Due to main condenser tube damage in May, 2011, seawater flowed into the reactor and other facilities of Hamaoka NPS Unit 5. The pitting corrosion was observed in the SUS weld metal cladding layer, welded to the inner face of the RPV base metal. In terms of the availability of RPV’s required functions, RPV would be capable of continuous use based on component health assessment in December, 2015. However, development of non-destructive inspection methods to SUS weld metal cladding was needed to conduct the ...
英字タイトル:
Applicability of non-destructive inspection methods to SUS weld metal cladding

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 ...
英字タイトル:
Effect of sea water intrusion from main condenser, damaged by break on reactor core internals, Hamaoka Unit 5 (No.3)

In this research, research into the causes of the event of piping micro leakage of Hamaoka Nuclear power plant Unit 5 was carried out .Due to main condenser tube damage in May, 2011, seawater flowed into the reactor and other facilities of Unit 5. After that, piping purification was carried out and kept filled with water. Crevice corro- sion was confirmed at the leakage piping and it was estimated to happen at purification process. The leakage piping would not be cleaned sufficiently in the purification pro...
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Investigation on leakage point of welding part of control rod drive system piping of Hamaoka NPS unit5.

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