Dual optical communication network for class 1E reactor protection systems

Reactor protection systems require periodic testing. Testing of reactor protection systems requires the exchange of status information between independent channels of plant protection systems ("PPS's") and trains of engineered safety features ("ESF's"). Digital implementation of these systems introduces the inherent problem of maintaining channel/train independence while sustaining communications integrity and function. Typical fiber optic communication networks provide the required electrical isolation and independence between channels and trains. However, they do not address the failure modes associated with them. A communication network for nuclear plant protection systems includes monitoring and control channels, including a first pair of channels having first and second channels, the first pair of channels communicating through fiber optic data paths with a second pair of channels having third and fourth channels; a plurality of engineered safety feature trains, including first and second trains, the first train communicating directly with the first pair of channels and the second train, the second train communicating directly with the second pair of channels and the first train; a first vital power bus powering the first channel; a second vital power bus powering the second channel, and redundantly powering the first train and first vital power bus; a third vital power bus powering the third channel; and a fourth vital power bus powering the fourth channel, and redundantly powering the second train together with the third vital power bus.