We summarized the results of investigation on the inspection plans at our nuclear power stations as well as the cause and recurrence prevention measures for technical specification noncompliance, and submitted a report to the Nuclear and Industrial Safety Agency (NISA) of the Ministry of Economy, Trade and Industry on February 28, 2011.
On March 2, 2011, NISA judged this matter (inadequate equipment maintenance) to be a noncompliance to the technical specification for the nuclear reactor facility of our nuclear power stations, and instructed us to investigate for the root cause and discuss recurrence prevention measures for this matter and report the results. However, the implementation of the demanded actions was temporarily suspended due to the Tohoku-Chihou-Taiheiyou-Oki Earthquake occurred on March 11, 2011.
On May 23, 2012, NISA instructed us again to report the results, however, as a substantial amount of time was required to identify issues of each operation process, we requested for postponement of the report due date on July 17 (Interim report to be submitted by August 13 and the final report to be submitted by September 28). (Previously announced on February 28, March 2, 2011, May 23 and July 17, 2012)
In our root cause analysis, the total of 20 cases have been selected (For cases attributable to the same cause, one representative case was selected per each operation process for organizational factor extraction). We have summarized the issues which lie in each operation process and the selected representative cases, and submitted the interim report to NISA today.
We will continue extracting the organizational factors from the selected representative cases to be considered and discuss recurrence prevention measures in consideration of the issues and organizational factors being analyzed for the "Technical specification noncompliance due to the inadequate equipment maintenance at Kashiwazaki-Kariwa Nuclear Power Station". The summarized results will be submitted to NISA by September 28.
Attachment
1: "Root Cause Analysis Process Chart"(PDF 50.9KB)
2: "Direct Cause, Root Cause Attributed to the Organizational System and Recurrence Prevention Measures of the Technical Specification Noncompliance Due to Inadequate Equipment Maintenance at Kashiwazaki-Kariwa Nuclear Power Station, Fukushima Daiichi Nuclear Power Station and Fukushima Daini Nuclear Power Station (Interim Report)"(PDF 348KB)
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