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

Abstract The wall thinning management program at Hamaoka Nuclear Power Station stipulate object points and test frequencies dependi ng on wall thinning environment (flow condition, material). Currently, object points and test frequency are determined conservative ly, which contribute to an increase of radiation exposure of filed workers. Development of measurement technology and improvement of prediction technology for a progress of wall thinning may enable utilities to conduct a more effective wall thinn...
英字タイトル:
Expectations of Wall Thinning Management For Development of Measurement Technology and Improvement of Prediction Technology for Progress of Wall Thinning

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...
英字タイトル:
Investigation on leakage point of welding part of control rod drive system piping of Hamaoka NPS unit5.

In the process of achieving cold shutdown of Hamaoka Nuclear Power Station Unit 5 on May 14, 2011, sea water flowed into the reactor and other equipment due to main condenser tube leakage. By clean-up operation, chloride ion concentration went below 10 ppm, the target prescribed to prevent crevice corrosion. On Dec, 2015, the component health assessment had summarized by surveys focusing on material corrosion, deposit and residual chloride. Since, each equipment have been under wet or dry lay-up condition. ...
英字タイトル:
Cleanup and lay-up around reactor pressure vessel related to sea water intrusion event at Hamaoka Nuclear Power Station Unit 5