Turbine protection system evaluation: Final report

Databases from operating nuclear power plants indicate that malfunction of the turbine protection system (TPS) initiates a significant number of spurious plant transients. Most such transients result in reactor shutdowns, thereby reducing plant availability and adversely affecting the thermal cycle life of plant pressure boundary components. Improved nuclear power plant availability can result from reducing false-alarm emergency plant shutdowns initiated by faulty turbine protection systems. Analyses suggest that potentially corrective retrofit actions can provide significant cost-benefits while helping utilities achieve scram reduction goals. This report determines the magnitude and cost impact of lost plant availability due to TPS malfunctions, identifies the root causes of the equipment malfunctions, and determines appropriate corrective actions and develops methods of evaluating their cost-effectiveness and assessing the potential effects on plant licensing