ML19340A684

NRR E-mail Capture - Request for Additional Information for WBN2 Request for One-Time Extension of Completion Time for TS 3.7.8 (L-2019-LLA-0020)

ML19340A684
Person / Time
Site:	Watts Bar
Issue date:	12/05/2019
From:	Kimberly Green Plant Licensing Branch II
To:	Wells R Tennessee Valley Authority
References
L-2019-LLA-0020
Download: ML19340A684 (4)

Text

From: Green, Kimberly Sent: Thursday, December 5, 2019 12:27 PM To: Wells, Russell Douglas

Subject:

Request for Additional Information for WBN2 Request for One-Time Extension of Completion Time for TS 3.7.8 (L-2019-LLA-0020)

Attachments: RAI for L-2019-LLA-0020.docx

Dear Mr. Wells,

By application dated February 7, 2019 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML19038A483), as supplemented by letter dated October 24, 2019 (ADAMS Accession No. ML19297F537), Tennessee Valley Authority (TVA) requested changes to the technical specifications for Watts Bar Nuclear Plant, Unit 2 to support maintenance on 6.9 kilovolt (kV) Shutdown Board (SDBD) 1A-A and associated 480 volt (V) boards and motor control centers.

The U.S. Nuclear Regulatory Commission (NRC) staff is reviewing your submittal and has identified an area where additional information is needed to complete its review. Attached, please find a request for additional information (RAI).

A draft RAI was previously transmitted to you by email dated November 22, 2019. At your request, the NRC held a clarification call with TVA on December 5, 2019, to clarify the NRC staffs request. No changes were made to the draft RAI as a result of the clarification call; however, minor editorial changes were made to the text to define two acronyms.

A response to the attached RAI is requested by January 17, 2020.

If you have any questions, please let me know.

Regards, Kim Green (301) 415-1627 kimberly.green@nrc.gov

Hearing Identifier: NRR_DRMA Email Number: 333 Mail Envelope Properties (MN2PR09MB401629976BA81D28783329CD8F5C0)

Subject:

Request for Additional Information for WBN2 Request for One-Time Extension of Completion Time for TS 3.7.8 (L-2019-LLA-0020)

Sent Date: 12/5/2019 12:26:43 PM Received Date: 12/5/2019 12:26:00 PM From: Green, Kimberly Created By: Kimberly.Green@nrc.gov Recipients:

"Wells, Russell Douglas" <rdwells0@tva.gov>

Tracking Status: None Post Office: MN2PR09MB4016.namprd09.prod.outlook.com Files Size Date & Time MESSAGE 1295 12/5/2019 12:26:00 PM RAI for L-2019-LLA-0020.docx 39001 Options Priority: Normal Return Notification: No Reply Requested: No Sensitivity: Normal Expiration Date:

REQUEST FOR ADDITIONAL INFORMATION TENNESSEE VALLEY AUTHORITY WATTS BAR NUCLEAR PLANT, UNIT 2 DOCKET NO. 50-391 CHANGES TO TECHNICAL SPECIFICATION 3.7.8 By application dated February 7, 2019 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML19038A483), Tennessee Valley Authority (TVA, the licensee) requested changes to the technical specifications (TSs) for Watts Bar Nuclear Plant, Unit 2 (WBN2) to support maintenance on 6.9 kilovolt (kV) Shutdown Board (SDBD) 1A-A and associated 480 volt (V) boards and motor control centers.

The proposed changes for WBN2 would create a new CONDITION A in the TS 3.7.8, Essential Raw Cooling Water (ERCW) System, ACTIONS table which would have a longer COMPLETION TIME compared to existing CONDITION A. The new CONDITION A would describe the situation where one ERCW train is inoperable and four NOTES above the CONDITIION would restrict the entry into the CONDITION. In the February 7, 2019, request, the four NOTES above the CONDITION description would state:

1. Only applicable during the Unit 1 spring 2020 outage (U1R16) but no later than May 1, 2020.

2. Only applicable when Unit 1 is defueled.

3. Only applicable when Ultimate Heat Sink (UHS) temperature is 71 ºF.

4. Only applicable during planned maintenance on 6.9 kV shutdown board 1A-A and associated 480 V boards and motor control centers.

TVA supplemented the February 7, 2019, request with a letter dated October 24, 2019 (ADAMS Accession No. ML19297F537). Among the information and changes requested in the supplement, TVA proposed changing the first note above the CONDITION description to state:

1. Only applicable during the Unit 1 spring 2020 outage (U1R16) but no later than May 31, 2020.

The U.S. Nuclear Regulatory Commission (NRC) staff reviewed the TVAs request in the February 7, 2019, letter, as well as the supplement provided in the October 24, 2019, letter.

Section 3.2.2 of the February 7, 2019, letter stated:

Although this license amendment request is not a risk-informed submittal, the risk impacts of the proposed SDBD maintenance lineup were evaluated for WBN Unit 2 for a duration of seven days.

The bounding estimates of the risk associated with the SDBD maintenance evolution were determined to be very small.

Section 3.2.4 of the February 7, 2019, letter stated that a review of the past four years of plant data has shown that the ERCW temperature throughout the months of March and April does not exceed 71ºF and only exceeded 65ºF for a few days in 2017 with a maximum value of 67.3ºF and overall average of 55.5ºF. This statement appears to say that ERCW temperature going above 71 ºF during the months of March and April (i.e. during within the proposed maintenance period) is not credible.

The October 24, 2019, supplement showed ERCW temperatures exceeding 71ºF towards the middle to later periods of May in 2017 and 2018. The supplement did not contain ERCW temperature data for May 2019. Given the proposed Note allowing applicability of the proposed CONDITION through May 31, 2020, it appears ERCW temperature going above 71 ºF during the maintenance period is credible.

Section 2.2 of the LAR states that if the UHS temperature is found to be greater than 71ºF, then the analytical assumptions for justifying the extended completion time for Condition A are no longer met and Condition B is entered for an inoperable ERCW train for reasons other than Condition A. The NRC staff understands this to mean that the COMPLETION TIME for Condition B is 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> and would be entered when Condition A is exited for such a situation.

Based on the NRC staffs review of the application and supplement, it appears the request is proposing TSs that would, in fact, allow continued operation for up to 10 days with one ERCW train inoperable.

Requests for Additional Information Title 10 of the Code of Federal Regulations Section 50.36(b) requires TS to be derived from the analyses and evaluation included in the safety analysis report, and amendments thereto.

1. Please provide ERCW temperature data for May 2019.

2. Please either confirm that the statements in Section 3.2.2 of the February 7, 2019, letter remain valid, or provide a revised statement that accounts for the October 24, 2019, supplement.

3. Please provide an evaluation that demonstrates the acceptability of continued operation for up to 10 days with one ERCW train inoperable. Alternatively, provide proposed TSs that will not allow continued plant operation in the proposed CONDITION A after 7 days or after one of the NOTES above the CONDITION A restricting the entry into the CONDITION are not met.