Evaluation of Dynamic Pressures from Steam Explosions Applied to Advanced Light Water Reactors

The occurrence of a steam explosion for advanced light water reactors (LWRs), whether within or below the reactor pressure vessel in the cavity, is analyzed to determine the possible hazard to structures as a result of dynamic explosion pressures. In current LWRs, in-vessel steam explosions have been determined not to pose a risk-significant threat, while ex-vessel explosions are considered in safety analyses. In advanced LWRs, such analyses are important to demonstrate that such structures will maintain their integrity so that core debris coolability is possible. This paper presents an approach to calculate the dynamic pressures from a steam explosion using the TEXAS-V model and evaluate its effects on surrounding structures using ANSYS. Scenarios for advanced LWRs are reviewed, and a severe accident scenario is used as an example to present our methodology. Such evaluation methods should be considered in future safety studies and be verified with direct comparison to data for energetic fuel-coolant interaction, such as those provided from past KROTOS tests or with current experiments in the international SERENA project.