ML111080729
| ML111080729 | |
| Person / Time | |
|---|---|
| Site: | Waterford  (NPF-038) |
| Issue date: | 04/18/2011 |
| From: | Robert Williams Entergy Operations |
| To: | Kalyanam N Plant Licensing Branch IV |
| Kalyanam N, NRR/DLPM, 415-1480 | |
| Shared Package | |
| ML111080692 | List: |
| References | |
| Download: ML111080729 (9) | |
Text
Steam Generator Batwing Inspections Spring 2011 Refuel 17 Outage Preliminary Results Page 1 of 9 An augmented inspection of Steam Generator #1 (SG-1) and Steam Generator #2 (SG-2) was performed during RF17 under work orders 259170-01 and 259181-01 respectively to monitor the batwing degradation. The purpose was to visually inspect the batwings and accessible tubes to establish the extent of condition or any unforeseen change. Batwing inspections completed to date have all met the established acceptance criteria indicating that there have been no changes to the critical variables or extent of condition previously evaluated.
SG2 batwing inspections are complete. SG1 batwing inspections are complete with the exception of the SG1 FOSAR.
RF17 batwing inspections include:
x Visual exam of upper batwing weld and wrap around bar
- verify no upper batwing weld/clip failures in stay cavity area
- verify no gross deformation twisting of wrap around bar x Through-tube bundle diagonal (45 Degree) visual inspection of upper stay cavity area
- provide assurance that stabilized tubes are attenuating forces developed by broken batwings x Bottom-up visual inspection of stay cavity area
- monitor batwing degradation
- verify no indications of gross tube deformation x Foreign object search and retrieval (FOSAR)
- verify no large batwing segments are present
- remove accessible foreign objects Steam Generator #1 All inspections results found to date are bounded by the batwing inspection acceptance criteria.
Condition Reports No conditions reports generated as a result of batwing inspections of SG 31.
Upper Weld and Wrap Around Bar Inspection Results 3/4 SAT - All welds intact; no degradation observed Details 3/4 No abnormalities on weld repair observed compared to RF16
Steam Generator Batwing Inspections Spring 2011 Refuel 17 Outage Preliminary Results Page 2 of 9 45º Through-Tube Bundle Inspection Results 3/4 Acceptance criteria met - no tubes observed with greater than 33% through tube wear per Westinghouse letter LTR-SGDA-07-217 Details 3/4 Minor intrados wear observed small hot leg wear scar (potentially thru wall) observed at a stabilized tube at the stay cavity boundary. Best estimate location is row 35 column 79. This is near the same location as identified in SG 32.
3/4 Tube wear at batwing to tube interface similar to RF16 no tubes observed with greater than 40% through tube wear 3/4 One loose batwing segment, approximately 2 foot long, was observed.
Bottom-Up Video Inspection Not Yet Performed
Steam Generator Batwing Inspections Spring 2011 Refuel 17 Outage Preliminary Results Page 3 of 9 Figure 1a Small intrados wear (SG 31 hot leg)
Steam Generator Batwing Inspections Spring 2011 Refuel 17 Outage Preliminary Results Page 4 of 9 Inspection not yet performed Figure 1b: RF17 SG-1 Composite Figure 1c: RF16 SG-1 Composite
Steam Generator Batwing Inspections Spring 2011 Refuel 17 Outage Preliminary Results Page 5 of 9 Steam Generator #2 All inspections results found to date are bounded by the batwing inspection acceptance criteria.
Condition Reports 3/4 CR-WF3-2011-02347 documents intrados tube wear appearing to be through wall and through portions of the stabilizer. This indication was previously identified at RF16 and documented by CR-WF3-2009-06486.
o Detailed investigation determined minimal growth from RF16 to RF17. The indication was about 25% thru tube and met the 33% wear acceptance criteria. Note Westinghouse letter LTR-SGDA-11-070 supports 40% thru tube wear at this location.
3/4 CR-WF3-2011 documents a loose part on the hot leg tube sheet at tube row 144 column 74.
Retrievable was unsuccessful. Westinghouse is evaluating.
Tube row 144 column 74 was plugged in 2006 with a sentinel plug due to batwing issues.
Eddy current review shows that the part has been at this location since 2006. Eddy current review has determined that that no wear is occurring on nearby active tubes.
Upper Weld and Wrap Around Bar Inspection Results 3/4 SAT - All welds intact; no degradation observed.
Details 3/4 No abnormalities on weld repairs observed compared to RF16.
45º Through-Tube Bundle Inspection Results 3/4 Acceptance criteria met - tube wear less than 33% through tube.
(ref. Westinghouse letter LTR-SGDA-07-217)
Details 3/4 Intrados through tube wear with stabilizer wear observed. Confirmed as one of the first ring of tubes around the stay cylinder, location confirmed at hot leg, Row 35, Col 77).
(CR-WF3-2009-06486, CR-WF3-2011-02347, CR-WF3-2011-02450)
The indication was about 25% thru tube and met the 33% wear acceptance criteria. Note Westinghouse letter LTR-SGDA-11-070 supports 40% thru tube wear at this location.
Per Westinghouse letter LTR-SGDA-11-070, assuming the worst case initial wear condition and assuming a continuation of high wear rate during cycle 17 the stabilizer will remain intact 3/4 Tube wear at batwing to tube interface similar to RF16 No tubes observed with greater than 33% through tube wear
Steam Generator Batwing Inspections Spring 2011 Refuel 17 Outage Preliminary Results Page 6 of 9 Figure 2a: Intrados Tube Wear(RF16 to RF17 Comparison
Steam Generator Batwing Inspections Spring 2011 Refuel 17 Outage Preliminary Results Page 7 of 9 Bottom-Up Video Inspection 3/4 Acceptance criteria met No missing batwing pieces larger than 36 long per Westinghouse letter LTR-SGDA 204)
Details Preliminary review has determined that no significant changes since RF16.
Detailed review has commenced.
Steam Generator Batwing Inspections Spring 2011 Refuel 17 Outage Preliminary Results Page 8 of 9 Figure 3a: RF17 SG-2 Composite
Steam Generator Batwing Inspections Spring 2011 Refuel 17 Outage Preliminary Results Page 9 of 9 Figure 3b: RF16 SG-2 Composite