ML16062A251

Request for Additional Information Regarding Request to Use F* Steam Generator Alternate Repair Criteria

ML16062A251
Person / Time
Site:	Watts Bar
Issue date:	02/26/2016
From:	Robert Schaaf Plant Licensing Branch II
To:	Arent G Tennessee Valley Authority
References
MF7218
Download: ML16062A251 (5)

Text

1 NRR-PMDAPEm Resource From: Schaaf, Robert Sent: Friday, February 26, 2016 2:14 PM To: Gordon Arent; Casey, Kevin E (kec asey@tva.gov); Daniels, Desiree L Cc: Render, Diane; Saba, Farideh; Beasley, Benjamin

Subject:

Request for Additional Information Regard ing Request to Use F* Steam Generator Alternate Repair Criteria (CAC No. MF7218)

Attachments:

Watts Bar 2 - Encl - RAIs re Proposed SG ARC Amendment - MF7218.pdfBy letter dated December 15, 2015 (Agencywide Documents Access and Management System (ADAMS) Accession No.

ML15362A023), the Tennessee Valley Authority (TVA) submitted an application for a license amendment request to revise portions of the Watts Bar Nuclear Plant, Unit 2, technical specifications, to allow implementation of the F* alternate repair criterion for steam generator tubes for Watts Bar Nuclear Plant (WBN), Unit 2.

The Nuclear Regulatory Commission (NRC) staff is reviewing TVA's submittal and has determined that additional information is required to complete its review. The specific information requested is attached to this e-mail.

You may accept this draft as the formal Request for Additional Information (RAI) and provide a response by March 28, 2015. Alternatively, you may request clarification of the attached requests with the NRC staff in a conference call. Please confirm receipt of these RAIs, and the date by which a response will be submitted if no clarification is needed.

Regards, Robert G. Schaaf Robert G. Schaaf Senior Project Manager, Watts Bar/Bellefonte Plant Licensing Branch II-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Mail Stop O-8G9A Washington, DC 20555 301-415-6020 (o) Robert.Schaaf@nrc.gov

Hearing Identifier: NRR_PMDA Email Number: 2684 Mail Envelope Properties (24e491245cb04a67b308789bef724699)

Subject:

Request for Additional Information Regarding Request to Use F* Steam Generator Alternate Repair Criteria (CAC No. MF7218) Sent Date: 2/26/2016 2:13:49 PM Received Date: 2/26/2016 2:13:49 PM From: Schaaf, Robert Created By: Robert.Schaaf@nrc.gov Recipients: "Render, Diane" <Diane.Render@nrc.gov> Tracking Status: None "Saba, Farideh" <Farideh.Saba@nrc.gov> Tracking Status: None "Beasley, Benjamin" <Benjamin.Beasley@nrc.gov>

Tracking Status: None "Gordon Arent" <garent@tva.gov> Tracking Status: None "Casey, Kevin E (kecasey@tva.gov)" <kecasey@tva.gov> Tracking Status: None "Daniels, Desiree L" <dlboyd@tva.gov>

Tracking Status: None Post Office: HQPWMSMRS07.nrc.gov

Files Size Date & Time MESSAGE 1347 2/26/2016 2:13:49 PM Watts Bar 2 - Encl - RAIs re Proposed SG ARC Amendment - MF7218.pdf 49675 Options Priority: Standard Return Notification: No Reply Requested: No Sensitivity: Normal Expiration Date: Recipients Received:

ENCLOSUREREQUEST FOR ADDITIONAL INFORMATIONREGARDING THE PROPOSED AMENDMENT TO USE THE F* ALTERNATE REPAIR CRITERION FOR STEAM GENERATORS WATTS BAR NUCLEAR PLANT UNIT 2DOCKET NO. 50-391By letter dated December 15, 2015 (Agencywide Document and Management System (ADAMS) Accession No. ML15362A023), the Tennessee Valley Authority (the licensee), submitted a license amendment request to revise portions of the Watts Bar Nuclear Plant, Unit 2,technical specifications, to allow implementation of the F* alternate repair criterion (ARC) for steam generator tubes. In order to complete its review of the above document, the staff requests the following additional information:1.The proposed amendment inserts the parenthetical words "(or repair)" in various places in Technical Specifications (TS) 3.4.17 "Steam Generator (SG) Tube Integrity," 5.7.2.12 "Steam Generator (SG) Program," and 5.9.9 "Steam Generator Tube Inspection Report." As noted in the model safety evaluation for plant-specific adoption of Technical Specifications Task Force Traveler (TSTF-510), Revision 2 (ADAMS Accession No. ML112101513), the term "repair criteria" is only used when a specific repair method has been approved for use by theapplicable unit. While the title "F* Alternate Repair Criterion"usesthe word "Repair," the F* Alternate Repair Criterion is,in fact,analternate pluggingcriterion.Please discuss your plans to remove the proposed addition of theparenthetical words "(or repair)" in the following places:TS 3.4.17TS 3.4.17 ASR 3.4.17.25.7.2.12.c5.7.2.12.d5.7.2.12.d.22.While the submittal states that the SG tubes are expanded for the full depth of the tubesheet, some of the analyses/testingin thetechnical support document (SG-SGMP-13-15-P (Enclosure 6) and SG-SGMP-13-15-NP(Enclosure 8)),appear to only address the situation where the bottom of the roll transition is near the top of the tubesheet. Please confirm that the F* ARCwill only be applied to tubes that have been expanded for essentially the full depth of the tubesheet (i.e., the roll transition is within 1inch of the top of the tubesheet). Please confirm that all tubes whose bottom of the roll transition is greater than 1inch below the top of the tubesheet have been plugged, or provide a basis for why these tubes do not need to be plugged.3.In Tables 1, 2, and3 of Enclosures6and8, there are entries for hot-leg and cold-leg these entries, since it is not clear what two 4.Tube slippage is not expected to occur for any of the U.S. Nuclear Regulatory Commission (NRC)-approved alternate repair criteriafor flaws within the tubesheet(e.g.,H*, C*, F*). However, should slippage occur, it warrants assessment since it is unexpected and could draw into question assumptions regarding the integrity of other joints. Please discuss your plans to modify your proposalto include monitoring andreporting requirementsregarding tube slippage.5.The proposed amendment adds the F* Alternate Repair Criterion under TS 5.7.2.12.c, which is consistent with TSTF-510. It appears the "Reviewer's Note" contained in themodel safety evaluation was inadvertently added to this section of the TS. Please discuss your plans for removing this Reviewer's Note.6.In past reviewsof alternate repair criterion license amendment requests such as H*, NRC identified aconcern that cracks could exist in the tube-to-tubesheet welds. It was not clear to the NRC staff how the integrity of the welds would be assured if the licensee did not apply H* to all tubes.The NRC sought clarification from the licensee on their intent of the application of H*, specifically the wording "may be applied" rather than "shall be applied." The NRC had noted that qualified inspection techniques did not exist for the tube-to-tubesheet welds. As a result, adoption of H* resultedin licenseesrequiring H* to be applied (i.e., it was not an alternative to the depth-based plugging limit).Please discuss your plans for requiring F* to be applied rather than providing an option for it to be applied, for example:5.7.2.12.cProvisions for SG tubeplugging criteria. Tubes found by inservice inspection to contain flaws with a depth equal to or exceeding 40% of the nominal tube wall thickness shall be plugged.The following alternate tube plugging criteria shall be applied as an alternativetothe 40%depth based criteria:1.Tubes with service-induced flaws located in the portion of the tube from the top of the tubesheet to 1.64 inches below the top of the tubesheet, or from the bottom of the roll transition to 1.64inches below the bottom of the roll transition, whichever is lower, shall be plugged. Tubes with service-induced flaws located below this elevationdo not require plugging.Also, discuss your plans for redefining the inspection distance (in TS 5.7.2.12.d) to start from 1.64-inches below the bottom of the roll transition or the top of the tubesheet, whichever is lower, on the hot-leg to 1.64-inches below the bottom of the roll transition or the top of the tubesheet, whichever is lower, on the cold-leg.7.In Section 4.1 of Enclosures6and8, you indicate that a Loss of AC Power (LOAP) to the Plant Auxiliaries and a postulated Steam Line Break (SLB) are the only events in the current licensing basis that evaluate the effects of the release of steam from the secondary system.You further state that only the SLB condition needs to be considered in the development of F*, since it is the only design basis event.You indicated that the LOAP is a Category II event.The facility must be operated in accordance with its current design and licensing basis. Please justify why it is not necessary for the licensee to ensure that any primary-to-secondary leakage that may occur during a LOAP remains less than or equal to what was assumed in the design and licensing basis.Please demonstrate that use of the F* alternate repair criterion will not create the potential for an increase in the primary-to-secondary leakage that may occur during a LOAP.

1 NRR-PMDAPEm Resource From: Schaaf, Robert Sent: Friday, February 26, 2016 2:14 PM To: Gordon Arent; Casey, Kevin E (kec asey@tva.gov); Daniels, Desiree L Cc: Render, Diane; Saba, Farideh; Beasley, Benjamin

Subject:

Request for Additional Information Regard ing Request to Use F* Steam Generator Alternate Repair Criteria (CAC No. MF7218)

Attachments:

Watts Bar 2 - Encl - RAIs re Proposed SG ARC Amendment - MF7218.pdfBy letter dated December 15, 2015 (Agencywide Documents Access and Management System (ADAMS) Accession No.

ML15362A023), the Tennessee Valley Authority (TVA) submitted an application for a license amendment request to revise portions of the Watts Bar Nuclear Plant, Unit 2, technical specifications, to allow implementation of the F* alternate repair criterion for steam generator tubes for Watts Bar Nuclear Plant (WBN), Unit 2.

The Nuclear Regulatory Commission (NRC) staff is reviewing TVA's submittal and has determined that additional information is required to complete its review. The specific information requested is attached to this e-mail.

You may accept this draft as the formal Request for Additional Information (RAI) and provide a response by March 28, 2015. Alternatively, you may request clarification of the attached requests with the NRC staff in a conference call. Please confirm receipt of these RAIs, and the date by which a response will be submitted if no clarification is needed.

Regards, Robert G. Schaaf Robert G. Schaaf Senior Project Manager, Watts Bar/Bellefonte Plant Licensing Branch II-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Mail Stop O-8G9A Washington, DC 20555 301-415-6020 (o) Robert.Schaaf@nrc.gov

Hearing Identifier: NRR_PMDA Email Number: 2684 Mail Envelope Properties (24e491245cb04a67b308789bef724699)

Subject:

Request for Additional Information Regarding Request to Use F* Steam Generator Alternate Repair Criteria (CAC No. MF7218) Sent Date: 2/26/2016 2:13:49 PM Received Date: 2/26/2016 2:13:49 PM From: Schaaf, Robert Created By: Robert.Schaaf@nrc.gov Recipients: "Render, Diane" <Diane.Render@nrc.gov> Tracking Status: None "Saba, Farideh" <Farideh.Saba@nrc.gov> Tracking Status: None "Beasley, Benjamin" <Benjamin.Beasley@nrc.gov>

Tracking Status: None "Gordon Arent" <garent@tva.gov> Tracking Status: None "Casey, Kevin E (kecasey@tva.gov)" <kecasey@tva.gov> Tracking Status: None "Daniels, Desiree L" <dlboyd@tva.gov>

Tracking Status: None Post Office: HQPWMSMRS07.nrc.gov

Files Size Date & Time MESSAGE 1347 2/26/2016 2:13:49 PM Watts Bar 2 - Encl - RAIs re Proposed SG ARC Amendment - MF7218.pdf 49675 Options Priority: Standard Return Notification: No Reply Requested: No Sensitivity: Normal Expiration Date: Recipients Received:

ENCLOSUREREQUEST FOR ADDITIONAL INFORMATIONREGARDING THE PROPOSED AMENDMENT TO USE THE F* ALTERNATE REPAIR CRITERION FOR STEAM GENERATORS WATTS BAR NUCLEAR PLANT UNIT 2DOCKET NO. 50-391By letter dated December 15, 2015 (Agencywide Document and Management System (ADAMS) Accession No. ML15362A023), the Tennessee Valley Authority (the licensee), submitted a license amendment request to revise portions of the Watts Bar Nuclear Plant, Unit 2,technical specifications, to allow implementation of the F* alternate repair criterion (ARC) for steam generator tubes. In order to complete its review of the above document, the staff requests the following additional information:1.The proposed amendment inserts the parenthetical words "(or repair)" in various places in Technical Specifications (TS) 3.4.17 "Steam Generator (SG) Tube Integrity," 5.7.2.12 "Steam Generator (SG) Program," and 5.9.9 "Steam Generator Tube Inspection Report." As noted in the model safety evaluation for plant-specific adoption of Technical Specifications Task Force Traveler (TSTF-510), Revision 2 (ADAMS Accession No. ML112101513), the term "repair criteria" is only used when a specific repair method has been approved for use by theapplicable unit. While the title "F* Alternate Repair Criterion"usesthe word "Repair," the F* Alternate Repair Criterion is,in fact,analternate pluggingcriterion.Please discuss your plans to remove the proposed addition of theparenthetical words "(or repair)" in the following places:TS 3.4.17TS 3.4.17 ASR 3.4.17.25.7.2.12.c5.7.2.12.d5.7.2.12.d.22.While the submittal states that the SG tubes are expanded for the full depth of the tubesheet, some of the analyses/testingin thetechnical support document (SG-SGMP-13-15-P (Enclosure 6) and SG-SGMP-13-15-NP(Enclosure 8)),appear to only address the situation where the bottom of the roll transition is near the top of the tubesheet. Please confirm that the F* ARCwill only be applied to tubes that have been expanded for essentially the full depth of the tubesheet (i.e., the roll transition is within 1inch of the top of the tubesheet). Please confirm that all tubes whose bottom of the roll transition is greater than 1inch below the top of the tubesheet have been plugged, or provide a basis for why these tubes do not need to be plugged.3.In Tables 1, 2, and3 of Enclosures6and8, there are entries for hot-leg and cold-leg these entries, since it is not clear what two 4.Tube slippage is not expected to occur for any of the U.S. Nuclear Regulatory Commission (NRC)-approved alternate repair criteriafor flaws within the tubesheet(e.g.,H*, C*, F*). However, should slippage occur, it warrants assessment since it is unexpected and could draw into question assumptions regarding the integrity of other joints. Please discuss your plans to modify your proposalto include monitoring andreporting requirementsregarding tube slippage.5.The proposed amendment adds the F* Alternate Repair Criterion under TS 5.7.2.12.c, which is consistent with TSTF-510. It appears the "Reviewer's Note" contained in themodel safety evaluation was inadvertently added to this section of the TS. Please discuss your plans for removing this Reviewer's Note.6.In past reviewsof alternate repair criterion license amendment requests such as H*, NRC identified aconcern that cracks could exist in the tube-to-tubesheet welds. It was not clear to the NRC staff how the integrity of the welds would be assured if the licensee did not apply H* to all tubes.The NRC sought clarification from the licensee on their intent of the application of H*, specifically the wording "may be applied" rather than "shall be applied." The NRC had noted that qualified inspection techniques did not exist for the tube-to-tubesheet welds. As a result, adoption of H* resultedin licenseesrequiring H* to be applied (i.e., it was not an alternative to the depth-based plugging limit).Please discuss your plans for requiring F* to be applied rather than providing an option for it to be applied, for example:5.7.2.12.cProvisions for SG tubeplugging criteria. Tubes found by inservice inspection to contain flaws with a depth equal to or exceeding 40% of the nominal tube wall thickness shall be plugged.The following alternate tube plugging criteria shall be applied as an alternativetothe 40%depth based criteria:1.Tubes with service-induced flaws located in the portion of the tube from the top of the tubesheet to 1.64 inches below the top of the tubesheet, or from the bottom of the roll transition to 1.64inches below the bottom of the roll transition, whichever is lower, shall be plugged. Tubes with service-induced flaws located below this elevationdo not require plugging.Also, discuss your plans for redefining the inspection distance (in TS 5.7.2.12.d) to start from 1.64-inches below the bottom of the roll transition or the top of the tubesheet, whichever is lower, on the hot-leg to 1.64-inches below the bottom of the roll transition or the top of the tubesheet, whichever is lower, on the cold-leg.7.In Section 4.1 of Enclosures6and8, you indicate that a Loss of AC Power (LOAP) to the Plant Auxiliaries and a postulated Steam Line Break (SLB) are the only events in the current licensing basis that evaluate the effects of the release of steam from the secondary system.You further state that only the SLB condition needs to be considered in the development of F*, since it is the only design basis event.You indicated that the LOAP is a Category II event.The facility must be operated in accordance with its current design and licensing basis. Please justify why it is not necessary for the licensee to ensure that any primary-to-secondary leakage that may occur during a LOAP remains less than or equal to what was assumed in the design and licensing basis.Please demonstrate that use of the F* alternate repair criterion will not create the potential for an increase in the primary-to-secondary leakage that may occur during a LOAP.