ML18304A461

Final RAI River Bend TSFTF-425 (L-2018-LLA-0056)

ML18304A461
Person / Time
Site:	River Bend
Issue date:	10/31/2018
From:	Lisa Regner Plant Licensing Branch IV
To:	Folds T, Schenk T Entergy Nuclear Operations
References
L-2018-LLA-0056
Download: ML18304A461 (5)

Text

NRR-DMPSPEm Resource From: Regner, Lisa Sent: Wednesday, October 31, 2018 3:49 PM To: Schenk, Timothy A; FOLDS, TITUS Cc: Regner, Lisa

Subject:

Final RAI River Bend TSFTF-425 (L-2018-LLA-0056)

Attachments: Final RAIs River Bend TSFTF-425.docx Final Request for Additional Information (L-2018-LLA-0056)

On October 23, 2018, the U.S. Nuclear Regulatory Commission (NRC) staff sent Entergy Operations, Inc. (the licensee) a draft Request for Additional Information (RAI). The RAI questions relate to a license amendment request (LAR) that proposes to modify the technical specifications to allow risk-informing specific surveillance frequency requirements and allowing their relocation to a licensee controlled program (TSTF-425).

Entergy informed the NRC staff that the questions were understood and Mr. Titus Folds requested a 45-day response time. The NRC staff has agreed to allow the licensee to provide a response to this final RAI on or before December 17, 2018. If Entergy does not respond by this date, the requested completion date for the LAR decision may not be met by the NRC.

By letter dated February 28, 2018, (ADAMS Accession No. ML18067A115), the licensee requested an amendment to the Operating License for River Bend Station. The proposed amendment requests to implement TSTF-425. The NRC staff requires additional information to complete its review of this request as detailed in the attached document.

Lisa M. Regner Senior Project Manager Branch 4, Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission OWFN 9E01

' 301-415-1906 Lisa.Regner@nrc.gov 1

Hearing Identifier: NRR_DMPS Email Number: 648 Mail Envelope Properties (BN6PR09MB14916BED1DF0416F5B184DEAE5CD0)

Subject:

Final RAI River Bend TSFTF-425 (L-2018-LLA-0056)

Sent Date: 10/31/2018 3:48:41 PM Received Date: 10/31/2018 3:48:44 PM From: Regner, Lisa Created By: Lisa.Regner@nrc.gov Recipients:

"Regner, Lisa" <Lisa.Regner@nrc.gov>

Tracking Status: None "Schenk, Timothy A" <TSCHENK@entergy.com>

Tracking Status: None "FOLDS, TITUS" <TFOLDS@entergy.com>

Tracking Status: None Post Office: BN6PR09MB1491.namprd09.prod.outlook.com Files Size Date & Time MESSAGE 1488 10/31/2018 3:48:44 PM Final RAIs River Bend TSFTF-425.docx 28807 Options Priority: Standard Return Notification: No Reply Requested: No Sensitivity: Normal Expiration Date:

Recipients Received:

REQUEST FOR ADDITIONAL INFORMATION BY THE PROBABILISTIC RISK LICENSE AMENDMENT REQUEST FOR EXTENSION OF APPLICATION FOR TECHNICAL SPECIFICATION CHANGE REGARDING RISK-INFORMED JUSTIFICATION FOR THE RELOCATION OF SPECIFIC SURVEILLANCE FREQUENCY REQUIREMENTS TO A LICENSEE CONTROLLED PROGRAM (TSTF-425)

ENTERGY OPERATIONS, INC.

RIVER BEND STATION, UNIT 1 DOCKET NOS. 50-458 (EPID: L-2018-LLA-0056)

By letter dated February 28, 2018 (Agencywide Documents Access and Management System (ADAMS) Accession Number ML18067A115), Entergy Operations, Inc. (Entergy, the licensee),

submitted a license amendment request (LAR) regarding the River Bend Station, Unit 1. The proposed amendment would modify the River Bend TS by relocating specific surveillance frequencies to a licensee-controlled program with the implementation of Nuclear Energy Institute (NEI) 04-10, "Risk-Informed Technical Specification Initiative 58, Risk-Informed Method for Control of Surveillance Frequencies." The licensee states that the proposed are consistent with Nuclear Regulatory Commission (NRC) approved industry/Technical Specification Task Force (TSTF) Standard Technical Specifications (STS) change TSTF-425, Revision 3 (ADAMS Accession No. ML090850642).

The Probabilistic Risk Assessment (PRA) Licensing Branch A (APLA) of the Division of Risk Assessment (DRA) staff has reviewed the LAR and determined that additional information, related to PRA considerations described in the LAR, is required for the APLA staff to complete the review.

Regulatory Basis Title 10 of the Code of Federal Regulations (10 CFR) Part 50.36(c)(3), requires that Technical Specification will include surveillance requirements. Surveillance requirements are requirements relating to test, calibration, or inspection to assure that the necessary quality of systems and components is maintained, that facility operation will be within safety limits, and that the limiting conditions for operation will be met. Nuclear Energy Institute (NEI) 04-10, Revision 1, Risk-Informed Technical Specifications Initiative 5B, Risk-Informed Method for Control of Surveillance Frequencies" (ADAMS Accession No. ML071360456), provides guidance for relocating the surveillance frequencies from the TSs to a licensee-controlled program by providing an NRC-approved methodology for control of the surveillance frequencies. The guidance in NEI 04-10, Revision 1, is acceptable for referencing in licensing actions to the extent specified and under the limitations delineated in NEI 04-10, and the NRC safety evaluation providing the basis for NRC acceptance of NEI 04-10 (ADAMS Accession No. ML072570267).

Enclosure

Request for Additional Information APLA RAI-1 External Hazards - Evaluation LAR Section 3.3 states that the River Bend Station (RBS) does not have a fire PRA model and that a bounding fire risk evaluation, based on information from the Individual Plant Examination of External Events (IPEEE) and other available insights for fire risk will be performed for surveillance test interval (STI). Section 3.5 of the LAR states that RBS does not have a PRA model or applications associated with external hazards such as seismic, high wind or external flooding, and that a qualitative or bounding approach will be used to assess external event hazard risk at RBS for STI changes.

i. Describe how the plants IPEEE and other available insights will be used for the STI fire risk evaluation, including discussion of the fire methodology used and the treatment of SSCs not evaluated in the IPEEE.

ii. Please describe, in more detail, how each of the external initiating events seismic, high winds, and external flooding will be assessed in terms of the NEI 04-10 guidance, e.g.

how the qualitative or bounding (step 10) evaluation described in the NEI 04-10 guidance will be used.

APLA RAI-2 External hazards - Updating Section 3.5 of Attachment 2 to the LAR states that external hazards were evaluated in the IPEEE and that a qualitative or bounding approach will be used to assess external event hazards risk. The LAR does not explain however, how the risk from external hazards evaluated in the RBS IPEEE is updated to reflect new information when used in performing a qualitative or bounding analysis in support of STI extension evaluations in accordance with NEI 04-10, Section 4, Step 10. The LAR states that the IPEEE program was a "one-time review". Hazard characteristics can change over time due to physical changes and changes in the available information.

i. Describe monitoring for, and incorporating as needed, new information for the fire, high winds, including updated tornado and hurricane climatology, external flooding, and seismic events, such as the need to update site-specific ground motion response spectra.

APLA RAI-3 Unresolved Peer-review Facts and Observations (F&O)

The dispositions for the following five unresolved internal flooding and large early release (LERF) PRA Facts & Observations (F&Os) state that the unresolved findings have minimal impact and that the impact of the findings is expected to be assessed in case-by-case STI evaluations. However, the licensee does not describe how the impact of the unresolved F&Os will be evaluated, or does not provide a justification for concluding that the F&Os have a minimal impact on the application.

• F&O RB-6096 related to SR IFSO-A4 identified that no evaluation was performed to identify human induced flooding mechanisms as stated by the supporting requirement.

• F&O RB-6101 related to SR LE-F3 identifies that a review of key assumptions in the 2

LERF analysis has not been performed.

• F&O RB-6106 related to SR IFQU-A5 identified that a consistency check of the Human Error Probabilities (HEPs) was not performed.

• F&O RB-6108 related to SR IFQU-A7 states that the Human Failure Events (HFE) values in the dependency analysis were not seeded with sufficiently high values to ensure that cutsets with multiple HFEs were not truncated.

• F&O RB-6110 related to SR IFQU-B3 identified that a review of sources of modeling uncertainty in the internal flooding PRA and their impact on the results was not performed.

For each for the five F&Os listed above address the following:

a. Provide detailed justification why the F&O has no impact on the application, or

b. Describe and justify the evaluation, if any, that will be performed on a case-by-case STI evaluation to address the impact of each unresolved F&O, or

c. Propose a mechanism that ensures the F&O will be resolved in the PRA model and associated documentation prior to implementation of the SFCP. This mechanism should provide an explicit description of actions that will be taken and any changes that will be made to the PRA model or documentation to resolve this F&O.

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