1．はじめに国内の沸騰水型原子力発電設備の再循環系配管（以下PLR配管と記す）で使用されている低炭素オーステナイト系ステンレス鋼（以下SUS316L系材と記す）配 管の一部でひび割れが発見され、超音波探傷試験（以下UTと記す）による深さ測定が行われた。この測定に用いられたUT手法は、横波を用いた端部エコー法（以下従来UTと呼ぶ）を適用した。その後の金属調査の結果、ひび割れは応力腐食割れ（Stress CorrosionCracking 以下SCCと記す）であることが判明した。また従来UTで測定したひび割れ......

The distribution of eddy current is disturbed in the presence of cracks. An equivalent solenoid model and a loop current model were proposed respectively to model the bypasses of eddy currents to the underside and longitudinal end of a crack. Eddy current testing signals were qualitatively analyzed by using the equivalent current models. Simulation showed that the signal due to the bypass of eddy current to the under side of a crack was appropriate for the evaluation of crack depth, and the signal due ...
英字タイトル:
Enhancement of Defect Sizing Ability by ECT Data Fusion

To validate the FEM simulation technique presented in the previous report, we made pipe butt welded joints between base metals of the same material SUS316L and between base metals of the dissimilar materials SUS316L and STPT370. Shot peening (SP) on the outer surface or the inner surface of these welded joints induces high compressive residual stresses on the surface. After heat treatment with the peak temperature of 623 K was applied to the welded joints, they retained high compressive residual stresses ...
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Evaluation of the sustainability of compressive residual stress by introduced a stress improvement method (the second report) ?Residual stress change of welded joint with shot peening by thermal cycle and stress loading.

When the steel structure is built such as nuclear power plant, residual stress occurs in or near the welding joint and it may cause the stress collision cracking(SCC). Therefore, as prediction of SCC, surface treatment such as the shot peening(following SP) is carried out in the weld, but the case analyzed about residual stress reforming by the SP does not exist. So, we developed the analysis method that can predict compressive residual stress relaxation behavior during shot peening by modelling dynami...
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Evaluation of the sustainability of compressive residual stress by introduced a stress improvement method (the first report) -Development of analysis method of the shot peening using idealized explicit FEM

The PIRT process was developed as a part of the systematic and documented means of demonstrating the validation of best estimate simulation codes in USNRC licensing of nuclear power plants. In this paper the PIRT process was applied for finding influential factors giving an impact on the accuracy of ultrasonic testing and eddy current testing and related problems required to improve the accuracy and also reports the results that the problems were ranked from the viewpoint of importance, knowledge and c...
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Accuracy of Non-destructive Examination Techniques to Detect Fatigue Crack

In order to keep stable and continuous operation of the power plants or chemical plants, an ice plug technology are often introduced to them specially for the room temperature water pipe, because of this effect to reduce volume of drainage and the isolation range. Water in the pipe are frozen from outside with liquid nitrogen as coolant, and this pipe is closed with this frozen water as called “ice plug effect” which generates the adhesive and the frictional force at the inner surface of the pipe. There...
英字タイトル:
Ice plug application technology for the maintenance of chemical reagent pipe system

Phased array provides many advantages over conventional ultrasonic testing method, but phased array has also limitations. This paper describes typical results of the experimental sound field analysis generated from the array probe. A photo-elastic ultrasonic visualization technique was applied in this study. The so und field of shear wave generated from the array probe was equivalent to that from the fixed angle probe....
英字タイトル:
Evaluation of Phased Array UT Conditions using Ultrasonic Visualization Technique

Ultrasonic testing (UT) is one of the most appropriate non-destructive testing because of capabilities for flaw detection and flaw height sizing of flaw. Interpretation and analysis of UT data are not easy, to identify and classify relevant indications are sometimes very difficult. UT personnel shall be qualified to an appropriate level in accordance with a code and standard. In addition, personnel should keep and improve their skills. In this paper, an FEM UT simulation was applied to make UT training data...
英字タイトル:
Prototype of UT Training Simulator using Large Scale FEM Simulation

As one of plans to improve a skill of UT inspector, a methodo utilize ultrasonic waves predicted by UT simulation is su ggested. Therefore, modeling methods of metal microstructurebased on solidification simulation and the actual flaw dete ction conditions were developed, and UT simulation is carried out using the models. The validity in the simulation model is verified compared with experimental results. A method to apply simulation results to UT skill training is suggested....
英字タイトル:
Application of FEM simulation for UT skill training

In ultrasonic testing for austenitic welds, it is generally said that the flaw detection in the weld is difficult because of spurious echoes by dispersion of the ultrasonic wave. Therefore, the ultrasonic examination personnel are required to have high level abilities to classify these echoes. It is important to train to maintain and improve the abilities. For the effective training, many samples are need with a variety of flaw characteristics and size. However, it is difficult to prepare such samples...
英字タイトル:
Defect Model in TU simulation for UT training tool