ML17263A116

Technical Specification (TS) 5.9.8 - Post Accident Monitoring System (Pams) Report

ML17263A116
Person / Time
Site:	Watts Bar
Issue date:	09/20/2017
From:	Simmons P Tennessee Valley Authority
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
Download: ML17263A116 (3)

Text

Tennessee Valley Authority, Post Office Box 2000, Spring City, Tennessee 37381 September 20,2017 10 cFR 50.4 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, D.C. 20555-0001 Watts Bar Nuclear Plant, Unit 1 Facility Operating License No. NPF-90 NRC Docket No. 50-390

Subject:

Technical Specification (TS) 5.9.8 - Post Accident Monitoring System (PAMS) Report The program requirements for the Watts Bar Nuclear Plant WBN) Post Accident Monitoring System (PAMS) requires a report to be submitted within 14 days when Condition B of Technical Specification (TS) Limiting Condition for Operation 3.3.3, "Post Accident Monitoring (PAM) lnstrumentation," is entered. On August 7,2017, the containment isolation valve indication for steam generator blowdown valve 1-FCV-1-32 was determined to be inoperable. On September 6, 2017, WBN entered TS 3.3.3 Condition B for this event when the inoperable condition had been present for 30 days, requiring a Special Report to the NRC. This special report is provided in the Enclosure.

There are no new regulatory commitments in this letter. Please direct any questions concerning this matter to Kim Hulvey, WBN Licensing Manager, at (423) 365-7720.

Respectfully, UW {r, C S,'^r,tr4o^-s Paul Siilmons Site Vice President Watts Bar Nuclear Plant Enclosure cc: See Page 2

U.S. Nuclear Regulatory Commission Page 2 September 20,2017 cc (Enclosure):

NRC Regional Administrator - Region Il NRC Senior Resident !nspector - Watts Bar Nuclear Plant NRC Project Manager - watts Bar Nuclear Plant

Enclosure Technical Specification 5.9.8 PAMS Report BackEround The Watts Bar Nuclear Plant WBN) Technical Specification (TS) 3.3.3, "Post Accident Monitoring (PAM) !nstrumentation," specifies the operability requirements for PAM instrumentation. TS Table 3.3.3-1, Function 1 1, "Containment lsolation Valve Position,"

requires two operable indication channels per penetration flow path. On August 7,2017, the outboard Steam Generator Blowdown (SGBD) isolation valve 1-FCV-1-32 on WBN Unit 1 was determined to have inoperable valve position indication. The green closed position light came on but did not turn off when the valve was opened, causing dual position indication. The red open position indication operates properly.

TS 3.3.3 Limiting Condition for Operation (LCO) Condition A allows a single indication channel to be inoperable for 30 days. lf the indication channel is not restored within 30 days, LCO Condition B is entered, which requires action in accordance with TS 5.9.8 to be taken immediately. TS 5.9.8 requires a report to be submitted to the Nuclear Regulatory Commission within 14 days.

On line efforts to repair this indication included adjusting the existing closed limit switch without success. Additionally, a change to a spare limit switch installed on the valve was also unsuccessful.

This report outlines the preplanned alternate method of monitoring, the cause of inoperability, and the plans and schedule for restoring the instrumentation channels of the Function to OPERABLE status.

Preplanned Alternate Method of Monitorinq With the outboard SGBD isolation valve indication inoperable, operations personnelwill use blowdown flow indication and indication of closure of 1-FCV-1-184, the inboard blowdown isolation valve, to validate blowdown isolation.

Cause of lnoperabilitv The outboard SGBD isolation valves are Target Rock solenoid valves with reed switches to support position indication. Efforts to restore proper indication have not been successful.

More intrusive maintenance to address this issue will require the isolation of SGBD.

Actions and Schedule to Restore lnstrumentation Function to Operable Gondition Replacement of the outboard SGBD isolation valve indication requires the valve to be closed and de-energized. Loss of blowdown has an adverse impact on steam generator chemistry, and should be performed when the unit is not at power. The actions to replace the SGBD isolation valve reed switches will be scheduled to be performed during the next unit 1 refueling outage anticipated to occur in the Fall of 2018.