Sonic-IR which is based on the thermographic detection of the temperature rise due to fric tional heating at the crack faces under ultrasonic excitation, has an advantage in the det ection of closed cracks. In this study, feasibility of the Sonic-IR technique for the dete ction of stress corrosion cracking is experimentally investigated by using plate specimens....
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Evaluation of Detectability of Stress Corrosion Cracking by Sonic-IR Technique

This paper describes the result of demonstration test using WesDyne International's inspection system in terms of its sizing capability of crack from the inner diameter (ID) of PWR RV head penetrations, detectability of the crack e mbedded under repair welding, which was applied for isolation from the primary water environment, and the propagation of ultrasonic wave from the ID penetration to the inside of J-weld. The result of the laboratory tests have demon strated the sizing capabilities of both ultraso...
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Sizing Capabilities of Crack for the Inspection of PWR RV Head Penetrations

Sonic-IR which is based on the thermographic detection of the temperature rise due to frictional heating at the crack faces unde r ultrasonic excitation, has an advantage in the detection of closed cracks. Additionally, there is possibility to apply this te chnique to the inspection of complex geometry components because it is nearly non-contact technique. In this study, feasibility of the Sonic-IR technique for the detection of weld cracking is experimentally investigated by using small bore piping speci...
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Feasibility Study of the Sonic-IR Technique for the Inspection of Small Bore Piping Weld

Abstract In a small diameter piping, stresses are generated due to internal fluid or pump vibrations especially around the welding parts. Authors have successfully de veloped a pipe strain sensor which is able to measure such stresses. Unlike conventional methods using strain gages and adhesive bond, the sensor can measure the stra in without putting adhesive bond on the piping surface. However, the strain sensor can provide measurements with a level of accuracy equivalent to that of conventiona l method u...
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Development of Piping Strain Sensor for Stress Evaluation

Two magnetic methods are proposed for the evaluation of initial degradations of type 304 stainless steel in stress corrosion cracking (SCC). The first one is the measurement of the distribution of chromium depletion by means of a magnetic force microscope (MEM). MEM observations are performed for some samples sensitized in various conditions, and the obtained results coincide with the expected ones from the chromium behavior. Moreover, the phase distributions in the solution-annealed and sensitized states a...
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Evaluation of Initial Degradation in Stress Corrosion Cracking by Magnetic Methods

Special attentions have been increasingly paid for the diagnosis of social infrastructures after the collapse of ceiling of Sasago tunnel of Chuo Expressway. It is reported that the main cause was due to the age-related degradation of chemical anchors. Chemical anchors are also frequently used in nuclear power stations. Here we have been trying to apply PFM (Probabilistic Fracture Mechanics) to the diagnosis of social infrastructures using Dr. Mainte, an integrated simulator to optimize maintenance activi...
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A Study of Application of PFM (Probabilistic Fracture Mechanics) to the Diagnosis of Social Infrastructures ]

Dr. Mainte, an integrated simulator for maintenance optimization of LWRs (Light Water Reactors) has been developed based on PFM (Probabilistic Fracture Mechanics) analyses in terms of safety, availability and economic efficiency, environmental impact and social acceptance. For the further improvement of maintenance activities, the importance of reducing human errors is often pointed out. Human errors are well recognized to be affected by mental stress conditions. Due to the amendment of Industrial Safe...
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Effects of Human Error and its Reduction Analyzed by Dr. Mainte, Integrated Simulator of Maintenance Optimization of LWRs 2

Dr. Mainte, an integrated simulator for maintenance optimization of LWRs (Light Water Reactors) has been developed based on PFM (Probabilistic Fracture Mechanics) analyses. The concept of the simulator is to provide a decision-making system to optimize maintenance activities for representative components and piping systems in nuclear power plants totally and quantitatively in terms of safety, availability and economic efficiency, environmental impact and social acceptance. For the further improvement ...
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Effects of Human Error and its Reduction Analyzed by Dr. Mainte, Integrated Simulator of Maintenance Optimization of LWRs