ML062490464
| ML062490464 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 08/31/2006 |
| From: | Brandi Hamilton Duke Energy Carolinas, Duke Power Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| Download: ML062490464 (6) | |
Text
BRUCE H HAMILTON Vice President 14% nergya Oconee Nuclear Station Duke Energy Corporation ONOI VP / 7800 Rochester Highway Seneca, SC 29672 864 885 3487 864 885 4208 fax August 31, 2006 bhhamitton@duke-energy.com U.S. Nuclear Regulatory Commission ATTN:
Document Control Desk Washington, D.C.
20555-0001
SUBJECT:
Duke Power Company LLC d/b/a Duke Energy Carolinas, LLC Oconee Nuclear Station - Unit 3 Docket No.
50-287 Inservice Inspection Summary Report for Class CC Component Year 30 IWL Examinations Pursuant to 10CFR50.55a(b) (2) (viii), Duke Energy Corporation submits the attached ISI Summary Report for ASME Class CC component conditions observed during the year 30 IWL examinations.
Questions regarding the attached report may be directed to R.
P. Todd at (864) 885-3418.
Very truly yours, Bruce. H. Hamilton, Vice President Oconee Nuclear Site Attachment wwl. duke-energy. corn oq
Oconee Nuclear Station Unit 3
Class CC ISI Summary Report for Year 30 IWL Examination
~ý a*
Dte: a8-2 -?0 Date:
Reviewed By:
Approved By:
By:
(AuthoiIed Nuclear Inservice Inspector)
Date: e-2o 406 Date: 6'/
ANII Review
Oconee Nuclear Station, Unit 3 Class CC ISI Summary Report for Year 30 IWL Examinations Page 2 of 5 A.
ASME Code and Regulatory Requirements for Class CC ISI Summary Reports 10CFR50.55a(g) (4) (v) (C) requires that concrete containment pressure retaining components and their integral attachments, and the post-tensioning systems of concrete containments must meet the inservice inspection,
- repair, and replacement requirements applicable to components which are classified as ASME Code Class CC.
This inservice inspection summary report addresses requirements of 10CFR50.55a(b) (2) (viii)
(D) for conditions observed during performance of the Oconee Unit 3 concrete containment year 30 IWL examinations, conducted in accordance with the requirements of the ASME Boiler and Pressure Vessel Code,Section XI, Subsection IWL, 1992 Edition with the 1992 Addenda.
The ASME Boiler and Pressure Vessel Code,Section XI, 1992 Edition with the 1992
- Addenda, Article IWA-6000, Records And Reports, paragraph IWA-6210, requires the Owner to prepare inservice inspection summary reports for inservice inspections performed on Class 1 and 2 pressure retaining components and their supports.
IWA-6000 does not address inservice inspection summary reports for Class CC pressure retaining components and their supports, and the Code does not require preparation and submittal of summary reports for Class CC components.
As such, this Class CC ISI Summary Report does not contain all of the information specified in IWA-6220 or IWA-6230, but provides that information required by 10CFR50.55a(b) (2) (viii).
Please note that this report is being submitted within 90 calendar days following the completion of the 3EOC22 refueling outage at Oconee Unit 3.
Although some conditions requiring reporting were known prior to
- 3EOC21, not all IWL Category L-A and L-B Examination were complete until after 3EOC21.
Duke Energy Corporation is maintaining a
separate Inservice Inspection Program for Class CC pressure retaining components.
Therefore, this ISI Summary Report contains only that information applicable to Class CC components.
ISI Summary Reports for other Code Class components are submitted separately.
B.
Description of Condition Requiring Reporting
- 1. The following conditions are reportable in accordance with 10CFR50.55a(b) (2) (viii)
(D) (2).
These conditions were identified during the performance of ASME Code,Section XI, Table IWL-2500-1, Category L-B examinations conducted in accordance with Oconee procedure MP/0/A/1400/022.
Oconee Nuclear Station, Unit 3 Class CC ISI Summary Report for Year 30 IWL Examinations Page 3 of 5
- a. The absolute difference between the amount of filler grease removed and the amount replaced exceeded 10 percent of the tendon net duct volume for 14 tendons examined.
Specific tendons affected and the amount of excess grease installed is detailed in Table 1.
TABLE 1 Net Difference Net Difference Between Volume of Net Duct Volume Between Volume Filler Grease Removed and Tendon ID No.
(Gallons) of Filler Replaced Grease Removed
(% Net Duct Volume) and Replaced (Gallons) 62H51 61 8
13 62H25 61 12 19 51H105 61 16.5 27 24H14 61 11 18 35H96 61 13.5 22 35H38 61 36 59 46H84 61 18.3 30 13H13 61 13 21 3D09 52 19.5 38 2D44 54 10 19 3D11 53 19.5 37 ID52 48 18 38 2D01 46 21 46 2D13 55 18 33
- b.
The absolute difference between the amount of filler grease removed and the amount replaced may have exceeded 10 percent of the tendon net duct volume for 4 other tendons examined, as detailed below.
- i.
Tendons 34V05,
- 34V29, 35H63 were removed and replaced during Unit 3
Steam Generator Replacement during refueling outage 3EOC21.
The sheaths for these tendons were refilled with sheathing filler grease after the new tendons were installed, but the quantity of grease installed was not recorded. Therefore, it is possible that the difference between the amount removed and the amount installed could have exceeded 10% of the net duct volume for these tendons.
However, because these tendons were replaced, these conditions have no impact on the acceptability of these tendons.
Oconee Nuclear Station, Unit 3 Class CC ISI Summary Report for Year 30 IWL Examinations Page 4 of 5 ii.
Tendon 12V25 had forty four gallons of grease drained from its tendon sheath prior to Steam Generator Replacement activities during refueling outage 3EOC21.
During 3EOC21, the Steam Generator Replacement Tendon Contractor added sheathing filler grease to this tendon sheath, but the quantity of grease installed was not recorded.
After completion of IWL examinations and
- tests, Duke installed an additional 12 gallons of grease.
Therefore, the absolute difference between the amount of sheathing filler grease removed initially and the total amount replaced cannot be determined and may have exceeded 10 percent of the tendon net duct volume.
- 2.
The following condition is reportable in accordance with 10CFR50.55a(b) (2) (viii)
(D) (3).
During the performance of ASME Code,Section XI, Table IWL-2500-1, Category L-A visual examinations conducted in accordance with procedures QAL-13 and QAL-14, grease leakage was detected on various surfaces of the concrete containment.
The location and extent of these conditions is consistent with that previously reported in our letter dated August 21, 2000 following the year 25 IWL examinations.
Oconee Nuclear Station, Unit 3 Class CC ISI Summary Report for Year 30 IWL Examinations Page 5 of 5 Technical Evaluation Although 10CFR50.55a(b) (2) (viii)
(D) (2) does not require that an evaluation of these conditions be submitted in this ISI Summary Report, an evaluation is provided below.
- 1. Conditions Reportable per 10CFR50.55a(b) (2) (viii)
(D) (2)
All tendons for which the absolute difference between the amount of sheathing filler grease installed and the amount replaced exceeded (or may have exceeded) 10 percent of the net duct volume of the tendon were visually examined for corrosion.
The anchorhead at one end of 2D01 and 2D44 and on the bottom end of 34V29 and 12V25 were described as having a corrosion level
'C';
(i.e.,
pitting less than 0.003 inches).
Approximately 25% of button heads on one end of 13H13 were also described as having a corrosion level 'C'.
No other anchorage component among tendons described in Table 1
(except the bearing plates in some cases) was described as having a
corrosion level of 'C' or worse, and no anchorage component was corroded to such an extent as to affect its load carrying capability or its acceptability. In addition, tendons 24H14 and 12V25 each had a wire removed for visual examination and testing, and no corrosion was present on the entire length of the examined wires.
- 2.
Conditions Reportable per 10CFR50.55a(b) (2) (viii)
(D) (3)
Corrective actions identified in our letter dated August 21, 2000 were begun after the year 25 IWL examinations and continue to reduce the number of identified leaks, primarily from tendon anchorage areas.
However, because all tendon anchorage leakage has not been eliminated, and because all of the affected areas have not been cleaned to remove evidence of past leakage, general visual examinations continue to identify these conditions.