ML22042B326

Summary of February 8, 2022, Meeting with Tennessee Valley Authority Regarding a Proposed License Amendment Request to Revise the Allowable Value for Trip of Turbine-Driven Main Feedwater Pump at Watts Bar Nuclear Plant, Unit 1

ML22042B326
Person / Time
Site:	Watts Bar
Issue date:	02/14/2022
From:	Kimberly Green Plant Licensing Branch II
To:	Tennessee Valley Authority
Green K
References
EPID L-2022-LRM-0008
Download: ML22042B326 (4)

Text

February 14, 2022 LICENSEE: Tennessee Valley Authority FACILITY: Watts Bar Nuclear Plant, Unit 1

SUMMARY

OF FEBRUARY 8, 2022, MEETING WITH TENNESSEE VALLEY AUTHORITY REGARDING A PROPOSED LICENSE AMENDMENT REQUEST TO REVISE THE ALLOWABLE VALUE FOR TRIP OF TURBINE-DRIVEN MAIN FEEDWATER PUMP AT WATTS BAR NUCLEAR PLANT, UNIT 1 (EPID L-2022-LRM-0008)

On February 8, 2022, the U.S. Nuclear Regulatory Commission (NRC) staff conducted a virtual observation (i.e., public) meeting with representatives of the Tennessee Valley Authority (TVA).

The purpose of the meeting was to discuss TVAs proposed license amendment request (LAR) to change the allowable value (AV) for Function 6.(e)1, Auxiliary Feedwater - Trip of all Main Feedwater Pumps - Turbine-Driven Main Feedwater Pumps, in Watts Bar Nuclear Plant (Watts Bar), Unit 1, Technical Specification (TS) Table 3.3.2-1.

The meeting notice and agenda, dated January 18, 2022, are available at Agencywide Documents Access and Management System (ADAMS) Accession No. ML22018A089. TVAs presentation slides for the meeting are available at ADAMS Accession No. ML22035A000. The list of participants is enclosed.

TVA stated it plans to revise the AV for Function 6.(e)1 from 48 psig (pounds per square inch) to 43.3 psig. This change will make the AV consistent with the Function 6.(e)1 AV for Watts Bar Unit 2. TVA added that the change to the AV does not involve any hardware changes to the instrument.

TVA explained the difference between the AVs for Watts Bar Units 1 and 2, which was previously described in a response to a request for additional information during the initial development of the Watts Bar, Unit 2, TSs (ADAMS Accession No. ML13085A219). TVA stated that Unit 2s calculation of the AV was in accordance with TSTF-493, but Unit 1 had not yet updated its methods to be consistent with TSTF-493.

TVA further explained that its branchs technical instruction, EEB-TI-28, Setpoint Calculations, was previously provided to the NRC (ADAMS Accession Nos. ML101380297 and ML101390102), and that the NRC evaluated the instruction as part of the licensing basis for Watts Bar, Unit 2, as documented in NUREG-0847, Supplement 23, Safety Evaluation Report Related to the Operation of Watts Bar Nuclear Plant, Unit 2 Docket Number 50-391, (ADAMS Accession No. ML11206A499).

TVA described its calculation of the new AV for function 6.(e)1 and stated that the calculation was performed in accordance with EEB-TI-28. In short, the AV is based on the setpoint of the pressure switch minus the normal measurable accuracy of the pressure switch. The setpoint for the switch of interest is 50 psig. This value will remain the same in the TS. TVA calculated the

measurable accuracy of the pressure switch to be 6.7 psig. The difference between the two values is 43.3 psig, and is what TVA plans to propose the new AV to be. TVA noted that the current AV of 48 psig is too limiting for the accuracy and repeatability of the switches since their nominal setpoint is 50 psig.

The NRC staff asked the licensee if there were analytical limits associated with the TS function 6.e(1). The licensee explained that the function in question is not credited in any of the Watts Bar Updated Final Safety Analysis Report Chapter 15 accident analyses and, therefore, do not have associated analytical limits. The auxiliary feedwater (AFW) actuation function associated with 6.e(1) is an anticipatory function and the function that is credited in the plant accident analysis is the AFW actuation on low steam generator level, which is function 6.b in TS Table 3.3.2-1. The NRC staff stated that if this function is confirmed to be a non-credited function, then there would be no need to evaluate the change to the AV other than to verify that proper setpoint calculation methods were used to account for instrument uncertainty. The NRC staff also asked the licensee to include a functional description of the affected function in the forthcoming LAR to support the safety evaluation for the license amendment.

TVA plans to submit the LAR to the NRC by the end of March 2022, and will request approval by within 12 months from the date of the submittal.

No regulatory decisions were made at this meeting.

Please direct any inquiries to me at 301-415-1627 or by e-mail to Kimberly.Green@nrc.gov.

/RA/

Kimberly J. Green, Senior Project Manager Plant Licensing Branch II-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-390 and 50-391

Enclosure:

List of Participants cc: Listserv

LIST OF PARTICIPANTS FEBRUARY 8, 2022, PUBLIC MEETING WITH TENNESSEE VALLEY AUTHORITY REGARDING WATTS BAR NUCLEAR PLANT, UNIT 1 PROPOSED LICENSE AMENDMENT REQUEST FOR REVISION TO ALLOWABLE VALUE FOR TRIP OF TURBINE-DRIVEN MAIN FEEDWATER PUMP Name Affiliation Kim Green U.S. Nuclear Regulatory Commission (NRC)

Raul Hernandez NRC Hang Vu NRC Tarico Sweat NRC Rich Stattel NRC Kayleh Hartage NRC Russ Wells Tennessee Valley Authority (TVA)

Daniel Fox TVA Dean Baker TVA Ron Cox TVA Gordon Williams TVA Enclosure

ML22042B326 OFFICE DORL/LPL2-2/PM DORL/LPL2-2/LA DORL/LPL2-2/BC DORL/LPL2-2/PM NAME KGreen RButler DWrona KGreen DATE 02/10/2022 2/11/2022 2/14/2022 2/14/2022