規制動向1．はじめに平成15年10月に施行された改正電気事業法により事業者に新たに実施することが義務付けられた定期事業者検査において、欠陥が検出された場合に、その設備の健全性を評価しなければならないこととなった。これは、健全性が確認できれば補修や取替を行わずに運転継続が可能となることであり、発電プラントの合理的な運転に大きく寄与するものである。健全性評価は、「日本機械学会　発電用原子力設備規格　維持規格（2002年改訂版）JSME S NA1-2002 」（以下「維持規格」という）に従って行うこととなって......

BWR owners and plant fabricators have been making efforts to decrease the ISI parts where UT is difficult to be conducted. For that purpose, UT verification test for both detection and sizing qualification through deposit of pipe weld joint started in 2009 and will last until 2011. In 2009, UT verification test for stainless steel pipe weld joint has been performed. Test samples are stainless steel pipes with welds and sizes are 600A.350A.150A with EDM notches and/or SCC cracks. Angle beam methods and...
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Result of UT verification test for Stainless Steel through weld deposit

BWR owners and plant fabricators have been making efforts to decrease the ISI parts where UT is difficult to be cond ucted. For that purpose, UT verification test for both detection and sizing qualification through deposit of pipe wel d joint started in 2009 and will last until 2011. In 2009, UT verification test for stainless steel pipe weld joint has been performed. Test samples are stainless steel pipes with welds and sizes are 600A.350A.150A with EDM notches a nd/or SCCs. Angle beam methods and phased...
英字タイトル:
Result of UT verification test for Stainless Steel through weld deposit

When their Cr contents were increased to the same level as those of the alloy 82(18-22mass%Cr), the weld metals of alloy 182(13-17mass%Cr) sustained only slight SCCs in the as-welded state, and no crack was detected after the post weld h eat treatment (SR+LTA) of stress relief annealing at 893 K followed by aging at 673 K. These results suggest that the higher Cr content of the alloy 82 is responsible for its higher resistance to SCC than that of the alloy 182. The carbi de, Nijo(Mn, Cr).Siz (G phase) was ...
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Effect of Chromium Content on Stress Corrosion Cracking of Shielded Metal Arc Weld Metalfor 600 Type Alloy in High Temperature Pressurized Pure Water

The SCC susceptibility of the weld metal was evaluated from the maximum depth and number of cracks occurring during the CBB (Creviced Bent Beam) test in high temperature pressurized water using plate specimens cut from shielded metal arc weld metals. When the specimen received a heat treatment consisting of stress relief annealing (SR) for 72 ks at 893 K and subsequent ageing (LTA) for 720 ks at 673 K, however, the significant influences of the increases in C and Nb contents on the SCC susceptibility were...
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Effects of C and Nb Contents on Stress Corrosion Cracking of Shielded Metal Arc Weld Metalfor 600 Type Alloy in High Temperature Pressurized Pure Water

We have developed a new index, called the resilience index, that evaluates the dynamic stability of the system safety of a nuclear power plant during a severe accident by considering the ability to recover system safety functions that have become lost in the situation. In this paper, a detailed evaluation procedure for the resilience index is described. The system safety of a PWR plant during a severe accident is then assessed according to the resilience index in order to discuss the applicability of ...
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Development of Resilience Evaluation Method for Nuclear Power Plants (Part 3: Study on Evaluation Method and Applicability of Resilience Index)

Stress improvement processes are countermeasures against stress corrosion cracking in nuclear power plant components. It is necessary to confirm whether compressive residual stress induced by stress improvement processes can be sustained under operation environment. In order to evaluate stability of the compressive residual stress in 60-year operating conditions, the 0.07% cyclic strains of 200 times at 593 K were applied to the welded specimens, then a thermal aging treatment for 1.66×106 s at 673 K...
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Sustainability of compressive residual stress by stress improvement processes

We aimed to demonstrate the applicability of X-ray computer tomography (CT) with refractive contrast to the 3-dimensional (3D) imaging of minute cracks produced in weld metals of Ni-base alloy and austenitic stainless steel (SUS316L) caused by Stress Corrosion Cracking (SCC). The CT imaging experiments were performed at beam BL19B2 of SPring-8. The X-ray energy was adjusted to 37KeV using a Si double ? crystal monochromator. In summary, clear images of fine cracks in austenitic stainless steel due to ...
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Detection of Cracks due to Stress Corrosion Cracking in Weld Metals of Nickel-base Alloys and Austenitic Stainless Steels by Synchrotron Radiation CT Imaging(

1．はじめにオーステナイト系ステンレス鋼配管突合せ溶接部のき裂深さサイジング技量に関して、（社）日本非破壊検査協会規格NDIS0603「超音波探傷試験システムの性 能実証における技術者の資格及び認証」附属書（規定）「軽水型原子力発電所用機器に対するPD資格試験」［1］（以下、NDIS0603と記す）が制定され、国内でもき裂深さサイジングの技量の指標（測定誤差の判定基準）が示された。一方で、発電用原子力設備の低炭素ステンレス鋼管における健全性評価においては、現時点ではUTで測定したき裂深さに4.4mmを加算......

This paper describes two contents about reliability of crack depth sizing on ultrasonic testing. One is verification with appropriate acceptance cr iteria of the Japanese Performance Demonstration Code (NDIS 0603 Appendix) . Another is investigation about the true crack depth measurement method....
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Reliability of Crack Depth Sizing on Ultrasonic Testing