This study demonstrates the mechanism of y ? a transformation in creep test on the basis of the energy o f the system. The experimental result shows that the strain energy around M23Co carbide becomes very high due to dislocations stored during creep. As a result, the system free energy in the local region near the carbide increases with increasing creep time but it decreases by the formation of ferromagnetic a phase....
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Formation of ferromagnetic phase in SUS304 steel by strain energy stored during creep test

The formation of the ferromagnetic a phase during creep deformation in SUS304 steel was simulated by a hase-field method. In order to consider the precipitation and growth of the phase simultaneously, we have onstru cted a model based on experimental results. In this model, strain energy stored near M23Co carbide uring creep deformation increases the driving force for precipitation of the a phase. This strain energy is stimated on the basis of distribution function of dislocation density in space near the ...
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Phase-field simulation on the formation of ferromagnetic phaseduring creep deformation in SUS304 steel

The feasibility study of RI-ISI (Risk-Informed In-Service Inspection) has been carried out based on 2-loop PWR as the pilot pl ant. The knowledge about failure potential derived from “Whole Maintenance Program for Piping” and results of PSA were combined in this work. The risk matrix of EPRI was referred to when the importance of piping segments was classified. It turns out that RI-ISI could reduce the number of welds required for inspection by present way, while the risk level remains at the same level....
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Study for Advancement of Maintenance Management for Piping Using Risk Information

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......

State of microstructure in metallic materials can be expressed as numerical values based on a concept of system free energy, and the energy value is used as a measure of damage analysis of the materials. In this study, change in the system free energy of the FG-HAZ in 9Cr heat resistant ferritic steels during creep is evaluated as summation of chemical free energy, strain energy and surface energy, which are obtained by a series of experiments, i.e., chemical analysis using extracted residues, X-ray d...
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Microstructural analysis of HAZ in the welded joints of 9Cr heat resistant ferritic steels for fast reactor

Microstructural states of metallic materials can be expressed by system free energy, and the estimation of the system free energy is useful for damage analysis of the materials. In this study, chang e with creep time in the system free energy of the FG-HAZ in 9Cr heat resistant ferritic steels is estimated on the basis of a series of experiments such as chemical analysis by using extracted resid ues, X-ray diffraction, and scanning transmission observations. The change in the system free energy is expresse...
英字タイトル:
Microstructural analysis of HAZ in the welded joints of 9Cr heat resistantferritic steels for fast reactor