In the loss of coolant accident in a PWR nuclear power plant, the loss of coolant will cause the core to melt, resulting in the release of large amounts of radioactive fission products from the core. Therefore, nuclear power plants must have effective protective measures to prevent the release of radioactive fission products to protect workers, the surrounding population, and the environment from radiological hazards. Most of the current scholars have conducted detailed studies using modular software such as MELCOR, but the three-dimensional distribution of the source material in the breach space cannot be visualized using this method.
In this paper, a typical pressurized water reactor nuclear power plant is taken as the research object. CFD method is used to analyze the condition of coolant loss accident, study the force of radioactive aerosols matter from different heights away from the wall under the accident condition, and consider the influence of ventilation system on the distribution and migration characteristics of the source matter in space.
The results show that the migration behavior of particles is mainly affected by gravity and drag force. For particles with small size, the combined action of gravity and thermophilic force causes them to deposit at the wall surface, while for particles with large size, gravity causes them to deposit at the wall surface. The particle deposition on the wall surface can be effectively reduced by increasing the flow velocity and decreasing the fluid temperature at the breach.