ML16243A465: Difference between revisions

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By letter dated April 22, 2016, (Agencywi de Documents Access and Management System (ADAMS) Accession Number ML16120A203), NextEra Energy Seabrook, LLC (the licensee) submitted information summarizing the results of the 2015 steam generator tube inspections at Seabrook Station. These inspections were performed during refueling outage 17. In order to complete its review of the document listed above, the staff requests the following additional  
By letter dated April 22, 2016, (Agencywi de Documents Access and Management System (ADAMS) Accession Number ML16120A203), NextEra Energy Seabrook, LLC (the licensee) submitted information summarizing the results of the 2015 steam generator tube inspections at Seabrook Station. These inspections were performed during refueling outage 17. In order to complete its review of the document listed above, the staff requests the following additional  


information:  
information:
: 1. Section A:  The last sub-bullet on page 1 contains a statement regarding the augmented inspections performed after the bobbin coil inspections, to improve the probability of detection (POD) of axial outside diameter stress corrosion cracking (ODSCC) flaws at tube support plates. The sub-bullet appears to indicate that approximately 68 percent of hot-leg tubes were inspected (from three inches above the top-of-the-tubesheet to the H*
: 1. Section A:  The last sub-bullet on page 1 contains a statement regarding the augmented inspections performed after the bobbin coil inspections, to improve the probability of detection (POD) of axial outside diameter stress corrosion cracking (ODSCC) flaws at tube support plates. The sub-bullet appears to indicate that approximately 68 percent of hot-leg tubes were inspected (from three inches above the top-of-the-tubesheet to the H*
depth) in targeted zones that are prone to sludge deposition, using the +PointŽ probe. A bullet on page 2 indicates that for the ODSCC indication, the inspection scope was increased from 68 percent to 100 percent of the hot-leg tubes (from three inches above to three inches below the top-of-the-tubesheet) in the affected SG (SG-C). Please clarify the scope of the examinations in the tubesheet and at the top of the tubesheet. Were 68 percent of all tubes (not just tubes in the targeted zones) inspected from +3 inches to the H* depth in all four SGs?  Were 100 percent of all tubes in SGs A and C inspected from +3 to -3 inches on the hot-leg?  
depth) in targeted zones that are prone to sludge deposition, using the +PointŽ probe. A bullet on page 2 indicates that for the ODSCC indication, the inspection scope was increased from 68 percent to 100 percent of the hot-leg tubes (from three inches above to three inches below the top-of-the-tubesheet) in the affected SG (SG-C). Please clarify the scope of the examinations in the tubesheet and at the top of the tubesheet. Were 68 percent of all tubes (not just tubes in the targeted zones) inspected from +3 inches to the H* depth in all four SGs?  Were 100 percent of all tubes in SGs A and C inspected from +3 to -3 inches on the hot-leg?
: 2. In reviewing the reported volumetric indications in Table 4, it appears that the indication in the tube in row 22 column 97 in SG B was present in 2009 with a 32 percent through-wall depth, but was not reported (since Table 4 also states that the indication is a newly reported TSP indication). Please confirm and discuss why the indication was not reported previously, or clarify the information in the table (since normally a 32 percent through-wall wear flaw would be readily detectible with a high probability of detection).  
: 2. In reviewing the reported volumetric indications in Table 4, it appears that the indication in the tube in row 22 column 97 in SG B was present in 2009 with a 32 percent through-wall depth, but was not reported (since Table 4 also states that the indication is a newly reported TSP indication). Please confirm and discuss why the indication was not reported previously, or clarify the information in the table (since normally a 32 percent through-wall wear flaw would be readily detectible with a high probability of detection).
: 3. The report states on page 9 that all tube plugs were inspected and classified as Category 1, Westinghouse procedure MRS 2.4.2 Gen-44, Revision 1; "Visual Inspection of Plugs."  The U.S. Nuclear Regulatory Commission staff is not familiar with the characteristics of a Category 1 plug. Please clarify whether any degradation was noted on the plugs during the visual inspection.  
: 3. The report states on page 9 that all tube plugs were inspected and classified as Category 1, Westinghouse procedure MRS 2.4.2 Gen-44, Revision 1; "Visual Inspection of Plugs."  The U.S. Nuclear Regulatory Commission staff is not familiar with the characteristics of a Category 1 plug. Please clarify whether any degradation was noted on the plugs during the visual inspection.
: 4. Section I on page 11 states, "Since there is no observed operating leakage from the remaining SGs (SG-A, SG-C and SG-D), the predicted accident induced leakage for each of these is zero."  Please clarify this statement. Please confirm that since there was no observed operational leakage from SGs A, C, and D, the predicted accident-induced leakage from the tubesheet expansion region is zero, from these three SGs. Also, please confirm that there were no other sources of accident-induced leakage (other than the expansion region in SG B) in all four SGs.}}
: 4. Section I on page 11 states, "Since there is no observed operating leakage from the remaining SGs (SG-A, SG-C and SG-D), the predicted accident induced leakage for each of these is zero."  Please clarify this statement. Please confirm that since there was no observed operational leakage from SGs A, C, and D, the predicted accident-induced leakage from the tubesheet expansion region is zero, from these three SGs. Also, please confirm that there were no other sources of accident-induced leakage (other than the expansion region in SG B) in all four SGs.}}

Revision as of 01:16, 27 April 2019

Draft RAIs on Steam Generator Tube Inspection Report for Refueling Outage 17
ML16243A465
Person / Time
Site: Seabrook NextEra Energy icon.png
Issue date: 08/30/2016
From: Justin Poole
Plant Licensing Branch 1
To: Browne K
NextEra Energy Seabrook
References
MF7686
Download: ML16243A465 (3)
v • d • e


Text

1 NRR-PMDAPEm Resource From: Poole, Justin Sent: Tuesday, August 30, 2016 4:07 PM To: Browne, Kenneth

Subject:

DRAFT RAIs on SG Inspection Report for RFO 17 Attachments:

MF7686 DRAFT RAIs.docx Ken, By letter dated April 22, 2016, (ADAMS Accession Numbers ML16120A203), NextEra Energy Seabrook, LLC (NextEra), submitted its Steam Generator Tube Inspection Report for refueling outage 17. In reviewing NextEra's report, the NRC staff has developed the attached DRAFT request for additional information (RAI). Please review to ensure that the RAI questions are understandable, the regulatory basis is clear, there is no proprietary information contained in the RAI, and to determine if the information was previously docketed. If further clarification is needed, and you would like to discuss the questions in a conference call, let us know. This email does not convey a formal NRC staff position, and it does not formally request for additional information.

Justin C. Poole Project Manager NRR/DORL/LPLI-2 U.S. Nuclear Regulatory Commission (301)415-2048

Hearing Identifier: NRR_PMDA Email Number: 3023 Mail Envelope Properties (Justin.Poole@nrc.gov20160830160600)

Subject:

DRAFT RAIs on SG Inspection Report for RFO 17 Sent Date: 8/30/2016 4:06:57 PM Received Date: 8/30/2016 4:06:00 PM From: Poole, Justin Created By: Justin.Poole@nrc.gov Recipients: "Browne, Kenneth" <Kenneth.J.Browne@nexteraenergy.com>

Tracking Status: None Post Office: Files Size Date & Time MESSAGE 880 8/30/2016 4:06:00 PM MF7686 DRAFT RAIs.docx 27479 Options Priority: Standard Return Notification: No Reply Requested: No Sensitivity: Normal Expiration Date: Recipients Received:

ENCLOSURE REQUEST FOR ADDITIONAL INFORMATION 2015 STEAM GENERATOR TUBE INSPECTIONS SEABROOK STATION DOCKET NUMBER 50-443

By letter dated April 22, 2016, (Agencywi de Documents Access and Management System (ADAMS) Accession Number ML16120A203), NextEra Energy Seabrook, LLC (the licensee) submitted information summarizing the results of the 2015 steam generator tube inspections at Seabrook Station. These inspections were performed during refueling outage 17. In order to complete its review of the document listed above, the staff requests the following additional

information:

1. Section A: The last sub-bullet on page 1 contains a statement regarding the augmented inspections performed after the bobbin coil inspections, to improve the probability of detection (POD) of axial outside diameter stress corrosion cracking (ODSCC) flaws at tube support plates. The sub-bullet appears to indicate that approximately 68 percent of hot-leg tubes were inspected (from three inches above the top-of-the-tubesheet to the H*

depth) in targeted zones that are prone to sludge deposition, using the +PointŽ probe. A bullet on page 2 indicates that for the ODSCC indication, the inspection scope was increased from 68 percent to 100 percent of the hot-leg tubes (from three inches above to three inches below the top-of-the-tubesheet) in the affected SG (SG-C). Please clarify the scope of the examinations in the tubesheet and at the top of the tubesheet. Were 68 percent of all tubes (not just tubes in the targeted zones) inspected from +3 inches to the H* depth in all four SGs? Were 100 percent of all tubes in SGs A and C inspected from +3 to -3 inches on the hot-leg?

2. In reviewing the reported volumetric indications in Table 4, it appears that the indication in the tube in row 22 column 97 in SG B was present in 2009 with a 32 percent through-wall depth, but was not reported (since Table 4 also states that the indication is a newly reported TSP indication). Please confirm and discuss why the indication was not reported previously, or clarify the information in the table (since normally a 32 percent through-wall wear flaw would be readily detectible with a high probability of detection).
3. The report states on page 9 that all tube plugs were inspected and classified as Category 1, Westinghouse procedure MRS 2.4.2 Gen-44, Revision 1; "Visual Inspection of Plugs." The U.S. Nuclear Regulatory Commission staff is not familiar with the characteristics of a Category 1 plug. Please clarify whether any degradation was noted on the plugs during the visual inspection.
4.Section I on page 11 states, "Since there is no observed operating leakage from the remaining SGs (SG-A, SG-C and SG-D), the predicted accident induced leakage for each of these is zero." Please clarify this statement. Please confirm that since there was no observed operational leakage from SGs A, C, and D, the predicted accident-induced leakage from the tubesheet expansion region is zero, from these three SGs. Also, please confirm that there were no other sources of accident-induced leakage (other than the expansion region in SG B) in all four SGs.
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