05000387/LER-2016-014

LER-2016-004, Secondary Containment Declared Inoperable Due to Airlock Doors Open Due to a Human Performance Error

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
3872016004R00 - NRC Website

LER 16-014-00 for Susquehanna, Unit 1, Regarding Secondary Containment Declared Inoperable Due to Airlock Doors Open Due to a Human Performance Error

ML16161A475
Person / Time
Site:	Susquehanna
Issue date:	06/09/2016
From:	Franke J A Susquehanna, Talen Energy
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
PLA-7489 LER 16-014-00
Download: ML16161A475 (4)

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 internet e-mail to 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 5, 0 percent Rated Thermal Power Unit 2 — Mode 1, approximately 100 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.

EVENT DESCRIPTION

On April 13, 2016 at approximately 21:15, a supplemental Radiation Protection Technician (RPT) attempting to enter the Unit 1 Reactor Building (RB1) [EIIS System Identifier: NG] opened the inner (RB1 side) airlock [EIIS Component Identifier: AL] door [EIIS Component Identifier: DR] without ensuring the outer door from the Unit 1 Turbine Building (TB1) [EIIS System Identifier: NM] was closed behind him. This airlock serves as a secondary containment boundary [EIIS System Identifier: NG]; 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.

The following is a time line of the event that occurred on April 13, 2016:

21:15 A supplemental RPT returning to his work location in the Unit 1 Reactor Building entered the airlock from the Turbine Building. A contractor scaffold crew entered the airlock behind him. The RPT proceeded to swipe his security keycard through the security card reader and opened the inner (RB1 side) door without noticing that the contractor crew was still entering the airlock and did not ensure that the outer (TB1 side) door was closed. The airlock alarm [EIIS Component Identifier: ALM] sounded as soon as the RPT opened the inner door. The RPT shut the door as soon as the alarm sounded.

The RPT stated that the cause of the alarm was his failure to notice the work crew entering the airlock behind him and his failure to verify that the outer (TB1 side) door was closed prior to opening the inner (RB1 side) door.

The condition requires a Licensee Event Report (LER) in accordance with 10 CFR 50.73(a)(2)(v)(C).

CAUSE OF EVENT

The direct cause of the event was a lack of situational awareness that led to the failure of the RPT to notice the work crew entering the airlock behind him, as well as his failure to ensure the outer (TB1 side) airlock door was fully closed prior to opening the inner (RB1 side) door.

ANALYSIS/SAFETY SIGNIFICANCE

An engineering evaluation was performed and concluded that secondary containment could have performed its safety function of isolating, as assumed in the accident analysis, and also of re-establishing 0.25 inches vacuum (drawdown) within the assumed accident analysis time (10 minutes). Therefore, the subject event did not cause a loss of safety function. This event will not be counted as a safety system functional failure (SSFF) for the NRC performance indicator based on the engineering analysis that shows there was no loss of ability to fulfill the safety function.

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 Internet e-mail to 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.

CORRECTIVE ACTIONS

Corrective actions included the following:

1. The RPT was coached on situational awareness and proper airlock use.

2. Expectations for passing through airlocks were reinforced during Radiation Protection shift crew briefings.

PREVIOUS SIMILAR EVENTS

The following are recent LERs involving loss of secondary containment due to door issues:

Due to Degraded Latch Mechanism," dated May 26, 2016.

Due to Degraded Latch Mechanism," dated May 24, 2016.

Human Performance Error," dated May 16, 2016.

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

to Random Occurrence," dated April 18, 2016.

to Random Occurrence," dated April 18, 2016.

Not Been Properly Latched," dated January 29, 2016.

Boundary Door 104-R Breached," dated September 18, 2015.

Found Ajar," dated June 25, 2015.

Surveillance Requirement 3.6.4.1.1," dated May 11, 2015.

Personnel Error Resulting in Entry into Secondary Containment Technical Specification Limiting Condition for Operation," dated December 31, 2014.