A Study on Data Center Network Architecture for NPPs

The APR1400 Instrumentation and Control (I&C) system is designed with the network-based distributed control architecture. Further, it uses the conventional Tree-based network architecture. It connected with switches and cables having 100Mbps bandwidth in part. The NPP's Data communication systems in I&C consist of the following three kinds of data communication networks or links with different protocols; Safety system data network (SDN) for safety systems, Serial data link (SDL) for safety systems and Data communication network and also information (DCN-I) network for non-safety systems. Recently, the new systems, including its equipment and instruments, have been added on NPPs. Thus, we verified the present state in NPP's networks and considered its weakness. Then we found more reliably redundant network architecture and optimized network algorithm for the NPPs. In this paper, we review some network architecture, having stronger redundancy than conventional NPP network architecture. It is concerned with application of Data Center Networks (DCN) architectures for the NPPs. Originally, DCN architectures and algorithms are designed for huge number of hosts over thousands. And some of them, e.g., VL2, need high bandwidth switches for upper hierarchy. Also, DCN architecture uses many switches more than Tree-based topology. It may affect the complexity in Computer Room and I&C Equipment Room. Maybe the application of DCN architecture in NPP is not the best way now. But we have to do our best to reduce the time delay in NPP networks. Replacing the conventional Tree-based network with the Fat-tree architecture will secure the sufficient bandwidth and reduce the network delay.