ML19336B968

COL Docs - FW: Vogtle LAR 19-018 Discussion

ML19336B968
Person / Time
Site:	Vogtle
Issue date:	12/02/2019
From:	NRC
To:	NRC/NRR/DNRL
References
Download: ML19336B968 (2)

Text

From: Rankin, Jennivine Sent: Monday, December 2, 2019 1:17 PM To: Vogtle PEmails

Subject:

FW: Vogtle LAR 19-018 discussion For discussion at Vogtle Public Meeting on 12/5.

From: Rankin, Jennivine Sent: Wednesday, November 27, 2019 7:02 AM To: Kellenberger, Nicholas <X2NRKELL@SOUTHERNCO.COM>

Subject:

Vogtle LAR 19-018 discussion Good morning Nick -

During the review of LAR 19-018 regarding the Passive Containment Cooling System Wetted Perimeter Test modification, the NRC staff had the following question they would like to discuss.

Would it be possible to discuss it at the December 5, public meeting? Please let me know if SNC can support a discussion then. We could start it at 9 am.

The LAR proposes changes to the location where the wetted perimeter percentage is measured. The original measurement was to be at the interface between the dome and the cylindrical portion of the structure which is at 244 ft elevation. The change measures the percentage of wetted perimeter between the spring line (244 ft elevation) and 266 ft elevation.

Measuring the percentage wetted perimeter at a different location appears to change the surface area wetted by the PCS water flow. The change in wetted surface area could change the evaporation rate assumed for heat energy removal from containment. This appears to result in a departure from a method of evaluation described in the FSAR (as updated) used in establishing the design basis or in the safety analysis (WCAP-15846 revision 5).

The LAR technical evaluation discusses percent coverage as equivalent to flow rate. There is no discussion how the change in wetted surface area affects the heat transfer rate assumed in the design basis analysis. Can SNC explain if the assumptions and methodology in the WGOTHIC analysis are affected by this change as it pertains to heat transfer rate?

Thanks, Jennie Jennie Rankin, Project Manager Vogtle Project Office Office of Nuclear Reactor Regulation

Hearing Identifier: Vogtle_COL_Docs_Public Email Number: 505 Mail Envelope Properties (BN6PR09MB1298C5A3956D6F5D949952D398430)

Subject:

FW: Vogtle LAR 19-018 discussion Sent Date: 12/2/2019 1:16:56 PM Received Date: 12/2/2019 1:16:58 PM From: Rankin, Jennivine Created By: Jennivine.Rankin@nrc.gov Recipients:

"Vogtle PEmails" <Vogtle.PEmails@nrc.gov>

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