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)
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<Reports from December 27th, 2007 to January 9th, 2008>
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○ 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In light of the event that there were control rods that could not be withdrawn,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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