دانلود کتاب روش‌هایی برای یافتن نشتی آستر استخر در نیروگاه‌های هسته‌ای

This report addresses the challenge of localizing leakage-relevant defects in thin austenitic stainless-steel pool liners at nuclear power plants, with particular emphasis on inspections performed under water and under access-limited conditions. The work combines a state-of-the-art review of non-destructive testing (NDT) techniques and robotic deployment concepts with targeted experimental investigations, aiming to assess both technical capability and practical applicability. The literature review evaluates mechanical wave-based, electromagnetic, and visual inspection methods with respect to defect sensitivity, robustness in submerged environments, compatibility with robotic platforms, and suitability for detecting surface-breaking defects relevant to leakage. Electromagnetic techniques, in particular Alternating Current Field Measurement (ACFM), are identified as well aligned with the characteristics of leakage-relevant cracks due to their high surface sensitivity, tolerance to lift-off and coatings, and demonstrated performance in underwater and nuclear environments. Phased Array Ultrasonic Testing (PAUT) offers complementary capabilities where quantitative imaging, weld interrogation, or more detailed defect characterization is required. Visual inspection and photogrammetry provide efficient screening and documentation but lack depth information, while Acoustic Emission and conventional eddy current techniques are assessed as less suitable for direct leakage localization in this application. To support and contextualize the review, controlled experiments were performed on a 3 mm EN 1.4307 (304L) stainless-steel plate in both free and concrete-bonded configurations, focusing on shear-horizontal (SH) guided waves generated using electromagnetic acoustic transducers (EMATs). The experiments demonstrate that SH0 waves at 600 kHz enable stable, couplant-free transmission measurements and can detect narrow, elongated artificial defects under controlled conditions. The results clarify how defect orientation, polarization, mode content, and boundary conditions influence detectability, while also highlighting practical limitations in achievable resolution for very small defects. The experiments are intended to elucidate detection mechanisms and scanning behaviour rather than to establish absolute detection limits for the smallest possible leaks. Based on the combined findings, the report concludes that effective leakage localization in nuclear pool liners requires a pragmatic, deployment-oriented approach. ACFM is recommended as the primary near-term technique for underwater localization of surface-breaking cracks in thin liners, with PAUT applied selectively where additional characterization is needed. Visual inspection and photogrammetry should be used to guide and contextualize targeted NDT, while other techniques may contribute in complementary or supporting roles. Together, the results provide a clear basis for prioritizing inspection methods and for planning future development toward more reliable and efficient leakage localization with reduced operational impact.