Experimental Investigation and CFD Analysis of Steam Ingress Accidents in HTGRs

This study focuses on the short-term phenomena due to steam ingress following an SG tube rupture accident in HTGRs, instead of covering a long-term scenario induced by a small amount of steam ingress during plant lifetime. Our ultimate goal is to better understand water/steam ingress accidents in HTGRs, where the Rankine cycle is adopted as the power conversion cycle. General Atomics’ 350 MWth Modular High Temperature Gas-cooled Reactor (MHTGR) was chosen as the prototypic reactor design. The models of steam nuclear graphite oxidation proposed in the literature are surveyed, and will be examined, validated or improved if needed. Furthermore, this study aims to develop and validate a predictive tool for steam ingress accidents. To measure the steam concentration evolution in an integral effect test (IET) facility, a tunable diode laser absorption spectroscopy (TDLAS) measurement system was developed. The TDLAS measuring system is a non-intrusive and non-perturbative diagnostic technique that can be used to measure the steam temperature and concentration at various conditions.