Safety Parameter Display System


The 1979 accident at the Three Mile Island nuclear power plant led to studies performed by the Nuclear Regulatory Commission (NRC) that identified the need for extensive improvements in management response to accidents at nuclear power plants. One improvement included the requirement that all nuclear power plants install a Safety Parameter Display System (SPDS). The SPDS is typically a display subsystem of the Emergency Response Facility Data System (ERFDS). The data acquisition subsystem (DAS) of the ERFDS acquires physical plant parameters used by the SPDS, such as temperature, pressure, level, valve position, radiation level and flow.

Color-coded graphic displays produced by the SPDS provide a concise display of critical plant variables to control room operators and emergency support personnel in the Technical Support Center (TSC) and Emergency Operations Facility (EOF). The primary function of the SPDS is to aid the operator in the rapid detection of abnormal operating conditions. During emergency operation, the SPDS provides the operator with an overview of the plant safety status keyed to Emergency Operating Procedures. The SPDS is a monitoring system only and has no plant control or protection capabilities.

The eDNA SPDS Solution

The eDNA SPDS solution contains two components of eDNA: the eDNA Calculation service and the eDNA View. The Calculation service collects data from the nuclear power plant’s Emergency Response Facility Data System (ERFDS) and performs comparisons and calculations on that data. The comparisons may include the largest measurement from a related set of data or the average of several measurements. The data from the Calculation service is then presented on a graphical display created using eDNA View.

The calculation points may directly pass through the data value from the ERFDS onto a two-dimensional trend. The calculation may also present decision trees with the end points referencing Emergency Operating Procedures.  The versatility of the Calculation service and eDNA View provide effective presentation of data for an SPDS.

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