ML23065A061

NRR E-mail Capture - for Your Action - Request for Additional Information (RAI) 14 - Vogtle - AST, TSTF-51, TSTF-471, and TSTF-490 LAR (L-2022-LLA-0096)

ML23065A061
Person / Time
Site:	Vogtle
Issue date:	03/03/2023
From:	John Lamb NRC/NRR/DORL/LPL2-1
To:	Lowery K, Pournaras D Southern Nuclear Operating Co
References
L-2022-LLA-0096
Download: ML23065A061 (4)

Text

From: John Lamb Sent: Friday, March 3, 2023 9:30 AM To: Pournaras, DeLisa S.; Lowery, Ken G.

Subject:

For Your Action - Request for Additional Information (RAI) #14 - Vogtle - AST, TSTF-51, TSTF-471, and TSTF-490 LAR (L-2022-LLA-0096)

Importance: High DeLisa and Ken, By letter dated June 30, 2022, (Agencywide Documents Access and Management System (ADAMS) Accession Package Number ML22181B066), as supplemented by letter dated February 6, 2023 (ML23037A856), Southern Nuclear Operating Company, Inc. (SNC, the licensee) submitted a License Amendment Request (LAR) to revise Vogtle Electric Generating Plant (Vogtle), Units 1 and 2, Technical Specifications (TS). The proposed LAR would revise the Vogtle, Units 1 and 2, current licensing basis to implement an alternative radiological source term for evaluating design basis accidents as allowed by Title 10 of the Code of Federal Regulations (10 CFR), Section 50.67, Accident Source Term. In addition, the proposed LAR requests to incorporate Technical Specification Task Force (TSTF) Travelers TSTF-51-A, Revise containment requirements during handling irradiated fuel and core alterations, Revision 2; TSTF-471-A, Eliminate use of term CORE ALTERATIONS in ACTIONS and Notes, Revision 1; and TSTF-490-A, Deletion of E Bar Definition and Revision to RCS Specific Activity Technical Specification, Revision 0.

The U.S. Nuclear Regulatory Commission (NRC) staff reviewed the impact of implementing an alternative radiological source term for evaluating design basis accidents (DBAs) on all DBAs currently analyzed in the Vogtle, Units 1 and 2, updated final safety analysis report (UFSAR) that could have the potential for significant dose consequences. The NRC staff determined that more information is needed to complete its review.

On February 24, 2023, the NRC staff provided draft RAI question #14 to SNC to make sure that the RAI was understandable, the regulatory basis is clear, to ensure there is no proprietary information, and to determine if the information was previously docketed. On March 3, 2023, NRC staff held a clarifying call with SNC and SNC stated that it would provide the RAI response

1. 14 in 31 days from the date of this email.

If you have any questions, you can contact me at 301-415-3100.

Sincerely, John REQUEST FOR ADDITIONAL INFORMATION (RAI)

By letter dated June 30, 2022, (Agencywide Documents Access and Management System (ADAMS) Accession Package Number ML22181B066), as supplemented by letter dated February 6, 2023 (ML23037A856), Southern Nuclear Operating Company, Inc. (SNC, the

licensee) submitted a License Amendment Request (LAR) to revise Vogtle Electric Generating Plant (Vogtle), Units 1 and 2, Technical Specifications (TS). The proposed LAR would revise the Vogtle, Units 1 and 2, current licensing basis to implement an alternative radiological source term for evaluating design basis accidents as allowed by Title 10 of the Code of Federal Regulations (10 CFR), Section 50.67, Accident Source Term. In addition, the proposed LAR requests to incorporate Technical Specification Task Force (TSTF) Travelers TSTF-51-A, Revise containment requirements during handling irradiated fuel and core alterations, Revision 2; TSTF-471-A, Eliminate use of term CORE ALTERATIONS in ACTIONS and Notes, Revision 1; and TSTF-490-A, Deletion of E Bar Definition and Revision to RCS Specific Activity Technical Specification, Revision 0.

The Nuclear Regulatory Commission (NRC) staff reviewed the impact of implementing an alternative radiological source term for evaluating design basis accidents (DBAs) on all DBAs currently analyzed in the Vogtle, Units 1 and 2, updated final safety analysis report (UFSAR) that could have the potential for significant dose consequences. The NRC staff determined that more information is needed to complete its review.

Regulatory Analysis Basis

1. Section 10 CFR Part 50.67, Accident Source Term, allows licensees seeking to revise their current accident source term in design basis radiological consequence analyses to apply for a license amendment under § 50.90. The application shall contain an evaluation of the consequences of applicable design basis accidents previously analyzed in the safety analysis report. Section 50.67(b)(2) requires that the licensee's analysis demonstrates with reasonable assurance that:

(i) An individual located at any point on the boundary of the exclusion area for any 2-hour period following the onset of the postulated fission product release, would not receive a radiation dose in excess of 0.25 Sv (25 rem) total effective dose equivalent (TEDE).

(ii) An individual located at any point on the outer boundary of the low population zone, who is exposed to the radioactive cloud resulting from the postulated fission product release (during the entire period of its passage), would not receive a radiation dose in excess of 0.25 Sv (25 rem) TEDE.

(iii) Adequate radiation protection is provided to permit access to and occupancy of the control room under accident conditions without personnel receiving radiation exposures in excess of 0.05 Sv (5 rem)

TEDE for the duration of the accident.

2. Plant Design Criterion 19, Control Room, provides for conformance with Section 10 CFR 50.90, Application for amendment of license, construction permit, or early site permit, states, in part, that whenever a holder of an operating license under this part, desires to amend the license, application for an amendment must be filed with the Commission, as specified in § 50.4 of this chapter, as applicable, fully describing the changes desired, and following as far as applicable, the form prescribed for original applications.

3. NRC Regulatory Guide (RG) 1.183, Alternative Radiological Source Terms for Evaluating Design Basis Accidents at Nuclear Power Reactors, July 2000 (ADAMS Accession No. ML003716792).

RAI #14 (Gap Fractions)

SNC states:

An exception to the RG-1.183 linear heat generation limit (LHGR) of 6.3 kW/ft (footnote

11) has been requested. For Vogtle Units 1 and 2, it is requested that 40% of the rods be allowed to exceed the 6.3kW/ft limit and those 40% of rods be approved for a LHGR limit of 7.4 kW/ft. This is consistent with the LHGR limit depicted in Figure A.1 of PNNL-18212 Revision 1.

The NRC staff acknowledges that 7.4 kW/ft is consistent with the Figure A.1 curve for burnups between 54 and 62 GWd/MTU. In order for the gap fractions presented in PNNL-18212 Rev. 1 to be valid though, the entire rod-average power envelope presented in Figure A.1 of PNNL-18212 Rev. 1, should bound the power history of each rod.

Please explain how adherence to the entirety of the curve presented in Figure A.1 will be ensured. Alternatively, please provide further justification for the use of the PNNL-18212 Rev. 1 gap fractions, including rod operational power histories that bound the limiting plant-specific power histories.

Hearing Identifier: NRR_DRMA Email Number: 1980 Mail Envelope Properties (MN2PR09MB508406B6BB302F62D2740C1FFAB39)

Subject:

For Your Action - Request for Additional Information (RAI) #14 - Vogtle - AST, TSTF-51, TSTF-471, and TSTF-490 LAR (L-2022-LLA-0096)

Sent Date: 3/3/2023 9:29:53 AM Received Date: 3/3/2023 9:29:00 AM From: John Lamb Created By: John.Lamb@nrc.gov Recipients:

"Pournaras, DeLisa S." <DSPOURNA@SOUTHERNCO.COM>

Tracking Status: None "Lowery, Ken G." <KGLOWERY@southernco.com>

Tracking Status: None Post Office: MN2PR09MB5084.namprd09.prod.outlook.com Files Size Date & Time MESSAGE 6790 3/3/2023 9:29:00 AM Options Priority: High Return Notification: No Reply Requested: No Sensitivity: Normal Expiration Date: