ML15098A606

NRR E-mail Capture - STP Agenda Items for 4/8 Public Call

ML15098A606
Person / Time
Site:	South Texas
Issue date:	04/03/2015
From:	Harrison A South Texas
To:	Lisa Regner Plant Licensing Branch IV
References
TAC MF2400, TAC MF2409
Download: ML15098A606 (5)

Text

NRR-PMDAPEm Resource From: Harrison Albon [awharrison@STPEGS.COM]

Sent: Friday, April 03, 2015 11:00 AM To: Regner, Lisa Cc: Stang, John; Blossom, Steven

Subject:

STP Agenda Items for 4/8 public call Attachments: 15003241 Cover Letter Supplement 2 LAR.pdf Follow Up Flag: Follow up Flag Status: Flagged Lisa, John, Proposed STP agenda items for our public call next Wednesday:

• See attached talking points on June supplement content

• Clarification/dialog on strainer design question

• Staff reactions to responses to Round 2 RAIs o Note that we would plan to submit the BAP and SCVB-17 RAI responses in the June supplement Can we have a separate call to discuss schedule and logistics for upcoming audit? We would like to set a date and location (recommend Albuquerque).

Regards, Wayne Harrison STP Licensing (979) 292-6413 1

Hearing Identifier: NRR_PMDA Email Number: 1980 Mail Envelope Properties (8C918BCF8596FB49BD20A610FA5920CF022668F0)

Subject:

STP Agenda Items for 4/8 public call Sent Date: 4/3/2015 11:00:23 AM Received Date: 4/3/2015 11:00:23 AM From: Harrison Albon Created By: awharrison@STPEGS.COM Recipients:

"Stang, John" <John.Stang@nrc.gov>

Tracking Status: None "Blossom, Steven" <sdblossom@STPEGS.COM>

Tracking Status: None "Regner, Lisa" <Lisa.Regner@nrc.gov>

Tracking Status: None Post Office: CEXMBX01.CORP.STPEGS.NET Files Size Date & Time MESSAGE 601 4/3/2015 11:00:23 AM 15003241 Cover Letter Supplement 2 LAR.pdf 290234 Options Priority: Standard Return Notification: No Reply Requested: No Sensitivity: Normal Expiration Date:

Recipients Received: Follow up

TALKING POINTS FOR DISCUSSION June 2015 NOC-AE-15003241 10CFR50.12 10CFR50.90 U. S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, DC 20555-0001 South Texas Project Units 1 and 2 Docket Nos. STN 50-498 and STN 50-499 Supplement 2 to STP Pilot Submittal and Requests for Exemptions and License Amendment for a Risk-Informed Approach to Address Generic Safety Issue (GSI)-191 and Respond to Generic Letter (GL) 2004-02 (TAC NOS. MF2400 - MF2409)

References:

1. Letter, G. T. Powell, STPNOC, to NRC Document Control Desk, Supplement 1 to Revised STP Pilot Submittal and Requests for Exemptions and License Amendment for a Risk-Informed Approach to Resolving Generic Safety Issue (GSI)-191, November 13, 2013, NOC-AE-15003241, ML13323A183

2. Letter, G. T. Powell, STPNOC, to NRC Document Control Desk, Description of Revised Risk-Informed Methodology and Responses to Round 2 Requests for Additional Information Regarding STP Risk-Informed GSI-191 Licensing Application, March XX, 2015, NOC-AE-15003220, MLXXXXXX This submittal supplements the STP Risk-Informed GSI-191 application (Reference 1) with the information from RAI responses and with the Risk over Deterministic (RoverD) methodology as the primary framework for the technical basis and a proposed change to the Technica l Specifications. It contains sufficient information to be used as a stand -alone reference for the review of the STP licensing application and for closure of GL2004 -02 for STP.

The requested licensing actions are for approval of a risk-informed approach for resolving GSI-191 for STP Units 1 and 2 as the pilot plants for other licensees pursuing a similar approach. The results of the reviews will also support closure of Generic Letter (GL) 2004 -02, "Potential Impact of Debris Blockage on Emergency Recirculation during Design Basis Accidents at Pressurized-Water Reactors," for STP Units 1 and 2.

STPNOC seeks NRC approval of the proposed exemptions and amendment to the license based on a determination that the STP risk-informed approach and the risk associated with the postulated failure mechanisms due to GSI-191 concerns meets the guidance, key principles for risk-informed decision-making, and the acceptance guidelines in RG 1.174.

TALKING POINTS FOR DISCUSSION The STP piloted risk-informed approach to resolving GSI-191 shows that the risk associated with debris from pipe breaks that generate quantities of debris that are not bounded by plant -

specific prototypical testing is very small, in accordance with the acceptance criteria of RG 1.174. The effects of debris that is bounded by the plant-specific testing are deterministically mitigated in accordance with NRC-accepted methodology for resolution of GL 2004-02.

The risk associated with GSI-191 concerns includes the effects on long-term cooling due to debris accumulation on Emergency Core Cooling System (ECCS) and Containment Spray System (CSS) sump strainers in recirculation mode, as well as core flow blockage due to in -

vessel effects, following loss of coolant accidents (LOCAs). A full spectrum of postulated LOCAs is analyzed, including double-ended guillotine breaks (DEGBs) for all pipe sizes up to the largest pipe in the reactor coolant system. The changes to CDF and LERF associated with GSI-191 concerns are quantified by applying the LOCA frequencies published in NUREG-1829, and then compared to RG 1.174 acceptance guidelines. provides the methodology for the proposed risk-informed approach to addressing the GSI-191 issue as described in GL 2004-02, consistent with RG 1.174 guidance. describes the proposed exemptions from certain regulatory requirements in accordance with the provisions of 10CFR50.12. This submittal revises the proposed licensing basis to change the proposed exemption to 10CFR50.46(b)(5) described in Reference 1 to an exemption to 10CFR50.46(d).

The requests for exemptions address regulatory requirements that concern the ECCS and CSS functions for emergency core cooling, containment heat removal, and containment atmosphere cleanup following postulated LOCAs:

x Enclosure 2-1, 10CFR50.46 - (d), ..other requirements applicable to ECCS x Enclosure 2-2, GDC 35 - Emergency core cooling x Enclosure 2-3, GDC 38 - Containment heat removal x Enclosure 2-4, GDC 41 - Containment atmosphere cleanup provides the License Amendment Request (LAR), pursuant to 10CFR50.90, for approval of the proposed changes to the STP Units 1 and 2 licensing basis including page markups for the affected TS pages and Updated Final Safety Analysis Report (UFSAR) pages.

In this supplement STPNOC is proposing addition of a required action specific to the effects of debris to TS 3/4.5.2, ECCS Subsystems - Tavg Greater Than or Equal to 350° and TS3/4.6.2, Depressurization and Cooling Systems - Containment Spray System. The LAR includes technical and regulatory evaluations for the proposed change, a no significant hazards consideration determination pursuant to 10CFR50.92, and an environmental considerations review. The Plant Operations Review Committee has approved the proposed change . In accordance with 10CFR50.91(b), STPNOC has notified the State of Texas by transmitting a copy of this letter and enclosure to the State of Texas Official. Changes to the STP Technical Specifications and UFSAR are to be implemented pursuant to NRC approval of LAR.

To support the completion of work and resolution schedule for closure of GL2004-02 for STP, STPNOC requests approval of the proposed exemption requests and license amendment request by November 30, 2015.

TALKING POINTS FOR DISCUSSION A 90-day implementation period is requested to provide time to revise the applicable STP licensing documents and implement the Technical Specification changes. There are no other commitments in this letter.

If there are questions regarding this submittal, please contact Mike Murray at 361-972-8146, or me at 361-972-7566.

I declare under penalty of perjury that the foregoing is true and correct.

Executed on __________________

G. T. Powell Site Vice President awh

Enclosures:

1. STP Piloted Risk-Informed Approach to Closure for GSI-191 1-1 Introduction This explains how the methodology works. It would also describe how we used CASA for debris generation and transport.

1-2 Deterministic Basis This is an update to the STP 12/2008 GL2004-02 response letter and the responses to the 2009 RAIs. (2009 RAI responses may fit better as a separate submittal or their own Enclosure.)

1-3 Risk-Informed Basis This is RoverD and should look substantially like what was included in the last RAI response.

1-4 Regulatory Basis Summary - brief discussion of need for exemptions and LAR 1-5 Summary and Conclusion

2. Requests for Exemptions for STP Piloted Risk-Informed Approach to Closure for GSI-191 2-1 Request for Exemption from 10CFR50.46(d) 2-2 Request for Exemption from General Design Criterion 35 2-3 Request for Exemption from General Design Criterion 38 2-4 Request for Exemption from General Design Criterion 41

3. License Amendment Request for STP Piloted Risk-informed Approach to Closure for GSI-191 Attachment 1: Technical Specification Page Markups Attachment 2: Clean Technical Specification Pages Attachment 3: Technical Specifications Bases Page Markups (Information Only)

Attachment 4: STPEGS UFSAR Page Markups These will incorporate the SCVB RAI responses. Proposed UFSAR App. 6A will be much simpler than the previously submitted version due to RoverD.

4. List of Commitments

5. Definitions and Acronyms