NL-19-0498, License Amendment Request for Technical Specification Improvement to Revise Actions for One Steam Supply to Turbine Driven Auxiliary Feedwater Pump Inoperable SNC Response to NRC Request for .
| ML19120A210 | |
| Person / Time | |
|---|---|
| Site: | Vogtle  |
| Issue date: | 04/30/2019 |
| From: | Gayheart C Southern Nuclear Operating Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| NL-19-0498 | |
| Download: ML19120A210 (6) | |
Text
.t. Southern Nuclear APR 3 0 2019 Docket Nos.: 50-424 50-425 U.S. Nuclear Regulatory Commission A TIN: Document Control Desk Washington, D. C. 20555-0001 Cheryl A. Gayheart Regulatory Affatrs Dtrector Vogtle Electric Generating Plant-Unit 1 and 2 3535 Colonnade Parkway Birmingham, AL 35243 205 992 5316 tel 205 992 7601 tax cagayhea@ southernco.com NL-19-0498 License Amendment Request for Technical Specification Improvement to Revise Actions for One Steam Supply to Turbine Driven Auxiliary Feedwater Pump Inoperable SNC Response to NRC Request for Additional Information Ladies and Gentlemen:
By letter dated December 19, 2018 (Agencywide Documents Access and Management System Accession Number ML18353B056), Southern Nuclear Operating Company (SNC) submitted a license amendment request (LAR) for the Vogtle Electric Generating Plant (VEGP), Units 1 and 2. This LAR requested adoption of TSTF-412, Revision 3, "Revise Actions for One Steam Supply to Turbine Driven Auxiliary Feedwater Pump Inoperable."
By email dated April 15, 2019, the U.S. Nuclear Regulatory Commission (NRC) staff notified SNC that additional information is needed for the staff to complete their review. The enclosure to this letter provides the SNC response to the NRC request for additional information (RAI).
This letter contains no NRC commitments. If you have any questions, please contact Jamie Coleman at 205.992.6611.
I declare under penalty of perjury that the foregoing is true and correct. Executed on the
?i>~day of April2019.
Respectfully submitted, Director, Regulatory Affairs Southern Nuclear Operating Company
U.S. Nuclear Regulatory Commission NL-19-0498 Page 2 CAG/tle/sm
Enclosure:
Regional Administrator, Region II NRR Project Manager-Vogtle 1 & 2 Senior Resident Inspector-Vogtle 1 & 2 RType: CVC7000
Vogtle Electric Generating Plant-Unit 1 and 2 License Amendment Request for Technical Specification Improvement to Revise Actions for One Steam Supply to Turbine Driven Auxiliary Feedwater Pump Inoperable SNC Response to NRC Request for Additional Information Enclosure SNC Response to NRC RAJ
Enclosure to NL-19-0498 SNC Response to NRC RAI NRC RAI Section 2.2 of Enclosure 1 of the LAR states:
SNC is not proposing any variations or deviations from the technical specification changes described in TSTF-412, Revision 3, or the NRC staff's model safety evaluation published in the Federal Register on July 17, 2007 (72 FR 39089).
Upon review of the LAR and comparison of existing Vogtle TS to the STS as modified by TSTF-412, there appear to be variations between the Vogtle Technical Specification (TS) and Standard Technical Specification (STS) and deviations in the adoption of TSTF-412.
Vogtle TS contain an existing Conditions A, B and C which allow for Completion Time in accordance with the Risk Informed Completion Time. STS as modified by TSTF-412 do not contain risk informed completion times. Existing Condition C in Vogtle TS describes the situation where two AFW trains are inoperable. The associated Required Action is to restore Auxiliary Feedwater (AFW) trains to OPERABLE status within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> or with a Completion Time in accordance with the Risk Informed Completion Time. For the situation where two AFW trains are inoperable, the STS as modified by TSTF-412 require the plant to be in MODE 3 in 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and plant specifically appropriate lower MODE within a plant specifically appropriate time.
(1) Please provide an explanation of the variation between Vogtle TS and STS as modified by TSTF-412 as well as the deviations from the TS changes described in TSTF-412.
(2) Please provide a discussion of the need for a new Condition C in Vogtle TS, which describes a very limited case of two inoperable AFW trains, given the existing Condition C apparently applies to all cases of two inoperable AFW trains.
SNC Response to RAI (1) The following variations exist between the Vogtle Electric Generating Plant, Units 1 and 2, (VEGP) TS prior to implementation of the LAR and the STS (NUREG-1431) on which TSTF-412 is based:
(a) VEGP TS 3.7.5 does not have an Applicability of "Mode 4 when steam generator is relied upon for heat removal." As a result, current VEGP Conditions B, C and E do not specify the Mode Applicability and the STS condition for required AFW train inoperable in Mode 4 _is not necessary. The VEGP TS differences in the Mode 4 Applicability do not affect the applicability of TSTF-412 to the VEGP TS.
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Enclosure to NL-19-0498 SNC Response to NRC RAI (b) VEGP TS 3.7.5 differs from the STS on which TSTF-412 is based in that VEGP has previously implemented a Risk Informed Completion Time (RICT)
Program (Reference 1) that has not been incorporated into the STS. VEGP Actions A, B, and C permit calculation of a RICT in lieu of the fixed Completion Times. The RICT Program does not affect the proposed Condition C, which does not include the option to determine a RICT. It is possible for the plant to be in Condition A, Condition B, and Condition C.
under the proposed change, but the fixed Completion Time of proposed Condition C would limit the use of a RICT in Conditions A and B. Therefore, the incorporation of a RICT Program does not affect the applicability of TSTF-412. The inclusion of a RICT in existing Condition C (revised to Condition D in the proposed change) is discussed in the response to the second question.
(2) New Condition C as proposed by the LAR utilizes the technical analysis in TSTF-412 for the specific case of the turbine driven AFW train inoperable due to one inoperable steam supply conc'urrent with one motor driven AFW train inoperable to provide a pre-analyzed 24-hour Completion Time without the need to calculate a RICT and invoke the requirements of the RICT Program (e.g., risk management actions, cumulative risk tracking subject to the risk limits).
The provisions required to enter existing Condition C, which is proposed to be new Condition D with modification, contain limitations (identified in the Note of existing Condition C) not present in the new Condition C, for example:
A RICT may only be utilized in Modes 1 and 2 (VEGP TS Section 5.5.22, Constraint b), which would therefore necessitate a 1-hour Completion Time when the plant is in Mode 3; A RICT must be calculated within the 1-hour Completion Time for emergent conditions (VEGP TS Section 5.5.2, Constraint c.2); and The calculated RICT is limited to 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> (VEGP TS Section 5.5.2, Constraint e) whereas 24-hours is the standard Completion Time for the proposed Condition C.
In addition to one AFW train being Operable, another train must be PRA Functional, as defined in NEI-06-09, to utilize the RICT (VEGP TS Section 5.5.2, Constraints e and f).
Therefore, proposed Condition C provides a predetermined Completion Time appropriate for the condition without invoking the requirements and constraints of the RICT Program inherent in existing Condition C.
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Enclosure to NL-19-0498 SNC Response to NRC RAI Reference
- 1. ML15127A669, USNRC to SNC (Mr. James J. Hutto), "Vogtle Electric Generating Plant, Units 1 and 2-Issuance of Amendments Regarding Implementation of Topical Report Nuclear Energy Institute NEI 06-09, 'Risk-Informed Technical Specifications Initiative 48, Risk-Managed Technical Specification (RMTS)
Guidelines,' Revision 0-A (CAC Nos. ME9555 and ME9556)," August 8, 2017.
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