ML22318A310

NRR E-mail Capture - Comanche Peak - Draft Request for Additional Information - Proposed Alternative P-1 Regarding IST of Safeguards Building Sump Pumps

ML22318A310
Person / Time
Site:	Comanche Peak
Issue date:	11/10/2022
From:	Dennis Galvin NRC/NRR/DORL/LPL4
To:	Hicks J Vistra Operating Co. (VistraOpCo)
References
L 2022-LLR-0058
Download: ML22318A310 (4)

Text

From: Dennis Galvin Sent: Thursday, November 10, 2022 8:40 AM To: Jack Hicks (Jack.Hicks@luminant.com)

Cc: Barnette, James

Subject:

Comanche Peak - Draft Request for Additional Information - Proposed Alternative P-1 Regarding IST of Safeguards Building Sump Pumps (EPID: L 2022-LLR-0058)

Attachments: Comanche Peak Proposed Alternative P-1 for Sump Pumps - Draft RAI Issued 2022-11-10.pdf

Dear Mr. Hicks,

By [[letter::CP-202200273, Third Supplement to License Amendment Request (LAR)20-006 Application to Revise Technical Specifications to Adopt Risk Informed Completion Times, TSTF-505, Revision 2, Provide Risk-Informed Extended Completion Times - RITSTF Initiative|letter dated July 20, 2022]] (Agencywide Documents Access and Management System (ADAMS) Accession No. ML22201A555), Vistra Operations Company, LLC (Vistra OpCo, the licensee) submitted proposed alternative P-1 to the Nuclear Regulatory Commission (NRC) regarding Comanche Peak Nuclear Power Plant Units 1 and 2 (Comanche Peak). The proposed alternative requests the use of an alternative inservice test (IST) for the safeguards building sump pumps.

To complete its review, the NRC staff has prepared a request for additional information (RAI) in DRAFT form. To arrange a clarification call for the draft RAIs and to discuss the due date for the RAI response, please contact me at (301) 415-6256.

Respectfully, Dennis Galvin Project Manager U.S Nuclear Regulatory Commission Office of Nuclear Reactor Regulation Division of Operating Reactor Licensing Licensing Project Branch 4 301-415-6256 Docket Nos. 50-445 and 50-446

Hearing Identifier: NRR_DRMA Email Number: 1827 Mail Envelope Properties (SA1PR09MB8111278D9FD09CECE71813EAFB019)

Subject:

Comanche Peak - Draft Request for Additional Information - Proposed Alternative P-1 Regarding IST of Safeguards Building Sump Pumps (EPID L 2022-LLR-0058)

Sent Date: 11/10/2022 8:39:45 AM Received Date: 11/10/2022 8:39:00 AM From: Dennis Galvin Created By: Dennis.Galvin@nrc.gov Recipients:

"Barnette, James" <James.Barnette@luminant.com>

Tracking Status: None "Jack Hicks (Jack.Hicks@luminant.com)" <Jack.Hicks@luminant.com>

Tracking Status: None Post Office: SA1PR09MB8111.namprd09.prod.outlook.com Files Size Date & Time MESSAGE 973 11/10/2022 8:39:00 AM Comanche Peak Proposed Alternative P-1 for Sump Pumps - Draft RAI Issued 2022-11-10.pdf 94993 Options Priority: Normal Return Notification: No Reply Requested: No Sensitivity: Normal Expiration Date:

DRAFT REQUEST FOR ADDITIONAL INFORMATION PROPOSED ALTERNATIVE P-1 REGARDING INSERVICE TESTING OF SAFEGUARDS BUILDING SUMP PUMPS VISTRA OPERATIONS COMPANY LLC COMANCHE PEAK UNIT 1 AND 2 DOCKET NOS. 50-445 AND 50-446 By [[letter::CP-202200273, Third Supplement to License Amendment Request (LAR)20-006 Application to Revise Technical Specifications to Adopt Risk Informed Completion Times, TSTF-505, Revision 2, Provide Risk-Informed Extended Completion Times - RITSTF Initiative|letter dated July 20, 2022]] (Agencywide Documents Access and Management System (ADAMS) Accession No. ML22201A555), Vistra Operations Company, LLC (Vistra OpCo, the licensee) submitted proposed alternative P-1 to the Nuclear Regulatory Commission (NRC) regarding Comanche Peak Nuclear Power Plant Units 1 and 2 (Comanche Peak). The proposed alternative requests the use of an alternative inservice test (IST) for the safeguards building sump pumps (SBSPs).

To complete its review, the NRC staff requests the following additional information.

EMIB-RAI-1 Comanche Peak Alternative Request P-1, Section Description of Basis for Use, second paragraph, states:

In addition, Regulatory Guide (RG) 1.175 Revision 1, "An Approach for Plant-Specific, Risk-Informed Decision- making: Inservice Testing," (ML21140A055) states that for LSSCs [low safety significant components], like the SBSPs, the testing may be less rigorous. This philosophy of demonstrating that the SBSPs have adequate design margin (greater than 50 gpm) is consistent with RG 1.175 testing strategy for LSSCs.

The Comanche Peak IST plan for pumps and valves for the third 10-Year IST program interval, Revision 4, Table 0, Inservice Pump Testing Plan, on pages 5 and 6 specifies that the SBSPs are LSSC (ML21082A299). Please confirm that the SBSPs remain LSSC for the 4th 10-Year IST program interval.

EMIB-RAI-2 Comanche Peak Alternative Request P-1, Section Description of Basis for Use, fourth paragraph, states:

The SBSPs are of low safety significance and are not explicitly modeled in the Probabilistic Risk Assessment (PRA) for internal events analysis. As stated previously, the SBSPs are installed to prevent flooding from a LOCA [loss-of-coolant accident]. Alarms associated with these pumps alert the operator of potential leakage in the Safeguards Building and mitigate the consequences of the leakage. The proposed alternative test will provide reasonable assurance that the sump pumps will perform their intended functions and not impact the assumptions in the PRA

[probabilistic risk assessment] assessment.

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The licensee states that the SBSPs are of low safety significance and are not explicitly modeled in the PRA for internal events analysis at CNPP Units 1 and 2. Please explain the applicable PRA assumptions and how the proposed alternative test will provide reasonable assurance without impacting the assumptions in the PRA assessment.

EMIB-RAI-3 The Comanche Peak IST plan for pumps and valves for the third 10-Year IST program interval, Revision 4, Table 0 on pages 5 and 6 specifies the test schedule for the SBSPs as 6 years for the Group A test and 6 years for the Comprehensive Pump Test (CPT).

The NRC safety evaluation dated June 26, 2013, authorizing Alternative Request P-1 for the Third 10-Year IST Program interval (ML13148A437) at Comanche Peak states that the licensee established a 6-year staggered test frequency which resulted in one pump per unit tested every 18 months. The Comanche Peak Alternative Request P-1 for the Fourth 10-Year IST Program specifies that the Alternative Request P-1 for the Third 10-Year IST Program interval is a precedent for the Alternative Request P-1 for the Fourth 10-Year IST Program interval.

However, Alternative Request P-1 for the Fourth 10-Year IST Program interval does not provide information regarding this frequency of the SBSP testing.

Please describe the staggered test frequency approach for the SBSPs during the Fourth 10-Year IST Program interval at CPNPP Units 1 and 2. Also, please specify any differences between Alternative Request P-1 for the Fourth 10-Year IST Program interval and Alternative Request P-1 that the NRC authorized for the Third 10-Year IST Program interval.

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