The Electric Power Research Institute (EPRI) published a 2016 report on the use of laser peening to mitigate stress corrosion cracking (SCC) in nuclear reactors. Laser peening has been applied to critical welds in Japanese nuclear pressure vessels to mitigate SCC since the 1990s.
From the abstract: “During the past two decades, stress corrosion cracking (SCC) has become the most relevant phenomenon affecting nuclear plant availability and plant lifetime management. SCC can lead to increased costs for operation, maintenance, assessment, repair, and replacement of boiling water reactor (BWR) and pressurized water reactor (PWR) components.”
“The experimental results demonstrate that surface stress improvement (SSI) treatments are effective measures in preventing future initiation of primary water stress corrosion cracking. When properly applied, SSI treatments – converting residual stress status from tension to compressive to a certain depth – successfully eliminate the potential for future SCC initiation at surfaces exposed to reactor coolant.”
The report highlights the role of compressive residual stresses in preventing crack initiation at failure-prone points. This is a valuable application for the nuclear power industry given the high costs associated with plant maintenance and the serious consequences of containment failure.
More from the report:
“Laser peening has emerged as a leading technology that extends the fatigue life and improves fatigue strength of a wide variety of metal alloys in a broad range of applications and industries. The technology is currently being utilized extensively by the commercial aerospace industry to prevent the fretting fatigue of highly stressed rotating turbine engine components and more recently by the U.S. military for extending the lifetime of important assets.”
Laser peening is a proven method for mitigating stress corrosion cracking effects, along with other common types of metal failure, making it a popular surface enhancement method within the power generation industry. In addition to its application in nuclear power plants, laser peening is routinely applied to gas-fired turbine engine components to enhance their reliability, fatigue resistance, and damage tolerance.
Click here to access the full EPRI report.
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