ML16048A426

Email L. Regner to L. Sterling, Risk RAIs for Integrated Leak Rate Testing License Amendment Requests

ML16048A426
Person / Time
Site:	South Texas
Issue date:	09/10/2015
From:	Lisa Regner Plant Licensing Branch IV
To:	Sterling L South Texas
References
MF6176, MF6177
Download: ML16048A426 (2)

Text

1 NRR-PMDAPEm Resource From: Regner, Lisa Sent: Thursday, September 10, 2015 10:19 AM To: Sterling, Lance (lsterling@STPEGS.COM)

Cc: Regner, Lisa; Kistler, Marilyn; Rich ards, Drew (amrichards@STPEGS.COM)

Subject:

DRAFT NRC RAI: Integrated Le ak Rate Testing LAR (MF6176/77)By letter dated April 29, 2015 (Agencywide Document s Access and Management System (ADAMS) Accession No. ML15128A352), as supplemented by letter dated June 29, 2015 (ADAMS Accession No. ML15198A147), STP Nuclear Operating Company (STPNOC) requested amendments to Operating Licenses NPF-76 and NPF-80 in the form of changes to the Technical Specifications (TS) for South Texas Project Units 1 and 2, respectively.

The license amendment request (LAR) proposes a change to TS 6.8.3.j, "Containment Leakage Rate Testing Program," to allow a permanent extension of the Type A primary containment integrated leak rate test (ILRT) frequency to once every 15 years. The NRC staff has reviewed the risk-related information in the license amendment request and identified areas where additional information is needed to complete its review.

Please let me know if you have questions on the below questions. If clarification is not needed, your response is requested 30 days from the date of this email unless other arrangements are made with me. If you prefer to consolidate your answers from the ILRT RAI sent by email on September 3, this is acceptable. Your preliminary date for response is October 10.

1. In the letter dated June 29, 2015 (ADAMS Accession Number ML15198A147) the licensee states that STP's internal events probabilistic risk assessment (PRA) does not meet Regulatory Guide (RG) 1.200, Revision 2, requirements for the technical elements related to uncertainty analysis in internal flooding (IFSO-B3, IFSN-B3, IFEV-B3, and IFQU-B3). It further states that "the internal flood event scenarios performed under the Individual Plant Examination (IPE) all screened out with no significant internal flooding initiating event considered for quantification." The staff's understanding of this statement is that no quantification was performed for internal flood sequences under IPE. Please clarify whether quantification of internal flood sequences is performed by the current PRA model. What is the contribution to total core damage frequency (CDF) from internal flooding?

2. In the letter dated June 29, 2015, the licensee states that the scope of STP's PRA is Level I and Level II, including external and internal hazards, such as internal floods, seismic events, internal fires, high winds, and external flooding. The license amendment request (LAR) states that STP's PRA complies with RG 1.200, Revision 2 with the exception of the fire PRA and the seismic PRA. The LAR does not specifically discuss the quality of other external events models, such as high winds and external flooding. Briefly describe the quality of STP's high winds and external flooding PRA.

Lisa Regner Sr. PM NRR/DORL/LPL4-1 301-415-1906

O8D08

Hearing Identifier: NRR_PMDA Email Number: 2664 Mail Envelope Properties (3a2a97c8d1044e0d9492ff3f434b9fd1)

Subject:

DRAFT NRC RAI: Integrated Leak Rate Testing LAR (MF6176/77) Sent Date: 9/10/2015 10:19:12 AM Received Date: 9/10/2015 10:19:13 AM From: Regner, Lisa Created By: Lisa.Regner@nrc.gov Recipients: "Regner, Lisa" <Lisa.Regner@nrc.gov>

Tracking Status: None "Kistler, Marilyn" <mkkistler@STPEGS.COM>

Tracking Status: None "Richards, Drew (amrichards@STPEGS.COM)" <amrichards@STPEGS.COM> Tracking Status: None "Sterling, Lance (lsterling@STPEGS.COM)" <lsterling@STPEGS.COM> Tracking Status: None

Post Office: HQPWMSMRS05.nrc.gov Files Size Date & Time MESSAGE 2751 9/10/2015 10:19:13 AM

Options Priority: Standard Return Notification: No Reply Requested: No Sensitivity: Normal Expiration Date: Recipients Received:

1 NRR-PMDAPEm Resource From: Regner, Lisa Sent: Thursday, September 10, 2015 10:19 AM To: Sterling, Lance (lsterling@STPEGS.COM)

Cc: Regner, Lisa; Kistler, Marilyn; Rich ards, Drew (amrichards@STPEGS.COM)

Subject:

DRAFT NRC RAI: Integrated Le ak Rate Testing LAR (MF6176/77)By letter dated April 29, 2015 (Agencywide Document s Access and Management System (ADAMS) Accession No. ML15128A352), as supplemented by letter dated June 29, 2015 (ADAMS Accession No. ML15198A147), STP Nuclear Operating Company (STPNOC) requested amendments to Operating Licenses NPF-76 and NPF-80 in the form of changes to the Technical Specifications (TS) for South Texas Project Units 1 and 2, respectively.

The license amendment request (LAR) proposes a change to TS 6.8.3.j, "Containment Leakage Rate Testing Program," to allow a permanent extension of the Type A primary containment integrated leak rate test (ILRT) frequency to once every 15 years. The NRC staff has reviewed the risk-related information in the license amendment request and identified areas where additional information is needed to complete its review.

Please let me know if you have questions on the below questions. If clarification is not needed, your response is requested 30 days from the date of this email unless other arrangements are made with me. If you prefer to consolidate your answers from the ILRT RAI sent by email on September 3, this is acceptable. Your preliminary date for response is October 10.

1. In the letter dated June 29, 2015 (ADAMS Accession Number ML15198A147) the licensee states that STP's internal events probabilistic risk assessment (PRA) does not meet Regulatory Guide (RG) 1.200, Revision 2, requirements for the technical elements related to uncertainty analysis in internal flooding (IFSO-B3, IFSN-B3, IFEV-B3, and IFQU-B3). It further states that "the internal flood event scenarios performed under the Individual Plant Examination (IPE) all screened out with no significant internal flooding initiating event considered for quantification." The staff's understanding of this statement is that no quantification was performed for internal flood sequences under IPE. Please clarify whether quantification of internal flood sequences is performed by the current PRA model. What is the contribution to total core damage frequency (CDF) from internal flooding?

2. In the letter dated June 29, 2015, the licensee states that the scope of STP's PRA is Level I and Level II, including external and internal hazards, such as internal floods, seismic events, internal fires, high winds, and external flooding. The license amendment request (LAR) states that STP's PRA complies with RG 1.200, Revision 2 with the exception of the fire PRA and the seismic PRA. The LAR does not specifically discuss the quality of other external events models, such as high winds and external flooding. Briefly describe the quality of STP's high winds and external flooding PRA.

Lisa Regner Sr. PM NRR/DORL/LPL4-1 301-415-1906

O8D08

Hearing Identifier: NRR_PMDA Email Number: 2664 Mail Envelope Properties (3a2a97c8d1044e0d9492ff3f434b9fd1)

Subject:

DRAFT NRC RAI: Integrated Leak Rate Testing LAR (MF6176/77) Sent Date: 9/10/2015 10:19:12 AM Received Date: 9/10/2015 10:19:13 AM From: Regner, Lisa Created By: Lisa.Regner@nrc.gov Recipients: "Regner, Lisa" <Lisa.Regner@nrc.gov>

Tracking Status: None "Kistler, Marilyn" <mkkistler@STPEGS.COM>

Tracking Status: None "Richards, Drew (amrichards@STPEGS.COM)" <amrichards@STPEGS.COM> Tracking Status: None "Sterling, Lance (lsterling@STPEGS.COM)" <lsterling@STPEGS.COM> Tracking Status: None

Post Office: HQPWMSMRS05.nrc.gov Files Size Date & Time MESSAGE 2751 9/10/2015 10:19:13 AM

Options Priority: Standard Return Notification: No Reply Requested: No Sensitivity: Normal Expiration Date: Recipients Received: