In the present study, a semi-destructive method for estimating the mechanical properties, including plastic strain, of materials was developed using the instrumental indentation technique (IIT). The formula for estimating plastic strain was derived using true stress-true strain curves that were measured by IIT. The developed method requires only one parameter, namely, the work hardening coefficient, for estimating the plastic strain of pre-strained materials. The usefulness of the developed method was ...
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Study on Evaluation Method of Plastic Damage using an Indentation Technique for Degradation Diagnosis of Steel Structures

1.緒言 東日本大震災以降、規制要件の強化や電力市場の自由化等、電力業界を取り巻く環境は大きく変化し、高品質かつ低廉な電力の供給が求められる。電気事業者としては、設備の安全(信頼)性の維持・向上と効率的な業務 運営の両立のため、保全の最適化に取り組んでおり、保全の有効性評価をこれまで以上に機能させていくことが重要となる。 今回、保全の有効性評価をより実効的に行う取組みとして、関西電力グループで実施した保全最適化の活動を紹介する。 2.保全最適化の取組みの概要 関西電力の原子力発電所における保全活動において......
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Approach toward Maintenance Optimization by Kansai Electric Power Co.

１. ストレステスト導入の経緯と実施状況1.1 ストレステスト導入の経緯政府から、平成23年7月11日に、「我が国原子力発電所の安全性の確認について（ストレステストを参考にした安全評価の導入等）」が公表され、それを受け、原子力安全・保安院から7月22日に電力事業者に対し、福島第一原子力発電所事故を踏まえた、安全性に関する総合評価（ストレステスト）を指示された。1.2 ストレステストの内容ストレステストでは、原子力発電所が想定を超える地震や津波等に襲われた場合を想定し、安全上重要な施設や機器等がどの程度......

A new electromagnetic method for the nondestructive evaluation of gears is proposed. A permanent magnet generates a static magnetic field and a coil of several hundred turns wrapped around it is used to pick up eddy currents induced inside rotating gears. This electromagnetic nondestructive evaluation method is applied to the rotating machine with gears. By monitoring the movement of the gear in a rotating machine, the wear of teeth of gear has been evaluated. ...
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Study of Evaluation Method for the Amount of Wear-Out of Gears with Electromagnetic Sensor

In this paper, to study the wear properties of the pipe materials for the nuclear power stations, a high temperature impact fretting testing was carried out. Employing two piezo actuators, impact fretting test rig can generate impact fretting under various impact loads, fretting amplit udes and frequencies. It also enables us to control water temperature, dissolved oxygen and water pressure. AISI type 304 stainless steel, which is used as a pipe material in nuclear power stations, was used as specimens. Al...
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Evaluation of pipe wall thinning phenomenon by the high temperature impactfretting testing

In order to study the wear properties of the pipe materials for the power generating plants, impact fretting wear tests of AISI304 disks against Al2O3 balls and AISI304 balls were carried out in high temperature pure water. SEM, EPMA, 3D-profilometer and nano-indenter were used for observation, analysis and measurement of wear scars. The maximum wear depth of the disk increased with an increase in water temperature and decreased with an increase in impact frequency below 80°C. However, the maximum we...
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Chemical Effect on Impact Fretting Wear of AISI304 Stainless Steel in High Temperature Pure Water

An evaluation method of the occurrence probability of a through-wall crack in a reactor vessel of a fast breeder reactor due to fatigue-creep interaction has been proposed. Input data were p repared for a trial evaluation and the proposed evaluation method was applied. The result was c ompared with the allowable occurrence probability derived from the safety requirements for FBR....
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Development of a Reliability Evaluation Method for Fatigue-Creep Interaction Failure of an FBR Reactor Vessel 髙屋 茂 Shigeru TAKAYA

The experimental fast reactor Joyo is the first sodium cooled fast reactor (SFR) that was constructed in Japan. In 2007, it was confirmed that the top of the irradiation test sub-assembly (S/A) of “MARICO-2” (material testing rig with temperature control) had been broken and bent as an obstacle inside of the Joyo reactor vessel and had damaged the upper core structure (UCS). This incident necessitated the replacement of the UCS and the retrieval of the MARICO-2 sub-assembly for Joyo restoration. This p...