05000328/LER-2003-003, Re Excessive Leakage of Containment Purge System Containment Isolation Valve
| ML031150516 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 04/23/2003 |
| From: | Purcell R Tennessee Valley Authority |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| LER 03-003-00 | |
| Download: ML031150516 (7) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications 10 CFR 50.73(a)(2)(v), Loss of Safety Function |
| 3282003003R00 - NRC Website | |
text
April 23, 2003 U.S. Nuclear Regulatory Commission 10 CFR 50.73 ATTN: Document Control Desk Washington, D.C. 20555 Gentlemen:
TENNESSEE VALLEY AUTHORITY - SEQUOYAH NUCLEAR PLANT UNIT 2 -
DOCKET NO. 50-328 - FACILITY OPERATING LICENSE DPR LICENSEE EVENT REPORT (LER) 50-328/2003-003-00 The enclosed report provides details concerning excessive leakage of a containment purge system containment isolation valve. This event is being reported, in accordance with 10 CFR 50.73(a)(2)(i)(B), as any operation or condition which was prohibited by Technical Specification.
This letter is being sent in accordance with NRC RIS 2001-05.
Sincerely, Original signed by Richard T. Purcell Enclosure cc (Enclosure):
INPO Records Center Institute of Nuclear Power Operations 700 Galleria Parkway Atlanta, Georgia 30339-5957 Mr. Michael L. Marshall Jr., Senior Project Manager U.S. Nuclear Regulatory Commission MS-0-8G9A One White Flint North 11555 Rockville Pike Rockville, Maryland 20852-2739
Abstract
On February 28, 2003, at 1851 Eastern standard time (EST), Technical Specification (TS) Limiting Condition for Operation (LCO) 3.6.1.9, Action b, was exceeded because of excessive leakage through a containment purge exhaust containment isolation valve and the inability to repair the valve within the TS allowed outage time (AOT) of 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. On February 27, 2003, during performance of a surveillance instruction it was determined that containment penetration X-6 leakage was above TS acceptance criteria of.05La. Penetration X-6 contains two 24-inch air-operated butterfly valves. Before expiration of the TS AOT, NRC staff enforcement discretion was obtained for an additional 144 hours0.00167 days <br />0.04 hours <br />2.380952e-4 weeks <br />5.4792e-5 months <br /> to identify the source of leakage, repair or replace the components, and perform verification testing. Troubleshooting found the inboard containment isolation valve had failed to fully close resulting in leakage through the valve seat. The valve failed to fully close because the actuator yoke key sheared as a result of inadequate key engagement.
The valve is air operated with the operator mounted below the valve centerline. The key was replaced, the valve was tested and found acceptable, and the system was returned to service.
Review of historical documents determined that inadequate actuator key engagement occurred either during plant construction or during valve assembly by the manufacturer. Similar valves will be inspected for adequate key engagement.
NRC FORM 366 (7-2001)
(If more space is required, use additional copies of (If more space is required, use additional copies of (If more space is required, use additional copies of (If more space is required, use additional copies of (If more space is required, use additional copies of NRC Form 366A) (17) D.
Safety System Functional Failure:
This event did not result in a safety system functional failure in accordance with 10 CFR 50.73(a)(2)(v).
VIII.
COMMITMENTS
None.