05000416/LER-2019-004, Loss of High Pressure Core Spray Due to Instrument Inverter Failure
| ML19297H202 | |
| Person / Time | |
|---|---|
| Site: | Grand Gulf  |
| Issue date: | 10/24/2019 |
| From: | Emily Larson Entergy Operations |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| GNRO-2019/00046 LER 2019-004-00 | |
| Download: ML19297H202 (6) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(ii)(A), Seriously Degraded 10 CFR 50.73(a)(2)(iii) 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)(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 |
| 4162019004R00 - NRC Website | |
text
GNR0-2019/00046 October 24, 2019 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555-0001 Entergy Ope rations, Inc.
P.O. Box 756 Port Gibson, Mississippi 39150 Eric A. Larson Site Vice President Grand Gulf Nuclear Station Tel: 601-437-7500 10 CFR 50.73
SUBJECT:
Grand Gulf Nuclear Station, Unit 1 Licensee Event Report 2019-004-00, Loss of High Pressure Core Spray Due to Instrument Inverter Failure NRC Docket No. 50-416 Renewed Facility Operating License No. NPF-29 Attached is Licensee Event Report 2019-004-00, Loss of High Pressure Core Spray due to instrument inverter failure. This report is being submitted in accordance with 10 CFR 50.73(a)(2)(v)(D) for an event or condition that at the time of discovery could have prevented the fulfillment of the safety function of structures or systems that are needed to mitigate the consequences of an accident.
This letter contains no new commitments. If you have any questions or require additional information, please contact Jim Shaw at 601-437-2103.
Sincerely, Eric A. Larson EAL/fas
Attachment:
Licensee Event Report 2019-004-00
GNR0-2019/00046 Page 2 of 2 cc:
NRC Region IV - Regional Administrator NRC Senior Resident Inspector, Grand Gulf Nuclear Station NRR Project Manager
GNR0-2019/00046 Attachment Licensee Event Report 2019-004-00
NRCFORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 03/31/2020 (04-2018)
, the NRG may not conduct or sponsor, and a oerson is not reauired to resoond to the information collection.
- 1. Facility Name
~- Docket Number
~.Page Grand Gulf Nuclear Station, Unit 1 05000 416 1 OF3
- 4. Title Loss of Hiah Pressure Core Sorav Due to Instrument Inverter Failure
- 5. Event Date
- 6. LER Number
- 7. Report Date
- 8. Other Facilities Involved Sequential Rev Facility Name Docket Number Month Day Year Year Number No.
Month Day Year N/A 05000 NIA 08 28 2019 2019
- - 004
- - 00 10 24 2019 Facility Name Docket Number N/A 05000 N/A
- 9. Operating Mode
- 11. This RePOrt is Submitted Pursuant to the Reauirements of 1 O CFR §: (Check all that aoolv) 1 0 20.2201(b) 0 20.2203(a)(3)(i) 0 50.73(a)(2)(ii)(A) 0 50. 73(a)(2)(viii)(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(a)(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) 0 50. 73(a)(2)(iv)(A) 0 50. 73(a)(2)(x)
- 10. Power Level 0 20.2203(a)(2)(ii) 0 50.36(c)(1 )(ii)(A) 0 50.73(a)(2)(v)(A) 0 73. 71(a)(4) 0 20.2203(a)(2)(iii) 0 50.36(c)(2) 0 50.73(a)(2)(v)(B) 0 73. 71 (a)(5) 100 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) 181 50. 73(a)(2)(v)(D) 0 73. 77(a)(2)(ii) 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)
O Other (Specify in Abstract below or in NRC Form 366A
- 12. Licensee Contact for this LER Licensee Contact rilephone Number (Include Area Code)
µim Shaw, Manager Regulatory Assurance
!(601) 437-2103 Cause System Component Manufacturer Reportable To ICES
Cause
System Component Manufacturer Reportable To ICES 8
BG IPWSUP Topaz y
- 14. Supplemental Report Expected Month Day Year D Yes (If yes, complete 15. Expected Submission Date) IZJ No
- 15. Expected Submission Date
~bstract (Limit to 1400 spaces, i.e., approximately 14 single-spaced typewritten lines)
On August 28, 2019, at 13: 16, the Grand Gulf Nuclear Station Unit 1, Control Room received High Pressure Core Spray (HPCS)
Out-of-Service annunciator, HPCS SYS OOSVC. HPCS was declared INOPERABLE and the following Technical Specification (TS)
Action statements were entered: ECCS TS 3.5.1 Action 8.1 and Primary Containment Isolation Valves TS 3.6.1.3 Action A.1.
The Direct Cause for the event is that the HPCS system instrument inverter lost inverter output that resulted in the inability to automatically initiate HPCS. Immediate corrective actions were taken to replace the instrument inverter restoring HPCS to an operable condition on August 28, 2019, at 23:15.
This report is made pursuant to 1 O CFR 50.73(a)(2)(v)(D) for an event or condition that at the time of discovery could have prevented the fulfillment of the safety function of structures or systems that are needed to mitigate the consequences of an accident.
There were no consequences to the general safety of the public, nuclear safety, industrial safety and radiological safety for this event.
NRC FORM 366 (04-2018)
Plant Conditions
YEAR 2019 SEQUENTIAL NUMBER
- - 004 Grand Gulf Nuclear Station (GGNS) Unit 1 was operating at approximately 100 percent power in MODE 1. There were no structures, systems, or components that were inoperable that contributed to the event.
Description
REV NO.
- - 00 On August 28, 2019, at 13: 16 CDT, the Control Room received the following High Pressure Core Spray (HPCS)[BG] annunciator, HPCS SYS OOSVC. In addition to the HPCS Out-of-Service alarm, the TRIP UNIT OOFile/PWRLOSS and HPCS LOGIC POWER FAILURE status lights were illuminated.
The Control Room operators responded to the alarm and declared HPCS (a single train system) INOPERABLE and entered Emergency Core Cooling Systems Technical Specification (TS) 3.5.1 Action statements for Condition B.
Additionally, the HPCS suction minimum flow valve opened as designed due to loss of instrument inverter power and Primary Containment Isolation Valves (PCIV) TS 3.6.1.3 Action statement for Condition A was entered for the affected isolation valve. The associated breaker was opened, and the minimum flow valve was manually closed per the required action as stated in TS 3.6.1.3 Condition A.1.
Instrument and Control Maintenance was contacted to investigate the event and the cause was determined to be an issue with the HPCS instrument inverter. The instrument inverter converts 125 VDC to 120 VAC. The investigation identified that inverter output was approximately O VAC.
Technical Specification LCO 3.5.1 was met with the replacement of the instrument inverter. TS LCO 3.6.1.3 was met when the HPCS minimum flow valve was restored to normal configuration. H PCS was declared operable on August 28, 2019, at 23: 15.
Reportability
This event was reported as an event or condition that, at the time of discovery, could have prevented the fulfillment of the safety function of structures or systems that are needed to mitigate the consequences of an accident per 10 CFR 50.72(b)(3)(v)(D). The event notification is EN 54244.
This event is also reportable per 10 CFR 50.73(a)(2)(v)(D).
Direct Cause:
The lost of instrument inverter VAC output power resulted in the inability to automatically initiate HPCS, resulting in a loss of safety function.
Immediate Corrective Actions
The inverter was replaced and functionally tested satisfactory.
Safety Significance
There were no actual consequences for this event. There was no radiological release from the Secondary Containment as a result of this event. There were no other actual consequences to safetv of the qeneral public, nuclear safetv, industrial safety and NRC FORM 3668 (02-2018)
Page 2 of 3 (04-2018)
U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 3/31/2020 l¥-
\\.
j LICENSEE EVENT REPORT (LER)
CONTINUATION SHEET (See NUREG-1022, R.3 for instruction and guidance for completing this form http://www.nrc.gov/reading-rm/doc-collections/nuregs/staff/sr1022/r3l)
, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.
- 3. LER NUMBER Grand Gulf Nuclear Station, Unit 1 05000-416 radiological safety.
Previous Similar Event:
A five-year review of similar events was conducted, and no similar events were revealed. YEAR 2019 SEQUENTIAL NUMBER
- - 004 Page 3 of 3 REV NO
- - 00