05000387/LER-2017-002

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LER-2017-002, Secondary Containment Breach due to Simultaneous Opening of Airlock Doors
Susquehanna Steam Electric Station Unit 1
Event date:
Report date:
Reporting criterion: 10 CFR 50.73(a)(2)(v)(C), Loss of Safety Function - Release of Radioactive Material
3872017002R00 - NRC Website
LER 17-002-00 for Susquehanna, Unit 1, Regarding Secondary Containment Breach due to Simultaneous Opening of Airlock Doors
ML17102B408
Person / Time
Site: Susquehanna Talen Energy icon.png
Issue date: 04/12/2017
From: Berryman B
Susquehanna, Talen Energy
To:
Document Control Desk, Office of Nuclear Reactor Regulation
References
PLA-7581
Download: ML17102B408 (4)


Reported lessons learned are incorporated into the licensing process and fed back to industry.

Send comments regarding burden estimate to the FOIA, Privacy and Information Collections Branch (T-5 F53), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by e-mail to Infocollects.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 control number, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.

CONDITIONS PRIOR TO EVENT

Unit 1 — Mode 1, approximately 097 percent Rated Thermal Power Unit 2 — Mode 1, approximately 092 percent Rated Thermal Power There were no structures, systems, or components that were inoperable at the start of the event that contributed to the event. Unit 2 was in coast down prior to the refueling outage.

EVENT DESCRIPTION

On February 17, 2017 at approximately 1040, three maintenance workers entered the Refuel Floor Air Lock [EIIS: AL]. The first worker entered the airlock followed by the second and third workers and began to open the second door [EIIS: DR] before the third individual closed the first door. This caused an alarm [EIIS: ALM] for a momentary breach of Secondary Containment [EIIS: VA]. When they heard the alarm, both workers shut the doors. This airlock serves as a secondary containment boundary; as such, having both doors open at the same time results in failure to meet Technical Specification 3.6.4.1 as a result of not satisfying Surveillance Requirement 3.6.4.1.3.

CAUSE OF THE EVENT

The cause of the event was less than adequate situational awareness.

ANALYSIS/ SAFETY SIGNIFICANCE

Technical Specification 3.6.4.1 Surveillance Requirement 3.6.4.1.3 requires that one secondary containment access door in each access opening is closed. This event is being reported pursuant to 10 CFR 50.73(a)(2)(v)(C) as having both Secondary Containment airlock doors momentarily open simultaneously resulting in a condition that could have prevented fulfillment of a safety function to mitigate the consequences of an accident by controlling the release of radioactive material.

There was no actual safety consequence as a result of this event. Engineering analysis of this event has determined that secondary containment could have performed its safety function of isolating, as assumed in the accident analysis, and also of re-establishing 0.25 in w.g. vacuum (drawdown) within the assumed accident analysis time (10 minutes). This event will not be counted as a safety system functional failure (SSFF) for the NRC performance indicator.

CORRECTIVE ACTIONS

Corrective actions completed included coaching of the individual who opened the second airlock door.

Reported lessons learned are incorporated into the licensing process and fed back to industry.

Send comments regarding burden estimate to the FOIA, Privacy and Information Collections Branch (T-5 F53), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by e-mail to Infocollects.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 control number, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.

Ai/ '41

PREVIOUS SIMILAR EVENTS

Doors," dated March 8, 2017 (PLA-7576).

Doors," dated January 26, 2017 (PLA-7569).

to a Human Performance Error," dated November 21, 2016 (PLA-7547).

Doors," dated December 1, 2016 (PLA-7544).

to a Human Performance Error," dated August 17, 2016 (PLA-7515).

to a Human Performance Error," dated June 15, 2016 (PLA-7493).

to a Human Performance Error," dated June 9, 2016 (PLA-7492).

due to personnel error," dated June 9, 2016 (PLA-7492).

to Human Performance Error," dated May 16, 2016 (PLA-7466).

Elevation 779 of the Unit 2 Reactor Building being Opened at the Same Time," dated May 10, 2016 (PLA-7467).

Not Been Properly Latched," dated January 29, 2016 (PLA-7432).

Boundary Door 104-R Breached," dated September 18, 2015 (PLA-7383).

Found Ajar," dated June 25, 2015 (PLA-7353).

Surveillance Requirement 3.6.4.1.1," dated May 11, 2015 (PLA-7329).