On-line confirmation of Zion plant variables

Each electric utility participating in EPRI's SPDS Signal Validation project was requested to submit a list of the variables that were to be used in the design of the Safety Parameter Display System (SPDS). Millstone 2, a Combustion Engineering plant was selected as the host plant, i.e., the plant for which to design and install signal validation software. Zion Station was selected as the reference plant, i.e. the plant to check the Millstone design against to ensure the results were generic to most PWR's. At the onset of this project, Zion already had a functional SPDS, so it was relatively easy to compile and submit a list of variables. This was done by the participants and the variables were presented in tabular form. To everybody's surprise, a comparison between plants showed a wide variance in perception of what was required of the SPDS. Due to this diversity, it was decided to take a fresh look at the Zion SPDS and confirm that the selected variables were indeed adequate