Plant Protection System, Variable Set Point Card Test and Repair Project

In late May 2024, Nuclear Electronic Solutions (NES) was engaged by a nuclear power plant for the urgent repair of a suspected failed Variable Set Point (VSP) Circuit Card Assembly (CCA) within the facility’s Plant Protection System (PPS). The VSP cards were obsolete, with no available replacements or operable spares. Given the critical nature and urgency of the repair, NES promptly mobilized its engineering team to address the issue.

The VSP card is a complex electronic component that receives numerous analog input signals, processes them, and outputs various analog signals to other parts of the PPS. Testing the VSP card required generating input signals and measuring output signals to isolate the failure. Initially, NES analyzed the VSP card’s functions within the PPS and then focused on the card itself, including modeling several circuit functions. Following this analysis, measurements of critical components were performed in both unpowered and powered states. When no anomalies were detected, NES decided to develop a test station to vary input signals to the card while monitoring the output signals.

NES engineers collaborated closely with the power plant engineers and technicians to design and build a high-fidelity, functional Test Station for the VSP card. Within 10 days, NES completed the design, construction, and validation of the Test Station, incorporating design improvements and developing a comprehensive test procedure.

Testing revealed that an operational amplifier within the VSP card circuitry was intermittently malfunctioning. The amplifier was removed and replaced, and subsequent testing confirmed that the VSP card was functioning correctly. Upon reinstallation of the fully operational VSP card, plant technicians also identified and rectified an additional issue with another circuit card assembly in the PPS.

This VSP card repair effort exemplifies the engineering expertise, rapid design and development capabilities, and collaborative customer engagement at Nuclear Electronic Solutions.