Evaluation of detection capability of eddy current probes with stochastic decision threshold for inspecting pits on austenitic stainless steel welding

2021 ◽  
pp. 1-15
Author(s):  
Jing Wang ◽  
Haicheng Song ◽  
Takuma Tomizawa ◽  
Noritaka Yusa ◽  
Yuanjin Ling
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Defect Detection ◽  
Eddy Current ◽  
Probability Of Detection ◽  
Decision Threshold ◽  
The Novel ◽  
Detection Capability ◽  
Stainless Steel Welding ◽  
Proposed Model

It is still a big challenge to calculate the probability of defect detection for inspecting pits on austenitic stainless steel welding using traditional POD models. Because we determine the decision threshold, the POD curve has a lot of changes as the decision threshold changes, there is no clear reason to insist which threshold is reasonable. This study proposes a new probability of detection (POD) model to quantitatively assess the detection capability of eddy current probes for inspecting pits on austenitic stainless steel welding. The experimental results show that the proposed model is more reasonable than traditional ones. The novel POD model was employed to analyze three eddy current probes, uniform, TR, plus-point probes on austenitic stainless steel welding. The results reveal that the uniform eddy current probe has the best detection capability for inspecting pits on among the three probes.

Probabilistic evaluation of detection capability of eddy current testing to inspect pitting on a stainless steel clad using multiple signal features

2020 ◽  
Vol 64 (1-4) ◽  
pp. 47-55
Author(s):  
Takuma Tomizawa ◽  
Haicheng Song ◽  
Noritaka Yusa
Keyword(s):  
Stainless Steel ◽  
Eddy Current ◽  
Pressure Vessels ◽  
Eddy Current Testing ◽  
Probability Of Detection ◽  
Current Testing ◽  
Multiple Signal ◽  
Signal Features ◽  
Inner Surface ◽  
Drill Holes

This study proposes a probability of detection (POD) model to quantitatively evaluate the capability of eddy current testing to detect flaws on the inner surface of pressure vessels cladded by stainless steel and in the presence of high noise level. Welded plate samples with drill holes were prepared to simulate corrosion that typically appears on the inner surface of large-scale pressure vessels. The signals generated by the drill holes and the noise caused by the weld were examined using eddy current testing. A hit/miss-based POD model with multiple flaw parameters and multiple signal features was proposed to analyze the measured signals. It is shown that the proposed model is able to more reasonably characterize the detectability of eddy current signals compared to conventional models that consider a single signal feature.

Reliability Assessment of PLR Piping Based on Domestic SCC Data

2007 ◽  
Author(s):  
Hideo Machida
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Stress Corrosion ◽  
Stress Corrosion Crack ◽  
Nuclear Power ◽  
Human Error ◽  
Crack Depth ◽  
Reliability Assessment ◽  
Probability Of Detection ◽  
Japanese Study

This paper describes effects of a probability of detection (POD) of a stress corrosion crack on the reliability of the piping in a nuclear power plant (NPP). Various POD curves were proposed using the results of Japanese study on the detection for the stress corrosion crack which is frequently observed in austenitic stainless steel piping of boiling water reactor (BWR). Based on the proposed POD curves, the reliability of a flawed pipe was analyzed using probabilistic fracture mechanics (PFM) code. The results suggest that the detectable crack depth and oversight probability (e.g. human error) is important on the reliability of piping with the stress corrosion crack. The reliability of piping depends on the detectable crack depth rather than the oversight probability when the detectable crack depth is larger than 3mm. Meanwhile, it depends on the oversight probability, when the detectable crack depth is 3mm or less.

Sign in / Sign up

Export Citation Format

Share Document