Research On The Transport And Transmission Efficiency Of Nuclear Power Plant Containment Aerosol Particles

The coolant boundary in Nuclear power plant may have breakage or leakage accident during the operation,which may lead to terrible effects on the environment,society and people.It is of great importance to monitor the leak of the coolant and quantify the flow rate as soon as possible to prevent the severe accident.Among the existing monitoring methods,the monitoring of radioactive aerosol particles in the containment is one of the monitoring methods that have received extensive attention at present.In this method,the uniformity of particle distribution determines the representativeness of particle sampling during monitoring.The accuracy of monitoring will be greatly affected if not uniform.Therefore,the distribution of particles in the containment is a key issue to be considered.In this paper,the transport and distribution of aerosol particles in containment are studied by means of theoretical analysis,numerical simulation and experimental research.In the study of the influence of the flow field in the containment on particle motion,a new turbulence pulsation generation method is proposed,which can quickly calculate the transport of particles in the flow field by applying the known flow field statistics data,and it does not need to calculate the flow field at the same time.The method greatly saves calculation time.The main contents and conclusions of this study are as follows:The turbulent flow field has a great influence on the distribution of particles in the near wall area.Turbophoresis causes particles to gather in the central area and near the wall of the flow field,and the effect increases gradually with the increase of Reynolds number.Through model experiment,the COV of particle concentration in the containment model is 68.14%,the reconstructed experimental COV is 130.7%after the reconstruction of the particle images.The relative error between the reconstructed COV and the COV simulated at the same position was less than 25%.The simulation calculate three different particle sizes of 0.5?m,1?m and 3?m,which transmission efficiency in the containment is 0.167%,0.116%and 0.0685%.The transmission efficiency of 3?m particles is 58.98% lower than 1?m particles.It is concluded that small particle size particles are easier to be sampled by monitoring system.The research can provide a theoretical basis for improving the containment aerosol monitoring system in nuclear power plants.