Developing PCC and DCC integral effects test experiments at the High Temperature Test Facility

Among the Next-Generation Nuclear Plant (NGNP) designs, 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. To perform a thorough study license these types reactors, sufficient information needs be provided about phenomena that occur during accident scenarios. While several experimental research efforts have been dedicated in past investigate scenarios, knowledge gaps still exist characteristic pressurized depressurized conduction cooldown (PCC/DCC) transients as well for normal operation This paper summarizes Oregon State University High Temperature Test Facility (HTTF) test matrix, campaign, selected tests results. is scaled Integral (IET) capable mimicking dimensions operational conditions Modular Gas Cooled Reactor (MHTGR). The goal provide data on DCC, PCC operating scenarios reference design. PCC, mixing, heat up described this were performed at prototypical temperatures, initial pressure (∼200 kPa), thermal input less than 70 kW. Presented show temperature distributions core, upper plenum, cross duct, or lower plenum. Based profiles attempts stratified flow, natural convection up, mixing made. Furthermore, evaluates campaign light Very Gas-cooled Phenomena Identification Ranking Table (PIRT) proposes experiments complement existing PCC/DCC testing database validation thermal-hydraulic codes.