ND-23-0043, ITAAC Closure Notification on Completion of ITAAC 2.1.02.08d.i (Index Number 32)

ITAAC Closure Notification on Completion of ITAAC 2.1.02.08d.i (Index Number 32)

ML23034A121
Person / Time
Site:	Vogtle
Issue date:	02/03/2023
From:	Coleman J Southern Nuclear Operating Co
To:	Office of Nuclear Reactor Regulation, Document Control Desk
References
ND-23-0043, ITAAC 2.1.02.08d.i
Download: ML23034A121 (1)

Text

Jamie M. Coleman Regulatory Affairs Director Vogtle 3 & 4 7825 River Road Waynesboro, GA 30830 706-848-6926 tel February 3, 2023 Docket No.:

52-026 ND-23-0043 10 CFR 52.99(c)(1)

U.S. Nuclear Regulatory Commission Document Control Desk Washington, DC 20555-0001 Southern Nuclear Operating Company Vogtle Electric Generating Plant Unit 4 ITAAC Closure Notification on Completion of ITAAC 2.1.02.08d.i [Index Number 32]

Ladies and Gentlemen:

In accordance with 10 CFR 52.99(c)(1), the purpose of this letter is to notify the Nuclear Regulatory Commission (NRC) of the completion of Vogtle Electric Generating Plant (VEGP) Unit 4 Inspections, Tests, Analyses, and Acceptance Criteria (ITAAC) Item 2.1.02.08d.i [Index Number 32], for verifying the line flow resistance values from the pressurizer through the Automatic Depressurization System (ADS) Stages 1-3 valves. This ITAAC also inspects and analyzes the piping flow path to verify the line routings are consistent with the line routings used for the design flow resistance calculations. The closure process for this ITAAC is based on the guidance described in NEI 08-01, Industry Guideline for the ITAAC Closure Process Under 10 CFR Part 52, which is endorsed by the NRC in Regulatory Guide 1.215.

This letter contains no new NRC regulatory commitments. Southern Nuclear Operating Company (SNC) requests NRC staff confirmation of this determination and publication of the required notice in the Federal Register per 10 CFR 52.99.

If there are any questions, please contact Kelli Roberts at 706-848-6991.

Respectfully submitted, Jamie M. Coleman Regulatory Affairs Director Vogtle 3 & 4

Enclosure:

Vogtle Electric Generating Plant (VEGP) Unit 4 ITAAC Completion of ITAAC 2.1.02.08d.i [Index Number 32]

JMC/DLW/sfr

U.S. Nuclear Regulatory Commission ND-23-0043 Page 2 of 2 cc:

Regional Administrator, Region ll Director, Office of Nuclear Reactor Regulation (NRR)

Director, Vogtle Project Office NRR Senior Resident Inspector - Vogtle 3 & 4

U.S. Nuclear Regulatory Commission ND-23-0043 Enclosure Page 1 of 3 Southern Nuclear Operating Company ND-23-0043 Enclosure Vogtle Electric Generating Plant (VEGP) Unit 4 Completion of ITAAC 2.1.02.08d.i [Index Number 32]

U.S. Nuclear Regulatory Commission ND-23-0043 Enclosure Page 2 of 3 ITAAC Statement Design Commitment 8.d) The RCS provides automatic depressurization during design basis events.

Inspections/Tests/Analyses i) A low pressure flow test and associated analysis will be conducted to determine the total piping flow resistance of each ADS valve group connected to the pressurizer (i.e., ADS Stages 1-3) from the pressurizer through the outlet of the downstream ADS control valves. The reactor coolant system will be at cold conditions with the pressurizer full of water. The normal residual heat removal pumps will be used to provide injection flow into the RCS discharging through the ADS valves.

Inspections and associated analysis of the piping flow paths from the discharge of the ADS valve groups connected to the pressurizer (i.e., ADS Stages 1-3) to the spargers will be conducted to verify the line routings are consistent with the line routings used for design flow resistance calculations.

Acceptance Criteria i) The calculated ADS piping flow resistance from the pressurizer through the sparger with all valves of each ADS group open is 2.91E-6 ft/gpm2.

ITAAC Determination Basis Multiple ITAAC are performed to verify that the Reactor Coolant System (RCS) provides automatic depressurization during design basis events. The subject ITAAC requires a low pressure flow test and analysis using the Normal Residual Heat Removal (RNS) pumps to provide injection flow with the RCS at cold conditions with the pressurizer full of water.

Inspections and analysis of the piping flow paths from the discharge of the Automatic Depressurization System (ADS) valve groups to the spargers are conducted to verify the line routings are consistent with the line routings used for design flow resistance calculations.

Together, these inspections, tests, and analyses will demonstrate the flow resistance from the pressurizer through the sparger with all valves in each ADS group open is 2.91 x 10-6 ft/gpm2.

A preoperational test was conducted in accordance with Unit 4 preoperational test procedure (Reference 1) to determine the flow resistance from the pressurizer through the outlet of the downstream ADS control valves. Initial conditions were established with the RCS filled and the pressurizer water solid. Temporary flow instruments were installed on the pressurizer surge line, RNS suction line from the In-containment Refueling Water Storage Tank (IRWST), and the ADS Stages 1-3 Group A common tailpipe. Pressure transmitters were installed to measure RCS pressure and ADS discharge tailpipe pressure to determine differential pressure. All instruments were connected to a Data Acquisition System (DAQ).

Both trains of RNS were placed in service to the RCS, and the Group A ADS Stages 1-3 valves were opened. RNS flow was maximized and when flow, pressurizer pressure, and ADS discharge tailpipe pressure stabilize, the DAQ was started. When sufficient data was gathered, the RNS was removed from service and the Group A ADS Motor-Operated Valves (MOVs) were

U.S. Nuclear Regulatory Commission ND-23-0043 Enclosure Page 3 of 3 closed. The data was collected (Reference 2) and an analysis of the data (Reference 5) provided a calculation for flow resistance for ADS Stages 1-3 Group A. This testing and analysis were repeated for ADS Stages 1-3 Group B valves.

An inspection of the discharge piping flow paths from the pressurizer, through the ADS valve groups to the spargers was performed for Unit 4 (Reference 3) by comparing the as-built line routings to the as-designed line routings to verify they were consistent with (bounded by) the line routings used for design flow calculations. This as-built inspection and associated comparison to the as-designed line routing along with the low pressure test and associated analysis form the complete ADS piping flow resistance verification.

The flow resistance for Unit 4 Group A ADS Stages 1-3 valves was calculated to be 1.85 x 10-6 ft/gpm2 and 1.81 x 10-6 ft/gpm2 for Unit 4 Group B ADS Stages 1-3 valves (References 4 and 5).

These results confirm that the calculated ADS piping flow resistance from the pressurizer through the sparger with all valves of each ADS group open is 2.91 x 10-6 ft/gpm2.

References 2 through 5 are available for NRC inspection as part of the Unit 4 ITAAC 2.1.02.08d.i Completion Package (Reference 6).

ITAAC Finding Review In accordance with plant procedures for ITAAC completion, Southern Nuclear Operating Company (SNC) performed a review of all findings pertaining to the subject ITAAC and associated corrective actions. This review found there were no relevant ITAAC findings associated with this ITAAC. The ITAAC completion review is documented in the ITAAC Completion Package for ITAAC 2.1.02.08d.i (Reference 6) and is available for NRC review.

ITAAC Completion Statement Based on the above information, SNC hereby notifies the NRC that ITAAC 2.1.02.08d.i was performed for VEGP Unit 4 and that the prescribed acceptance criteria were met.

Systems, structures, and components verified as part of this ITAAC are being maintained in their as-designed, ITAAC compliant condition in accordance with approved plant programs and procedures.

References (available for NRC inspection)

1. 4-PXS-ITPP-503 Rev. 1.0, TPC for Passive Core Cooling System Pre-Core Flow Testing with RV Head Installed Preoperational Test Procedure

2. SV4-PXS-T0W-1191260, Rev. 0, (ITAAC) Perform Preop Test IAW 4-PXS-ITPP-503

3. SV4-RCS-ITR-800032 Rev. 0, Unit 4 Inspections and Associated Analysis of the ADS Stages 1-3 Piping Flow Path: ITAAC 2.1.02.08d.i

4. SV4-PXS-T2R-070 Rev. 0, Vogtle Unit 4 4-PXS-ITPP-503 Section 4.6 ADS Stages 1, 2, and 3 Flow Line Resistance Test Engineering Report

5. SV4-PXS-T2C-007 Rev. 0, Vogtle Unit 4 4-PXS-ITPP-503 Section 4.6 ADS Stages 1, 2, and 3 Flow Line Resistance Test Calculation

6. 2.1.02.08d.i-U4-CP-Rev0, ITAAC Completion Package