CNS-15-075, License Amendment Request (LAR) for Changes to Technical Specification (TS) 3.3.2, Engineered Safety Feature Actuation System (ESFAS) Instrumentation and TS 3.3.5, Loss of Power (LOP) Diesel Generator (DG) Start..

License Amendment Request (LAR) for Changes to Technical Specification (TS) 3.3.2, Engineered Safety Feature Actuation System (ESFAS) Instrumentation and TS 3.3.5, Loss of Power (LOP) Diesel Generator (DG) Start..

ML15231A012
Person / Time
Site:	Catawba
Issue date:	08/17/2015
From:	Henderson K Duke Energy Carolinas
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
CNS-15-075
Download: ML15231A012 (8)

Text

• DUKE Kelvin Henderson Vice President SENERGY Catawba Nuclear Station Duke Energy CNOIVP I4800 Concord Road CNS-1-075York, SC 29745 o: 803.701.4251 August 17, 2015 f: 803.701.3221 10 CFR 50.90 U.S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, DC 20555-0001

Subject:

Duke Energy Carolinas, LLC (Duke Energy)

Catawba Nuclear Station, Units 1 and 2 Docket Numbers 50-413 and 50-414 License Amendment Request ([AR) for Changes to Technical Specification (TS) 3.3.2, "Engineered Safety Feature Actuation System (ESFAS) Instrumentation" and TS 3.3.5, "Loss of Power (LOP) Diesel Generator (DG) Start Instrumentation" Resolution of Operable But Degraded Condition Due to Non-Conservative TS Response to NRC Request for Additional Information

References:

1. Letters from Duke Energy to NRC, dated November 24, 2014 (ADAMS Accession Number ML14330A327) and July 31, 2015 (ADAMS Accession Number not yet available)

2. Letter from NRC to Duke Energy, dated May 18, 2015 (ADAMS Accession Number ML15132A773)

The November 24, 2014 Reference 1 letter requested NRC review and approval to revise the Allowable Value parameter for the TS 3.3.2 Table 3.3.2-1, "Engineered Safety Feature Act,.,-uatio System instrumentation" function for Auxiliary Feedwater Loss of Offsite Power (Function 6.d.) and for the TS 3.3.5 Loss of Voltage function in Surveillance Requirement (SR) 3.3.5.2 in order to make this parameter more restrictive. The existing parameter was determined to be non-conservative and this parameter is presently classified as Operable But Degraded in the Catawba Corrective Action Program. In addition, the Nominal Trip Setpoint parameter for this function is being slightly lowered in order to gain additional margin to what is known as a "double sequencing event". Finally, as part of this [AR, applicable footnotes are also being added to the affected TS 3.3.2 function in accordance with TS Task Force Traveler TSTF-493, Revision 4, "Clarify Application of Setpoint Methodology for LSSS Functions".

Reference 2 transmitted NRC Requests for Additional Information (RAIs) associated with the November 24, 2014 Reference 1 letter.

The July 31, 2015 Reference 1 letter provided responses to all but one of the Reference 2 RAIs.

This letter indicated that the outstanding RAI response would be provided by August 17, 2015.

The purpose of this letter is to formally respond to the outstanding RAl. The enclosure to this *'")

www.duke-energy corn

,. U.S. Nuclear Regulatory Commission "i" Page 2 August 17, 2015 letter provides Duke Energy's response. The format of the enclosure is to restate the RAI question, followed by its response.

The conclusions of the original Regulatory Evaluation and Environmental Consideration contained in the November 24, 2014 Reference 1 letter are unaffected as a result of this RAI response.

Pursuant to 10 CFR 50.91, a copy of this LAR supplement has been forwarded to the appropriate State of South Carolina official.

There are no regulatory commitments contained in this letter or its enclosure.

If you have any questions or need additional information on this matter, please contact L.J.

Rudy at (803) 701-3084.

I declare under penalty of perjury that the foregoing is true and correct.

Executed on August 17, 2015.

Very truly yours, Kelvin Henderson Vice President, Catawba Nuclear Station LJR/s Enclosure

U.S. Nuclear Regulatory Commission Page 3 August 17, 2015 xc (with enclosure):

V.M. McCree Regional Administrator U.S. Nuclear Regulatory Commission - Region II Marquis One Tower 245 Peachtree Center Ave., NE Suite 1200 Atlanta, GA 30303-1257 G.A. Hutto Ill Senior Resident Inspector U.S. Nuclear Regulatory Commission Catawba Nuclear Station G.E. Miller (addressee only)

NRC Project Manager U.S. Nuclear Regulatory Commission One White Flint North, Mail Stop 8 G9A 11555 Rockville Pike Rockville, MD 20852-2738 S.E. Jenkins Manager Radioactive & Infectious Waste Management Division of Waste Management South Carolina Department of Health and Environmental Control 2600 Bull St.

Columbia, SC 29201

• Enclosure RESPONSE TO NRC REQUESTS FOR ADDITIONAL INFORMATION (RAts)

Subject:

License Amendment Request (LAR) for Changes to Technical Specification (TS) 3.3.2, "Engineered Safety Feature Actuation System (ESFAS) Instrumentation" and TS 3.3.5, "Loss of Power (LOP) Diesel Generator (DG) Start Instrumentation" Resolution of Operable But Degraded Condition Due to Non-Conservative TS Page 1 of 5

Enclosure REQUEST FOR ADDITIONAL INFORMATION REGARDING CATAWBA NUCLEAR STATION. UNITS 1 AND 2 LICENSE AMENDMENT REQUEST TS 3.3.2, "ENGINEERED SAFETY FEATURE ACTUATION SYSTEM INSTRUMENTATION" TS 3.3.5. "LOSS OF POWER DIESEL GENERATOR STARTUP INSTRUMENTATION" DOCKET NOS. 50-413 AND 50-414 By letter dated November 24, 2014 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML14330A327), Duke Energy Carolinas (Duke) submitted a license amendment request for the Catawba Nuclear Station, Units 1 and 2. The proposed amendment would revise the allowable value in the subject TSs to correct a non-conservative value. In order for the NRC staff to complete its review of the relief request, the following additional information is requested.

6. Please provide a curve showing the minimum voltages at the 4160 V safety-related buses during the starting of LOCA loads after the safety injection signal based on the minimum switchyard voltage (based on agreement with the transmission system operator). Super-impose on this curve, the analytical and reset voltage values of the undervoltage relay settings to demonstrate that adequate margin exists so that the motors would not trip out by the undervoltage relay during a LOCA load sequencing.

Duke Energy Response:

Refer to the two attached figures. These figures assume that the 230 kV switchyard voltage is at the minimum expected value such that there is adequate voltage for the degraded grid voltage relays to reset.

Unit 1 figure:

The maximum loss of voltage trip setpoint is used in the figure.

This maximum value assumes that the relay has drifted to the maximum value dictated by the total loop uncertainty. This figure shows that the 4.16 kV switchgear voltage does not dip to 85.48% (current loss of voltage trip maximum setpoint). Additionally, the requested value for the loss of voltage relay setpoint (adjusted to the maximum drift value) of 84.23% is also shown on the figure.

Unit 2 figure:

The voltage transient at 21.9 seconds is due to the switching on and off of loads used to create bounding voltages for the 600 V system as part of the motor operated valve analysis; therefore, it is not reflective of an actual transient. Based upon the figure, the degraded grid voltage relay would not be capable of resetting due to the degraded grid timer timing out prior to the voltage recovering above the reset voltage. This is due to the fact that the 4.16 kV motor start times have been increased to take into account timer Page 2 of 5

Enclosure tolerances and additional conservatisms. This was done to ensure that the worst case motor operated valve voltage is determined. However, the switchgear voltage is capable of recovering above the degraded grid voltage reset point prior to the timer timing out when the above conservatisms are removed. The lowest voltage occurs when the containment spray (Duke Energy designation "NS") pump motor starts concurrently with the auxiliary feedwater (Duke Energy designation "CA") pump motor. The automatic starting of the NS pump motors has been deleted as part of the Emergency Core Cooling System Water Management license amendments (Amendments 257/252 for Units 1/2, respectively). As such, the voltage during this transient is bounding once the analysis is re-performed with the automatic (and random) starting of the NS pump motors removed from this time period. Even with the conservative assumption of the concurrent start of the NS and CA pump motors, the switchgear voltage remains above 85.48% (the current loss of voltage trip maximum setpoint). Additionally, the requested value for the loss of voltage relay setpoint (adjusted to the maximum drift value) of 84.23% is also shown on the figure.

Page 3 of 5

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