Abstract
Timely preventive maintenance is of great importance for safety equipment on NPP's. But preventive maintenance becomes complicated when we face systems in where these activities can be performed only during outage period and reactor shutdown must be executed in case of safety related equipment failure during operation to perform corrective actions. For preventive maintenance strategy degradation monitoring is not always sufficient and degradation trending (extrapolation) should be performed to provide predictability of the extent of degradation and timely preventive or mitigative actions. Degradation trending in proactive maintenance case plays very important role. Current paper is devoted to the analysis and application of mathematical models to the degradation assessment of systems with dependent components. The main attention in present work was paid to the mathematical description of the degradation mechanism. Developed mathematical model allows assess and perform trending of degradation processes during various time moments. Methods can be applied for assessment of various risk estimates of hazardous systems such as systems at nuclear power plants.
