Nuclear reactor safeguard system utilizing photoelectric devices

Within all nuclear power plants, some form of protection and safeguards system exists. Since this system insures the safe operation status of nuclear power plants under fault conditions, it must be designed to meet the single failure criteria set by Governmental regulation. Accordingly, two trains of identical logic are provided which receive identical signals and control separate actuators. The two logic trains are completely separated, electrically and physically, to assure that in the event of a single failure of either train the other train will provide the necessary actuations. In order to accomplish this end, this invention provides communication between the redundant protection and safeguard logic trains by means of light. Signals may be generated or received by means of phototransistors or photodiodes. A light-transmitting dielectric is positioned between the light-emitting and light-receiving components to provide electrical insulation between the redundant logic trains. Information may be transmitted between the trains in multiplex form. (LL)