ML14232A425
| ML14232A425 | |
| Person / Time | |
|---|---|
| Site: | Watts Bar  |
| Issue date: | 08/21/2014 |
| From: | Walsh K Tennessee Valley Authority |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| Download: ML14232A425 (3) | |
Text
Tennessee Valley Authority, Post Office Box 2000, Spring City, Tennessee 37381 August 21, 2014 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 10 CFR 55.5 TS 5.7.2.15
Subject:
Technical Specification (TS) 5.7.2.15 - Explosive Gas and Storage Tank Radioactivity Monitoring Program The program requirements for the Waste Gas Holdup System are specified in TS 5.7.2.15 and are implemented in Technical Instruction Tl-266, Explosive Gas and Storage Tank Radioactivity Monitoring Program. On June 11, 2014, the oxygen analyzer for the Waste Gas Holdup System was declared inoperable. Section 2.5 of Tl-266 specifies that a special report be prepared if the inoperable condition exist for a period of 30 days continuously. This special report is provided in.
There are no new regulatory commitments in this letter. If you have any questions, please contact Gordon Arent, Director of Watts Bar Site Licensing, at (423) 365-2004.
Kevin T. Walsh Site Vice President Watts Bar Nuclear Plant Enclosure cc: See Page 2
U.S. Nuclear Regulatory Commission Page 2 August 21, 2014 Enclosure cc (Enclosure):
NRC Regional Administrator - Region II NRC Senior Resident Inspector - Watts Bar Nuclear Plant NRC Project Manager - Watts Bar Nuclear Plant Institute of Nuclear Power Operations Technical Specification 5.7.2.15 Waste Gas Monitoring System Special Report
Background
The Waste Gas Oxygen Analyzer (WGA) O-XIC-43-450 is used to monitor the oxygen content in the Waste Disposal System (WDS) to preclude potentially explosive gas mixture from accumulating in the WDS.
On June 11, 2014 a Service Request (SR) 897384 (PER 909699) was written to document that the WGA failed calibration. The WGA was considered inoperable because automatic oxygen measuring capabilities and associated alarm capabilities no longer existed. Technical Instruction Tl-266, Explosive Gas and Storage Tank Radioactivity Monitoring Program, Section
2.5 states
A special report to the NRC shall be prepared if any of the following conditions exist for a period of 30 days continuously:
Any sample point on O-XIC-43-450 (Waste Gas Oxygen Analyzer) is inoperable Loss of alarm capabilities associated with O-XIC-43-450 or O-XR-43-232 0-02AN-43-227 (Waste Gas Compressor Oxygen Analyzer) is inoperable This report should identify the cause of inoperability, actions taken to restore the monitor(s)/alarm functions to operability and a summary of the actions taken to prevent recurrence.
Cause of lnoperability The most probable cause why the WGA failed was due to degradation of the oxygen sensor 0-02E-43-450. The degradation was most likely due to aging.
Actions Taken to Restore Monitor(s)!Alarm Functions to Operable Condition Upon loss of the WGA, Operations secured the Waste Gas Compressors and Chemistry performed surveillance instruction O-Sl-77-3 to collect grab samples from the in-service Waste Gas Decay Tank on a daily bases. The oxygen sensor was replaced and a conditional calibration (O-Sl-43-212) was successfully performed. The WGA was return to service on 07/23/14. No loss of safety function occurred because the surveillance requirement provided adequate assurance that there was no potential for explosive gas mixture to accumulate in the WDS.
Summary of Actions Taken to Prevent Recurrence To prevent recurrence the Chemistry Department coordinated with the Materials Group to increase stocking levels of the oxygen sensor (0-02E-43-450) and a Long Term Asset Management (L TAM) Item, WBN-14-0568, was written to address WGA (O-XIC-43-450) obsolescence.
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