The Design and Arrangement Principals of the Floating Trash-intercepting Net in Cooling Water- intake Open Channel of Coastal Nuclear Power Plants

The importance of the intake cooling water is considered a non-safety related area, and thus may not get the same focus and attention as is expected for safety related areas and nuclear class equipments. However, the operating situations of cooling water-intake systems have direct impact on the reliability and safety of the coastal nuclear power plants. With the changes of marine ecological environment, the bloomed marine organisms invaded into and blocked the water-intake systems. These events have increased in frequency and happen in every type of nuclear power plant, most of which had a negative impact on power generation, sometimes leading to plant shutdown to fix the problem. The trash-intercepting nets are the first physical defense measures to prevent the cooling water intake system from blocking by marine organisms. Most of recent researches have studied on the passive defense measures, nevertheless, it is significant to consider the hydrodynamic characteristics of intake open channel and surrounding sea areas when designing and setting the trash-intercepting nets. This paper illustrates a research mainly focusing on an active defense methodology to design and arrange the floating trash-intercepting net in the traditional water-intake open curved channel on the basis of the hydrodynamic conditions. Therefore, this research was carried out by using numerical models to simulate the flow pattern in the traditional open channel, a scaled physical experiment in the laboratory to demonstrates the flow conditions on the one hand, and the effects of different types and layouts of the floating nets on the other. The reported research provides an idea to prevent the intake cooling water from blockage actively and scientific support to the design and arrangement of the floating nets as well.