05000498/LER-2002-001, Re Control Room Envelope Ventilation System Failed to Maintain a Positive Pressure in the Control Room
| ML021220350 | |
| Person / Time | |
|---|---|
| Site: | South Texas  |
| Issue date: | 04/25/2002 |
| From: | Halpin E South Texas |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| NOC-AE-02001310 LER-02-001-00 | |
| Download: ML021220350 (7) | |
| Event date: | |
|---|---|
| Report date: | |
| 4982002001R00 - NRC Website | |
text
Le~ I-XFAfR Nuclear Operating Company South TexPs Pro/eS Elecri.c Generting Station PO Sox 28,9 Wadsworth Texas 77483 April 25, 2002 NOC-AE-02001310 File No.: G25 10CFR50.73 STI: 31437910 U. S. Nuclear Regulatory Commission Attention: Document Control Desk One White Flint North 11555 Rockville Pike Rockville, MD 20852 South Texas Project Unit 1 Docket No. STN 50-498 Licensee Event Report 02-001 Control Room Envelope Ventilation System Failed to Maintain a Positive Pressure in the Control Room Pursuant to 10CFR50.73, South Texas Project submits the attached Unit 1 Licensee Event Report 02-001 regarding the discovery that the control room envelope ventilation system was unable to maintain a positive pressure in the control room relative to adjacent areas. Failure of a fire damper in the control room ventilation system resulted in all trains of control room envelope ventilation being unable to maintain the required positive pressure of Technical Specification surveillance requirement 4.7.7.e.3 for a period of about thirty-four hours.
This event did not have an adverse effect on the health and safety of the public.
The only commitments in this report are contained in the Corrective Action section of the attachment.
If there are any questions on this submittal, please contact W. R. Bealefield, Jr. at (361) 972-7696 or me at (361) 972-7849.
64.4 E. D. Halpin Plant General Manager Attachment: LER 02-001 (South Texas, Unit 1) cv"
/V
NOC-AE-02001310 Page 2 of 2 cc:
(paper copy)
(electronic copy)
Ellis W. Merschoff Regional Administrator, Region IV U.S. Nuclear Regulatory Commission 611 Ryan Plaza Drive, Suite 400 Arlington, Texas 76011-8064 U. S. Nuclear Regulatory Commission Attention: Document Control Desk One White Flint North 11555 Rockville Pike Rockville, MD 20852 Richard A. Ratliff Bureau of Radiation Control Texas Department of Health 1100 West 49th Street Austin, TX 78756-3189 Cornelius F. O'Keefe U. S. Nuclear Regulatory Commission P. O. Box 289, Mail Code: MN116 Wadsworth, TX 77483 A. H. Gutterman, Esquire Morgan, Lewis & Bockius LLP M. T. HardtlW. C. Gunst City Public Service Mohan C. Thadani U. S. Nuclear Regulatory Commission R. L. Balcom/D. G. Tees Reliant Energy, Inc.
A. Ramirez City of Austin C. A. Johnson/A. C. Bakken III AEP - Central Power and Light Company Jon C. Wood Matthews & Branscomb C. M. Canady City of Austin Electric Utility Department 721 Barton Springs Road Austin, TX 78704
Abstract
On February 26, 2002 Unit 1 was operating in Mode 1 at 100% power. Unit 1 was in a "B" train extended allowed outage (EAOT) maintenance state. Instrument & Control maintenance personnel were performing a preventive maintenance task to replace backup power supply batteries in two plant fire detection panels for the Electrical Auxiliary Building (EAB). During the maintenance, at approximately 1030, a return air fire damper failed closed. This condition changed the air balance relationship between the EAB and the Control Room Envelope (CRE) ventilation systems. The CRE ventilation subsystem was unable to maintain the required positive differential pressure of at least 0.125 inches water gauge. Plant Operations personnel became aware of the change in differential pressure and initiated troubleshooting efforts to determine the cause. At approximately 1405 on February 26, engineering personnel informed the control room that the fire damper was tripped closed. Operations personnel did not believe that CRE ventilation system operability was affected. On February 27 a differential pressure test was performed on the CRE which identified the inability to meet the positive differential pressure of Technical Specification (TS)
Surveillance requirements 4.7.7.e.3. The Shift Supervisor declared all three trains of CRE ventilation inoperable at 1035 and entered TS action 3.7.7.c. Following repairs to the fire damper, Control Room ventilation systems were declared operable at 2045 on February 27, 2002.
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 NRC Form 366A) (17)
ADDITIONAL INFORMATION
The failed relay was a model MR201/T manufactured by AIR Products and Controls.
A review of the South Texas Project Corrective Action Program database did not identify any other fire damper failures caused by energizing the ETLs or any other inadvertent actuation of fire dampers during the past 3 years.