Tackling Erosion in Nuclear Piping Systems

Various mechanisms degrade power piping in nuclear power plants. The most important mechanism has been flow-accelerated corrosion (FAC). FAC has caused ruptures and leaks and has led to numerous piping replacements. U.S. utilities are using a combination of EPRI software and aggressive inspection programs to deal with FAC. However, current technology does not deal with erosive forms of attack including, cavitation erosion, flashing erosion, droplet impingement, and solid particle erosion. These forms of degradation have caused shutdowns and leaks have become a maintenance issue. To deal with these problems EPRI has begun a series of projects in this area. The first of these was a comprehensive report on erosion in piping systems. This work was followed with a computerized training module designed to educate utility engineers about erosive attack. Further steps are planned to deal with these forms of degradation. The first will be a meeting with knowledgeable EPRI and utility engineers to prioritize the damage mechanisms. From this meeting a research plan will be developed. This paper will present a description of erosive damage mechanisms and describe the planned R&D to deal with these mechanisms.