Integral effects testing of the beyond design basis accidents in VHTR

Among the Next Generation Nuclear Plant (NGNP) designs, the modular High-Temperature Gas-cooled Reactors (HTGRs) are very attractive, due to their inherent safety features, high power conversion efficiency, and potential of providing high-temperature process heat. The performance of HTGR systems during accident scenarios is a key consideration in the design, safety analysis, and licensing of these reactors since it is during these events that peak core temperatures and vessel wall temperatures can be reached. A key part of the HTGRs deployment in the US is the development of an integral test facility (IET) that enables testing of accident scenarios and supports gas cooled reactors thermal-hydraulic codes verification and validation. This talk will scope the modeling efforts, design, test matrix, and instrumentation of the OSU High Temperature Test Facility (HTTF). Also, the HTTF benchmark on the Lower Plenum Mixing, Pressurized Conduction Cooldown (PCC) and DCC (Depressurized Conduction Cooldown) will be outlined.