ML15348A112

Technical Specification (TS) 5.7.2.15 - Explosive Gas and Storage Tank Radioactivity Monitoring Program

ML15348A112
Person / Time
Site:	Watts Bar
Issue date:	12/14/2015
From:	Walsh K Tennessee Valley Authority
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
Download: ML15348A112 (3)

Text

Tennessee Valley Authority, Post Office Box 2000, Spring City, Tennessee 37381 December 14,2015 TS 5.7.2.15 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) 5.7.2.1 5 - Explosive Gas and Storage Tank Radioactivity Monitoring Program The program requirements for the Watts Bar Nuclear Plant WBN) Waste Gas Holdup System are specified in Technical Specification 5.7.2.15 and are implemented in Technical lnstruction Tl-266, "Explosive Gas and Storage Tank Radioactivity Monitoring Program." On October 15,2015, the oxygen analyzer alarm function 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 the Enclosure.

There are no new regulatory commitments in this letter. Please direct any questions concerning this matter to Gordon Arent, WBN Licensing Director, 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 December 14,2015 cc (Enclosure):

NRC RegionalAdministrator - Region ll NRC Senior Resident lnspector - Watts Bar Nuclear Plant, Unit 1 NRC Project Manager - Watts Bar Nuclear Plant, Unit 1

Enclosure Technical Specification 5.7.2.1 5 Waste Gas Monitoring System Special Report Backqround The Watts Bar Nuclear Plant WBN) Waste Gas Oxygen Analyzer WGA) 0-XlC-43.450 is used to monitor the oxygen content in the Waste Disposal System WDS) to preclude a potentially explosive gas mixture from accumulating in the WDS.

On October 15,2015 it was determined that the alarm capability was impaired. The WGA is not considered operable because alarm capabilities are impaired. This alarm function was restored to service on November 24,2015.

Technical lnstruction 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 0-XlC-43-450 (Waste Gas Oxygen Analyzer) is inoperable

. Loss of alarm capabilities associated with 0-X1C43450 or 0-XR-43-232

. 0-O2AN-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 recunence.'

Cause of lnoperabilitv The WGA function is common to both WBN Unit 1 and 2. An upgrade to the WGA system was required to support Unit 2 operation. The WGA alarm function was impaired due to the installation of a new automatic Programmable Logic Controller (PLC) sequencer and associated recorder as part of.a Unit 2 Startup upgrade.

Actions Taken to Restore Monitor(s)/Alarm Functions to Ooerable Condition Upon loss of the WGA alarm function, Chemistry performed surveillance instruction 0-Sl-77-3to collect grab samples from the in-service Waste Gas Decay Tank on a daily basis.

The new PLC was installed and the communications issue with the recorder resolved. The WGA was returned to service on November 24,2015, after successful completion of post modification testing (PMT). No loss of safety function occurred because the surveillance requirement provided adequate assurance that there was no potentialfor an explosive gas mixture to accumulate in the WDS.

Summary of Actions Taken to Prevent Recurrence The delay in restoring the alarm function was due to the need to perform troubleshooting on the design change that installed a new automatic PLC sequencer to the gas monitoring system. Severalwiring issues were identified, corrected, and then the system was restored to service.

Tennessee Valley Authority, Post Office Box 2000, Spring City, Tennessee 37381 December 14,2015 TS 5.7.2.15 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) 5.7.2.1 5 - Explosive Gas and Storage Tank Radioactivity Monitoring Program The program requirements for the Watts Bar Nuclear Plant WBN) Waste Gas Holdup System are specified in Technical Specification 5.7.2.15 and are implemented in Technical lnstruction Tl-266, "Explosive Gas and Storage Tank Radioactivity Monitoring Program." On October 15,2015, the oxygen analyzer alarm function 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 the Enclosure.

There are no new regulatory commitments in this letter. Please direct any questions concerning this matter to Gordon Arent, WBN Licensing Director, 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 December 14,2015 cc (Enclosure):

NRC RegionalAdministrator - Region ll NRC Senior Resident lnspector - Watts Bar Nuclear Plant, Unit 1 NRC Project Manager - Watts Bar Nuclear Plant, Unit 1

Enclosure Technical Specification 5.7.2.1 5 Waste Gas Monitoring System Special Report Backqround The Watts Bar Nuclear Plant WBN) Waste Gas Oxygen Analyzer WGA) 0-XlC-43.450 is used to monitor the oxygen content in the Waste Disposal System WDS) to preclude a potentially explosive gas mixture from accumulating in the WDS.

On October 15,2015 it was determined that the alarm capability was impaired. The WGA is not considered operable because alarm capabilities are impaired. This alarm function was restored to service on November 24,2015.

Technical lnstruction 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 0-XlC-43-450 (Waste Gas Oxygen Analyzer) is inoperable

. Loss of alarm capabilities associated with 0-X1C43450 or 0-XR-43-232

. 0-O2AN-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 recunence.'

Cause of lnoperabilitv The WGA function is common to both WBN Unit 1 and 2. An upgrade to the WGA system was required to support Unit 2 operation. The WGA alarm function was impaired due to the installation of a new automatic Programmable Logic Controller (PLC) sequencer and associated recorder as part of.a Unit 2 Startup upgrade.

Actions Taken to Restore Monitor(s)/Alarm Functions to Ooerable Condition Upon loss of the WGA alarm function, Chemistry performed surveillance instruction 0-Sl-77-3to collect grab samples from the in-service Waste Gas Decay Tank on a daily basis.

The new PLC was installed and the communications issue with the recorder resolved. The WGA was returned to service on November 24,2015, after successful completion of post modification testing (PMT). No loss of safety function occurred because the surveillance requirement provided adequate assurance that there was no potentialfor an explosive gas mixture to accumulate in the WDS.

Summary of Actions Taken to Prevent Recurrence The delay in restoring the alarm function was due to the need to perform troubleshooting on the design change that installed a new automatic PLC sequencer to the gas monitoring system. Severalwiring issues were identified, corrected, and then the system was restored to service.