Validation of a CFD Code for the Analysis of Hydrogen Behaviors and Thermal Hydraulics in Containments

During the process of core melt-down accident in light water reactors, large quantities of hydrogen generated by drastic water-metal reaction are released to the containment. Subsequently, hydrogen-rich layer may be formed under the dome of the containment, threatening the integrity of nuclear Power Plants (NPPs). In the framework of a China national R&D project, China Nuclear Power Research Institute (CNPRI) has developed a three dimensional CFD Code for the assessment of hydrogen behaviors and relative thermal hydraulics in containment. The code solves the time-dependent Navier-Stokes Equations with multi-gas species. Validation with International Standard Problems (ISP) and other test data based on a Phenomena Identification and Ranking Table (PIRT) has been undergoing together with the development of this code. In this paper, the test cases of HYJET, COPAIN and TOSQAN 101 Test are validated. Stratification, buoyancy induced mixing in gases, convection heat transfer and condensation on surface are evaluated in the former two cases, while gas entrainment and mixing by spray droplets in the later one. Excellent agreements between experimental data and model predictions are obtained. In order to meet the requirements for application of the code in practical NPP design and safety analysis, further validations of other phenomena in PIRT should be performed in the near future.