ML24156A007

NRR E-mail Capture - Final RAI - D.C. Cook Nuclear Plant, Unit Nos. 1 and 2 - License Amendment Request Regarding Reserve Feed Enclosure

ML24156A007
Person / Time
Site:	Cook
Issue date:	05/30/2024
From:	Scott Wall NRC/NRR/DORL/LPL3
To:	Scarpello M Indiana Michigan Power Co
Wall S
References
L-2024-LLA-0040
Download: ML24156A007 (6)

Text

From: Scott Wall Sent: Thursday, May 30, 2024 2:29 PM To: Michael K. Scarpello Cc: Helen L Levendosky; Joe Tanko; Bradford M Culwell

Subject:

FINAL RAI - D.C. Cook Nuclear Plant, Unit Nos. 1 and 2 - License Amendment Request Regarding Reserve Feed Enclosure (EPID No. L-2024-LLA-0040)

Dear Michael Scarpello,

By letter dated April 3, 2024 (Agencywide Documents and Access Management System Accession No. ML24094A288), as supplemented by letter dated May 16, 2024 (ML24137A221),

Indiana Michigan Power Company (I&M, the licensee) submitted a license amendment request (LAR) for the Donald C. Cook Nuclear Plant (CNP), Units Nos. 1 and 2 (CNP). The proposed LAR would revise Technical Specification (TS) 3.8.1, AC Sources - Operating, by adding a footnote for TS 3.8.1, Required Action A.3 to allow a one-time completion time (CT) extension from 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> to 288 hours0.00333 days <br />0.08 hours <br />4.761905e-4 weeks <br />1.09584e-4 months <br /> to support the replacement of the 12AB (Train B) Loop Feed Enclosure and associated bus for the Train B reserve feed preferred power source.

The NRC staff has reviewed the submittals and determined that additional information is needed to complete its review. The specific questions are found in the enclosed request for additional information (RAI). During a telephone call on May 30, 2024, the I&M staff indicated that a response to the RAIs would be provided by July 3, 2024.

If you have questions, please contact me at 301-415-2855 or via e-mail at Scott.Wall@nrc.gov.

Scott P. Wall, LSS BB, BSP Senior Project Manager Plant Licensing Branch III Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation 301.415.2855 Scott.Wall@nrc.gov

Docket Nos. 50-315 and 50-316

Enclosure:

Request for Additional Information

cc: Listserv

RAI (Reserve Feed Enclosure)

REQUEST FOR ADDITIONAL INFORMATION

LICENSE AMENDMENT REQUEST FOR ONE-TIME EXTENSION OF COMPLETION TIME FOR INOPERABLE AC SOURCE - OPERATING

INDIANA MICHIGAN POWER COMPANY

DONALD C. COOK NUCLEAR PLANT, UNIT NOS. 1 AND 2

DOCKET NOS. 50-315 AND 50-316

INTRODUCTION

By letter dated April 3, 2024 (Agencywide Documents and Access Management System Accession No. ML24094A288), as supplemented by letter dated May 16, 2024 (ML24137A221),

Indiana Michigan Power Company (I&M, the licensee) submitted a license amendment request (LAR) for the Donald C. Cook Nuclear Plant (CNP), Units Nos. 1 and 2 (CNP). The proposed LAR would revise Technical Specification (TS) 3.8.1, AC Sources - Operating, by adding a footnote for TS 3.8.1, Required Action A.3 to allow a one-time completion time (CT) extension from 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> to 288 hours0.00333 days <br />0.08 hours <br />4.761905e-4 weeks <br />1.09584e-4 months <br /> to support the replacement of the 12AB (Train B) Loop Feed Enclosure and associated bus for the Train B reserve feed preferred power source.

The U.S. Nuclear Regulatory Commission (NRC) staff determined that the following information is needed to complete its review.

Regulatory Basis

Title 10 Code of Federal Regulations (CFR) Part 50, Section 50.36, Technical Specifications, requires, in part, that the TS shall be included by applicants for a license authorizing operation of a production or utilization facility. 10 CFR 50.36(c) requires that TS include items in five specific categories related to station operation. These categories are (1) Safety limits, limiting safety system settings, and limiting control settings, (2) Limiting conditions for operation (LCOs)

(3) Surveillance requirements, (4) Design features, and (5) Administrative controls.

The NRC staffs guidance for the review of TSs is provided in chapter 16.0, Technical Specifications, of NUREG-0800, Revision 3, Standard Review Plan for the Review of Safety Analysis Reports for Nuclear Power Plants: LWR [Light-Water Reactor] Edition (SRP),

March 2010 (ML100351425). The NRC staff uses Branch Technical Position (BTP) 8-8, Onsite (Emergency Diesel Generators) and Offsite Power Sources Allowed Outage Time Extensions (ML113640138), to evaluate LARs for one-time or permanent (completion time) extensions for the emergency diesel generators (EDGs) and offsite power sources.

Electrical Engineering Branch (EEEB) Questions

=

Background===

TS 1.3, Completion Times, states:

Limiting conditions for operation (LCOs) specify minimum requirements for ensuring safe operation of the unit. The ACTIONS associated with an LCO state Conditions that typically describe the ways in which the requirements of the LCO can fail to be met. Specified with each stated Condition are Required Action(s) and Completion Time(s).

The Completion Time is the amount of time allowed for completing a Required Action. It is referenced to the time of discovery of a situation (e.g., Inoperable equipment or variable not with limits) that requires entering an ACTIONS Condition unless otherwise specified, proving the units is in a MODE or specified condition stated in the Applicability of the LCO.

Required Actions must be completed prior to the expiration of the specified Completion Time.

LAR Section 1 states that the proposed change would revise TS 3.8.1, AC Sources -

Operating, to extend the CT one-time for Required Action A.3 for inoperable offsite circuit from 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> to 288 hours0.00333 days <br />0.08 hours <br />4.761905e-4 weeks <br />1.09584e-4 months <br />. The LAR Section 2.3 states, in part, that:

this modification is expected to take approximately 8 days with approximately 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> of contingencies. Therefore, a requested one-time allowance of 12 days, or 288 hours0.00333 days <br />0.08 hours <br />4.761905e-4 weeks <br />1.09584e-4 months <br />, is being requested.

SRP BTP 8-8 states, in part, that:

The licensee must provide justification for the duration of the requested AOT

[Allowed Outage Time] (actual hours plus margin based on plant-specific past operating experience).

Note: For the purpose of this RAI, the terms AOT and CT are used interchangeably.

LAR Section 4.2, Precedents, lists four precedents for similar type outages at other nuclear plants for inoperable offsite circuits for one-time CT extensions but does not provide any operating experience at DC Cook that could support the duration of proposed CT extension.

The LAR does not provide the basis and justification to support the 288-hour (12 day) CT extension request. The licensee in the LAR estimated approximately 8 days to complete the modification implementation with contingencies of 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> which equals 10 days. The LAR does not provide the basis and justification for this estimation. In addition, there is a gap between the above 10-day estimation and the requested 12-day CT extension.

EEEB-RAI-1

• Please provide a description of the contingencies associated with the proposed CT extension.

• Please provide a basis and justification for the duration of the requested 288-hour CT extension that includes time to complete the modification and contingencies. The basis and justification could be based on the plant operating experience(s), if any.

• Please provide an explanation of the time gap between the 10 -day estimation and requested 12-day extended CT.

PRA [probabilistic risk assessment] Licensing Branch B (APLB) Questions

APLB-RAI-1

Regulatory Guide (RG) 1.174, An Approach for Using Probabilistic Risk Assessment in Risk-informed Decisions on Plant-Specific Changes to the Licensing Basis, January 2018, Rev. 3, (ML17317A256), provides different approaches in the review of deterministic with risk insights versus risk-informed applications. LAR Section 3.0, Technical Evaluation, indicated that the licensee, in proposing a one-time extension to TS 3.8.1, Condition A.3, applied RG 1.177 Plant Specific, Risk Informed Decision Making: Technical Specifications, January 2021, Rev. 2, (ML20164A034), by considering engineering issues and applying risk insigh ts. However, LAR Section 4.3, No Significant Hazards Consideration Determination, indicated that the proposed completion time has been evaluated on a risk-informed basis.

• Please clarify whether the licensee intended to submit this LAR as a deterministic with risk insights or a risk-informed application.

APLB-RAI-2

RG 1.200, Acceptability of Probabilistic Risk Assessment Results for Risk-Informed Activities, December 2020, Rev. 3, (ML20238B871) states, in part, that:

F&Os [Facts and Observations] that are not closed using an NRC-endorsed process should be evaluated by the licensee or applicant for their impact on a risk-informed application and addressed with documented justification with necessary changes made to the PRA prior to the use of PRA in t he risk-informed application.

to Enclosure 2 of the LRA indicates that the Fire PRA F&O CFA2 -01 (2010 Full Scope) status is partially open. The disposition provided is that the impact is limited to a small portion of the uncertainty analysis due to minor documentation inconsistencies and does not impact the overall technical quality of the Fire PRA.

• Please provide a detailed discussion of the hot short probabilities that have not been incorporated, the inconsistencies between the value(s) presented in the documentation and those used in the model(s), and the impact of these uncertainties on this LAR application.

PRA Licensing Branch C (APLC) Questions

APLC-RAI-1 to enclosure 2 of the LAR indicates that the Seismic PRA F&O 2 -1 (2019 FSPR) is open. The disposition provided is that the studies performed in 15C4313-RPT-003 Attachment E show that, while there may be some cracking, it is not widespread at the RLE level.

• Please provide the locations where the 15C4313-RPT-003 study indicates cracking may occur. Additionally, provide a detailed discussion of the impacts on the PRA quantitative results, defense-in-depth considerations, and identification of risk-significant configurations presented in the LAR if cracking at these locations was accounted for in the seismic model.

APLC-RAI-2 to enclosure 2 of the LAR indicates that the Seismic PRA F&O 28-11 (2018 Full Scope) is open. The disposition provided is that sensitivity studies performed in 15C4313-RPT-003 between uncracked and cracked properties show that structural variability has a minor impact on response compared to the soil property variability. I&M will review the small number of impacted risk significant components on a case-by-case basis, adjusting frequency range of interest by an additional +/- 15 percent to ensure structural variability is captured in the fragility calculations.

• Please provide a detailed discussion of the impacts on the PRA quantitative results, defense-in-depth considerations, and identification of risk-significant configurations presented in the LAR if structural variability is accounted for in the seismic model.

Hearing Identifier: NRR_DRMA Email Number: 2509

Mail Envelope Properties (SA1PR09MB96059520298DC5BEA1D004AF92F32)

Subject:

FINAL RAI - D.C. Cook Nuclear Plant, Unit Nos. 1 and 2 - License Amendment Request Regarding Reserve Feed Enclosure (EPID No. L-2024-LLA-0040)

Sent Date: 5/30/2024 2:29:20 PM Received Date: 5/30/2024 2:29:22 PM From: Scott Wall

Created By: Scott.Wall@nrc.gov

Recipients:

"Helen L Levendosky" <hllevendosky@aep.com>

Tracking Status: None "Joe Tanko" <jmtanko@aep.com>

Tracking Status: None "Bradford M Culwell" <bmculwell@aep.com>

Tracking Status: None "Michael K. Scarpello" <mkscarpello@aep.com>

Tracking Status: None

Post Office: SA1PR09MB9605.namprd09.prod.outlook.com

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