ML15289A585

Request for Additional Information Regarding License Amendment Request Regarding Residual Heat Removal System

ML15289A585
Person / Time
Site:	McGuire
Issue date:	10/26/2015
From:	Geoffrey Miller Plant Licensing Branch II
To:	Capps S Duke Energy Carolinas
Miller G
References
CAC MF6666
Download: ML15289A585 (6)

Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 Mr. Steven D. Capps -

Vice President McGuire Nuclear Station Duke Energy Carolinas, LLC 12700 Hagers Ferry Road Huntersville, NC 28078-8985 October 26, 2015

SUBJECT:

MCGUIRE NUCLEAR STATION, UNIT 1: REQUEST FOR ADDITIONAL INFORMATION REGARDING LICENSE AMENDMENT REQUEST REGARDING RESIDUAL HEAT REMOVAL SYSTEM (CAC NO. MF6666)

Dear Mr. Capps:

By letter dated August 28, 2015 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML15244B179), Duke Energy Carolinas, LLC (Duke Energy) submitted a license amendment request to temporarily change McGuire Nuclear Station, Unit 1, Technical Specifications for correction of a degraded condition affecting the 1A Residual Heat Removal pump motor air handling unit.

The U.S. Nuclear Regulatory Commission (NRC) staff has reviewed the licensee's submittal and determined that additional information is needed in order to complete our review. The enclosed document describes this request for additional information (RAI). On October 15, 2015, Duke Staff indicated that a response to the RAI would be provided within 3 weeks.

If you have any questions, please call me at 301-415-2481.

Docket No. 50-369

Enclosure:

Request for Additional Information cc w/encl: Distribution via Listserv G. Edward Miller, Project Manager Plant Licensing Branch 11-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation

REQUEST FOR ADDITIONAL INFORMATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO A LICENSE AMENDMENT REQUEST REGARDING A TEMPORARY EXTENSION TO RESIDUAL HEAT REMOVAL ALLOWED OUTAGE TIME DUKE ENERGY CAROLINAS, LLC MCGUIRE NUCLEAR STATION, UNIT 1 DOCKET NO. 50-369 By letter dated August 28, 2015 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML15244B179), Duke Energy Carolinas, LLC (Duke Energy) submitted a license amendment request (LAR) to temporarily change McGuire Nuclear Station, Unit 1, Technical Specifications (TSs) for correction of a degraded condition affecting the 1 A Residual Heat Removal pump motor air handling unit.

Based on the NRG staff's review of this amendment request, the NRG staff has determined the following additional information is necessary to support completion of its technical review:

Background:

Duke Energy stated in the amendment that defense-in-depth measures will be installed for the duration of the repairs to the 1 A residual heat removal (RHR) air handling unit (AHU).

Issue:

Engineering change process was used to provide reasonable assurarn;:e that the defense-in-depth measures would support continued availability of tt;ie 1A RHR system train emergency core cooling system function and that the measure would not adversely impact the safety*

function of other systems, structures, and components that are not part of the 1 A RHR train system train.

Request:

Describe in detail the engineering change that supports this reasonable assurance. This should include (but not limited too):

1. Expected RHR 1 A room heat load calculations and one hour heat up (for no cooling or fan needed)

2. Available heat removal capacity with the temporary chiller/fan/cooling water supply

3. Required fire protection flow rate and water temperature requirements to support.the heat.removal capacity Internal missile analysis for this temporary equipment

4. Loss of refrigeration evaluation for this temporary AHU

5. Failure modes and affect analysis of this temporary AHU related to safety-related equipment in the area

6. Available clearance between the temporary AHU (chiller/fan/cooling water supply) and work that will be performed on the RHR 1A fan (provide drawings if available)

RAl2

Background:

Duke Energy stated in the amendment that the requested allowed outage time (AOT) required is 240 hours0.00278 days <br />0.0667 hours <br />3.968254e-4 weeks <br />9.132e-5 months <br />.

Issue:

• Of the 240 hours0.00278 days <br />0.0667 hours <br />3.968254e-4 weeks <br />9.132e-5 months <br /> requested for the AOT, sixty-five (65) hours are allocated during the repairs for unanticipated repairs; for example, fan wheel cracking, significant shaft damage.

Request:

1. Describe all the spare parts the will be on site related to the unanticipated repairs so that if needed, repairs will be performed within the new proposed AOT of 240 hours0.00278 days <br />0.0667 hours <br />3.968254e-4 weeks <br />9.132e-5 months <br />.

2. Describe if new cooling coils are part of this contingent, in case of damage during disassemble or reassembly.

3. For item 2, describe the addition testing that would be required for these new parts, if replaced, and has this time added to the time line to be completed in this new AOT of 240 hours0.00278 days <br />0.0667 hours <br />3.968254e-4 weeks <br />9.132e-5 months <br />.

RAl3

Background:

Duke Energy stated in the amendment that compensatory measures and commitments will be in place for the requested AOT time required of 240 hours0.00278 days <br />0.0667 hours <br />3.968254e-4 weeks <br />9.132e-5 months <br />.

Issue:

Several commitments are performed 'prior to exceeding' the 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> AOT. That is:

1. Testing of the chiller and AHU

2. Sump pump availability

3. Protected equipment

4. Monitor the National Weather Service

5. Contact Transmission Control Center

6. Establish roving fire watches in 6 areas

7. Procedure will have been developed to start alternate cooling Request:

Justify why the above noted commitments are not performed before exceeding the normal 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> AOT. Based on the proposed time line, after AHU inspections (i.e., at the end of 53 hours6.134259e-4 days <br />0.0147 hours <br />8.763227e-5 weeks <br />2.01665e-5 months <br />), if the AHU bearing needs to. be replaced, it would seem that the commitments should have been established before entering the initial work.

Describe why performing these 7 commitments at this point of the work has a benefit for defense-in depth function.

Describe why training is not part of these commitments as it relates to procedures for operating the temporary AHU equipment.

Additionally, please justify 1.vhy a regulatory commitment verses an obligation is the appropriate level of control for these activities. 1 RAl4

Background:

Duke Energy stated in the amendment that the potential break in the two inch cooling water supply hose could cause fire protection (RF) to start flooding on elevations 716' or 695' of the Auxiliary Building. Existing flooding analysis calculations have already reviewed the impact of a failure of six inch and eight inch RF piping, so failure of a two inch hose is bounded. Due to the lbw volume in the closed loop, a break in the 1.5 inch chilled water loop is not a flooding concern.

Issue:

The amendment lacks justification of the 2 inch rubber hose capability to withstand RF pressure.

Negative effects to the RHR room and RHR pump/motors have not been evaluated for water spray in the event of RF hose breakage.

Request:

Describe if water spray into the RHR 1A room has been evaluated for negative effects in the event of hose breakage.

Background:

1 Per discussion of draft RAls with licensee on Oct 15, it was identified that compensatory measures were proposed to be controlled as obligations. No further information is. necessary with regard to this part of RAI 3.

Duke Energy stated in the amendment that the proposed LAR involves a one-time extension to TS 3.5.2 to facilitate repairs to the 1 A RHR AHU. During the AHU repair evolution, important equipment (opposite train) will be protected and compensatory measures will be in place.

These activities are controlled by Duke Energy's normal risk management program.

Issue:

TS 3.5.2 Mode of applicability is 'Modes 1, 2, or 3. The repair work is assumed to have started with Unit 1 in Modes 1, 2 and 3. While in Mode 1, in the event of a Unit 1 reactor trip with the 1A RHR AHU ongoing maintenance, it is not clear the course of action during an unexpected shutdown. That is, the LAR does not specifically address, for example, TS 3.0.3 is entered during the extended repairs for Unit 1 RHR 1 A AHU.

Requ~st:

If Unit 1 must comply with TS and enters Mode 4 and Mode 5 with only one Operable RHR (since the AHU is being repaired), describe the necessary steps that would take place and include any additional compensatory measures and commitments that have not been previously addressed (while in Mode 1, 2 or 3). Specifically, address Mode 4 and Mode 5 actions with only one RHR pump Operable.

RAI 62

The amendment proposes to add a temporary footnote to the Completion Time in TS 3.5.2 Condition A. The language in the note is not consistent with the recommended style of Standard TSs. The footnote is not succinct and has potential for misinterpretation by Operators and Inspectors. Also, when a compensatory measure is a condition of a TS, it should not be referred to as a commitment in the TS wording. Please revise the Footnote to have an appropriate amount of detail and clarity.

2 RAI 6 was not included in the original draft RAI provided to Duke, but was identified for addition to this formal RAI on the October 15, 2015 discussion.

ML15289A585 OFFICE DORL/LPL2-1 /PM NAME GEMiller

• DATE 10/21/15 OFFICE

• DSS/$TSB/BC NAME RElliott (MChernoff for)

DATE 10/16/15 LPL2-1 R/F Sincerely,

/RA/

G. Edward Miller, Project Manager Plant Licensing Branch 11-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation RidsNrrDorllpl2-1 Resource RidsNrrPMMcGuireResource (hard copy)

RidsRgn2MailCenter Resource

• via e-mail DORL/LPL2-1 /LA DSS/SBPB/BC SFigueroa GCasto l

10/20/15 10/07/15 DSS/SRXB/BC NRR/LPL2-1/BC CJackson RPascarelli 10/21/15 10/26/15