Tonopah, AZ

Palo Verde Nuclear Generating Station Pipelines


Constructed in the early 1980s by the Arizona Public Service Company, the water reclamation supply system at Palo Verde Nuclear Generating Plant consists of thirty-six miles of prestressed concrete cylinder pipe (PCCP), with diameters ranging from 66 in. to 114 in. The circulating water system used in the three nuclear reactor units for secondary cooling includes PCCP with diameters ranging from 96 in. to 144 in. After failure of one pipe segment in 1996 and two segments in 1997, SGH conducted a condition assessment of the pipelines and designed repairs for distressed pipe.

During our investigation, we identified numerous pipe sections with distress in the form of corrosion and broken wires. We helped the plant by developing a failure risk management and maintenance planning program. Highlights of our work include the following:

  • Developed a pipeline condition assessment program consisting of internal and external inspection and nondestructive testing
  • Completed a electromagnetic inspection to identify broken wires
  • Characterized pipe condition near broken wires
  • Analyzed failure risk for pipes with broken wires and prioritized their repairs
  • Designed repairs, including installing carbon fiber-reinforced polymer liners, post-tensioning with tendons, and applying fiber-reinforced shotcrete
  • Oversaw repairs for forty pipe segments in five days (around the clock)
  • Designed and supervised construction of steel pipe and fittings at interconnections of the circulating water system near cooling towers and related shoring
  • Worked with the client to develop maintenance planning consisting of periodic inspections and repair at planned outages
  • Developed an data management tool summarizing all pipeline assets, inspections, repairs, and failure risk assessments

Project Summary

Failure Investigation | Repair & Rehabilitation
Structures | Advanced Analysis | Performance & Code Consulting
Science & Defense
Arizona Public Service Company
Specialized Capabilities
Repair & Strengthening | Nuclear | Buried Infrastructure | Risk & Resilience Assessment

Key team members

Rasko Ojdrovic
Rasko Ojdrovic
Senior Principal
Mehdi Zarghamee
Mehdi Zarghamee
Senior Principal