Weld residual stress and distortion affect to fatigue, SCC, static tensile strength, brittle fracture, or other failures in various components. Computational method is useful for evaluating weld residual stress and distortion as well as direct measuring method. Re cently developed methods by the authors for innovative numerical simulation of weld residual stress in various scales and fields are introduced. A lot of applications of the computational approach to weld residual stress evaluation are expected ...
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Innovative Computational Simulation of Weld Residual Stress from Mega- to Micro-Structures

The framework of intelligent support system for the maintenance of nuclear power plant is proposed in this paper with emphasis on the combined use of a portab le device and intelligent information processing. The purpose of this system is the realization of flexible inspection process and effective diagnosis process to be performed on-site with the aid of the mobile agent capable of performing various tasks moving along the network. The results of the scenario-based and f unction-based evaluation based on ...
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Application of Mobile Agent Technology for Maintenance Support of Nuclear Power Plants

Weld pass sequence generally affects residual stress profiles. In this study, the profiles of a multi pass bead on plate specimen were experimentally and analytically examined. Material used in this study was the low alloy steel SQV2A (JIS G 3120). Phase transformation usually occurs around welded area in SQV2A and also affects the profiles. Five pass bead on plate specimen was fabricated. Residual stress profiles of the specimen were measured by using the strain relief method. Longitudinal residual st...
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Residual Stress Analysis of Multi Pass Bead on Plate Specimen of Low Alloy Steel SQV2A by Considering Phase Transformation in Welding Process

It is very important to measure the aged deterioration of the cable used in thos nuclear power plants. We developed the nondestructive measurement technology of ble degradation which used microwave technology. In the present study, microwave requency used for the dielectric absorption measurements is the Q-band (43GHz)....
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Study of aged deterioration measurement technique of cable insulation

Various activities were doing for the decommissioning of Fukushima Daiichi nuclear power station. In present, activities are limited by remote operation or short time manual operation, because these areas are still high radiation rate. In this situation, it is expected to reduce the radiation rate of these areas by the decontamination, shielding and removal radiation souses, et al. At the national project “Development of remote decontamination technology for reactor building”, we selected adoptable de...
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Development of Remote Dry-ice Blast Decontamination Vehicle for the lower part of the Reactor Building such as floor and wall

Fiber Bragg Grating（FBG）is a kind of an optical device developed rapidly in these years and it has several excellent characteristics as a sensor for tempera- ture and/or strain. To investigate the applicability of FBG even as a vibration sensor for nuclear plant monitoring, novel measurement systems were devel- oped and tested. The results revealed that the FBGs had sensitivity to vibration and temperature even in radiation environments. Vibration and/or temperature of components around cooling system...
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Applicability of a sensor based on optical fiber Bragg grating to nuclear plant monitoring

The wavelet transform multi-resolution analysis for articles has revealed the lines of thought. The articles have carried in papers concerning a local referendum about the construction of a nuclear power station in a residential area, a seaside, a farm and a town. Employing this new method has clarified the line of thought in these four areas has been clarified. In the seaside three strong support opinions appeared in the first, middle and last part of the press, with a small number of adverse opinions at ...
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Examinations of Objective Approaches on the Social Consensus Formation Methodology in Public Facility Construction

The equipment diagnosis of Rokkasho reprocessing plant,was started from 2004 completion of the chemica l test.Target apparatus is rotation machine,such as a pump and a blower.The number is about 1700 sets. The pursuer has the qualification of ISO18436-2 and ISO18436-4. Moreover, it is working based on JEAG4221-2007. On the business of our company, the rotation machine is diagnosed using oscillating diagnosis and lubricating oil diagnosis. This report, the diagnosis method of a rotation machine and the Vibr...
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Condition monitoring and diagnostics for rotation equipments in the Rokkasho reprocessing plant. Equipment diagnosis by using the oscillating diagnosis.

Many number of horizontal shaft type ventilation fan system were installed and have been continuously operated in the Rokkasho reprocessing plant. The maintenance method by TBM(Time Based Maintenance) and periodical vibration diagnosis has been applied for the stable operation to keep containment function of the facilities. Although a bearing creep phenomenon of fan and motor is one of the important factors to evaluate the integrity, it has been said that it was not easy to recognize early from the mon...
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Vibration diagnosis for bearing creep phenomenon of horizontal shaft type ventilation fan in Rokkasho reprocessing plant.

In this paper, experimental and numerical studies are carried out to understand the pipe-wall thinning caused by the flow accelerated corrosion behind an orifice in a circular pipe. The measurement of mass transfer coefficient is carrie d out using a wall material of benzoic acid in a water flow, which allows the measurement of mass transfer behind the orifice in a circular pipe at Schmidt number 300 and 700, which is comparatively close to the actual condition in the prototype pipeline of nuclear power pl...
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Study on Mass Transfer Phenomenon behind an Orifice in a Circular Pipe - Effect of Schmidt Number -