ML083150622
| ML083150622 | |
| Person / Time | |
|---|---|
| Site: | Watts Bar  |
| Issue date: | 11/07/2008 |
| From: | Skaggs M Tennessee Valley Authority |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| Download: ML083150622 (4) | |
Text
November 7, 2008 10 CFR 50.4 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D. C. 20555 Gentlemen:
In the Matter of
)
Docket No. 50-390 Tennessee Valley Authority
)
WATTS BAR NUCLEAR PLANT (WBN) UNIT 1 - REPORT FOR INOPERABLE POST ACCIDENT MONITORING (PAM) INSTRUMENTATION In accordance with Technical Specification (TS) 5.9.8, PAMS Report, provided in is a report required by Condition B of TS Limiting Condition for Operation (LCO) 3.3.3, PAM Instrumentation. This report informs NRC that Steam Generator Blowdown Isolation Flow Control Valve (FCV), 1-FCV-1-14, has been inoperable for more than 30 days. The enclosed report outlines the reason the repair exceeded the 30 day allowed outage time, the preplanned alternate method of monitoring, the cause of the inoperability, and the plans and schedule for restoring the valve position indication.
Provided in Enclosure 2 is a listing of the regulatory commitments made in this submittal.
Should there be questions concerning this matter, please call Chris Riedl at (423) 365 1742.
Sincerely, Original signed by Greg Boerschig for M. D. Skaggs cc: See Page 2
U. S. Nuclear Regulatory Commission Page 2 November 7, 2008 Enclosure cc (Enclosure):
NRC Resident Inspector Watts Bar Nuclear Plant 1260 Nuclear Plant Road Spring City, Tennessee 37381 ATTN: John G. Lamb, Project Manager U.S. Nuclear Regulatory Commission Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation MS O-8 H4 Washington, DC 20555-0001 U.S. Nuclear Regulatory Commission Region II Sam Nunn Atlanta Federal Center 61 Forsyth St., SW, Suite 23T85 Atlanta, Georgia 30303 Watts Bar Nuclear Plant (WBN)
PAMS Report for Position Indication for Steam Generator Blowdown Isolation Flow Control Valve (FCV), 1-FCV-1-14 E1-1 Background Information and Cause of the Problem Encountered with 1-FCV-1-14:
1-FCV-1-14 is a containment isolation valve in the Steam Generator Blowdown (SGB) system.
Being a containment isolation valve, 1-FCV-1-14 has two primary functions:
- 1.
Isolate the steam generators from the SGB system when a Phase "A" containment isolation signal is initiated or when the Auxiliary Feedwater pumps start.
- 2.
Mitigate fission product leakage to the outside environment when a Phase "A" containment isolation signal is initiated.
The PAM function for the FCV is to ensure the valve is closed after an accident. This is accomplished through the position indication (open or closed position) for the FCV in the main control room. On September 24, 2008, the Operations staff identified that the indication for the FCV was not available when the valve was in the open position and Condition A of Technical Specification (TS) Limiting Condition for Operation (LCO) 3.3.3, PAM Instrumentation, was entered. It was confirmed that, once the valve was closed, the closed indication functioned properly. A Work Order (WO) was initiated to determine the problem with the open indication and Maintenance personnel found that the limit (reed) switch in the indication circuit required adjustment. The indication problem was also captured in TVAs Corrective Action Program as Problem Evaluation Report (PER) 153220.
Preplanned Alternate Monitoring Method:
As stated above, the PAM function for the FCV is to ensure the valve is closed after an accident and this indication was confirmed to be functioning properly. Based on this, no means of alternate monitoring was considered necessary.
Restoration Plan and Additional Information:
The required adjustment to the FCVs limit switch was completed on October 2, 2008, and the open position indication was confirmed to be working. However, the work on the FCV required the removal of a cover on the valve that was held in place by several bolts screwed into a collar on the valve. During the removal of the bolts, four bolts either broke or the threads on the bolt stripped. This resulted in the need to replace the valve collar. A requisition to purchase the replacement collar was initiated and the component was received. However, during the installation of the replacement collar, it was identified that the spacing of the bolt pattern was incorrect and due to this, the collar would not mate properly with the cover. This issue has been discussed with the vendor and a requisition for the correct replacement collar is being initiated.
Based on the anticipated delivery date for the collar, TVA plans to complete the repairs to the valve by December 19, 2008. The issues associated with the broken bolts were captured in TVAs Corrective Action Program as PER 154178.
Watts Bar Nuclear Plant (WBN)
List of Regulatory Commitments E2-1
- 1.
Based on the anticipated delivery date for the collar, TVA plans to complete the repairs to the valve by December 19, 2008.