ML23228A020

(BFN) Unit 1 - Special Report 259/2023-001 for Inoperable Post Accident Monitoring (PAM) Instrumentation

ML23228A020
Person / Time
Site:	Browns Ferry
Issue date:	08/15/2023
From:	Sivaraman M Tennessee Valley Authority
To:	Office of Nuclear Reactor Regulation, Document Control Desk
References
259/2023-001
Download: ML23228A020 (1)

Text

Post Office Box 2000, Decatur, Alabama 35609-2000

August 15, 2023 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) Unit 1 - Special Report 259/2023-001 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 July 4, 2023, Drywell Atmosphere Temperature Instruments, temperature indicator (TI) 1-TI-64-52AB and temperature recorder (XR) 1-XR-64-50, exceeded the maximum deviation of 21 degrees Fahrenheit as established in the acceptance criteria of 1-SR-3.3.3.1.1, Required PAM Instrumentation Channel Checks. PAM instrument 1-TI-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 B.1 requires actions to be initiated in accordance with TS 5.6.6 to submit a PAM Report within the following 14 days.

The 30 day action completion time for TS LCO 3.3.3.1 was exceeded on August 3, 2023.

CAUSE OF THE INOPERABILITY:

PAM instrument, 1-TI-64-52AB, was declared inoperable due to the Maximum Deviation value between the temperature indicator (1-TI-64-52AB) and temperature recorder (1-XR-64-50) failing to meet the acceptance criteria value of being less than 21 degrees Fahrenheit. The most U.S. Nuclear Regulatory Commission Page 2 August 15, 2023

likely cause for the temperature differential is the Resistance Temperature Detector (RTD)

(1-TE-64-52A) which feeds temperature indicator 1-TI-64-52AB. Due to the temperature element being located inside the Drywell, a Unit outage is required to repair the RTD.

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 control room recorder (1-XR-64-50) and one control room indicator (1-TI-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 September 2024 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 Michael W. Oliver, Acting Nuclear Site Licensing Manager, at (256) 729-7874.

Respectfully,

Manu Sivaraman BFN Site Vice President

cc:

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