3:45 PM - 4:00 PM
[1G10] GOTHIC analysis of pressure behavior after the ADS operation in Fukushima Daiichi Nuclear Power Plant unit 3
Keywords:Fukushima Daiichi NPS Unit 3, Reactor Pressure Vessel, Primary Containment Vessel, Gas Leak, GOTHIC
It is considered that most of the fuel debris relocated to the pedestal during the accident progression phase in the Fukushima Daiichi NPS Unit 3. In order to predict characteristics of debris and the condition of its accumulation, it is important to know the fuel enthalpy at the time of its relocation to the pedestal. This enthalpy is dependent on heat transfer between the core material and the coolant/structure and metal oxidation (hydrogen and heat generation) especially at the slumping. It is intended in this study to deduce the debris cooling and the hydrogen/heat generation history, applying the thermal-hydraulic analysis code GOTHIC, based on consistency between the calculated and measured pressure.
The focused time range of this study is, from ~2:30 of March 13th when the water level in the reactor reached the top of the effective fuel part, to slightly after 9:00 when the RPV pressure decreased due to the operation of the ADS. Although it is understood that there was gas flow from RPV to PCV during this period, such gas flow path(s) is not known. In this study, focusing on the pressure behavior just after the ADS operation, possible flow paths were evaluated.
The focused time range of this study is, from ~2:30 of March 13th when the water level in the reactor reached the top of the effective fuel part, to slightly after 9:00 when the RPV pressure decreased due to the operation of the ADS. Although it is understood that there was gas flow from RPV to PCV during this period, such gas flow path(s) is not known. In this study, focusing on the pressure behavior just after the ADS operation, possible flow paths were evaluated.