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)
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<Reports from Nov. 15 to Nov. 21, 2007>
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○ 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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