05000327/LER-2003-001, Re Manual Reactor Trip as a Result of Main Generator Trip
| ML033010267 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 10/27/2003 |
| From: | Kulisek D Tennessee Valley Authority |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| LER 03-001-00 | |
| Download: ML033010267 (9) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(iv), System Actuation 10 CFR 50.73(a)(2)(v), Loss of Safety Function |
| 3272003001R00 - NRC Website | |
text
October 27, 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 1 -
DOCKET NO. 50-327 - FACILITY OPERATING LICENSE DPR LICENSEE EVENT REPORT (LER) 50-327/2003-001-00 The enclosed LER provides details concerning a manual reactor trip as a result of a main generator trip and loss of load.
The main generator trip occurred during performance of quarterly simulated oil trip tests on the main turbine. This event is being reported, in accordance with 10 CFR 50.73(a)(2)(iv), as an event that resulted in a manual actuation of the reactor protection system.
This letter is being sent in accordance with NRC RIS 2001-05.
Sincerely, Original signed by:
David A. Kulisek Plant Manager Enclosure cc: See page 2
U.S. Nuclear Regulatory Commission Page 2 October 27, 2003 cc (Enclosure):
Mr. Michael Marshall, Senior Project Manager U.S. Nuclear Regulatory Commission MS 0-8G9 One White Flint North 11555 Rockville Pike Rockville, Maryland 20852-2739 INPO Records Center Institute of Nuclear Power Operations 700 Galleria Parkway Atlanta, Georgia 30339-5957
Abstract
On August 28, 2003, at approximately 1603 Eastern daylight time, main control room (MCR) operators initiated a manual reactor trip as a result of a loss of load event. Preceding the manual reactor trip, plant personnel were performing quarterly simulated oil trip tests on the main turbine.
During performance of the thrust-bearing trip test section of the procedure, a main generator trip occurred resulting in a 100-percent loss of load to the unit. MCR operators diagnosed the plant condition, determined that a loss of load event had occurred, tripped the reactor, and took actions to stabilize and maintain the unit in hot shutdown, Mode 3. The turbine tripped as a result of the manual reactor trip. Based on information that the reactor had not tripped and the successful manual trip, MCR operators made an Alert emergency declaration (failure of reactor protection).
The immediate cause of the event was a closed instrument isolation valve to the Unit 1 turbine auto-stop oil pressure switch. The event analysis identified two likely causes: 1) failure to properly implement the valve verification process, or 2) failure to maintain a configuration control process.
Immediate actions were taken to verify valve positions identified in the extent of condition evaluation. Individuals involved with auto-stop oil pressure switch maintenance were counseled and disciplined. Site personnel were provided event lessons learned that reinforced configuration control requirements. A design change was implemented to add visual indication of auto-stop oil pressure switch actuation.
NRC FORM 366 (7-2001)
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Previous LERs on Similar Events:
A review of previous reportable events for the past three years did not identify any
similar events
C.
Additional Information
The event corrective action document contains actions to address:
operator understanding of main steam flow indication error below 25 percent flow conditions.
reinforcement of initiation of corrective action documentation for out of position components revision of the turbine oil test procedure to check that appropriate annunciators actuate during the testing activities.
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).
E.
Loss of Normal Heat Removal Consideration This event did not result in a loss of normal heat sink because main steam isolation and steam dump valves were available.
VIII.
COMMITMENTS
None.