05000388/LER-2017-004

LER-2017-004, 1 OF 3

Susquehanna Steam Electric Station Unit 2
Event date:
Report date:
Reporting criterion:	10 CFR 50.73(a)(2)(v)(C), Loss of Safety Function - Release of Radioactive Material
3882017004R00 - NRC Website

comments regarding burden estimate to the Information Services Branch (T-2 F43), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by e-mail to Infocollects.Resource@nrc.00v. and to the Desk Officer, Office of Information and Regulatory Affairs, 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.

klc I- 1 FACILITY NAME 2. DOCKET NUMBER 3. LER NUMBER Susquehanna Steam Electric Station Unit 2 05000-388 NUMBER NO.

CONDITIONS PRIOR TO EVENT

Unit 1 — Mode 1, approximately 100 percent Rated Thermal Power Unit 2 — Mode 1, approximately 88 percent Rated Thermal Power

EVENT DESCRIPTION

On March 2, 2017 at approximately 10:30, three employees were entering the Unit 2 Airlock [EIIS Component Identifier: AL] on elevation 676' from the Reactor Building [EIIS System Identifier: NG] door. The first employee observed the green light, swiped their badge and entered into the airlock. The two additional employees also swiped their badges and traversed into the airlock. As the first employee opened the second door within the airlock, the airlock door alarm sounded briefly as the first door was not completely closed and latched. Upon hearing the alarm, the employees promptly reported the incident to oversight and Operations.

All personnel then provided statements with respect to the event.

CAUSE OF EVENT

The cause of the event was determined to be less than adequate use of 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 results 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). 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 supporting the system's ability to fulfill the safety function.

CORRECTIVE ACTIONS

Key corrective actions include the following:

1. Coaching was provided to the individuals involved with respect to the use of airlock doors (Complete).

comments regarding burden estimate to the Information Services Branch (T-2 F43), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by e-mail to Int ocollects.Resource@nrctiov. and to the Desk Officer, Office of Information and Regulatory Affairs, NEOB-10202, (3150-0104), Office of Management and Bridget, 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.

Susquehanna Steam Electric Station Unit 2 05000-388 NUMBER NO.

PREVIOUS SIMILAR EVENTS

The following recent LERs involving loss of Secondary Containment due to door issues:

Doors," dated March 8, 2017.

Open Due to Random Occurrence," dated April 18, 2016.

Open Due to Random Occurrence," dated April 18, 2016.

had not been Properly Latched," dated January 29, 2016.

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

Door Found Ajar," dated June 25, 2015.

Specification Surveillance Requirement 3.6.4.1.1," dated June 10, 2015.

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