Summary of Fatigue Monitoring Projects

To date, the FatiguePro system has been implemented at more than 30 nuclear plant sites world-wide, making it the industry's choice in automated fatigue monitoring. It has also been licensed for application to plants in Japan.

FatiguePro, developed by Structural Integrity Associates (SI) and licensed by the Electric Power Research Institute (EPRI), is a software system which performs on-line fatigue monitoring of critical nuclear power plant components. Using existing plant instrumentation, FatiguePro automatically tracks fatigue usage and plant transients per Technical Specification requirements. Results are employed in various software modules to count plant transients, compute fatigue usage, and compute fatigue crack growth. FatiguePro has been installed at over two dozen nuclear power plants worldwide. A summary of selected projects is presented below.

EPRI Demonstration Projects

Two FatiguePro pilot projects were originally conducted at San Onofre Unit 2 (PWR) and Quad Cities Unit 2 (BWR)¹. During these projects, significant experience was gained in understanding the importance of key transients and the key fatigue-sensitive locations in both BWR and PWR plants.

Commercial FatiguePro Projects

These projects were an actual implementation of the FatiguePro system at operating plants, and have provided additional insight into plant operations, the availability of plant data, and the significance of various transients to fatigue usage at critically stressed locations. Through FatiguePro Upgrade Project participation, many of these installations have fulfilled all Technical Specification cycle counting requirements and provided the technical basis for license renewal.

ANO-2 (Entergy Operations) - A FatiguePro system was installed, consisting of automated cycle counting and stress-based fatigue monitoring for charging and feedwater nozzles.

Brunswick Units 1/2 (Carolina Power and Light) - A pilot system was developed for feedwater nozzle and safe-end fatigue monitoring. The system is used to evaluate transients based on manually collected plant data. A separate module was developed to assess a manually input history of cyclic events.

Callaway (Union Electric) - A FatiguePro system was installed in 1995, including automatic cycle counting, cycle-based fatigue monitoring for four components, and stress-based fatigue monitoring for eight locations. This system operates on a PC connected to a LAN, where plant data is continuously sent to the PC and analyzed when desired by the operator.

Calvert Cliffs Units 1/2 (Baltimore Gas and Electric) - A FatiguePro system was installed in 1996, including automatic cycle counting, cycle-based fatigue monitoring for sixteen components, and stress-based fatigue monitoring for seven components. The cycle-based fatigue monitoring portion of the system includes partial cycle counting algorithms based on partial fatigue usage curves produced from an evaluation of the plant stress reports.

Chin-Shan Units 1/2 (Taiwan Power) - A FatiguePro system for the feedwater nozzles and RPV flange, as well as an automatic cycle counting system and a Reactor Pressure Vessel Integrity Monitoring System (RPVIMS) for pressure-temperature curve evaluation, were developed and installed for this plant. The system was installed in the summer of 1992. A partial cycle counting system was installed in mid-1995.

Diablo Canyon Units 1/2 (Pacific Gas & Electric) - A FatiguePro system was installed for seven component locations. The system is configured for continuous on-line monitoring. Surge line temperature gradient stress effects and the effects of thermal striping are included. The system also includes modules for automatically counting major plant cycles and for tracking pressure-temperature curves with the Reactor Pressure Vessel Integrity Monitoring System (RPVIMS) system. This plant served as the PWR pilot plant for the FatiguePro Upgrade Project.

Grand Gulf (Entergy Operations) - A FatiguePro system was installed, including an automatic cycle counting module, cycle-based fatigue monitoring of more than 50 Class 1 piping and RPV locations, and stress-based fatigue monitoring for three locations. This system operates on a PC with a LAN connection. Plant data is continuously sent to the LAN for easy access by the FatiguePro engineer.

Kuo-Sheng Units 1 and 2 (Taiwan Power) - A FatiguePro system was installed for the feedwater nozzles and CRD penetrations. The system also includes an automatic cycle counting system to count major plant cycles for all other high-fatigue-usage locations. A real-time, on-line Reactor Pressure Vessel Integrity Monitoring System (RPVIMS) is also installed to evaluate pressure-temperature curves.

Maanshan Units 1 and 2 (Taiwan Power) - A Reactor Pressure Vessel Integrity Monitoring System (RPVIMS) was implemented in a joint project with EPRI and Taiwan Power Company. This on-line system utilizes plant pressure and temperature data to perform a continuous evaluation of the margin to brittle fracture of the reactor pressure vessel beltline region. The accumulated effect of irradiation damage is also assessed. Also, a FatiguePro system for charging nozzles and surge nozzles and an automatic cycle counting system was installed in 1992.

Millstone Unit 3 (Northeast Utilities) - A FatiguePro system was implemented consisting of fatigue monitoring for the reactor coolant cold leg charging nozzle on this Westinghouse PWR. The system is configured for off-line operation.

Oyster Creek (GPU Nuclear) - A FatiguePro fatigue and crack-growth monitoring system was installed for BWR feedwater and CRD return nozzles. The system was coupled with an on-line data acquisition system for collecting feedwater sparger inlet thermal sleeve seal leakage.

Point Beach Units 1 and 2 (Wisconsin Electric) - A FatiguePro system was installed in 1994 to monitor the on-going fatigue usage at eight locations in each of these two Westinghouse units. An automated cycle counting system was also installed, linked to a cycle-based fatigue computation system for seven locations.

Prairie Island Units 1 and 2 (Northern States Power) - A FatiguePro system was implemented for the charging nozzles. The system is run off-line using a data acquisition system that collects data only when transients are detected.

Riverbend (Entergy Operations) - A FatiguePro system was implemented that includes stress-based fatigue monitoring for two feedwater nozzle locations. Cycle counting and cycle-based fatigue monitoring was installed for the Class 1 piping systems and the remaining critical RPV locations. Specialized data acquisition software was provided for installation on the plant computer for continual data acquisition. Data files are passed automatically to a local network, where they are subsequently processed via the LAN by the PC running FatiguePro.

San Onofre Units 2/3 (Southern California Edison) - A FatiguePro system was implemented that includes stress-based fatigue monitoring of four components.

Sequoyah Units 1 and 2 (Tennessee Valley Authority) - A FatiguePro system was installed that included stress-based monitoring for six components. Surge line temperature gradient stress effects and the effects of thermal striping were also included. A system to automatically count major plant cycles was also incorporated, along with fatigue crack growth monitoring of the feedwater nozzles.

Susquehanna Units 1 and 2 (PP&L Inc.) – A FatigueProsystem was installed, including automatic cycle counting, cycle-based fatigue monitoring of fourteen Class 1 piping locations and nine RPV locations, and stress-based fatigue monitoring for two locations. Plant data is sent to the LAN through a simple user-requested historical retrieve function. This plant served as the BWR pilot plant for the FatiguePro Upgrade Project.

Vermont Yankee (Yankee Atomic Electric) - A desk-top crack growth simulator was installed for the feedwater nozzles. The system was developed based on FatiguePro technology similar to that for the on-line system at Oyster Creek. By simultaneously considering three different inlet nozzle models, parametric studies could be performed to assess various expected transients and determine growth of cracks at the nozzle blend radius and the nozzle bore.

Vogtle Units 1 and 2 (Southern Nuclear Operating Company) - A FatiguePro system was installed for both units. It includes an automatic cycle counting system for all technical specification events, cycle-based fatigue monitoring of 13 locations, and stress-based fatigue monitoring of pressurizer surge and spray nozzles, pressurizer surge line, steam generator feedwater nozzles, normal and alternate CVCS charging nozzles, and pressurizer spray line. This system incorporates the new Windows-based version of FatiguePro operating on a PC connected to a LAN. Plant data is continuously sent to the PC and analyzed when desired by the operator.

Washington Nuclear Project Unit 2 (Washington Public Power Supply System) - A FatiguePro system was installed for the feedwater nozzles.

Waterford 3 (Entergy Operations) - A FatiguePro system was installed in 1996, consisting of automatic cycle counting and cycle-based fatigue monitoring on nine components in this CE plant.

Wolf Creek (Wolf Creek Nuclear Operating Company) - A FatiguePro system was installed in 1995, including an automatic cycle counting system, cycle-based fatigue monitoring for four locations, and stress-based fatigue monitoring for eight locations. This system operates on a PC connected to a LAN. Plant data is continuously sent to the PC and analyzed when desired by the operator.

McGuire 1 and 2 (Duke Energy) - A FatiguePro system was implemented consisting of automatic cycle counting.

ANO-1 (Entergy Operations) - A FatiguePro system was implemented consisting of automatic cycle counting as a part of a B&W Owners' Group (BWOG) effort.

Crystal River 3 (Florida Power Corporation) - A FatiguePro system was implemented consisting of automatic cycle counting as a part of a B&W Owners' Group (BWOG) effort.

Oconee Units 1, 2 and 3 (Duke Energy) - A FatiguePro system was implemented consisting of automatic cycle counting as a part of a B&W Owners' Group (BWOG) effort.

Japan - FatiguePro has been licensed and implemented at several Toshiba BWRs throughout Japan.