PNO-IV-02-077, A - Union Electric Co., Update - Automatic Reactor Trip While Reducing Power Due to Condensate Pump Failure
| ML023540144 | |
| Person / Time | |
|---|---|
| Site: | Callaway  |
| Issue date: | 12/19/2002 |
| From: | Graves D, Peck M NRC Region 4 |
| To: | |
| References | |
| PNO-IV-02-077A | |
| Download: ML023540144 (1) | |
December 19, 2002 PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE -- PNO-IV-02-077A This preliminary notification constitutes EARLY notice of events of POSSIBLE safety or public interest significance. The information is as initially received without verification or evaluation, and is basically all that is known by the Region IV staff on this date.
Facility Licensee Emergency Classification Union Electric Company Notification of Unusual Event Callaway Plant Unit 1 Alert Docket: 50-483 Site Area Emergency License: NPF-30 General Emergency X Not Applicable
SUBJECT:
UPDATE - AUTOMATIC REACTOR TRIP WHILE REDUCING POWER DUE TO A CONDENSATE PUMP FAILURE On December 14, 2002, at 4:20 a.m. (CST), a reactor trip occurred during a reactor downpower following a condensate pump lubricating oil leak. Following the trip, the control room operators restored steam generator water levels using the auxiliary feedwater system. The operators secured the turbine-driven auxiliary feedwater pump and continued to supply water to the steam generators using the motor-driven auxiliary feedwater pumps. The control room operators inadvertently allowed steam generator water levels to reach the low water level setpoint which generated another auxiliary feedwater actuation signal. However, the turbine-driven auxiliary feedwater pump tripped on overspeed during the pump start and was declared inoperable at 5:01 a.m. on December 15.
The NRC verbally granted enforcement discretion on December 16, 2002, to allow up to 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> to complete testing of the turbine-driven auxiliary feedwater pump in Mode 3 following repair.
The auxiliary feedwater pump tripped on overspeed as a result of binding of the governor valve stem due to component misalignment and inadequate stem clearance. On December 17, repairs and testing of the auxiliary feedwater pump were completed, and at 8:14 a.m., the turbine-driven auxiliary feedwater pump was declared operable without exceeding the completion time limits of the Technical Specifications. The reactor was taken critical at 2:17 p.m. on December 17, and was at approximately 88 percent power at 2:00 p.m. on December 19 awaiting completion of repairs to the condensate pump lubricating oil system.
Region IV has informed the EDO, NRR, and PA. The state of Missouri has been informed.
This information has been discussed with the licensee and is current as of 3:00 p.m. (CST) on December 19, 2002.
CONTACTS: David Graves, 817-860-8141 Michael Peck, 573-676-3183