- Fitness-for-service analysis of service water piping
- Material selection and replacement of service water piping
- Component and system reliability analysis
Intake Cooling Water System Assessment
Multi-faceted project to assess the integrity of intake cooling water systems in this facility. The project verified the need to replace existing piping through site surveys, failure analysis reviews, discussions with operations personnel, and review of piping performance at other sites. Materials performance of the top two suggested replacement options were surveyed. Recommendations were made to clarify and increase confidence in the decision making process to select between these two options. Data were developed on failures and nonroutine maintenance of mechanical components to help identify clear differences between the two options when estimating life cycle costs.
Evaluation of Fiberglass Reinforced Plastic Pipe
The buried portions of circulating water system and service water system at this client's power plant are fabricated from fiber reinforced plastic (FRP) pipe. Within the last two years, each system has suffered a failure that resulted in flooding and a forced shutdown of the plant. APTECH performed a third-party review of the past efforts taken. APTECH reviewed fabrication and installation specifications, operating history failure analysis, and the past program for evaluating the integrity of the circulating water and service water system. We performed industry surveys of FRP installations. This survey established relationships between loading conditions, stress, strength, environmental factors, and degradation. Material testing was performed to characterize the variability within the system and to determine the amount of degradation that had been experienced in the material properties.
Review of Existing Program for Evaluating the Integrity of Fiberglass Reinforced Plastic Piping in the Circulating Water and Service Water Systems
The program for insuring the structural integrity of two specific FRP pipe systems was evaluated by APTECH. The project included reviewing fabrication and installation specifications, operating history, failure analysis, and past efforts to evaluate the integrity of the systems. Recommendations were made for activities during and subsequent to the next refueling outage. Because of uncertainty in several areas of data, APTECH proposed a combined analysis methodology where a statistical trending analysis is merged with an engineering model to develop a probabilistic estimate of the time to failure in each system. Additionally, steps to increase both the confidence in the reliability estimates and the actual reliability of the systems were proposed.
Review of Structural Integrity Presentation for Large Bore ECW Piping Components
APTECH reviewed the report which provided technical justification for continued use of cast Al-Bronze large bore components. Previous dealloying performance assumptions were compared to current operating history and confirmed. Structural integrity evaluations done by another engineering firm were reviewed to assure that they addressed the large bore systems. Applicability of the evaluations to thick wall components was also analyzed. The previous structural integrity evaluation was determined to be still applicable to the components identified.
Aptech Engineering Services, Inc.
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