Improving secondary plant performance and reliability using digital control systems at Calvert Cliffs nuclear power plant (CCNPP), units 1 and 2

The original analog Feedwater (FW) Control System and Steam Generator Feedwater Pump Turbine (SGFPT) Speed Control System exhibited instability, reliability, control, and obsolescence problems prior to installing new digital controls for both systems. Like most of the secondary plant systems at CCNPP, these two systems are classified as Non-Safety Related (NSR). The problems exhibited by the old FW system and SGFPT Speed Control System have been eliminated by the new Full Range Digital Feedwater Control System and SGFPT Speed Control System. These new systems have proven their reliability and performance since their installation. BGE realized significant cost savings using in-house resources. The total costs for both system upgrades is approximately 5.5 million dollars. This is significant in that other nuclear utilities are spending approximately 5-8 million dollars per unit. Outage work was decreased by identifying and implementing pre-outage work items. A thorough testing program found all the problems before they could get into the plant. The testing programs provided the project team with a high confidence that the new systems would work. Having operations personnel involved with specifying and testing the systems helped smooth the path for integrating these systems into the plant