Bare metal visual examination (BMV) is required for dissimilar metal welds of class 1 component for PWR (Pressurized Water Reactor) in inspection and evaluation guidelines published by Japan Nuclear Safety Institute (JANSI). However, there have been no guidelines which specify the procedures for BMV. In 2021, the guideline stipulating specific procedures for BMV were established by JANSI. This guideline includes both lessons-learned related to the boric acid corrosion on reactor pressure vessel upper head a...
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Establishment of Bare Metal Visual Examination Guideline for Class 1 Pressure Vessels such as Reactor Pressure Vessel

The new regulatory inspection has been fully operational since April 2020, and several inspection findings have been published so far. In this paper, the views of the utility on these cases have been introduced, as well as the status of our efforts and issues related to the new inspection system, which is a beneficial and effective system for improving the safety of nuclear power plants....
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Efforts and issues of Kansai Electric Power for new regulatory inspection system for nuclear power plant

Facing the introduction of new regulatory inspection which is a performance-based inspection from 2020, the word “performance” is very commonly used in many placed and occasions in Japan. This word “performance” represents many different meanings depending on the persons and situations etc. The performance-based inspection is an effective and efficient tool for realizing it goal of achieving safety. Moreover licensee’s performance-based activity is also a key of the plant safety. In this kind of performance...
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Common cause behind the problems found in the new inspection system trial ~ Suitable performance selection for the performance based activities ~

In Japan, CBM (Condition Based Maintenance) has not been adequately introduced yet due to the lack of field data. To reduce possibilities of equipment failure because of improper work practice we have to optimize the condition monitoring technique. Mihama units 1 and 2 were decided to be decommissioned, so that a lot of equipment can be used to collect many kinds of condition monitoring data such as vibration, lubrication and thermography diagnosis including trends of degradation conditions without concerns...
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The effective plan utilizing decommissioning plants to develop the condition monitoring technology

Takahama unit No.3 is KEPCO’s first unit that has passed the safety screening against the new regulatory requirements. A new regulation “The Review for Safety Improvement on Nuclear Power Plants” was started by NRA(Nuclear Regulation Authority) and requires operators to report the results, at periodic intervals, of the review on operator’s voluntary activities for safety improvements and effects of operator’s performance. In this lecture, I will explain Takahama Unit 3’s activities. ...
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The Review for Safety Improvement of Takahama Unit No.3

The Kansai Electric Power Group declared “Zero Carbon Vision 2050” on February 26, 2021 to achieve a zero-carbon society in 2050 and would be committed to implementing the following three approaches. (i) We will provide our society with the best available solution toward zero-carbon emissions on the demand side along with supporting its implementation across all sectors. (ii) With priority given to safety, our group will seek to achieve the best energy mix which can lead to full decarbonization ensure secur...
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“Zero Carbon Vision 2050” of the Kansai Electric Power Group

It is reformed the regulatory inspection framework for nuclear facilities to Risk-Informed and Performance-based inspection framework. Considering the word "Performance-based", I introduce examples of status of Corrective Action Program (CAP) system program, education of Significance Determination Process (SDP), Temporary Configuration Change (TCC) in The Kansai Electric Power, so that we licensee should recognize mind change to this challenge from checklist type/prescriptive former inspection framework to ...
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Challenges of Kansai Electric Power based on pilot program of regulatory inspection system reform for nuclear power plant

The cause of the steam generator tubing failure that was identified during the 23rd plant outage at Takahama Unit 4 was presumed to be caused by wear of the tubing due to repeated contact with exfoliated dense scale, which was formed on the tubing surface. It is suspected that the scale exfoliated because the scale could not follow the heat expansion and shrinking of the tubing applied during plant startup and shutdown operations, and then partial cracking occurred, resulting in exfoliation of partial scale...
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Affection of Long-Term Plant Outage on Steam Generator Tube Failure Identified at Takahama Unit 4