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Corporate Information

 
Press Release (Nov 22,2007)
Nonconformances Found in the Inspection and Restoration Works Performed after the Niigata-Chuetsu-Oki Earthquake (November 22nd)
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 November 16th to November 22nd, 2007
     (Completed on the following date)
  • Unit No.1 Main transformer oil extraction and internal inspection: 
      Planned to be completed on November 22nd 
  • Unit No.1 Skimmer surge tank inspection:
      November 20th
  • Unit No.2 In-core inspection (Phase1 and Phase2): 
      November 19th
  • Unit No.2 House transformers (2B) visual inspection:
      November 17th
  • Unit No.2 House transformers (2B) oil extraction and internal inspection: 
      November 19th
  • Unit No.2 Excitation transformers visual inspection
      November 17th 

 ○ Inspection and restoration to be commenced between November 23rd to November 29th, 2007  
     (To be commenced on the following date)  
  • Unit No.1 Main exhaust duct inspection: 
      November 28th
  • Unit No.1 In-core inspection (Phase3):
      November 26th
  • Unit No.2 Fuel, control rod inspection
      November 27th
  • Unit No.2 Turbine internal inspection: 
      November 28th  
  • Unit No.4 Removal of spent fuel pool underwater work platform: 
      November 29th  
  • Unit No.5 Main transformer oil extraction and internal inspection:
      November 27th 
  • Unit No.5 In-core inspection (Phase1 and Phase2):
      November 22nd *
  • Unit No.6 In-core inspection (Phase1 and Phase2):
      November 26th 
  • Unit No.7 In-core inspection (Phase1 and Phase2): 
      November 20th *
  • Inspection of Minami Niigata trunk line #;2 bushing: 
      November 23rd 

                                                            *Work schedules added this week

 ○ Work Schedule for Major Inspection/Restoration from November 18th to December 15th, 2007
    • Work Schedule of the Main Inspection/Restoration of 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 November 
   15th to November 21st, 2007.  

 ○ Incidents Information (relating to the Chuetsu-Oki Earthquake)
<Reports from Nov. 15 to Nov. 21, 2007>
○ Other Findings • Unit No.1: Search of a red boot in the skimmer surge tank was conducted on November 19th and 20th and 1.5 pairs (3 pieces) of red boots were found and recovered. A total of 2 pairs have been recovered including 1 piece that had been recovered on August 22nd. (Confirmation completed on November 22nd.) • Unit No.5: The misaligned fuel assembly was returned to the right position within the fuel support and the fuel assembly was subsequently transferred to the spent fuel pool on November 20th (announced on November 20th). Detailed study will be carried out to find out the cause after the in-core inspection by measuring the curvature of the channel box, etc. • Unit No.7: Inspection of equipment on the reactor-side has been conducted from November 17th to 22nd in relation to the event that a control rod could not be withdrawn. There were no findings such as foreign material or large damage that could have caused the event. Based on the study conducted thus far, the event is presumed to be a temporary one having occurred due to interference caused by crud (metallic impurity such as iron rust) that temporarily increased the friction drag within the control rod drive mechanism. Even if similar events were to happen in the future, the function of the control rod drive mechanism would be maintained since the situation can be resolved by scram operation, etc. • Unit No.4: During the internal inspection of unit No.4 turbine, wear (maximum of about 4 mm) at the 9th and 10th-stage of the low-pressure turbine (A) rotor blades and stator blades presumed to have happened due to their contact were found (announced on November 20th). Subsequent inspection for the rest of the rotor blades and stator blades (stages 11th to 17th) revealed wear (maximum of about 3 mm) on the 11th-stage rotor blade (shroud-side) and stator blade and wear (maximum of about 2 mm) on the 12th to 14th-stage rotor blades (moisture separator blade) and stator blades. High-pressure turbine is planned for inspection as well.
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 136KB)
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