In the process of achieving cold shutdown following the shutdown of Hamaoka Nuclear Power Station Unit 5 on May 14, 2011, the readings of conductivity meters monitoring the purity of the water in the main condensers began to rise, and the conductivity of the water in the reactor also began to rise. After cold shutdown, investigation identified that a high volume of sea water had flowed into the reactor facility due to damage to the main condenser tubes. Evaluations focusing on corrosion of materials have b...
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Effect of sea water intrusion from main condenser, damaged by breakon reactor core internals, Hamaoka Unit 5

In the process of achieving cold shutdown following the shutdown of Hamaoka Nuclear Power Station Unit 5 on May 14, 2011, large quantities of seawater flowed into the reactor and other facilities due to main condenser tubes which had broken. The investigations focusing on corrosion of materials had been conducted through various methods, observation of equipments, material tests, cleaning tests, and inspection of RPV and its components. Based on these investigations, we had evaluated the impact on the...
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Effect of sea water intrusion from main condenser, damaged by break on reactor core internals, Hamaoka Unit 5(No.2)

This study proposes an electromagnetic method for the evaluation of the condition of the turbine in a nuclear power plant. Experimental re sults of a small turbine driven by an electric motor are shown in this paper. The results show that it is possible to detect the movement a nd condition of the impeller by applying the electromagnetic evaluation method. Moreover, an excitation experiment shows that the higher o rder vibration of the impeller can be detected and the distinction of the condition of with a...
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Material Evaluation of Cast Iron based on Eddy Current

Abstract: This study proposes an electromagnetic method for the evaluation of the condition of a turbine in a nuclear power plant. Experimental results of a small turbine driven by an electric motor are shown in th is paper. A high temperature superconductivity electromagnet is applied outside the case of the turbine to provide excitation magnetic field. On the other hand, pickup coils are placed near the impeller inside the case of the turbine. The experimental results show that it is not only possible to...
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Electromagnetic evaluation of the impeller of a turbine using a hightemperature superconductivity electromagnet

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