L-23-139, Response to Request for Additional Information Regarding Fall 2022 180-Day Steam Generator Tube Inspection Report

Response to Request for Additional Information Regarding Fall 2022 180-Day Steam Generator Tube Inspection Report

ML23164A048
Person / Time
Site:	Beaver Valley
Issue date:	06/13/2023
From:	Blair B Energy Harbor Nuclear Corp
To:	Office of Nuclear Reactor Regulation, Document Control Desk
References
L-23-139, EPID L-2023-LRO-0014
Download: ML23164A048 (1)

Text

energy harbor Energy Harbor Nuclear C01p.

Beaver Valley Power Station P.O. Box 4 Shippingport, PA 15077 Barry N. Blair 724-682-5234 Site Vice President, Beaver Valley Nuclear June 13, 2023 L-23-139 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555-0001

Subject:

Beaver Valley Power Station, Unit No. 1 Docket No. 50-334, License No. DPR-66 Response to Request for Additional Information Regarding Fall 2022 180-Day Steam Generator Tube Inspection Report (EPID: L-2023-LRO-0014)

By letter dated March 27, 2023 (Accession No. ML23087A063), Energy Harbor Nuclear Corp. submitted information summarizing the results of the steam generator (SG) inspections performed at Beaver Valley Power Station, Unit No. 1, during the fall 2022 refueling outage (1 R28).

By email dated May 2, 2023, the Nuclear Regulatory Commission (NRC) staff requested additional information to complete its review of the report. The Energy Harbor Nuclear Corp. response to the NRC request is attached.

There are no regulatory commitments contained in this submittal. If there are any questions or if additional information is required, please contact Mr. Phil H. Lashley, Manager - Fleet Licensing, at (330) 696-7208.

Barry N. Blair

Attachment:

Response to Request for Additional Information

Beaver Valley Power Station, Unit No. 1 L-23-139 Page 2 cc: NRC Region I Administrator NRC Resident Inspector NRR Project Manager Director BRP/DEP Site BRP/DEP Representative

Attachment L-23-139 Response to Request for Additional Information Page 1 of 13 The NRC staffs request for additional information is presented below in bold text, followed by the Energy Harbor Nuclear Corp. response.

RAI-1

The report section describing channel head bowl visual inspections states that during the 1R24 visual channel head inspection, an anomaly was observed on the divider plate to channel head weld in the hot leg of SG A. In addition, the report states the anomaly was re-inspected during 1R28 and that there was no change in the anomaly from 1R21 to 1R28. The report also states that an evaluation of the anomaly was previously performed and concluded that it is an artifact of manufacturing, not representative of a crack-like condition created by the operating environment or a fabrication flaw. The NRC staff review of the 1R21 and 1R24 steam generator tube inspection reports did not find mention of an anomaly in the visual inspection results discussion.

a. Provide greater detail about the anomaly appearance and the evaluation that concluded that it is an artifact of manufacturing rather than a crack-like condition.

Response

During the Beaver Valley Power Station, Unit No. 1 (BVPS-1), fall 2016 refueling outage (1R24), a visual anomaly was observed on the SG A divider plate-to-channel head weld. This anomaly was observed extending for a short distance at the juncture of the toe bead (edge bead) at the juncture of the weld and channel head clad. The anomaly is found on the hot leg side of SG A, located about 2/3 of the distance from the bottom of the channel head bowl to the tubesheet, on the manway side. Figure 1 provides more details.

Based on the A690 advanced material composition and Westinghouse proprietary filler material, the divider plate-to-channel head weld is judged not susceptible to primary water stress corrosion cracking.

When this anomaly was first discovered, the visual record from 1R24 was compared with the visual record from the spring 2012 refueling outage (1R21). There was no apparent change in condition from 1R21 to 1R24. Figure 1 presents the visual record from 1R24 while Figure 2 presents the visual record from 1R21.

The divider plate-to channel head weld may be surface ground; however, the fabricator is instructed to avoid grinding strikes on the channel head cladding due to the limited thickness. Other portions of the weld appear, such as on the nozzle side, to be ground flush to the channel head cladding over the length from the tubesheet

Attachment L-23-139 Page 2 of 13 to the bottom of the bowl. Figures 3 through 5 provide nozzle side images. On the manway side, the grinding does not appear to be taken to flush with the channel head cladding in the area of interest. As the scan is continued up towards the tubesheet, the grinding can be seen to progress closer and closer to the channel head cladding until it appears to have been taken to a flush condition. As the grinding gets closer to the cladding, the dark areas appear to get thinner and thinner until no dark areas are seen and a smooth surface is observed across the width of the weld. Figures 6 through 9 provide images of the weld below and above the visual anomaly.

Thus, the observed anomaly is most likely a visual by-product of surface irregularity of the toe bead at the juncture with the channel head cladding or at the juncture with interior beads. Since no apparent change is noted in the condition between 1R21, 1R24, and 1R28 (Figure 10 shows a comparison), no active condition is judged to be present. The tail anomaly, which progresses from the juncture of the toe bead to the channel head cladding, is most likely the end of one bead and the beginning of another bead. The tip of the tail anomaly is most likely a result of surface grinding consuming any postulated surface irregularity between the beginning and ending of the separate beads. Given the materials involved, operating experience of BVPS-1, and lack of change between visual inspections, it can be judged that the anomaly is a visual artifact of manufacture and not representative of a crack-like indication created by environment, nor a fabrication flaw.

b. Clarify if this anomaly was visually observed during the 1R21 channel head bowl visual inspections. If it was not, please explain the apparent typographical error in the statement that there was no change from 1R21 to 1R28.

Response

The anomaly was first identified during the inspections conducted in 1R24. The anomaly was not identified during the 1R21 inspection. However, the 1R21 inspection was recorded. During 1R24, the video recordings from the 1R21 visual inspection were reviewed and were able to be used for comparison.

The technical justification that was generated during 1R24 concluded that the anomaly was a visual artifact of manufacture and not representative of a crack-like indication created by environment, nor a fabrication flaw. Based on the conclusion of the report, this anomaly would not have been considered degradation. The 1R24 180-day report would have followed the technical specification (TS) reporting requirements in place at the time, which specified the report shall include degradation mechanisms found (TS 5.6.6.1.b).

Attachment L-23-139 Page 3 of 13 BVPS-1 received approval to implement Technical Specifications Task Force (TSTF)

Traveler TSTF-577 on May 2, 2022. The Electric Power Research Institute (EPRI) has also recently revised the Steam Generator Management Program: Steam Generator Integrity Assessment Guidelines to include a new Appendix G TEMPLATE FOR TSTF-577 180-DAY STEAM GENERATOR INSPECTION REPORT Question 13 of the new template is The results of primary side component visual inspections performed in each SG. The 1R28 180-day report followed the guidelines of the new template and included a discussion on the results of the primary side visual inspections.

The Steam Generator Program Owner during 1R24 is no longer with the company.

While the intent cannot be confirmed, based on the reporting requirements in place for 1R24 as compared to the reporting requirements in place for 1R28, it is believed that the anomaly was not included in the 1R24 report because it was not considered to be a degradation mechanism.

Based on the above, the statement that there was no change from 1R21 to 1R28 is appropriate and not a typographical error.

Attachment L-23-139 Page 4 of 13 Junction Area of Interest Chatlllelh ead Cladding Figure 1: Image of Visual Anomaly from I R24

Attachment L-23-139 Page 5 of 13 Figure 2: Image of Visual Anomaly from IR21

Attachment L-23-139 Page 6 of 13 Channelhead Cladding Grind surface taken to cladding Figure 3: First Image of Channelhead-to-Divicler Plate \Velcl on Nozzle Sicle

Attachment L-23-139 Page 7 of 13 Channelhead Cladding Figure 4: Second I mage of Cha1111ell1ead-to-Divider Plate Weld 011 l\"ozzle Side

Attachment L-23-139 Page 8 of 13 Cham1el11ead Cladding Figure 5: Third Image of Channelheacl-to-Divicler Plate Weld on Nozzle Side

Attachment L-23-139 Page 9 of 13

.Figure 6: i mage or Clla1111el11ead-to-1Jivicler !:'late Weld Helow Visual Anomaly on Manway Side

Attachment L-23-139 Page 10 of 13 Step or Ledge bef\veen grind surface and cladding Channelhead Cladding F igure 7: Image of Chanuell1eacl-to-Divicler Plate Welcl Above Visual Anomaly on Mauway Sicle

Attachment L-23-139 Page 11 of 13 Chru111elhead Cladding F igure 8: Image of Channelbeacl-to-Divicler Plate Weld Above Visual Anomaly on l\.'Ianway Side

Attachment L-23-139 Page 12 of 13 Channelhead Cladding Figure 9: Image of Channelhead-to-Divider Plate Weld Above Visual Anomaly on Manway Side

Attachment L-23-139 Page 13 of 13 Figure 10: BVPS-1 Channel Head Anomaly SG A Hot Leg, 1R21, 1R24 and 1R28 Results