Cr含有率については，その増加と共にFACが抑制されるという定性的な影響は知られており，単相流FACについてはその定量的な影響についても研究が進められている一方で，二相流FACに関しては定量的な影響は明らかでは無く，今後，二相流FACの減肉速度の予測評価を行う上では，Cr含有率と減肉速度の定量的な関係を明らかにする必要がある．二相流FACの減肉速度に与えるCr含有率の定量的な影響を明らかとすることを目的として，本速報ではFAC管理範囲から除外される高Cr含有率条件（1%程度以上）での気液二相流FAC試験を実施し，減肉速度の傾向について述べることとする．...
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Flow-Accelerated Corrosion Test about the Low Alloy Steel with Chromium Content of 0.99 mass% under Water-Steam Two-Phase Flow?

For the quantitative evaluation of importance of maintenance and management to the piping in the turbine system and the feedwater system, an evaluation method of the piping failure frequency due to wall thinning, one of the major aging phenomena in the secondary and BOP systems, were developed. Based on the uncertainty of the thinning rate, initial thickness and material strength, frequency of the piping failure was evaluated probabilistically. As a trial evaluation, the difference of the failure frequency ...
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Development of evaluation method of pipe failure frequency due to wall thinning

In the nuclear power plant under the severe accident, it is possible that the debris dust and the metallic powder are immixed in the coolant, and then the flow pattern can become the solid-liquid multiphase flow in the reactor coolant circulation system. In this study, the numerical analysis is conducted in order to evaluate the FAC profile in the piping under the solid-liquid multiphase flow. By using the FAC model, the mass transfer coefficient in the elbow was evaluated. The mass transfer coefficient bec...
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Piping System, Risk Management based on Wall Thinning Monitoring and Prediction (3) Evaluation of Wall Thinning Profile by Flow Accelerated Corrosion under Solid-Liquid Multiphase Flow

In Hamaoka Power Station, thinning management of piping system is considering earthquake In Hamaoka Power Station, thinning management of piping system is considering earthq uake resistance. Current management method is too conservative due to assumption that has large range thinning by liquid droplet impingement erosion (LDI). Therefore, we are developing reasonable earthquake safety evaluation method suited for locally-thinning caused by LDI. To understand the influence on earthquake resistance by the lo...
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Seismic safety evaluation of piping system with local wall thinning by LDI(Part1)- Thinning Management of piping system in Hamaoka Power Station

For seismic safety of piping system with local thinning surface by liquid droplet impingement erosion (LDI), hybrid tests?? were conducted to the piping with locally-thinned elbow. I n this presentation, determination method of the thinning shape on the elbow is developed.To determine the thinning shape by LDI, droplet behavior at the elbow is calculated in vario us flow and piping size conditions, and collision point and velocity for each droplet is evaluated. Then, the relationship between collision cond...
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Seismic safety evaluation of piping system with local wall thinning by LDI (Part 2)-Evaluation of local thinning shape by LDI

In order to evaluate seismic safety of piping systems with locally wall thinning by LDI, hybrid tests have been conducted incorporating a numerical analysis of whole s ystem with a loading test of elbow model. Seismic performance effects of wall thinning elbow were clarified by comparing three cases of different thickness elbow model s such as no defect, 50% thinning and 75% thinning. By these results, the almost same hystereses of the non-linear load displacement relations were obtained and the dam ages o...
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Seismic safety evaluation of piping systems with locally wall thinning by LDI (Part3)-Seismic performance effects of elbow pipes by loading tests