ML19296A034
| ML19296A034 | |
| Person / Time | |
|---|---|
| Site: | Summer  |
| Issue date: | 10/23/2019 |
| From: | Lippard G Dominion Energy, South Carolina Electric & Gas Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| 19-429 | |
| Download: ML19296A034 (5) | |
Text
V. C. Summer Nuclear Station Bradham Blvd & Hwy 215, Jenkinsville, SC 29065 Mailing Address:
P.O. Box 88, Jenkinsville, SC 29065 Dominion Energy.com October 23, 2019 Attn: Document Control Desk U. S. Nuclear Regulatory Commission Washington, DC 20555-0001 SOUTH CAROLINA ELECTRIC & GAS COMPANY VIRGIL C. SUMMER NUCLEAR STATION (VCSNS) UNIT 1 10 CFR 50.59 BIENNIAL REPORT
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Dominion
- iiiiii"' Energy Serial No.19-429 VCS-LIC/BAB RO Docket No. 50-395 License No. NPF-12 Pursuant to 10 CFR 50.59(d)(2), a report containing a brief description of any changes, tests, and experiments, including a summary of the evaluation of each, must be submitted to the NRC at intervals not to exceed 24 months. South Carolina Electric & Gas Company1 hereby submits the enclosed report, which covers the time frame from October 1, 2017 to September 30, 2019.
Should you have any questions, please call Michael S. Moore at (803) 345-4752.
Sincerely, George. Lippard Site Vice President V.C. Summer Nuclear Station Commitments contained in this letter: None Enclosure cc:
G. J. Lindamood - Santee Cooper L. Dudes - NRC Region II S. A. Williams - NRC Project Manager NRC Resident Inspector (1) In a letter dated July 30, 2019, South Carolina Electric & Gas Company (SCE&G) requested a License Amendment to amend the VC Summer operating license to reflect the name change from SCE&G to Dominion Energy South Carolina (DESC). The amendment request is currently under review by the NRC.
ENCLOSURE Serial No.19-429 Docket No 50-395
Enclosure:
Page 1 of 4 10 CFR 50.59 Summary of Changes and Evaluations Virgil C. Summer Nuclear Station - Unit 1 South Carolina Electric and Gas
50.59 Parent Log#
Doc.
2017-ECR 04 50883 2017-ECR 05 50884E Serial No.19-429 Docket No 50-395
Enclosure:
Page 2 of 4 10 CFR 50.59 Summary of Changes and Evaluations Change Description Evaluation Summary The Vital AC System (EV) Safety Related The evaluation of the proposed changes finds that Inverters (Uninterruptable Power Supplies) this design activity may be implemented without XIT5901, XIT5902, XIT5903, and XIT5904 are prior NRC approval. There is no increase in the scheduled for replacement due to aging frequency of occurrence of FSAR evaluated events.
concerns, obsolescence, spare part There is less than a minimal increase in the unavailability, and lack of vendor support and likelihood of SSC malfunction(s) as evaluated in the knowledge of the existing equipment.
FSAR. There is no increase in the consequences of FSAR evaluated events. The evaluation finds that there is no potential for creating a new type of event and/or accident. The evaluation finds that there is no impact on fission product barriers. Also, no new analytical methods were utilized in the design efforts for this proposed modification.
The activities under this major Engineering This evaluation has determined that a license Change Request (ECR) revision subject to this amendment is not required prior to implementation.
50.59 EVALUATION are the trip time delay This conclusion is reasonable because this settings for the 46T relays and activation of the evaluation has shown how a spurious actuation of trip mode operation for the Open Phase the OPIS does not result in meeting any of the eight Isolation Systems (OPIS's) installed by (8) criteria evaluated for a license amendment.
ECR50884 on XTF4, XTF5, and XTF31. In Furthermore, NRG has been involved and has particular, the spurious actuation failure mode supported the industry in development of systems is evaluated here as all other attributes were including those that are not Class 1 E that will detect screened out and not subject to evaluation.
open phase conditions, provide indication of open phase condition to plant operators, and be capable of separating the plant from GDC-17 offsite power sources that have an open phase condition fault.
Ref. BTP 8-9, Rev. 0 (ADAMS Accession No. ML15057A085) and NRG letter to NEI (ADAMS Accession No. ML14120A203).
50.59 Parent Change Description Log#
Doc.
2013-ECR The following two portions of the B Chiller 0001 50585W Replacement under ECR 50585W were screened IN as requiring Evaluation 1 OCFR50.59.
A The elimination of a manual action to throttle of Service Water to the chillers, which was previously performed manually to prevent the chillers from tripping under conditions of low Service Water temperature and low load, is made unnecessary by the design of the replacement chillers.
B. The use of a Triconex digital Class 1 E control system on the replacement chillers.
Serial No.19-429 Docket No 50-395
Enclosure:
Page 3 of 4 Evaluation Summary The modifications made as a result of this activity conform fully to the current licensing basis for the plant. All functions described in FSAR section 9.4.7.2.4 will be performed identically by the replacement chillers.
The redesign of the new chillers to operate down to a lower load eliminates the need for operator action to throttle Service Water. The elimination of this manual action to throttle is a slight change, but is an improvement, and is acceptable under the current licensing basis.
The existing chiller controls use analog controllers and relay logics, whereas, following this modification, the control system for each of these chillers will be a Triconex PLC Class 1 E digital controller (Each chiller will be equipped with an independent, triple redundant Triconex digital control system, i.e. Tricon PLC.) The detailed evaluation in the following sections has been performed in accordance with the NRG-endorsed NEI 01-01 (TR-102348) guidelines, demonstrates that:
a) the Triconex digital control system V10 Topical report 7286-545-1A has been accepted by NRC in its SER dated April 12, 2012 for safety-related use in nuclear power plants; b) all plant-specific conditions of approval specified in the NRC SER have been satisfied for the replacement chiller application, as discussed in detail in Appendix 2A; c) The potential for software common mode failure has been carefully considered. The Triconex plans, procedures, QA and V&V for the Triconex operating system software are extensive and robust, and have been approved in the NRC SER. The application software has been developed by NLI under its plans, procedures, QA and V&V, and tested extensively at the factory. The Triconex PLC hardware and software is assigned a Software Integrity Level (SIL) of 4 due to the PLC being used in a safety related application. NLI developed the user code per IEEE1012 guidance for the design, development, testing, and verification of safety related software to ensure the quality of the user generated software. On this basis, the potential for a software common mode failure that could disable all chillers is concluded to be highly unlikely, no more likely than the potential for common cause failures in the original chiller equipment.; and, d) This activity may be performed under 1 OCFR50.59.
50.59 Parent Log#
Doc; 2014-ECR 0006 71072A Change Description The iodine spike calculation DC00040-038 (Ref.4}, which supplies input to the dose calculations for a postulated Steam Generator Tube Rupture (SGTR} and Steam Line Break (SLB), was revised to:
- 1. Use worse case assumptions for reactor coolant (RC) mass (i.e., minimum versus maximum) when evaluating the iodine appearance rate and average RC activity concentrations.
- 2. Use worse combination of iodine activities for plant operation with 60 or 120 gpm letdown and 1 % failed fuel.
- 3. Explicitly account for an iodine appearance rate increase of 335 to support the SGTR dose calculation with a concurrent iodine spike.
- 4. Remove spike multipliers on RC activities other than iodine when evaluating a pre-accident iodine spike. These four (4) changes were utilized in dose calculation revisions for SLB (Ref. 10) and SGTR (Ref. 8) and, for purposes of this SAP-107 evaluation, are considered Changes 1 - 4. In addition, the revision to DC00040-038 also included additional post accident time periods (i.e., for evaluating the buildup of reactor coolant iodine concentrations) during a concurrent iodine spike for use in a supplemental SGTR dose calculation [DC00040-109 (Ref. 11 )], which was also revised. However, since DC00040-109 is not part of the plants licensing basis, it is being VOIDED under ECR-71072A. Given this, the results (i.e., average reactor coolant iodine concentrations) for the additional post accident time periods are not considered a change for purposes of this SAP-107 evaluation. In addition to the revised inputs resulting from the above changes, the updated SLB and SGTR dose calculations were also revised to include long term steam releases (8 - 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />) from the intact SGs. This change corrects an oversight in the computer code inputs in the previous revisions to the calculations.
Therefore, for purposes of this SAP-107 evaluation, change 5 becomes:
- 5. Inclusion of long term steam releases from the intact SG when evaluating dose.
Collectively, these five (5) changes lead to small increases in predicted dose consequences for a SLB and SGTR that need to be reflected in the FSAR.
Serial No.19-429 Docket No 50-395
Enclosure:
Page 4 of 4 Evaluation* Summary A full 10 CFR 50.59 Evaluation was performed for the proposed activity. Questions 1-8 were answered NO with explanation. Given the above determination, it is concluded that the proposed activity can be implemented without prior NRC approval.