ABSTRACT:
The occurrence of an energetic fuel-coolant interaction (FCI) below the reactor pressure vessel in the cavity of advanced light water reactors (ALWRs) must be analyzed to determine the possible hazard to structural walls as a result of dynamic liquid phase pressures. Such analyses are important to demonstrate that these cavity walls will maintain their integrity so that ex-vessel core debris coolability is possible. This paper reviews past studies which have examined this or related issues and proposes a methodology to analyze the occurrence of this physical event using the IFCI and TEXAS models for the FCI as well as dynamic shock wave propagation estimates using hand calculations as well as the CTH hydro-model. Scenarios for the ALWRs are reviewed and one severe accident scenario is used as an example to demonstrate the methodology. It is recommended that such methodologies be considered in future safety studies and be verified with direct comparison to energetic FCI data such as that being produced in KROTOS at JRC Ispra