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Corporate Information

 
Press Release (Jan 10,2008)
Nonconformances Found in the Inspection and Restoration Works Performed after the Niigata-Chuetsu-Oki Earthquake (January 10th)
We are announcing the status of major inspections and restoration works and 
nonconformances at TEPCO's Kashiwazaki-Kariwa Nuclear Power Station after 
the Niigata-Chuetsu-Oki Earthquake.  

1. Inspection/Restoration Status

 ○ Inspection and restoration completed between December 28th, 2007 to 
    January 10th, 2008.
    (Completed on the following date) 

  • Unit No.3 Reactor head opening: 
      January 8th 
  • Unit No.3 Inspection for spent fuel pool rack etc.:
      January 7th 

 ○ Inspection and restoration to be commenced between January 11th to 
    January 17th, 2008
    (To be commenced on the following date)

  • Unit No.1 Preparation for pressure suppression chamber inspection: 
      January 15th 
  • Unit No.4 Preparation for in-core inspection (Phase3): 
      January 12th 
  • Unit No.4 Preparation for reactor pressure vessel inspection (nozzle parts etc.): 
      January 16th 
  • Unit No.4 Main generator inspection: 
      January 15th 

 ○ Work Schedule of Major Inspection/Restoration from January 6th to February 2nd, 2008

  • Work Schedule of the Main Inspection/Restoration of the Kashiwazaki-Kariwa Nuclear 
    Power Station in Response to the Niigata-Chuetsu-Oki Earthquake (during 4 Weeks)
                                                                          ....Appendix

2. Nonconformances Found in the Inspection and Restoration Works Performed after 
   the Niigata-Chuetsu-Oki Earthquake

   Based on the "Public Announcement Regarding Nonconformance Found in the Inspection 
   and Restoration Works Performed after the Niigata-Chuetsu-Oki Earthquake", the Tokyo 
   Electric Power Company, Incorporated (TEPCO) provides this announcement containing 
   incidents information reported from December 27th, 2007 to January 9th, 2008.

 ○ Incidents Information (relating to the Chuetsu-Oki Earthquake)
Incidents Information (relating to the Chuetsu-Oki Earthquake)
<Reports from December 27th, 2007 to January 9th, 2008>
Reports from December 27th, 2007 to January 9th, 2008
○ Other Findings • Unit 7: In-core inspection (Phases 1 to 3) has been completed on December 26th, 2007. The portion of reactor well liner with two scratches (length: 3mm and 2mm) that had led to leakage and subsequently had been temporary repaired will be cut out for root cause analysis. The reactor well liner will be reinspected since the water in the reactor well must be drained for the above work. • Units 6 and 7: In light of the event that there were control rods that could not be withdrawn, inspection of control rod drives, control rods and reactor equipment have been conducted but no evidence for the cause has been identified such as foreign material or damage (announced on November 8th, November 22nd and December 6th, 2007). Considering the common factors among units 6 and 7, the inability to withdraw the control rod is assumed to have happened due to temporary increase of friction within the control rod drive due to the increase of cruds caused by the longer time that water flow had been stopped compared to that during normal plant shutdown. If a similar event should happen in the future, control rods can be withdrawn by means of scram operation, etc. In addition, interference due to cruds does not pose any threat to the control rod insertion function. • Unit 5: On November 29th, 2007, a wedge inserted in jet pump No. 1 to suppress vibration of the inlet mixer was found to be displaced. For all reactor internals except for jet pump No.1, no abnormality such as damages, deformation or displacement has been confirmed (announced on November 29th, December 3rd, and December 6th, 2007). In-core inspection (Phases 1 to 3) has been completed on December 27th, 2007. Detailed inspection for the cause of wedge misalignment will commence on January 18th, 2008. • Solid waste storage warehouse: 13,825 drums have been confirmed as of December 31st, 2007. In order to inspect the solid waste storage warehouse, drums whose soundness have been confirmed will be transferred to a temporary warehouse beginning on January 23rd, 2008. • Information on Nonconformances (those related to: the Chuetsu-Oki Earthquake; Grades As, A, B, C, and D; and non-graded)
Appendix: Work Schedule of the Main Inspection/Restoration of Kashiwazaki-Kariwa Nuclear 
          Power Station in Response to the Niigata-Chuetsu-Oki Earthquake
          (during 4 Weeks)(PDF 167KB)
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