2nd Research Coordination Meeting on Benchmarking of Calculation Methods of Piping Wall Thickness due to Erosion - Corrosion in NPPs
In the early 1980s, several PWR plants experienced steam leakage due to piping erosion/corrosion. A pipe rupture accident at the USA Surry NPP in 1986 prompted utilities to work toward the development of guidelines for management of pipe wall thinning.
Flow-accelerated corrosion (FAC) is wall thinning of steel piping due to turbulent and fast flowing water or wet steam that wears away the steel’s protective film (oxide layer) and leads to continued corrosion of the underlying metal. FAC is a chemical effect that is primarily influenced by pH, hydrodynamics, oxygen, and temperature. Geometric aspects of system design and piping layout play a big role in the occurrence of FAC. Wall thinning in piping and vessels because of FAC has caused sudden ruptures in high and moderate energy systems, resulting in plant transients, damage to safety and non-safety related equipment by leaking steam and water, and personnel injuries and deaths.
Even though industry efforts have been quite effective in reducing the number of piping and equipment failures caused by FAC, piping and components continue to degrade as plants age. Guidelines on where and how to inspect (software predictions), how to perform chemistry improvements to reduce damage rates, and proposals of material upgrades for replaced components are challenged by new economic studies, reduced time outages, and personnel ageing.
The IAEA has sponsored a coordinated research project (CRP # I21022) related to FAC in NPPs. This CRP is designed to compare outputs from various commercial FAC prediction software tools based on actual NPP data provided as inputs. This meeting is to review and discuss latest modelling activities covered by the CRP, and to provide feedback on the draft FAC guidelines document that is currently under development by CRP steering committee members.
This meeting is also a follow on meeting to the First RCM meeting that was held in Vienna, Austria, July 11 to 13, 2012.
FAC Guideline Overview
- Ageing Management Basics
- FAC Mechanisms Basics
- Research and Development
- Modelling Tools
- Operating Experience
- Developing a FAC Programme
- Plant Operation
- Inspection, Monitoring and Assessment
- Maintenance and Repair
Country Presentations (Continued)
Comparison of Results
IAEA Scientific Secretary
John Moore, Nuclear Engineer
Nuclear Power Engineering Section
Division of Nuclear Power, IAEA Department of Nuclear Energy
Please contact NENP Engineering Section - Contact Point if you have any questions.