NRC 2013-0097, Response to Request for Additional Information Fall 2012 Unit 2 (U2R32) Steam Generator Tube Inspection Report
| ML13288A142 | |
| Person / Time | |
|---|---|
| Site: | Point Beach  |
| Issue date: | 10/14/2013 |
| From: | Millen M Point Beach |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| NRC 2013-0097 | |
| Download: ML13288A142 (6) | |
Text
October 14, 2013 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555 Point Beach Nuclear Plant, Units 2 Docket 50-301 Renewed License No. DPR-27 Response to Request for Additional Information NEXT era" EN ERGY~
~
NRC 2013-0097 TS 5.6.8 Fall 2012 Unit 2 (U2R32) Steam Generator Tube Inspection Report
References:
(1)
(2)
NextEra Energy Point Beach, LLC letter to NRC, dated May 16, 2013, Fall 2012 Unit 2 (U2R32) Steam Generator Tube Inspection Report, (ML13140A015)
NRC electronic mail to NextEra Energy Point Beach, LLC, dated September 27, 2013, Point Beach Nuclear Plant, Unit 2 - Request for Additional Information re: Fall2012 (U2R32) Steam Generator Tube lnservice Inspection Report Review (TAG No. MF1866)
NextEra Energy Point Beach, LLC (NextEra) submitted the Fall 2012 Unit 2 (U2R32) Steam Generator Tube Inspection Report via Reference (1 ), documenting the scope and results of the inspection per prescribed Technical Specification Reporting Requirements.
The NRC Staff has determined that additional information is required to complete its evaluation (Reference 2). The Enclosure provides the NextEra response to Reference (2).
This letter contains no new Regulatory Commitments and no revisions to existing Regulatory Commitments.
NextEra Energy Point Beach, LLC, 6610 Nuclear Road, Two Rivers, WI 54241
Document Control Desk Page 2 If you have questions or require additional information, please contact Mr. Andrew Watry at 920/755-7393.
Very truly yours, NextEra -Energy Point Beach, LLC Licensing Manager Enclosure cc:
Administrator, Region Ill, USNRC Project Manager, Point Beach Nuclear Plant, USNRC Resident Inspector, Point Beach Nuclear Plant, USNRC PSCW
ENCLOSURE NEXTERA ENERGY POINT BEACH, LLC POINT BEACH NUCLEAR PLANT, UNITS 1 AND 2 RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION FALL 2012 UNIT 2 (U2R32) STEAM GENERATOR TUBE INSPECTION REPORT The NRC Staff determined that additional information was required (Reference 1) to enable the continued review of the Point Beach Nuclear Plant (PBNP) Fall 2012 Unit 2 (U2R32) Steam Generator Tube Inspection Report (Reference 2). The following information is provided by NextEra Energy Point Beach, LLC (NextEra) in response to the NRC Staff's request.
Please discuss which inspection period the steam generators are currently in. If the steam generators are in the last outage of the first sequential period, then please confirm that 100 percent of the row 1 and 2 tubes in the U-bend region have been inspected during this period.
NextEra Response PBNP Unit 2 is in the second inspection period which is 108 EFPM. The U2R32 steam generator inspection was the first inspection in the second inspection period.
It was indicated that no new wear due to suspected foreign objects or maintenance related activities were identified. Does the adjective "new" imply that there were such indications in the steam generator, but none of the ones detected were "new"? If so, please provide a summary of the indications found (regardless of whether they were new or old).
NextEra Response Possible loose part (PLP) signals were reported by bobbin and +Point inspections at the top of the tubesheet at the two locations listed in Table 2-1 below. A +Point inspection was performed at all the PLP locations identified by bobbin, in tubes surrounding PLP signals, and historical PLP signals. During the foreign object search and retrieval (FOSAR), PLPs were dispositioned per Table 2-1 comments.
There were 6 historical PLP signals and surrounding tubes inspected with +Point and five of the signals had no indications reported in U2R32. The only repeat indication is documented in Table 2-1.
Page 1 of 4
Table 2-1 Steam Row Column Location Comments Generator A
32 7
TSC No foreign object observed.
A Annulus 51 Top of Gasket piece identified during FOSAR and Tubesheet removed (0.188 inch height, 3.5 inch length, 0.040 inch width).
No wear based on 100% + Point of periphery tubes.
No PLP signal from ECT.
B 3
40 TSH Historical indication from U2R29. No objects were observed during FOSAR.
It was indicated that the secondary side inspections showed no significant degradation, that no anomalies were noted, and that no anomalous conditions adverse to structural integrity were reported. Please clarify if any corrosion, erosion, or degradation was identified during the secondary side inspections.
NextEra Response Secondary side inspections were performed using a camcorder with no anomalies recorded.
There was no sign of erosion, or degradation during the recent inspections. There was an expected protective magnetite layer on the interior surface of the primary moisture separators.
No material loss was noted during the secondary side inspections of the 36 J-nozzles, interior and exterior of the feed ring, primary moisture separators, and accessible areas of the mid deck extensions and brackets, flow diverters, mid-deck hatch and bolts, and secondary moisture separators.
Possible loose part indications that could not be visually inspected were left in service following the 2008 tube inspections. These locations were inspected with a rotating probe equipped with a +Point coil. Please discuss the results of these examinations.
In the 2012 report, it was indicated that two possible loose part indications were detected. Please confirm that these were the only indications identified. If more were detected, then please discuss.
NextEra Response There were 6 historical PLP signals and surrounding tubes inspected with +Point and five of the signals had no indications reported in U2R32. The only repeat indication is documented above in Table 2-1.
The two possible loose parts indications from U2R32 are documented above in NextEra Response to RAI 2. These were the only two PLP's identified during U2R32.
Page 2 of 4
Please discuss the results of the tube plug inspections (e.g., all present and in proper location, degradation detected, any evidence of leakage).
NextEra Response A video inspection of 4 installed plugs in SG B (hot and cold legs) showed that all plugs are dry, in their proper location, and no degradation was detected on any of the installed plugs.
Please discuss the results of the steam generator channel head inspections.
NextEra Response The steam generator channel heads were visually inspected. The inspections were performed prior to nozzle cover installation as early as possible after the primary manways were removed.
A detailed inspection per NSAL 12-01 was conducted approximately 36 inches radially on each side of the divider plate, centered on the bottom of the bowl. A scan was also conducted on the remaining portion of the channel head cladding to ensure no areas of degradation were present on the channel head cladding. No indications of rust or other indication of cladding degradation were present in any of the Unit 2 SG A and SG B channel head inspections.
Please confirm that the first sentence in Section 3. 0 should indicate Unit 2 rather than Unit 1.
NextEra Response The first sentence in Section 3.0 should read:
"The following degradation mechanisms were observed in the PBNP Unit 2 SGs during U2R32."
RAI8 Please identify which location had the new wear indication attributed to interaction between the tube and the anti-vibration bar (A VB). Presumably the 2008 entry for all of the A VB wear indications have depth estimates since with hindsight the new 2012 indication had a precursor signal in 2008.
NextEra Response One new indication was recorded in SG A at Anti-Vibration Bar 3, Row 79, Column 62, with 12% TW in 2012. Re-analysis of prior inspection data identified 8% TW in 2008 ~nd 10% TW in 2003.
Page 3 of 4
References (1) NRC electronic mail to NextEra Energy Point Beach, LLC, dated September 27, 2013, Point Beach Nuclear Plant, Unit 2-Request for Additional Information re: Fall 2012 (U2R32) Steam Generator Tube lnservice Inspection Report Review (TAC No. MF1866)
(2) NextEra Energy Point Beach, LLC letter to NRC, dated May 16, 2013, Fall 2012 Unit 2 (U2R32) Steam Generator Tube Inspection Report, (ML13140A015)
(3) FPL Energy, Point Beach Nuclear Plant letter to NRC, dated Sep 16, 2008, Spring 2008 Unit 2 (U2R29) Steam Generator Tube Inspection Report.
Page 4 of 4