05000425/LER-2019-001, Spurious Closure of Main Steam Isolation Valve Results in Manual Reactor Trip
| ML19148A469 | |
| Person / Time | |
|---|---|
| Site: | Vogtle  |
| Issue date: | 05/28/2019 |
| From: | Taber B Southern Nuclear Operating Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| NL-19-0552 LER 2019-001-00 | |
| Download: ML19148A469 (4) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(ii)(A), Seriously Degraded 10 CFR 50.73(a)(2) 10 CFR 50.73(a)(2)(ii)(B), Unanalyzed Condition 10 CFR 50.73(a)(2)(viii)(B) 10 CFR 50.73(a)(2)(ix)(A) 10 CFR 50.73(a)(2)(x) 10 CFR 50.73(a)(2)(v)(A), Loss of Safety Function - Shutdown the Reactor 10 CFR 50.73(a)(2)(v)(B), Loss of Safety Function - Remove Residual Heat 10 CFR 50.73(a)(2)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(i)(A), Completion of TS Shutdown 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability 10 CFR 50.73(a)(2)(i) 10 CFR 50.73(a)(2)(iv)(B), System Actuation 10 CFR 50.73(a)(2)(iv)(A), System Actuation |
| 4252019001R00 - NRC Website | |
text
~ Southern Nuclear MAY 2 8 2019 Docket No:
50-425 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C. 20555-0001 B. Keith Taber Vice President Vogtle Unrts 1-2 Vogtle Electric Generating Plant - Unit 2 Licensee Event Report 2019-001-00 7821 River RD Waynesboro GA, 30830 706-848-0004 tel 706-848-3321 fax NL-19-0552 Spurious Closure of Main Steam Isolation Valve results in Manual Reactor Trip Ladies and Gentlemen:
In accordance with the requirements of 10 CFR 50. 73(a)(2)(iv)(A), Southern Nuclear Operating Company is submitting the enclosed Licensee Event Report, 2019-001-00 for Vogtle Electric Generating Plant Unit 2. This letter contains no NRC commitments. If you have any questions, please contact Matthew Hom at (706) 848-1544.
Respectfully submitted, a~.~Z Vice President Vogtle 1&2 BKT/KCW Enclosure: Unit 2 Licensee Event Report 2019-001-00 Cc: Regional Administrator NRR Project Manager-Vogtle 1 & 2 Senior Resident Inspector-Vogtle 1 & 2 RType: CVC7000
Vogtle Electric Generating Plant-Unit 2 Licensee Event Report 2019-001-00 Spurious Closure of Main Steam Isolation Valve results in Manual Reactor Trip Enclosure Unit 2 Licensee Event Report 2019-001-00
NRCFORM3&6 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 03131/2020 (04-2018)
, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.
- 1. Facility Name
~- Docket Number
- Page Vogtle Electric Generating Plant, Unit 2 05000425 1 OF2
- 4. TiUe Spurious Closure of Main Steam Isolation Valve results in Manual Reactor Trip
- 5. Event Date
- 6. LER Number
- 7. Report Date
- 8. other Facilities Involved Sequential Rev Facility Name pocket Number Month Day Year Year Number No.
Month Day Year N/A
~5000 03 30 2019 2019
- - 001
- - 00 o5 ;.B' ltOI" Facility Name pocket Number N/A
~5000
- 9. Opntq Mode
- 11. 1hla Report Is &DniiiBd P\\nuantto the of 10 CfR §: (Checl< all that apply) 1 0 20.2201 (b) 0 20.2203(a)(3)(i) 0 50.73(a)(2)(ii)(A) 0 50.73(a)(2)(viiij(A) 0 20.2201(d) 0 20.2203(a)(3)(ii) 0 50.73(a)(2)(ii)(B) 0 50.73(a)(2)(viii)(B) 0 20.2203(a}(1) 0 20.2203(8)(4) 0 50.73{a)(2)(iii) 0 50.73(a)(2)(ix)(A) 0 20.2203(a)(2)(i) 0 50.36(c)(1)(i)(A) 181 50. 73(a)(2)(iv)(A) 0 50.73(a)(2)(x)
- 10. Power Lev*J 0 20.2203(a)(2)(ii) 0 50.36(c)(1 )(iQ(A) 0 50.73(a)(2)(v)(A) 0 73.71(a)(4) 030 0 20.2203(a)(2)(iiij 0 50.36(c)(2)
D 50.73(a)(2)(v)(B)
D 73.71(a)(5) 0 20.2203(a)(2)(iv) 0 50.46(a)(3)(ii) 0 50.73(a)(2)(v)(C) 0 73.77(a)(1) 0 20.2203(a)(2)(v) 0 50.73(a)(2)(i)(A) 0 50.73(a)(2)(v)(D) 0 73. n(a)(2)(iij 0 20.2203(a)(2)(vi) 0 50.73(a)(2)(i)(B) 0 50.73(a)(2)(vii) 0 73.77(a)(2)(iii) 0 50.73(a)(2)(i)(C) 0 Other (Specify in Abstrad below or in NRC Form 366A
- 12. Ucensee Contact for this LER icensea Conlacl
~~laphone Number (Include PJu Code)
~ogtle Electric Generating Plant Matthew Hom, Regulatory Affairs Manager 06-848-1544
- 13. Ccmplela One Unet'tlreach FalknDesabd in this~
Cause
System Component Manutadurer Reportable To ICES
Cause
System Component Manufacturer Reportable To ICES B
SB RLY T351 y
N/A
- 14. Supplemental Report Expected Month Day Year 0 Yes (If yes, complete 15. Expected Submission Date) 181 No
- 15. Expected Submission Date NIA NIA NIA Abstract (Umit to 1400 spaces, i.e., approximately 14 single-spaced typewritten lines)
On March 30,2019 at 2130, while Unit 2 was in Mode 1 and 30 percent power, exiting a refueling outage, when one of the Main Steam Isolation Valves (MSIV) failed closed unexpectedly. This resulted in an inability to maintain Steam Generator SG) levels and pressures. The unit was manually tripped. All systems responded as designed. All control rods fully nserted into the core, auxiliary feedwater was started, and decay heat was removed through the main steam lines through he steam dumps and into the condenser. The plant was stabilized in Mode 3.
Due to the manual actuation of systems listed in 10 CFR 50. 73(a)(2)(iv)(B), specifically the Reactor Protection System and he Auxiliary Feeclwater System, this event is reportable under 10 CFR 50. 73(a)(2)(iv)(A).
Because all systems responded as designed and had no adverse effects on the health and safety of the public, this event is pf very low safety significance.
NRC FORM 366 (02-2018)
A
Event Description
- 3. LERM.IISER SEQUENTIAl NUMBER
- - 001 REV NO
- - 00 On March 30, 2019 at 2130, while Unit 2 was operating in Mode 1 at 30 percent power, exiting a refueling outage, when the number 4 Main Steam Isolation Valve (MSIV) unexpectedly dosed due to the failure of a control relay coil. The control relay had been recently installed and passed its post-maintenance testing and had been energized for several days prior to the failure, which is its normal operating state. The operating aew attempted to reopen the valve, but this was unsuccessful.
Because they were unable to reopen the valve, the operating crew initiated a manual reactor trip. This resulted in a manual actuation of the Reactor Protection System and actuation of the Auxiliary Feedwater System. All systems responded as expected. The control rods fully inserted into the core, auxiliary feedwater was started, and decay heat was removed through the main steam lines, through the steam dumps, and into the condenser.
Because of the manual actuation of the Reactor Protection System and the Auxiliary Feedwater System, which are systems listed in 10 CFR 50.73(a)(2)(iv)(B), this event is reportable under 10 CFR 50.73(a)(2)(iv)(A).
B. Cause of Event
The cause of the event was a failure of a control relay coil due to infant mortality.
C. Safety Assessment
The safety significance of this event is very low. When the reactor was tripped, all systems responded as designed. All control rods fully inserted into the core, auxiliary feedwater was started, and decay heat was removed through the main steam lines and into the condenser.
There were no adverse effects to the health and safety of the public.
D. Corrective Actions
The relay was replaced with another relay from a different manufacturing batch.
E. Previous Similar Events
None NRC FORM 386A (04-2018)