As the neutron radiography method under the high gamma-ray environment, we inspected experimentally imaging methods which take the place of the indirect method of the film transcription. By the method of transcription from radioactivated Dy foil to imaging plate and the method of multiplication photography of the light from the scintillator which adhere to radioactivated Dy foil with a high sensitivity camera, we confirmed that we were able to observe the distribution of the neutron absorber with the c...
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The neutron radiography method under the high gamma-ray environment using the Dy foil

１．まえがき東海第二発電所（1978年11月営業運転開始）は、第21回定期事業者検査中の2005年（平成17年）5月、図１に示すシュラウドサポートシリンダ軸方向溶接継手（以下「V8」という）3箇所に応力腐食割れ（SCC）と推定される割れが確認され、（社）日本機械学会（以下JSME）の維持規格、及び（社）日本原子力技術協会（以下原技協）の炉内構造物点検評価ガイドライン（以下ガイドライン）を適用した評価により一定期間内の構造健全性を示し、割れを補修することなく継続使用し、3年、7年、10年経過後の最初の定......

Phased array ultrasonic testing (PAUT) has performed an important role for plant maintenances. However, many parts of cast austenitic stainless steels are difficult to be inspected by UT owing to their noises from large grains. We have been noticing that depending on the PAUT conditions, (e.g. incident angles and focal depths), the tendency of echoes from defects are different from that of grain noises. Thus we have developed new PAUT system which can analyze the tendency of echoes from comprehensive PA...
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Sizing Accuracy Improvement of Defects in Cast Austenitic Stainless Steel Using Post Processing Phased Array UT

In 2012, there are 50 commercial nuclear power plants in Japan. There are 20 nuclear power plants which are working for 30 ye ars or more. It is very important to measure the aged deterioration of the cable used in those nuclear power plants. Generall y, degradation of a cable was measured by the tensile test. It was difficult to measure an electrical property quickly and n ondestructively. We developed the nondestructive measurement technology of cable degradation which used microwave technology....
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Ageing study of cable insulation by means of microwave absorption method

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

After 2002, Stress Corrosion Cracking (SCC) came to be detected in the low carbon stainless steel PLR Piping of BWR plants. However, it worked on the improvement of ultrasonic examination technology for PLR Piping in Japan BWR Owners Group (JBOG) , because the mistake of the evaluation was caused as a rare case. In this study, it introduces the improvement of ultrasonic testing technology and evaluation....
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Know-How for the Ultrasonic Examination Practice & Evaluation of PLR Piping

加圧水型原子炉(PWR)の応力腐食割れに対して国内外で様々な工法が開発され、実機に適用されている。原子炉容器出入口管台の600合金使用部位の応力腐食割れ対策として、原子炉容器出入口管台 INLAY 工法が開発され、実機への適用実績がある。2018年3月～4月に九州電力掬川内原子力発電所1号機に対し、本工法が適用された。...

Many anchor bolts have been used for fixing many components in nuclear power plant (NPP), securing safety against seismic ev ents. Some methods have been developed to detect crack-like defects in bolts which may occur after seismic events. On the ot her hand, assuming long term use of NPP, a method to detect bolt thinning was thought to be needed. In this study, by using bolt specimens with an artificially grinded portion, a new method to detect thinning and to measure its depth was developed....
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Development of inspection method for thinned bolts by PA-UT

Inspection technique for complex surface profiles has been required in order to ensure the reliable operation and high operating rate of nuclear power plants, because many parts due to inspection have complex geometry. We have developed Pha sed Array (PA) ultrasonic testing with immersion technique which suitable to complex geometry. In this paper, we developed precise inspection technique for curvature surface profile such as a nozzle of pressure vessel. For curved surface pro file, Synthesis Aperture Foc...
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Development of Phased Array Inspection Technique for Nozzle Pipes with Curved Surface

Phased Array Ultrasonic Testing (PAUT) techniques for complex geometries are greatly progressing. We developed an immersion PAUT which is suitable for complex surface profiles such as nozzles and deformed welded areas. Furthermore, we have developed a shape adaptive beam steering technique for 3D complex surface structures with conventional array probe and flexible coupling gel which makes the immersion beam forming technique usable under dry conditions. This system consists of 3 steps. Step1 is surfac...
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Verification and Application of Beam Steering Phased Array UT Technique for Complex Structures