ML17200A084

Special Report 259/2017-001 for Inoperable Post Accident Monitoring (PAM) Instrumentation

ML17200A084
Person / Time
Site:	Browns Ferry
Issue date:	07/19/2017
From:	Bono S Tennessee Valley Authority
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
SR 259/2017-001
Download: ML17200A084 (2)

Text

Tennessee Valley Authority, Post Office Box 2000, Decatur, Alabama 35609-2000 July 19, 2017 10 CFR 50.4 ATTN : Document Control Desk U.S. Nuclear Regulatory Commission Washington , D.C. 20555-0001 Browns Ferry Nuclear Plant, Unit 1 Renewed Facility Operating License No. DPR-33 NRC Docket No. 50-259

Subject:

Browns Ferry Nuclear Plant (BFN) - Special Report 259/2017-001 for Inoperable Post Accident Monitoring (PAM) Instrumentation In accordance with Technical Specification (TS) 5.6.6, PAM Report, this letter provides notification of a PAM instrument that was not restored to Operable status within 30 days as required by TS Limiting Condition for Operation (LCO) 3.3.3.1, Post Accident Monitoring (PAM) Instrumentation.

BACKGROUND INFORMATION :

On June 5, 2017, during performance of Surveillance Requirement 1-SR-3.3.3.1 .1, Required PAM Instrumentation Channel Checks, Drywell Atmosphere Temperature Instruments, Temperature indicator (Tl) 1-Tl-64-52AB and Temperature Recorder (XR) 1-XR-64-50, were 12. 7 degrees Fahrenheit apart which exceeded the maximum deviation of 10.7 degrees Fahrenheit as established in the acceptance criteria of 1-S R-3.3.3. 1.1.

PAM instrument 1-Tl-64-52AB was declared inoperable and the required Actions of TS LCO 3.3.3.1 Condition A were entered.

TS LCO 3.3.3.1 requires two channels of Drywell Atmosphere Temperature to be Operable in Modes 1 and 2. With one required channel inoperable, TS 3.3.3.1 Required Action A.1 directs the required channel to be returned to Operable status in 30 days. If the required channel cannot be restored to Operable status in the required time period , TS 3.3.3.1 Required Action 8 .1 requires actions to be initiated in accordance with TS 5.6.6.

The 30 day action completion time for TS LCO 3.3.3.1 was exceeded on July 5, 2017.

U.S. Nuclear Regulatory Commission Page 2 July 19, 2017 CAUSE OF THE INOPERABILITY:

PAM instrument, 1-Tl-64-52AB, was declared inoperable due to the Maximum Deviation value between the temperature indicator (1 -Tl-64-52AB) and temperature recorder (1-XR-64-50) failing to meet the acceptance criteria value of being less than 10. 7 degrees Fahrenheit. The temperature deviation between 1-Tl 52AB and 1-XR-64-50 was recorded at 12. 7 degrees Fahrenheit. Troubleshooting on the instrument loop found that the most likely cause for the temperature differential was the Resistance Temperature Detector (RTD) (1-TE-64-52A) which feeds temperature indicator 1-Tl-64-52AB . Due to the temperature element being located inside the Drywell, a Unit outage is required which would exceed the time to complete the LCO within 30 days, as required by TS LCO 3.3.3.1, Condition A, restore required channel to OPERABLE status.

PREPLANNED ALTERNATE MONITORING METHOD:

There are two wide range Drywell Atmosphere temperature signals which are transmitted from separate temperature sensors and are continuously recorded and displayed on Channel 1 of one control room recorder (1 -XR-64-50) and one control room indicator (1-Tl-64-52AB) . The recorder and indicator are the primary indications used by Operations personnel during an accident. Drywell Atmosphere temperature recorder 1-XR-64-50 and RTD temperature element 1-TE-64-52C remain Operable for monitoring Drywell Atmosphere temperature. A preplanned alternate monitoring method is not required at this time .

PLANS AND SCHEDULE FOR RESTORING THE INSTRUMENT CHANNEL:

Replacement of RTD temperature element 1-TE-64-52A will occur during the next Unit 1 Refueling Outage scheduled for October 2018 or during a forced outage.

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.

cc:

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