Papers by Keyword: Through-Wall Crack

Abstract: During the past couple of decades, several limit load solutions have been proposed to resolve steam generator (SG) tube integrity issue. However, for estimation of specific load carrying capacity under different conditions, these solutions have to be modified by using lots of experimental data. The objective of this paper is to introduce a new burst pressure estimation scheme based on fracture mechanics analyses for SG tubes with a crack. In this context, closed-form equations were derived to get relevant parameters from three dimensional elastic-plastic finite element analyses and, then, a series of structural integrity analyses were carried out using the predicted J-integrals from the equations. Finally, in comparison with the experimental data as well as corresponding estimation results from conventional limit load solutions, it was proven that the proposed estimation scheme can be used as an efficient tool for integrity evaluation of cracked SG tubes.

Abstract: Through-wall axial cracks occurred by primary water stress corrosion are one of the serious defects in steam generator (SG) tubes (made of alloy 600) in pressurized water reactors. Therefore, it is necessary to detect and size them by eddy current testing (ECT) conducted during in-service inspection of SG tubes. To address this issue, it has been recently proposed an effective method, namely „M-shape profile“ approach, which relies on the difference in the amplitude between the pancake and plus point coils in a MRPC probe. Even though the M-shape curve approach is straightforward in principle, it requires time-consuming data processing if performed by human operators. In order to get rid of this tedious task, an automated system is developed in the present work. This paper addresses the principle of the M-shape approach together with the automated system and its performances for the detection of natural axial cracks in SG tubes. The results observed in the present work demonstrate the high potential of the developed system as a very promising tool for detecting through-wall cracks in many practical field applications.