Abstract: Condenser is a cooling device in the thermal cycle of a nuclear power plant. The exhausting steam undergoes heat exchange with the cooling water in the condenser to form condensed water for another thermal cycle. Due to the seawater used as cooling water, the leakage of condenser will lead to pollution of steam generator in the secondary circuit, which will affect the safety of the nuclear power plant. In this paper, the flow characteristics of the liquid phase leakage process of the condenser were studied numerically and experimentally. The leakage jet flow field under different flow conditions was analyzed by Euler-Euler two-phase flow model and k-ε turbulence model. The leakage process was measured and analyzed by particle image velocimetry and compared with numerical simulation results. The results show that the leakage amount is related to pressure difference between the gas space and coolant rather than the liquid phase flow condition in the pipeline during the two-phase leakage. The detection time of the leak can be set within 0.003s, and the existence of two backflow vortexes near the leakage jet will lead to the return of the tracer gas, which may have an impact on the mass transfer and convective diffusion of the tracer gas. For the current case, the mass flow rate of the coolant leakage is about 3.925×10^-3-9.813 ×10^-3kg/s.

Key words: nuclear power plant, condenser, vacuum jet, leak detection, PIV experimental validation