The four-dimensional (realtime three-dimensional) phased array ultrasonic testing system has been developed. The system enables realtime ultrasonic inspections using three-dimensional (3D) images as opposed to two-dimensional images obtained by the conventional phased array methods. In the system, objects are scanned volumetrica lly with focused beams generated by a matrix array probe and the results are displayed as 3D images in realtime through the conversion from measured data into voxel data using par...
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Four-Dimensional (Realtime Three-Dimensional) Phased Array Ultrasonic Testing

RF tags that are implemented RFID technology as tag has been used in various fields. Tags have been developed, such as resistance to chemic als and high temperature resistant RF tags are also used in specialized fields. The RF tag apply to the existing nuclear field, had been co ncerned about the effects of radiation to the RF tags. Now, since the RF tag with a goal to develop radiation-proof, we have examined, such as applying for maintenance of nuclear facilities under radiation environment. We report t...
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Application to the conservation of RF tags in the radiation environment

Additional RPV surveillance tests are required to extend the operation license of nuclear power plants under the new regulation. Since the number of surveillance test specimens is limited, it is important to establish a reconstitution technique of the surveillance test specimen using the remaining undeformed part of the tested specimen. To evaluate the applicability of electron beam welding, the confirmatory tests such as Charpy impact tests were conducted using unirradiated test specimens reconstituted ...
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Evaluating the Applicability of Electron Beam Welding to Reconstitution Method of RPV Surveillance Test Specimen

During the Fukushima Daiichi Nuclear Power Plant accident, fuels in the each core in units 1, 3 and 2 melted, and the melted core might dropped down into the lower plenum of the RPV. The core debris heated the bottom structure of reactor vessels and dropped down onto the pedestal through the melted pass of the vessel bottom structure. High temperature core debris might attack concrete or PCV bottom. In order to protect core concrete reaction, several types of core catchers were developed, but they are...
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Study on Compact-Type Core Catcher for Current Nuclear Power Plants

Urgent safety measures which secure power supply and cooling function and prevent flood are being implemented promptly in Shimane nuclear power station to prevent damage of nuclear r eactors and the spent fuel based on Fukushima Daiichi nuclear power plant accident from tsunami caused by the 2011 off the Pacific coast of Tohoku Earthquake on March 11, 2011.In or der to improve the safety of the power station furthermore, various safety measures such as enhancement of basic design facilities to prevent seve...
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Application of Filtered Containment Venting System to the Shimane No.2 NPP

Abstract: This paper discusses a development of the quantitative method to evaluate the reliability for the maintenance plan with respect to the risk impact both for Core Damage Frequency and Plant Trip Frequency. The quantitative approach includes the considerations for the effect of the Condition Based Maintenance (CBM) changing in addition to the Time Based Maintenance (TBM), and the reliability for the maintenance plan is evaluated using the actual plant-specific maintenance information collected ...
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A Study on the Reliability Evaluation Method for Maintenance Planning Using Risk Information

This paper discusses an improvement of the quantitative method to evaluate the reliability for the maintenance plan with respect to the risk impact both for CDF (Core Damage Frequency) and Plant Trip Frequency. The quantitative approach includes the considerations for the effect of the Condition Based Maintenance (CBM) changing in addition to the Time Based Maintenance (TBM), and the reliability for the maintenance plan is evaluated using component failure rate which is presumed from experimental maintena...
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A Study for the Reliability Evaluation Method for the Maintenance Plan Using the Risk Information II : - Part1 : The evaluation Method of failure rate based on degraded state analysis of component part ?

This paper discusses an improvement of the quantitative method to evaluate the reliability for the naintenance plan with respect to the risk impact both for CDF (Core Damage Frequency) and Plant T rip requency. The quantitative approach includes the considerations for the effect of the Condition Based Taintenance (CBM) changing in addition to the Time Based Maintenance (TBM), and the reliab ility for the naintenance plan is evaluated using component failure rate which is presumed from experimental naintena...
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A Study for the Reliability Evaluation Method for the Maintenance Plan Using the Risk Information II? Part 2: An application example of the evaluation method of failure ratebased on degraded state analysis of component part ?

The seismic tests were carried out to confirm the operability limit acceleration for the standard motor-operated butterfly valve actuator at three-direction each excitation. Based on the results, the design of seismic brackets that can operate valves even in 3 directions 20×9.8 m/s2 or more were performed on three representative models. In the model subjected to the seismic test, we mounted a designed seismic bracket and confirmed the operability of butterfly valve actuator by carrying out each vibrati...
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Seismic test results of motor-operated butterfly valve actuators for nuclear power plants

The research and education program “Advanced Research and Education Program for Nuclear Decommissioning (ARED)” is proceeded in Tokyo Tech with views to sustainable development of human resources having advanced knowledge and experiences concerning decommissioning engineering, and development of advanced technologies to resolve a number of complicated challenges. This paper reports about the present status of the development of human resources. ...
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Human resource development for the research and education program in Tokyo Tech