material-relocation behavior to pedestal based on availabe data such as pressure, water level and radiation dose rate measurements
Keywords:debris relocation, pedestal, debris enthalpy
In Fukushima Daiichi NPP Units 1 to 3, it is considered that a part of the core material including fuel relocated to the pedestal region through the reactor pressure vessel. As a result of comprehensive analysis of pressure gauges, water level gauges, environmental radiation dosimeters, live camera images, etc., the main relocation time of core materials to pedestal is judged to have been 0.5 hr or less for Unit 1, about 2 hr for Unit 2 and about 7 hr for Unit 3 respectively. This difference in relocation time is considered to be closely related to the enthalpy and characteritics of relocating core materials thus could provide useful information for estimation of fuel debris characteristics in the pedestal region.