05000416/LER-2019-005, Primary Containment Personnel Airlock Potential Loss of Safety Function Due to Inadequate Door Closure
| ML19311C250 | |
| Person / Time | |
|---|---|
| Site: | Grand Gulf  (NPF-029) |
| Issue date: | 11/07/2019 |
| From: | Emily Larson Entergy Operations |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| GNRO-2019/00047 LER 2019-005-00 | |
| Download: ML19311C250 (6) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(v), Loss of Safety Function |
| 4162019005R00 - NRC Website | |
text
~Entergy GNR0-2019/00047 November 7, 2019 ATTN: Document ControlDesk U.S. Nuclear Regulatory Commission Washington, DC 20555-0001 Entergy Operations, Inc.
P.O. Box 756 Port Gibson, Mississippi 39150 Eric A. Larson Site Vice President Grand Gulf N'uclear Station Tel: 601-437-7500 10 CFR 50.73
SUBJECT:
Licensee Event Report 2019-005-00, Primary Containment Personnel Airlock Potential Loss of Safety Function due to Inadequate Door*Closure
Dear Sir or Madam:
Grand Gulf Nuclear Station, Unit 1 NRC Docket No. 50-416 Renewed Facility Operating License No. NPF-29 Attached is Licensee Event Report 2019-005-00, Primary Containment Personnel Airlock Potential Loss of Safety Function due to Inadequate Door Closure. This report is being submitted in accordance with 10 CFR 50. 73(a)(2)(v)(C) for an event or condition that could have prevented the fulfillment of a safety function.
This letter contains no new commitments. If you have any questions or require additional information, please contact Jim Shaw at 601-437-2103.
Sincerely,
~ a ;t __
Eric A. Larson EAL/ram
Attachment:
Licensee Event Report 2019-005-00
GNR0-2019/00047 Page 2 of 2 cc:
NRC Region IV - Regional Administrator NRC Senior Resident Inspector, Grand Gulf Nuclear Station NRR Project Manager
GNR0-2019/00047 Attachment Licensee Event Report 2019-005-00
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION.APPROVED BY OMB: NO. 3150-0104 EXPIRES: 03/31/2020 (04-2018)
, the NRC may not conduct or sponsor, and a oerson is not reauired to resoond to the information collection.
. Page Grand Gulf Nuclear Station Unit 1 05000416 1 OF3
- 4. Title Primary Containment Personnel Airlock Potential Loss of Safety Function due to Inadequate Door Closure
- 5. Event Date
- 6. LER Number
- 7. Report Date 8: Other Facjlities Involved Sequential Rev Facility Name Docket Numper Month Day Year Year Month Day Year NIA Number No.
OSOOONIA 09 11 2019 2019 005 00 11 07 2019 Facility Name Docket Number NIA OSOOONIA
- 9. Operating Mode N/A N/A N/A Abstract (Limit to 1400 spaces, i.e., approximately 14 single-spaced typewritten lines)
On September 11, 2019 at 5: 19pm, the Grand Gulf Nuclear Station primary containment was unable to fulfill its safety function because both doors on one airlock were open simultaneously for approximately thirty seconds.
I The cause of this event is that the 208 primary containment airlock inner door latch pin position is not included in the electrical interlock 'or indication circuits. This caused the condition by allowing the outer airlock door open permissive to be met when the inner airlock door was not properly latched in the closed position. The 208-foot elevation airlock doors were immediately closed and verified latched and sealed. Additional corrective actions include revising the system operating procedure and the local operating placard instructions and a modification to ensure the proper closure, latching, and sealing of the 208-elevation airlock door.
I This report is made pursuant to 10 CFR 50.73(a)(2)(v)(C) 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
Grand Gulf Nuclear Station Unit 1 was operating at approximately 100 percent power in MODE1. There were no structures, systems, or components that were inoperable that contributed to the event.
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Description
On September 11, 2019; at 5:19pm, a Grand Gulf Nuclear Station Radiation Protection technician exited the pri'mary containment building [NH] through the personnel airlock located on 208-foot elevation. The individual opened the containment-side (inner) airlock door and entered the airlock. Once inside the airlock the technician closed the inner door using the established work practices and door operating instructions. The technician then opened the auxiliary building side (outer) door and exited the airlock and reclosed the outer door.
I As the Radiation Protection technician was exiting the outer door, Maintenanc~ Personnel approached the inner,door in preparation to exit containment through the airlock. The Maintenance Person*nel noticed that the inner door lcicking pins were extended to their locking position but outside the locking pin keepers. They also noticed the inner door's seals were inflated. They waited for the outer door to close before operating the containment airlock doors and hiting the containment-building. Both airlock doors were left in a closed, latched, and sealed configuration upon the '
1 successful exit of the Maintenance Personnel.
The time period that both doors were open, which prevented the containment from fulfilling its safety function, Vl,'.as approximately 30 seconds.
I What Happened:
When the Radiation Protection technician began the automatic closing cycle of the inner door by depressing th~
CLOSE push* button in the barrel, the hydraulic system did not provide adequate pressure to the rotary actuator to close the door unassisted. The technician pulled the door handle to assist the door closed, which required significant effort. The technician assisted the door to what they believed was a full closed position and held it there. The door's full-closed limit switch was satisfied, *and the subsequent time delay began. The door was not actually in a full-closed position at the end of the time delay, but the door had not reached an open position sufficient to reset the limit switch.
The same-door mechanical interlocking pawl was also lifted from the ratchet. The seal mechanism.began closing. The pins extended outside of the keeper, and the seals were inflated. The pressurized seals energized the green I
permissive lights in the barrel. The door-to-door Mechanical interlocking pawl was lifted. The red "door operatin:g" light was de-energized, and all electrical interlocks were satisfied. Seeing that all permissives were met, the technician depressed the open pushbutton for the outer door. The outer door operated as designed, and the technician exited the airlock barrel and closed the outer door.
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Reportability
This event was reported to the NRC via the emergency notification system (ENS) at 0049 hours5.671296e-4 days <br />0.0136 hours <br />8.101852e-5 weeks <br />1.86445e-5 months <br /> on September, 12, 2019, in accordance with 10 CFR 50. 72(b )(3)(v)(C). Reference ENS notification 54271 for the details.
A Licensee Event Report is required pursuant to Title 10 Code of Federal Regulations (10 CFR) 50. 73(a)(2)(v)(C) for an event or condition that had the potential to prevent the fulfillment of the safety function to control the release of radioactive material or mitigate the consequences of an accident.
NRC FORM 3668 (02-2018)
Page 2 of 3 U,S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150~0104 EXPIRES: [3/31/2020 (04-2018)
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LICENSEE EVENT REPORT (LER)
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1 CONTINUATION SHEET (See NUREG-1022, R.3 for instruction and guidance for completing this form http://www. nrc.qov/readinq-rm/doc-collections/nureqs/staff/sr1022/r3D Estimated burden per response to comply with this mandatory collection request: 80 hours9.259259e-4 days <br />0.0222 hours <br />1.322751e-4 weeks <br />3.044e-5 months <br />. Reported lessons learned are incorporated into the licensing process and fed. back to industry. Send comments regarding burden estimate to the Information Services Branch (T-2 F43),. U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by l' e-mail to lnfocollects.Resource@nrc.gov, and to the Desk Officer, Office of Information and Regulatory Affairs, NEOB-10202, (3150-0104), Office of Management and Budget, Washington, DC 20503. If a means used to impose an information collection does not display a currently valid OMB contr61 number, the NRC may not conduct or sponsor, and a person is not required to respond to, t~e information collection.
- 3. LER NUMBER.i YEAR SEQUENTIAL I
REV NUMBER NO.
I Grand Gulf Nuclear Station Unit 1 05000-416 2019
- - 005 l
- - 00 I
Cause
I The cause of this event is that the containment airlock door latch pin position is not included in the electrical interlock or indication circuits. This caused the condition by allowing the outer airlock door open permissive to be met when the inner airlock door was not properly latched in the closed position.
Corrective Actions
Immediate Corrective Actions
The 208-foot elevation airlock doors were immediately closed and verified latched and sealed.
Planned Corrective Actions
Revise system operating instructions to provide guidance for ensuring the airlock doors are fully closed, audible or visual verification that the latch pins have extended, and the door operator challenges the door prior to operating the oppqsite door in the airlock.
1 Revise the airlock local permanent information placard to align with the revised system operating instruction.
i Development of a modification to ensure proper closure, latching, and sealing of the 208-elevation ai.rlock door.
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Safety Significance
There were no actual consequences for this event. There was no radiological release from the primary containment as a result of this event. There were no other actual consequences to safety of the general public, nuclear safety, industrial safety and radiological safety.
Previous Similar Events
LER 2019-004-00, Secondary Containment Personnel Door Failure Due to Broken Hinges
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LER 2018-005-00, Secondary Containment Door Misaligned, Due to Inadequate Criteria, Could Have Prevented Fulfillment of a Safety Function r
LER 2018-006-00, Secondary Containment Roof Hatch Left Open Due To Inadequate Corrective Actions LER 2016-003-oo;*Loss of Secondary Containment-Secondary Containment Safety Function During Routine Roof lnsplection The causal analysis and correctives actions for the above identified events were reviewed and it has been determined t~at the causes and corrective actions for these event could not have prevented the event documented in Grand Gulf Nuclear Station LER 2019-005-00.
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