NL-23-0196, Response to Request for Additional Information Regarding License Amendment Request for Alternative Source Term, TSTF-51, TSTF-471, and TSTF-490
| ML23083B398 | |
| Person / Time | |
|---|---|
| Site: | Vogtle  |
| Issue date: | 03/24/2023 |
| From: | Brown R Southern Nuclear Operating Co |
| To: | Office of Nuclear Reactor Regulation, Document Control Desk |
| References | |
| NL-23-0196 | |
| Download: ML23083B398 (1) | |
Text
3535 Colonnade Parkway Birmingham, AL 35243 205 992 5000 March 24, 2023 NL-23-0196 10 CFR 50.90 ATTN: Document Control Desk U. S. Nuclear Regulatory Commission Washington, D. C. 20555-0001 Vogtle Electric Generating Plant - Units 1 and 2 Docket Nos. 50-424 & 50-425
Subject:
Response to Request for Additional Information Regarding License Amendment Request for Alternative Source Term, TSTF-51, TSTF-471, and TSTF-490 By letter dated June 30, 2022 (ML22181B066), Southern Nuclear Operating Company (SNC) submitted an application to 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 requested 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.
By email dated January 6, 2023 (ML23006A088), the Nuclear Regulatory Commission (NRC) staff issued a request for additional information (RAI). By letter dated February 6, 2023 (ML23037A856), SNC provided the SNC responses to the NRC staffs RAIs.
By email dated March 3, 2023 (ML23065A061), the NRC staff issued an additional request for additional information (RAI). The Enclosure to this letter provides the SNC response to the NRC staffs RAI.
The conclusions of the No Significant Hazards Consideration and Environmental Consideration contained in the original application have been reviewed and are unaffected by this response.
U. S. Nuclear Regulatory Commission NL-23-0196 Page 2 If you have any questions, please contact Amy Chamberlain at 205.992.6361.
I declare under penalty of perjury that the foregoing is true and correct. Executed on the 24th day of March 2023.
Respectfully submitted, R. Keith Brown Director, Regulatory Affairs Southern Nuclear Operating Company RKB/kgl/cbg
Enclosure:
Regional Administrator, Region ll NRR Project Manager - Vogtle 1 & 2 Senior Resident Inspector - Vogtle 1 & 2 State of Georgia Environmental Protection Division RType: CVC7000
Vogtle Electric Generating Plant - Units 1 and 2 Response to Request for Additional Information Regarding License Amendment Request for Alternative Source Term, TSTF-51, TSTF-471, and TSTF-490 Enclosure SNC Response to NRC RAI
Enclosure to NL-23-0196 SNC Response to NRC RAI E-1 NRC RAI-14:
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.
SNC Response to NRC RAI-14:
Adherence to the entirety of the curve presented in Figure A.1 will be ensured. An upper limit for rods exceeding the Footnote 11 applicability limits of 40% will be validated on a cycle-by-cycle basis as part of the Reload Safety Analysis Checklist (RSAC). The linear heat rates and burnups of that 40% will be within the PNNL-18212, Rev. 1, Table 2.9 gap fraction applicability limits (12.2 kw/ft up to 35 GWD/MTU, decreasing to 7.5 kw/ft at 62 GWD/MTU). This will also be validated on a cycle-by-cycle basis as part of the RSAC.