16.2 - Severe Accident Analysis (RRC-B) - EDF Hinkley Point

SUB-CHAPTER : 16.2PRE-CONSTRUCTION SAFETY REPORTCHAPTER 16: RISK REDUCTION AND SEVEREACCIDENT ANALYSESPAGE : 163 / 295Document ID.No.UKEPR-0002-162 Issue 04The average pressure during quenching is assumed to be 3 bar, which corresponds to asaturation temperature of 134°C and a steam enthalpy of around 2.72 MJ/kg. The averagedecay heat power in the oxide at that time is assumed to be constant at 26 MW.The temperature at which the volumetric solid fraction in the oxide reaches 50% is near 1400°Caccording to the relevant phase diagrams. This determines the minimum possible temperatureof the oxidic melt after bulk cooling and thus the maximum corresponding energy release.Characteristic times for the duration of the individual phases of the quenching process for anexemplary case with a sacrificial concrete layer of 10 cm thickness and flooding rates of 50 kg/sand 100 kg/s (one or two valves open) are given in Sub-section 16.2.2.4 - Table 9.