05000296/LER-2016-001, Regarding Inoperable Residual Heat Removal Pump Results in Condition Prohibited by Technical Specifications and Safety System Functional Failure

Regarding Inoperable Residual Heat Removal Pump Results in Condition Prohibited by Technical Specifications and Safety System Functional Failure

ML16078A138
Person / Time
Site:	Browns Ferry
Issue date:	03/21/2016
From:	Bono S Tennessee Valley Authority
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
LER 16-001-00
Download: ML16078A138 (9)

LER-2016-001, Regarding Inoperable Residual Heat Removal Pump Results in Condition Prohibited by Technical Specifications and Safety System Functional Failure

Event date:
Report date:
2962016001R00 - NRC Website

text

Tennessee Valley Authority, Post Office Box 2000, Decatur, Alabama 35609-2000 March 21, 2016 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, D.C. 20555-0001

Subject:

Browns Ferry Nuclear Plant, Unit 3 Renewed Facility Operating License No. DPR-68 NRC Docket No. 50-296 Licensee Event Report 50-296/2016-001-00 10 CFR 50.73 The enclosed Licensee Event Report provides details of the inoperability of the 3A Residual Heat Removal (RHR) Pump for longer than allowed by the Technical Specifications, and concurrent inoperability of 3B and 3D RHR Pumps. The Tennessee Valley Authority (TV A) is submitting this report in accordance with Title 10 of the Code of Federal Regulations (10 CFR) 50. 73(a)(2)(i)(B), as any operation or condition which was prohibited by the plant's Technical Specifications, and 10 CFR 50. 73(a)(2)(v)(B) and (D),

as an event or condition that could have prevented the fulfillment of the safety function of structures or systems that are needed to remove residual heat and mitigate the consequences of an accident.

There are no new regulatory commitments contained in this letter. Should you have any questions concerning this submittal, please contact J. L. Paul, Nuclear Site Licensing Manager, at (256) 729-2636.

Enclosure: Licensee Event Report 50-296/2016-001 Inoperable Residual Heat Removal Pump Results in Condition Prohibited by Technical Specifications and Safety System Functional Failure cc (w/ Enclosure):

NRC Regional Administrator - Region II NRC Senior Resident Inspector - Browns Ferry Nuclear Plant

ENCLOSURE Browns Ferry Nuclear Plant Unit 3 Licensee Event Report 50-296/2016-001-00 Inoperable Residual Heat Removal Pump Results in Condition Prohibited by Technical Specifications and Safety System Functional Failure See Enclosed LER 50-296/2014-003-00 describes a RHR SDC Inboard Suction Valve Isolation Relay [RLY]

which was rendered inoperable for longer than allowed by TS due to improper landing of leads during PM. The event is similar because an improperly connected wire resulted in a long period of inoperability for a safety system. CAs were to develop and deliver a case study to the Maintenance, Modifications, and Operations departments based on the details of this event, and to inspect HFA relay terminations.

LER 50-260/2015-001-00 describes a failure of the 2A RHR Pump to manually start from the control room due to a loose terminal wire. The event is similar because an improperly latched hand switch resulted in a long period of inoperability for a safety system. Corrective Actions for this event were to discipline the individuals responsible, to tighten the loose fastener, and to revise maintenance instructions to reduce the probability of recurrence.

CAs from these LERs would not have prevented this event.

B. Additional Information

There is no additional information.

C. Safety System Functional Failure Consideration:

The safety function of RHRS is to restore and maintain the coolant inventory in the reactor vessel so that the core is adequately cooled after a loss-of-coolant accident. During the concurrent inoperability of 3A, 3B, and 3D RHR Pumps, the BFN, Unit 3, RHRS was unable to perform its safety function to remove residual heat and mitigate the consequences of an accident. Therefore, in accordance with guidance in NUREG-1022, this event is considered a safety system functional failure.

D. Scram with Complications Consideration:

This event did not result in a reactor scram.

VIII. COMMITMENTS

There are no new commitments.