Study on the Optimization of b-Value for Analyzing Weld Defects in the Primary System.

Area of Science:

• Nuclear Engineering
• Materials Science
• Structural Health Monitoring

Background:

• Primary system piping in nuclear power plants is critical for safety.
• Early detection of crack growth is essential to prevent catastrophic failures.
• Existing monitoring systems may lack the sensitivity for real-time crack evaluation.

Purpose of the Study:

• To develop and validate a crack analysis algorithm for the Acoustic Leak Monitoring System (ALMS).
• To enable real-time detection and quantitative assessment of crack growth in nuclear power plant piping.
• To enhance the safety and structural integrity monitoring of critical infrastructure.

Main Methods:

• Conducted fracture tests on welded specimens simulating nuclear power plant cold leg sections.
• Measured acoustic emission (AE) signals correlated with strain using an AE testing system.
• Analyzed AE signals using Kaiser and Felicity effects, and calculated RMS-based b-value for crack stability assessment.

Main Results:

• AE signals effectively assessed crack stability and instability via Kaiser and Felicity effects.
• The RMS-based b-value demonstrated reduced sensitivity to signal attenuation, enabling stable crack progression assessment.
• RMS parameter, reflecting signal energy, proved effective for real-time crack growth monitoring.

Conclusions:

• The integrated AE analysis method provides a practical approach for real-time crack monitoring in nuclear power plant piping.
• This method enhances structural safety through quantitative crack progression assessment.
• The findings support the advancement of safety monitoring systems in critical industrial applications.