05000387/LER-2016-002

LER-2016-002, Secondary Containment Declared Inoperable Due to an Airlock Doors Open Due to Random Occurrence

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
Initial Reporting
ENS 51750	10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material
3872016002R00 - NRC Website

LER 16-002-00 for Susquehanna, Unit 1, Regarding Secondary Containment Declared Inoperable Due to an Airlock Doors Open Due to Random Occurrence

ML16109A259
Person / Time
Site:	Susquehanna
Issue date:	04/18/2016
From:	Franke J A Susquehanna, Talen Energy
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
PLA-7454 LER 16-002-00
Download: ML16109A259 (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.

Susquehanna Steam Electric Station, Unit 1 05000387

CONDITIONS PRIOR TO EVENT

Unit 1 — Mode 1, 79 percent Rated Thermal Power Unit 2 — Mode 1, 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 March 2, 2016 at approximately 1330, contract employees leaving the Unit 2 Reactor Building EIIS System Identifier: NG] through an airlock [EIIS Component Identifier: AL] verified a green light [EIIS Component Identifier: IL] with peer check three times, but received an alarm [EIIS Component Identifier:

ALM] when the airlock door [EIIS Component Identifier: DR] was about one quarter of the way open. The contract employees identified that workers had opened the door on the other side of the airlock. The workers on the other side were contract employees who indicated the green light was verified prior to the individual and crew entering the airlock. The individual also verified no one was in the airlock via the window in the door. The airlock door on the other side opened as they were entering.

After this incident, the airlock indication was tested and all equipment checked satisfactorily With both airlock doors open simultaneously, Secondary Containment was briefly inoperable due to failure to meet Surveillance Requirement (SR) 3.6.4.1.3.

This event was reported in accordance with 10 CFR 50.72(b)(3)(v)(C) as a condition that could have prevented fulfillment of a safety function (EN 51750). The condition also requires a Licensee Event Report (LER) in accordance with 10 CFR 50.73(a)(2)(v)(C).

CAUSE OF EVENT

The direct cause has been determined to be random occurrence.

ANALYSIS/SAFETY SIGNIFICANCE

The actual consequence was a brief entry into Technical Specification 3.6.4.1 and an eight hour notification of the event to the Nuclear Regulatory Commission (NRC).

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.

Susquehanna Steam Electric Station, Unit 1 05000387

CORRECTIVE ACTIONS

Although there were no identified human performance errors, a number of actions have been taken to improve human performance associated with airlock doors; these include the following:

1. A plant communication was prepared and disseminated describing proper actions associated with airlock doors and plant personnel were briefed on its content.

2. A station briefing sheet on airlock door operation has been added to the new to nuclear/Susquehanna supplemental worker Dynamic Learning Activity.

3. Supervisor observations of airlock door operation were completed.

PREVIOUS SIMILAR EVENTS

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

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