Creep-FatiguePro for Windows

Automated Life Consumption Monitoring System for Fossil Plant Equipment

Creep-FatiguePro is an automated life consumption monitoring system for fossil plant equipment developed by EPRI and Structural Integrity Associates (SI).

The accumulation of creep and fatigue damage over time are two principal degradation mechanisms which eventually lead to crack initiation in critical high temperature fossil power plant boiler and turbine components. In extreme cases, the growth of these cracks can lead to leakage and rupture. The monitoring and prediction of the rate of accumulation of creep-fatigue damage is, therefore, essential in developing an effective life assessment strategy to prevent catastrophic failures and to manage the remaining life of these components. Because the rate of accumulation of creep-fatigue damage is directly dependent on actual plant operating conditions, the ability to access plant operating data directly from the main plant computer system and process this data in real time is critical in the design of an advanced life consumption monitoring system.



SI has recently completed a major upgrade of the Creep-FatiguePro software from DOS to Windows, under sponsorship from EPRI's Boiler Life & Availability Improvement Program. This software system is typically configured to reside on a single dedicated personal computer (PC) located either at the plant or an off-site engineering office. An interface with the existing plant computer/data acquisition system is established to collect temperature, pressure, flow rate and other instrument data from the components to be monitored. Creep-FatiguePro accesses and processes this plant operating data, and then, in real-time, computes creep-fatigue stresses, damage accumulation and crack growth of known or postulated defects. By projecting the monitored damage and crack growth rates into the future, Creep-FatiguePro determines the expected additional operating time required to reach critical levels of damage accumulation or crack size. This information helps the utility engineer make accurate and timely decisions regarding component inspection need and schedule, run/repair/replace decisions for detected damage, and evaluate the impact of alternative plant operating modes on the life of critical boiler/turbine components. The new software has been successfully implemented and tested at two 250 MW fossil plants saving the owner several million dollars by deferring or eliminating major unscheduled and costly equipment repairs/replacements suggested by the equipment manufacturer.

Plants exhibiting the following characteristics are excellent candidates for Creep-FatiguePro and can expect to derive direct cost benefits through its utilization.

• Plants with components (boiler headers, high-energy piping, turbine shells and turbine rotors) recently inspected and found to contain significant service-induced damage or cracks.

Crack growth monitoring with Creep-FatiguePro can justify continued operation until such time that replacement becomes necessary.

• Plants approaching the age at which service-related damage is expected (around 15 years), but only limited manpower is available at the plant for life assessment and inspection planning activities.

Remote Life Consumption Monitoring (RLCM) of critical plant equipment transfers this task to SI. SI implements Creep-FatiguePro for remote monitoring of the selected plant components and regularly reports to the utility on equipment condition, inspection requirements and plant operations.

• Plants currently operating under, or contemplating a shift to, load-follow or on-off cyclic operation.

Acceleration of component life consumption rates compared to that of base-load operation could be expected. On-line monitoring is the best alternative for tracking remaining useful life and equipment wear and tear, which is one of the most difficult costs of unit cycling to quantify. Application of Creep-FatiguePro to such units allows development of economic models for converting monitoring results to plant cycling costs.

Over 30 power plants are using Creep-FatiguePro or its nuclear counterpart, FatiguePro. Each plant has realized considerable cost reduction through steps such as lengthened inspection intervals, reduction in unnecessary component replacement, changes to operating procedures, and avoidance of in-service component failures. For instance…

"Creep-FatiguePro reduces header, steam pipe, and turbine testing, improves remaining life calculations, and is a valuable tool in planning for component replacement. With it, we intend to manage the remaining life of key components, consciously balancing performance with life expenditure considerations."
Glenn Beckerite, Kansas City Power & Light Co.

In today's competitive marketplace with ever-tightening outage schedules, and shrinking O&M budgets, implementation of a plant-wide creep-fatigue life monitoring system can save utilities significant $$$ in the long run.


Technical Paper Publications:

"Life Assessment of Critical Boiler and Turbine Components Using EPRI's Creep-FatiguePro Software," presented at EPRI International Conference on Advances in Power Plant Life Assessment, March 11-13, 2002, Orlando, Florida.

To implement Creep-FatiguePro at your fossil plant, contact us.