ML19119A120

Long-Term Steam Dryer Inspection Plan at EPU Conditions

ML19119A120
Person / Time
Site:	Peach Bottom
Issue date:	04/29/2019
From:	Pat Navin Exelon Generation Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
CCN 19-66
Download: ML19119A120 (5)

Text

Exelon Generation DPR-44 Operating License 2.C(15)(h)

CCN 19-66 April 29, 2019 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Peach Bottom Atomic Power Station, Unit 2 Renewed Facility Operating License No. DPR-44 NRG Docket No. 50-277

Subject:

Peach Bottom Unit 2 Long-Term Steam Dryer Inspection Plan at EPU Conditions

References:

1. WCAP-17635-P, Rev. 3, Peach Bottom Atomic Power Station Units 2 and 3 Replacement Steam Dryer Comprehensive Vibration Assessment Program (CVAP), April 2014.

2. Peach Bottom Atomic Power Station, Units 2 and 3 - Extended Power Uprate License Amendment Request - Supplement 24 - Response to Request for Additional Information, dated April 11, 2014. ML14105A383

3. Issuance of Amendments - PBAPS Units 2 and 3 Extended Power Uprate, License Amendments 293/296 (including NRG Safety Evaluation Report), dated August 25, 2014.

4. Peach Bottom Atomic Power Station, Unit 2 - Results of Visual Inspections of Replacement Steam Dryer, Letter from Exelon to NRG dated December 7, 2016, ML16342B621.

5. Peach Bottom Atomic Power Station, Unit 2 - Results of Visual Inspections of Unit 2 Replacement Steam Dryer in the Second Refueling Outage After Reaching EPU Conditions, Letter from Exelon to NRG dated January 23, 2019, ML19024A195.

6. BWRVIP-139, Revision 1-A: BWR Vessel and Internals Project: Steam Dryer Inspection and Flaw Evaluation Guidelines. EPRI, Palo Alto, CA: 2017.

300201 0541 .

Attached is the long-term inspection plan for the Peach Bottom Unit 2 Replacement Steam Dryer that was developed using inspection results from the two refueling outages after reaching EPU conditions {P2R22 and P2R23) and industry operating experience.

This inspection plan is being submitted pursuant to Operating License Condition 2.C(15)(h) which requires that a long-term steam dryer inspection plan based on industry operating experience along with the baseline inspection results be submitted within 6 months following completion of the second refueling outage after the implementation of the EPU.

The inspection plan is in part based on WCAP-17635, Rev. 3 (Reference 1) which was submitted to the NRG in the Reference 2 letter. The letter was referenced in the NRG Safety Evaluation Report for Extended Power Uprate (Reference 3).

U.S. Nuclear Regulatory Commission Results of Visual Inspections of Unit 2 Replacement Steam Dryer in the Second Refueling Outage After Reaching EPU Conditions Docket No. 50-277 Page 2 5236$J If you have any questions concerning this letter, please contact Randal Schmidt at (61 O) 765-Patrick D. Navin Site Vice President Peach Bottom Atomic Power Station Attachment- Peach Bottom Unit 2 Long-Term Steam Dryer Inspection Plan at EPU Conditions cc: Regional Administrator, Region I USNRC USNRC Senior Resident Inspector, PBAPS D. J., Allard, Pennsylvania Bureau of Radiation Protection D. Tancabel, State of Maryland

ATTACHMENT Peach Bottom Unit 2 Long-Term Steam Dryer Inspection Plan at EPU Conditions

Attachment Peach Bottom Unit 2 Long-Term Steam Dryer Inspection Plan at EPU Conditions Page 1of2 Purpose This document provides the long-term inspection plan for the Peach Bottom Unit 2 Replacement Steam Dryer (RSD) as required by the Renewed Facility Operating License No. DPR-44, License Condition 2.C(15)(h). This license condition requires that the long-term inspection plan be submitted within 6 months following completion of the second refueling outage after the implementation of the EPU and be based on industry operating experience along with baseline inspection results.

RSD Long-Term Inspection Plan Input A long-term steam dryer inspection plan was developed for Peach Bottom Unit 2 following completion of the 2016 and 2018 refueling outages. These outages were the first and second refueling outages following implementation of EPU. The plan is based on WCAP-17635-P Section 5.5, inspection results from the 2016 and 2018 outages, recommendations from Westinghouse, the RSD manufacturer, and recent industry Operating Experience (OE).

WCAP-17635-P This document was submitted to and reviewed by the NRC during the EPU licensing process. Section 5 provides the inspection plan for the first inspection and subsequent inspection following EPU implementation. The plan was implemented in the 2016 and 2018 outages. The inspection scope is based upon Operating Experience (OE) for the Westinghouse steam dryer design from previous installations, high cyclical stress locations determined from dryer acoustic analysis, and finally, by higher stress locations where solution annealing of structural welds was not performed. In addition, general principles and conclusions from BWRVI P-139 and RG 1.20 were applied to the inspection plan .

Furthermore, the document states that the RSD is octagonal (high symmetry) and inspections will be performed on limited sections of the octagon. For a typical weld ID, there are 8 locations, one on each of the 8 sections of the dryer. If flaws are identified, the comparable locations on the other seven sections of the dryer will be examined in the same outage.

Inspection Results for the 2016 and 2018 Outages For both inspections, nine indications were found at two general locations: five were associated with a fillet welds for the hold down rod and lifting rod interface to the support ring, and four were associated with the seismic blocks. Details on the results of the 2016 outage were provided in Reference 4, and details on the results of the 2018 outage were provided in Reference 5.

The fillet welds for the hold down rod and lifting rod interface to the support ring are non-structural and were not explicitly modeled or analyzed as part of the structural qualification of the steam dryer. The seismic blocks exhibited wear on the contact areas where the seismic blocks sit on the RPV Steam Dryer Support Brackets when the RSD is installed in the reactor. All indications are acceptable for plant operations and will be periodically inspected.

Attachment Peach Bottom Unit 2 Long-Term Steam Dryer Inspection Plan at EPU Conditions Page 2 of 2 Westinghouse Recommendations To supplement the WCAP-17635-P inspection plan, Westinghouse recommended inspecting additional high stress locations and/or areas which should be inspected since some locations were not polished during fabrication. Some welds were inaccessible for polishing during the fabrication sequence and, due the lack of polishing, are more susceptible to IGSCC cracking than polished locations. The recommendations incorporated the latest analyses using the steam dryer instrumented data taken for EPU.

Recent Operating Experience Westinghouse was contacted regarding current operating experience of Westinghouse designed steam dryers. Since the issuance of the WCAP in 2014, the industry Operating Experience (OE) did not result in changes to the Westinghouse inspection recommendations for Peach Bottom Unit 2. Also, inspection results of the Peach Bottom Unit 3 RSD had similar results as the unit 2 RSD. Therefore, no additional inspections are necessary due to the recent OE.

Long-term RSD Inspection Plan The inspection plan includes inspection of the various locations over 10-year periods. This frequency is consistent with re-inspection frequency of BWRVIP-139 and Westinghouse recommendations. The RSD is octagonal (high symmetry) and inspections will be performed on limited sections of the octagon. For a typical weld ID, there are 8 locations, one on each of the 8 sections of the dryer. If flaws are identified, the comparable locations on the other seven sections of the dryer will be examined in the same outage.

Over the ten-year periods, the plan requires inspection of:

• One location per weld ID in accordance with WCAP-17635-P, Section 5.5.

• One location per weld ID in accordance with Westinghouse recommendations.

• All flaws found during inspections (Re-inspections).

The inspection plan is a "living document," which will be modified as appropriate to incorporate lessons learned from other dryer inspections, particularly lessons learned from inspections on Westinghouse steam dryers.

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Conclusion:==

A long-term inspection plan has been developed for the Peach Bottom Unit 2 Replaced Steam dryer. Submittal of the plan satisfies the Peach Bottom Unit 2 Facility Operating License Condition 2.C(15)(h) for the Replacement Steam Dryer.