ML17087A263

Response to Request for Additional Information Regarding License Amendment Request for Reactor Protection System (RPS) Electrical Protection Assembly (EPA) Electric Power Monitoring Surveillance...

ML17087A263
Person / Time
Site:	Brunswick
Issue date:	03/01/2017
From:	Gideon W R Duke Energy Progress
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
BSEP 17-0019
Download: ML17087A263 (5)

Text

ef-.DUKE March 1, 2017 Serial: BSEP 17-0019 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001

Subject:

Brunswick Steam Electric Plant, Unit Nos. 1 and 2 Renewed Facility Operating License Nos. DPR-71 and DPR-62 Docket Nos. 50-325 and 50-324 Wllllam R. Gideon Vice President Brunswick Nuclear Plant P.O. BoX 1o429 Southport, NC 28461 o:

Response to Request for Additional Information Regarding License Amendment for Reactor Prqtectlori System (RPS)

Protection (EPA) Electric Power Monitoring Surveillance Requirements (SAs) and 3.3.8.2.3

References:

1. Letter from William R. Gideon-Ene_rgy) to U.$. Ny,¢1ear Regulatory Gqmmlssion, Request.for License AmE1ndment

-Remctor Protection System (RPS) Electrical Protection Assembly {EPA) Electric Power Monitoring Surveillance .Requirements (SRs) 3.3.B.2.2and3.3.B;2.3, dated Aprll 13, 2016, ADAMS Accession Number ML161118203

2. NRC E-mail Capture, Brunswick Unit 1 and Unit 2 Request forAdditionallnfoimation Related to Reqt,1e$t to Revise SRs 3.3.8.2.2 and 3.$:8.2.3 (CAC Nos. MF7602 and MF7603},dated January 31, 2017, ADAMS Accession Number ML17031A292 Ladies and Gentlemen:

' -. ' By_letter dated*April 13,2016 {I.e., Reference 1}, Duke Energy Progress, LLC, a license amendment request (LAA) for the Brunswick Steam Electric, (BSEP), Unit No.s. 1 and 2. The proposed amendment would revise the Allowable Values of Surveillance RequiremE;'lnts (SR) coritainE!d, in Technical

{TS)

• RPS Electric Power Specifically, the TS change proposed to amend the Reactor Protection System (RPS) electric power m_onitoring Values for overvoltage and undervoltage contained within SR 3.3:8.2.2 and SB On January 31, 2017, by electrohlc mall (I.e., Reference 2), the NRC provided a request for additional information (RAI) regarding the LAR. Duke Energy's response is provided in the enclosure of this letter. No new regt!latory commitments are contained in this letter.

U.S. Nuclear Regulatory Commission Pa!Je 2 of 3 Please refer any questions regarding this submittal to Mr. Lee Grzeck, Manager -Regulatory Affairs, at (910) 457-2487.

I declare, under penalty of perjury, that the foregoing is true and correct. Executed on March 1, 2017. si:/)y William R. Gideon WRG/mkb

Enclosures:

'

1. Response to Request for Information

2. Nuclear Generation Group Calculation 1 C71-0016, Revision 1, Reactor Protection System Power Monitor OveNoltage, Undervoltage, Undetfrequency, and Time Delay Uncertainty and Setpoint Calculation U.S. Nuclear Regulatory Commission Page 3 of 3 ct: U. S. Nuclear Regulatory Commission, Region II ATTN: Ms. Catherine Haney, Regional Administrator 245 Ave, NE, Suite Atlanta, GA 30303-1257 U.$. Nuc;lear Regulatory Commission ATTN: Mr.

Hon (Mail Stop OWFN 8G9A) (Electronic Copy Only) 11555 Rockvifle Pike, Rockville, MD 20852-2738 cc (with Enclosure 1 only) U.S. Nuclear Regulatory Commission ATTN: Ms. Michelle P. Catts, NRC Senior Resident Inspector 8470 River Road Southport, NC 28461-8869 Chair -North Carolina Utilities.

Commission (Electronic Copy Only) 4325 Mail Service Center Raleigh, NC.

swatson@ncuc.net Response to Request for Additional Information BSEP 17-0019 Enclosure 1 Page 1 of 2 By letter dated April 13, 2016 (i.e., Reference 1 in the cover letter), Duke Energy Progress, LLC, submitted a license amendment request (LAR) for the Brunswick Steam Electric Plant (BSEP), Unit Nos. 1 and 2. The proposed amendment would revise the Allowable Values (AV) of Surveillance Requlrernents (SR) contained in Technical Specifications (TS) 3.3.8.2, RPS Electric Power Monitoring.

Specifically, the TS change proposed to amend the Reactor Protection System (RPS) electric power monitoring assembly Allowable Values for overvoltage and undervoltage contained within SR 3.3.8.2.2 and SR 3.3.8.2.3.

On January 31, 2017, by electronic mail Reference 2 in the cover letter), the NRC provided a request for cidditional information (RAI) regarding the LAR. Duke Energy's response is provided below. NRC RAI: Request 1: Section 2.2 ofEnclosure 1 oft_he sµbjecMicense amendment request (LAA) states, in part, tl)at "[dJuring the review of the EC [Engineering Change], fasues were identified with the current RPS EPA that could potentially allow the SSPV coils to operate above their design maximum vqltage rating and below their minimum voltage rating based .on worst case conditions and when calculated voltage drops are taken into account" The LAR did not explain the reason, the type; or the severity of the issues identified.

Therefore, the NRG staff requests the licensee to: (a} Explain t.he reason, the type 1 and the severity of the identified (b) Submit a copy of the updated calculation and associated methodology used to perform the calculation for NRC staff review, (c) If not included in the calculation, provide the voltage rating of the AVCO solenoids in order for the NRG staff to assure that the voltages selected are conservative with regard to the rated voltages.

BSEP Resbonse 1 (a): The design and licensing basis of the Electrical Protection Assembly (EPA) breaker setting is to protect the scram solenoid pilot valves. (SSPVs) tram prolonged exposure (i.e., greater than a few seconds) to vo,ltages beyond their limits of 115.+/-10 VAG (i.e., 10.5 to 125 VAC). In determining the ASCO setpoints*, circa August 19.96, Calculations 1 C71-0016, Rev. o and 2C72-00.19, *Rev. O; used the transient voltage conditions and not the sustained voltage values when determining the design limits. The maximurn voltage design limit was based on a maximum "surge" voltage of 138V per the General Electric (GE) Reactor Protection System (RPS) Design Specification, 22A1480, Revision 3, and the minimum voltage design limit is based on a minimum voltage "excursion" of 95 V per the BSEP 'Design Ba.sis Document (DBD)-03, Revision 001, Reactor Protection System. As a result, for the original ASCO type SSPVs, the overvoltage trip setpoint for EPA breakers 1/2-C71/C72-EPA5 and 1/2-C71/C72-EPA6 (i.e,, alternate power supply) was higher than required to ensure the SSPV coils operate below their design maximum voltage rating. The BSEP i 7-0019 Enclosure 1 Page 2 of 2 overvoltage trip setpoint (i.e., 130 VAC) for the alternate power supply through EPA-5/6 may not open the breake.r until voltage 131 VAC, potentially exposing the SSPVcoils to a voltage above their upper design limit of 125 VAC (i.e., 128 VACworst case when a nominal vc:iltage drop of 3 VAC to .the devipes is. taken into account).

Also, the undervoltage trip setpoint for 1/2-C71/C72-EPA1, 1/2-C71/C72-EPA2, 1/2-C71/C72-EPA3 and 1/2-C71./C72-EPA4 (i.e., normal power supply) was lower than required to ensure the SSPV coils operate above their design minimum voltage rating. The undervoltage trip setpoint (i.e., 107 VAC) for the normal power supply through EPA-1/21314 may not open until 106 VAC, potentially exposing the SSPV coils to a voltage below their lower design of 105 VAC (i.e., 103 VAC worst case when a nominal voltage drop of 3 VAC to the devices is taken into account).

BSEP Response 1 (b}: The requested setpoint calculation has been Included as Enclosure 2 of this submittal.

BSEP Response 1 Cc): The requested information is contained i.n the calculation provided in Enclosure 2 of this submittal.

• Request 2: Section 3 cif Enclosure 1 of the LAA states that the EPA provides underfrequency protection, the setpoint of which is in SRs 3.3.8;2.2 and 3.3.8!2.3 as being a frequency of i?

Hz. Howeveir, there is* no mention in the LAR whether there is any change pertaining to the frequency being required for the solenoid valve replacement.

Please confirm that there are no change$ to the freql1ency settings or associated equipment.

BSEP Response 2: There are no changes to the frequency settings.

Per Calculation 1 C71-0016, the. AVs and device setpoint remain the same (i.e., unchanged) at Hz and 57,7 Hz, respectively.

The Design Urriit fo'r the RPS EPA underfrequency function is 57.0 Hz. This value is based on the protective circuitry requirement of -5.0% of 60 Hz as found in BSEP DBD-03, Revision 007, Reac;tor Protection SystE1m. This is conservative b1::lsed on the minimum qualified frequency of 56.5 Hz'per.Brunswick Design Report (DR) 296, Rev. O, Wyte*Laboratories Test Report 444DOR96-1.

-