We announce that the report due dates for the following two instructions from NISA of the Ministry of Economy, Trade and Industry have been postponed, as we are still in the process of investigating the root cause of these matters.

1. Root cause analysis of the noncompliance to the technical specification regarding the operational restrictions of the emergency ventilation and air conditioning system in the Main Control Room in Unit 5 at Kashiwazaki-Kariwa Nuclear Power Station (additional instruction) (Received on May 16, 2012)

< Progress >
In order to analyze a wide variety of background factors of this issue and clarify the root cause, we have interviewed those who were involved in this matter since February 2000 (when the technical specification regarding this matter was first discussed) and investigated/reorganized the facts. As a result, more issues (direct issues) were found in each operation process. These issues have been analyzed to identify the root cause.

< Future schedule >
Effective recurrence prevention measures for the direct issues and root cause will be discussed. After validity confirmation, the summarized report will be submitted by August 13, 2012

< Instruction from NISA (Outline) >
Regarding the root cause analysis result and the recurrence prevention measures provided in our report submitted on April 16, 2012, we were instructed to start over the root cause analysis of the matter in accordance with the "Quality Assurance Code for Safety in Nuclear Power Plants (JEAC4111-2009)", as it has been judged that the root cause analysis was not done properly and the facts were not sufficiently organized. The analysis result must be submitted to NISA by July 17, 2012.

2. Noncompliance to the technical specification regarding the maintenance at Kashiwazaki-Kariwa Nuclear Power Station (Instruction) (Received on May 23, 2012)

< Progress >
As the Kashiwazaki-Kariwa Nuclear Power Station has been suspended for a long period of time since the Niigata-Chuetsu-Oki Earthquake in July 2007, it is an optimum timing for reviewing the maintenance process being implemented at the power station. Through investigating the facts at the time of the earthquake and interviewing those who were involved, issues that lie in each operation process have been clarified.

< Future schedule >
Organizational factor analysis, root cause analysis of the technical specification noncompliance regarding the equipment inspection cycle based on the investigation results and discussion on recurrence prevention measures will be done. Based on the results, the report will be summarized after validity confirmation and will be submitted to NISA by September 28, 2012. The root cause analysis of the technical specification noncompliance regarding the equipment inspection cycle at the Kashiwazaki-Kariwa Power Station, Fukushima Daiichi Nuclear Power Station and Fukushima Daini Nuclear Power Station will also be reported (instruction received on March 2, 2011). As it is estimated to take about 2 months until the result can be reported, an interim report will be submitted by August 13, 2012 after investigating/reorganizing the facts and clarifying issues.

< Instruction from NISA (Outline) >
Instruction was given to identify the direct cause/root cause of the technical specification noncompliance and determine the recurrence prevention measures. The result must be reported by July 23, 2012. The root cause analysis result of the technical specification noncompliance regarding the equipment inspection cycle at the Kashiwazaki-Kariwa Power Station, Fukushima Daiichi Nuclear Power Station and Fukushima Daini Nuclear Power Station must also be reported (instruction received on March 2, 2011).

Attachment: Root Cause Analysis Process Chart (PDF 225KB)

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