Characterization of leak detection in HLM system using LIFUS5/MOD3 facility

In the framework of EU MAXSIMA project, the safety of the Steam Generator (SG) adopted in the primary loop of the Heavy Liquid Metal Fast Reactors (HLMFR) has been treated by looking at consequences and damage propagation of a SG Tube Rupture event (SGTR) and by characterizing leak rates from typical cracks. Indeed, instrumentation able to promptly detect the presence of a crack in the steam generator tubes may be used to prevent its further propagation which would possibly lead to a full rupture of the tube. Indeed, the application of the leak before break concept is relevant for improving the safety of a reactor system and decreasing the probability of the pipe break event. In this framework, a new experimental campaign (Test Series C) has been carried out in LIFUS5/Mod3 facility, installed at ENEA C.R. Brasimone, in order to characterize and correlate the leak rate through typical cracks occurring in the pressurized tubes with signals detected by proper transducers. Test C1.3_60 was executed injecting water at about 20 bar and 200°C into Lead Bismuth Eutectic alloy (LBE). The injection was performed through a laser micro-holed plate of 60 micrometer in diameter. The analysis of the thermo-hydraulic data permitted to characterize the leakage through typical cracks which can occur in pressurized tubes of steam generator, while the analysis of the data acquired by the microphones and accelerometers highlighted that is possible to correlate the signals to the leakage, and the rate of release.