Code scaling applicability to a cold leg SBLOCA scenario in a nuclear power plant

The knowledge of thermalhydraulic phenomena occurring in Nuclear Power Plants (NPPs) during an accident is crucial in the assessment of nuclear safety. Several experimental facilities have been built to reproduce some accidental scenarios obtaining measured data to be compared with simulation results and to test the capability of the thermalhydraulic codes. This paper presents the scaling method used to obtain a NPP scaled-up TRACE5 input from a Large Scale Test Facility (LSTF) model to reproduce a cold leg Small Break Loss-of-Coolant Accident (SBLOCA) transient. The scaled-up TRACE5 model has been developed conserving the power-to-volume scaling ratios of LSTF components, initial and boundary conditions. A comparison of the simulation results between LSTF and NPP scaled-up TRACE5 models is provided throughout different graphs, which represent the main thermalhydraulic variables. Results show that the main physical phenomena produced during a cold leg SBLOCA are qualitatively reproduced with the NPP scaled TRACE5 model. (author)