05000395/LER-2022-002, (Vcsns), Unit 1, Potential Condition Prohibited by Technical Specification 3.8.1.1
| ML22101A284 | |
| Person / Time | |
|---|---|
| Site: | Summer  |
| Issue date: | 04/11/2022 |
| From: | Lippard G Dominion Energy South Carolina |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| 22-112 LER 2022-002-00 | |
| Download: ML22101A284 (3) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications |
| 3952022002R00 - NRC Website | |
text
V.C. Summer Nuclear Station Bradham Blvd & Hwy 215, Jenkinsville, SC 29065 Mailing Address:
P.O. Box 88, Jenki nsville, SC 29065 Dominion Energy.com April 11, 2022 Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555 DOMINION ENERGY SOUTH CAROLINA (DESC)
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Dominion
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Energy Serial No.22-112 VCS-LIC/JB RO Docket No. 50-395 License No. NPF-12 VIRGIL C. SUMMER NUCLEAR STATION (VCSNS) UNIT 1 LICENSEE EVENT REPORT 2022-002-00 POTENTIAL CONDITION PROHIBITED BY TECHNICAL SPECIFICATION 3.8.1.1 Dominion Energy South Carolina hereby submits Licensee Event Report (LER) 2022-002-00, for VCSNS. This report describes a potential condition prohibited by VCSNS Technical Specification 3.8.1.1 related to its 'B' Emergency Diesel Generator and is submitted in accordance with 10 CFR 50.73(a)(2)(i)(B). An update to the LER or notice of cancellation is expected to be available by July 21, 2022.
Should you have any questions, please call Mr. Justin Bouknight at (803) 941-9828.
Sincerely,
~~~
c:eo~~ l{;*pard Site Vice President V.C. Summer Nuclear Station Enclosure Commitments contained in this letter: None cc:
G. J. Lindamood - Santee Cooper L. Dudes - NRC Region II G. Miller - NRC Project Mgr.
NRC Resident Inspector J. N. Bassett-INPO Marsh USA, Inc.
Abstract
On February 9, 2022, VCSNS identified kilowatt oscillations in the load of the 'B' Emergency Diesel Generator (EOG) during the performance of surveillance test procedure STP-125.002B. The 'B' EOG satisfied STP-125.0028 acceptance criteria; however, since the kilowatt oscillations were not immediately explainable and based on engineering qualitative review for prompt operability, the 'B' EOG was conservatively declared inoperable. Until further review is completed, a possibility exists that VCSNS was outside of the conditions required by VCSNS Technical Specification (TS) Limiting Condition of Operation (LCO) 3.8.1.1.b prior to February 9.
VCSNS is currently evaluating this condition and will update this LER following completion of that evaluation, either confirming a period of inoperability or withdrawing the LER.
The evaluation and updated LER are expected to be available by July 21, 2022.
1.0 DESCRIPTION OF THE EVENT On February 9, 2022, VCSNS identified kilowatt oscillations in the load of the 'B' Emergency Diesel Generator (EOG) during the performance of surveillance test procedure STP-125.002B. The 'B' EOG satisfied STP-125.002B acceptance criteria. Since the kilowatt oscillations were not immediately explainable, the 'B' EDG was conservatively declared inoperable. This prompt operability review was based on qualitative engineering analysis. It is possible that VCSNS was outside of the conditions required by VCSNS Technical Specification (TS) Limiting Condition of Operation (LCO) 3.8.1.1.b prior to February 9.
During troubleshooting on February 9, an intermittently connecting pin was discovered in an Amphenol connector, which was causing the noisy signal and kilowatt oscillations. The Amphenol connector was replaced to correct the connection issue. This condition is currently under evaluation.
VCSNS TS 3.8.1.1.b requires two separate and independent EDGs and appurtenances during operating Modes 1 through 4. LCO 3.8.1.1 Action b.4.a requires restoration of the inoperable EDG within 14 days when the alternate AC power source (AAC) is available.
The evaluation and supplemental LER are expected to be available by July 21, 2022.
2.0 SIGNIFICANT SAFETY CONSEQUENCES AND IMPLICATIONS
The 'B' EDG is one of two safety-related (SR) power supplies on-site and provides the emergency on-site power supply to Engineered Safety Feature (ESF) loads on bus 1 DB, in the event of off-site power interruption. Bus 1 DB powers one of the two sets of redundant ESF equipment needed in postulated design basis accident (DBA) scenarios. In the event neither EOG is available to power its respective loads, a non-safety related AAC can provide power. The AAC is designed to provide back-up power to either ESF bus whenever one of the EDGs is out of service, particularly in Modes 1 through 4. The design of the AAC is capable of providing the required safety and non-safety related loads in the event of a total loss of offsite power and if both EDGs fail to start and load. Although the AAC is not designed for OBA loads, it is capable of supplying sufficient power to mitigate the effects of an accident. The AAC is not credited in the safety analysis.
3.0 CAUSE OF THE EVENT
Troubleshooting was performed following the February 9 performance of STP-125.002B and identified an intermittently connecting pin on the Amphenol connector. Replacement of the affected Amphenol connector corrected the 'B' EDG kilowatt oscillation condition.
4.0 IMMEDIATE CORRECTIVE ACTIONS
The 'B' EOG was conservatively declared inoperable following qualitative engineering review of the kilowatt oscillations during the February 9, 2022, STP-125.0028 run. Troubleshooting was performed and the Amphenol connector was replaced.
5.0 ADDITIONAL CORRECTIVE ACTIONS
None 6.0 ACTIONS TO PREVENT RECURRENCE Routine maintenance and surveillance of the EDGs will continue to ensure continued operability of both EDGs and identify adverse conditions requiring correction.
7.0 SIMILAR EVENTS
None 8.0 MANUFACTURER Colt Industries, Fairbanks-Morse Engine Division
9.0 ADDITIONAL INFORMATION
VCSNS continues to evaluate this condition and expects to either issue a notice of cancellation or supplement this LER by July 21, 2022. Page 3
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