Small-Scale Experiments Conducted to Support Investigation of HypotheticalDesign-Basis LOCA Phenomena in the Advanced Test Reactor

An unheated, integral thermal-hydraulic facility scaled to the Advanced Test Reactor (ATR) at the Idaho National Engineering Laboratory was designed, constructed, and operated to gather simulated large-break loss-of-coolant accident (LOCA) data for use in assessing codes used in ATR analysis. Eighteen experiments were performed in the facility to establish a data base consisting of qualitative and quantitative information for assessment purposes. The effects of initial liquid temperature, break location, and use of safety injection are examined. The results obtained offer significant insights about thermal-hydraulic processes in a complex loop during subatmospheric pressure operating conditions similar to those expected during a hypothetical LOCA in the ATR.