Abstract: The use of portable and high-energy x-ray system can provide a very promising approach for the inspection of aged concrete structures. However, due to the effect of large scattering of low-energy x-ray in a thick concrete, the noise properties and contrast of the radiographic images need to be optimized to ensure reliable interpretation. Therefore, in order to improve the inspection ability, an image denoising method with the combination of wavelet and curvelet transform and image contrast e...
英字タイトル:
Image Enhancement for Concrete Bridge Inspection with Portable 950 keV/ 3.95 MeV X-ray Source

The purpose of this study is to investigate environmental effects on low cycle fatigue crack growth of SUS316. Low cycle fatigue test and periodical observation on inner surface of a hollow specimen was conducted by developing new type of replica observation. The crack growth in PWR environment was measured and the investigation of environmental effects on crack initiation and propagation was conducted. Crack initiation rate of fatigue test in PWR environment is faster than in air condition. Crack pr...
英字タイトル:
Environmental Effect on Low Cycle Fatigue Crack Growth of SUS316

The purpose of this study is to investigate environmental effects on low cycle fatigue crack growth of SUS316. Low cycle fatigue test and periodical observation on inner surface of a hollow specimen was conducted by developing new type of replica observation. The crack growth in PWR environment was measured and the investigation of environmental effects on crack growth was conducted. Crack initiation rate of fatigue test in PWR environment is faster than in air condition. Crack initiation is estimated ...
英字タイトル:
Environmental Effect on Low Cycle Fatigue Crack Growth of SUS316

Abstract: Since more and more bridges built several decades ago in Japan have become aged and dangerous, the non-destructive evaluation of those bridges is really an urgent problem. CT system with portable 3.95MeV linacs for bridge inspection is considered to work on-site, considering the law of Japanese radiation protection allows using linacs up to 4MeV outside radiation controlled area. The system would confirm the internal steel si tuation of bridges and analyze structural strain and stress with 3D mod...
英字タイトル:
On-Site Bridge Inspection with Partial CT by 3.95Mev X-Band Linac Source

In situ CT application for NDE of degradation bridges is under development, with portable 950keV/3.95 MeV X-band linac as x-ray source. Collimator is adopted to reduce scattered X-ray noise. Material analysis and erosion estimation through dl-energy CT method is integrated in order to inspect the erosion situation of i nner steel rod. Reconstruction technique with incomplete projection data is studd considering limitation of projection angle range during onsite scanning. Furt hermore, based on 3D model bui...
英字タイトル:
Partial Inspection and Dual-energy CT Material Analysis with 950keV/3.95MeV X-Band Linac

Abstract Thermal fatigue crack may initiate at mixing tee where high and low temperature fluids flow in and mix. In order to prevent piping failure caused by thermal fatigue, an evaluation procedure of fluid temperature fluctuation at mixing tee using numerical simulation has been de veloped. This paper compared results of three computational grids of different resolution and discussed the effect of the grids resolution on predictions. The same simulation conditions were set same as WATLON experiments perf...
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Numerical Simulation of Temperature Fluctuation Downstream from a T-Junction-Evaluation of Computational Grid Influence Using LES Dynamic Model

Suffered SCC (stress corrosion cracking) at the primary cooling system in 1980, the “Fugen” power station introduced the three preventive technologies immediately. After the upgrade of the plant, no SCC occurred during the operation period. We have inspected the actual structural materials of the “Fugen” power statio n on its decommissioning stage to evaluate effectiveness of SCC management technologies, which are combin ing material replacement, induction heating stress improvement (IHSI) to reduce the w...
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Evaluation of effectiveness of SCC prevention technologies after long term operation at the “Fugen” Power Station

Wall thinning of the steel piping of the secondary cooling system after long term operation using the serviced materials of “Fugen” Power Station has been investigated as a series of the evaluation of the validity and availability of the utilization of serviced materials on the research projects focused on the aging. Reliability of the wall thinning rate of the steel piping has been examined referring the previous inspection data. Besides, prediction of the wall thinning rate, rationalization of the m...
英字タイトル:
Evaluation of wall thinning of the steel piping after long term operation at “Fugen” Power Station

In this study, the corrosion rate on the pipe wall downstream from an orifice was measured in order to validate the evaluation code for flow-accelerated corrosion (FAC). Three orifices with aperture ratios . = 0.62, 0.50, 0.41 was used in a test section with 50mm inner pipe diameter. The flow velocity was changed during the test to investigate the effect of mean cross-sectional flow velocity on the FAC rate. The water conditions were 150 degree centigrade, about 0.1ppb of dissolved oxygen concentration...
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FAC Rate Measurement downstream from an Orifice

Thermal embrittlement of cast austenitic stainless steel components from the decommissioned advanced thermal prototype reactor Fugen has been characterized. Cast stainless steel materials were obtained from recirculation pump casing. The actual time at temperature for the materials was 138,000 h at 275 oC. The “Fugen” material show modest decrease in Charpy-impact properties and a small increase in micro-Vickers hardness in ferrite phase because of thermal aging at relatively low service temperatures. ...
英字タイトル:
Research of Estimation Method of Thermal Aging Embrittlement on Cast Austenitic Stainless Steel