Safety performance of the 4S reactor on the ATWS events - statistical estimation of uncertainty

Result about ULOF is as follows. The coolant temperature in the nominal hottest assembly outlet, “Tc” is selected as metric, and the upper side value of 95% confidential section in Tc is below 900 °C that is acceptance criteria. Also in UTOP, it is shown that the fuel maximum temperature in the nominal hottest assembly, “Tf” satisfies acceptance criteria. This result shows that 4S reactor has margin for safety acceptance criteria.