ML22259A039

NRR E-mail Capture - Browns Ferry TSTF-505 Audit Questions - Part 5

ML22259A039
Person / Time
Site:	Browns Ferry
Issue date:	09/14/2022
From:	Kimberly Green Plant Licensing Branch II
To:	Eckermann J Tennessee Valley Authority
References
L-2022-LLA-0049
Download: ML22259A039 (3)

Text

From: Kimberly Green Sent: Wednesday, September 14, 2022 3:53 PM To: Eckermann, Jeremy Beau Cc: Victor, William Ross

Subject:

Browns Ferry TSTF-505 Audit Questions - Part 5 (EPID L-2022-LLA-0049)

Attachments: BFN TSTF-505 Audit Questions Part 5.docx

Beau,

The June 14, 2022, Audit Plan (ML22147A137) states that [t]hroughout the audit period, the NRC staff will submit audit questions and audit-related requests to TVA so that TVA can better prepare for audit discussions with NRC staff. Attached is the fifth set of NRC staff audit questions.

We look forward to discussing this question and TVAs response during the virtual audit meeting that is currently taking place. Please contact me at any time prior if a clarification discussion is needed.

Please post the response for the question to the Certrec Portal when the response is completed.

Let me know if you have any questions.

Kimberly Green Senior Project Manager Division of Operating Reactor Licensing U.S. Nuclear Regulatory Commission 301-415-1627

Hearing Identifier: NRR_DRMA Email Number: 1783

Mail Envelope Properties (DM6PR09MB54624FE03B511F97669D23228F469)

Subject:

Browns Ferry TSTF-505 Audit Questions - Part 5 (EPID L-2022-LLA-0049)

Sent Date: 9/14/2022 3:53:08 PM Received Date: 9/14/2022 3:53:00 PM From: Kimberly Green

Created By: Kimberly.Green@nrc.gov

Recipients:

"Victor, William Ross" <wrvictor@tva.gov>

Tracking Status: None "Eckermann, Jeremy Beau" <jbeckermann@tva.gov>

Tracking Status: None

Post Office: DM6PR09MB5462.namprd09.prod.outlook.com

Files Size Date & Time MESSAGE 791 9/14/2022 3:53:00 PM BFN TSTF-505 Audit Questions Part 5.docx 29772

Options Priority: Normal Return Notification: No Reply Requested: No Sensitivity: Normal Expiration Date:

AUDIT QUESTIONS LICENSE AMENDMENT REQUEST TO REVISE TECHNICAL SPECIFICATIONS TO ADOPT TSTF-505, REVISION 2 TENNESSEE VALLEY AUTHORITY BROWNS FERRY NUCELAR PLANT UNITS 1, 2, AND 3 DOCKET NOS. 50-259, 50-260, AND 50-296

Question 25 (APLC) -Difference Between CDF and LERF Mean and Point Estimate Values

In response to NRC staffs Audit Question 6, TVA provided updated values for CDF and LERF from internal events, fire, and seismic PRA for all three units. The staff notes that the mean values are greater than the point estimate of these quantities for all cases considered, and the differences are greater than 2 percent. Section 1 of Enclosure 9 to the LAR states. A comparison of CDF results from the normal model quantification and the parametric uncertainty evaluation shows that the difference between the point estimate and mean results is less than 2%. Therefore, SOKC is not a key source of uncertainty for the TSTF-505 application. The cited statement appears to contradict TVAs response to Audit Question 6. Explain this apparent contradiction or correct the cited statements to make them consistent with the updated PRA results.