MNS-15-062, Response to Request for Additional Information Regarding License Amendment Request (LAR) for Temporary Changes to Technical Specifications for Correction of an 'A' Train Nuclear Service Water System (Nsws) Degraded Condition

Response to Request for Additional Information Regarding License Amendment Request (LAR) for Temporary Changes to Technical Specifications for Correction of an 'A' Train Nuclear Service Water System (Nsws) Degraded Condition

ML15247A066
Person / Time
Site:	Mcguire, McGuire
Issue date:	08/11/2015
From:	Capps S Duke Energy Carolinas
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
MNS-15-062, TAC MF6409, TAC MF6410
Download: ML15247A066 (5)

Text

. ivJ~DUKEVice DUKEsteven D.Capps President

',., - ENERGYMoGuire Nuclear Station Duke Energy MG01VP I112700 Hagers Ferry Road Huntersville, NC 28078 o: 980.875.4805 f: 980.875.4809 Steven.Capps@duke-energy.com 10 CFR 50.90 August 11, 2015 Serial: MNS-1 5-062 U.S. Nuclear Regulatory Commission Washington, DC 20555-00 1 ATTENTION: Document Control Desk Duke Energy Carolinas, LLC (Duke Energy)

McGuire Nuclear Station, Units 1 and 2 Docket Nos. 50-369 and 50-370 Renewed License Nos. NPF-9 and NPF-17

Subject:

Response to Request for Additional Information Regarding License Amendment Request (LAR) for Temporary Changes to Technical Specifications for Correction of an 'A' Train Nuclear Service Water System (NSWS) Degraded Condition (TAC NOS. MF6409 AND MF6410)

By letter dated June 30, 2015, Duke Energy requested a license amendment for the Renewed Facility Operating Licenses (FOL) and Technical Specifications (TS) for the McGuire Nuclear Station, Units 1 and 2, to allow temporary changes to TS 3.5.2, Emergency Core Cooling System (ECCS) - Operating; TS 3.6.6, Containment Spray System (CSS); TS 3.7.5, Auxiliary Feedwater (AFW) System; TS 3.7.6, Component Cooling Water (CCW) System; TS 3.7.7, Nuclear Service Water System (NSWS); TS 3.7.9, Control Room Area Ventilation System (CRAVS); TS 3.7.11, Auxiliary Building Filtered Ventilation Exhaust System (ABFVES), and TS 3.8.1, AC Sources- Operating.

By letter dated July 27, 2015, Nuclear RegulatorY Commission (NRC) Staff requested additional information (RAI) needed to complete their review of the proposed LAR. The enclosure provides Duke Energy's responses to the RAI questions and contains no additional regulatory commitments.

Pursuant to 10CFR50.91, 'a copy of this LAR has been forwarded to the appropriate North Carolina state officials.

Please direct any comments or questions regarding this submittal to George Murphy at (980) 875-5715.

J.JS Nuclear

-. YAugust Regulatory Commission 11, 2015 Page 2 I declare under penalty of perjury that the foregoing is true and correct. Executed on August 11, 2015.

Sincerely, Steven D. Capps

Enclosure:

Response to Request for Additional Information

4.UtS Nuclear Regulatory Commission August 11, 2015 Page 3 cc wI/Attachments:

V. M. McCree Administrator, Region Il U.S. Nuclear Regulatory Commission Marquis One Tower 245 Peachtree Center Ave., NE, Suite 1200 Atlanta, GA 30303-1257 J. Zeiler NRC Senior Resident Inspector McGuire Nuclear Station G. E. Miller, Project Manager U.S. Nuclear Regulatory Commission 11555 Rockville Pike Mail Stop 0-8 G9A Rockville, MD 20852-2738 W. L. Cox, Ill, Section Chief North Carolina Department of Environment and Natural Resources Division of Environmental Health Radiation Protection Section 1645 Mail Service Center Raleigh, NC 27699-1 645

A Enclosure Response to Request for Additional Information NRC Request for Additional Information:

1.The proposed footnotes allow partial usage of the extra 14-day completion time over the course of multiple entries into the action statement. Multiple entries into the action statement seems inconsistent with the planned diagnostic and corrective work evolution described in the submittal.

Please iustify why it is necessary to allow partial usage of the extra 14 days.

Duke Energy Response:

MNS expects to inspect the obstruction within the normal TS 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> completion time and gain additional information that can be used to remove the obstruction at a later date. The information acquired will be used to compile the best equipment and resources to remove the obstruction to minimize total system unavailability. However, there is a possibility that the inspection may determine that some type of margin enhancement action is prudent. In this case, MoGuire will take the action using some portion of the 14 day extension.

Additionally, the inspection may also indicate that the.obstruction can be easily removed with available equipment and resources, in which case, McGuire will use the 14 day extension as needed to remove the obstruction. Finally, the 14 day extension will not add additional time to the unavailability time managed by the maintenance rule.

2. The submittal does not address why this maintenance evolution cannot be performed when one unit is in a refueling outage and, as such, would potentially represent a lower risk configuration and could afford additional time to respond to an event on the shutdown unit.

Please justify why this maintenance evolution is not more appropriately performed coincident with a refueling outage of one of the units.

Duke Energy Response:

Incorporation of the 'A' NSWS SNSWP piping work scope into the refueling outage of one unit would unnecessarily increase the risk of the evolution. The inlet and outlet isolation valves for both units have shared power supplies that would be at greater risk during an outage. The compensatory measures to protect an array of redundant system trains and shared systems would also be at greater risk during an outage. Additionally, the outage would reduce station focus on the A NSWS SNSWP piping work scope due to the number of activities in the outage.

The pre-activity defense in depth actions for aligning 'B' Train NSWS to its ESFAS suction source and maintaining the 'A' NSWS Train aligned to Lake Norman make the system fully functional on both Units 1 and 2 for all operating design basis events and analyzed accidents except an earthquake that damages the Lake Norman dam or associated Low Page 1 of 2

.pA A Level Intake (LLI). The dam and LLI were originally designed for an Operating Basis Earthquake (OBE).

The probability and risk from an OBE during the 14 day extended completion time window is very low as discussed in the LAR. In addition, more recent analysis demonstrates that the Cowan's Ford Dam and LLI supply to the 'A' Train NSWS would survive an OBE and is rugged enough to withstand a Safe Shutdown Earthquake (SSE).

The 'B' Train NSWS remains operable and defense in depth guidance is available for a beyond design basis total loss of NSWS flow.

Again, the 14 day extension will not add additional time to the unavailability time managed by the maintenance rule.

3. The submittal indicates that requested need date is October 31, 2015; however, the proposed expiration date for the TS footnote is December 31, 2016.

Given the implied urgency of the requested need date, the NRC staff requests that Duke provide additional iustification for allowing the temporary completion time extension to remain valid until December 31, 2016.

Duke Energy Response:

As indicated in the response to question 1 above, MNS expects to inspect the obstruction within the normal TS 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> completion time and gain additional information that can be used to remove the obstruction at a later date. The information acquired will be used to compile the best equipment and resources to remove the obstruction to minimize total system unavailability.

Equipment and resources identified during the inspection may not be immediately available due to long lead times. The final removal work schedule will be defined based on the associated lead times. However, equipment and resources will be identified and acquired as necessary to support the December 31, 2016, expiration date.

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