Study on a novel pre-filtration system for water intake safety in coastal nuclear power plants

In response to the frequent blockage events at the water intakes of coastal nuclear power plants (NPP), a novel pre-filtration system ensuring the security of water intake in NPP based on plate-and-frame rotating screen (PRS) has been carried out. Site characteristics of a NPP has been used as an example to carry out the research of hydraulic characteristics such as flow distribution, head loss of the pre-filtration system based on dynamic changes in resistance coefficients under different clogging rates by means of establishing appropriate flow model and Computational Fluid Dynamics (CFD) simulation. Meanwhile, theoretical calculation and analysis of the cleaning ability of the pre-filtration system for acetes chinensis has been carried out via putting forward a mesh cleaning assumption. It’s shows that both the results of hydraulic calculation and CFD simulation indicate that under the extreme operation condition where the PRS is completely clogged, the head loss of the PRS is lower than the design value of 2 m, indicating the structural safety of the PRS can be guaranteed in any blocking situation. As the diversion effect of bottom channel, when clogging rate of the PRS reaching 40%, resistance coefficient of tall plate-and-frame rotating screens (T-PRS) is 6.15 and cleaning ability of the pre-filtration system for acetes chinensis reaching the maximum value, i.e. 3.96 t/h, which providing important design reference to ensure the security of water intake in NPP.