In June 2018, the leakage of gases around the exhaust pipe attached to emergency diesel generator of Hamaoka Nuclear power plant Unit 5 and the breakage of an exhaust pipe expansion joint were found. As a result of investigation, we estimated that the cause of the event were the hit marks on the bellows of the expansion joint and low cycle fatigue caused by usual operation of the generator. It was estimated that the hit marks were made when the expansion joint was installed to the exhaust pipe. This paper s...
英字タイトル:
Investigation on breakage of the exhaust pipe expansion joint of diesel generator (B) of Hamaoka NPS unit5

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...
英字タイトル:
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...
英字タイトル:
Seismic safety evaluation of piping systems with locally wall thinning by LDI (Part3)-Seismic performance effects of elbow pipes by loading tests