LaSalle - both diesel generators inoperable for 29 minutes

LASALLE - 04/24/2003

ACCIDENT MITIGATION

"This report is being made pursuant to 10CFR50.72(b)(3)(v)(D), Event or Condition that could have prevented fulfillment of a Safety Function needed to Mitigate the Consequences of an Accident. On 04/23/03, at 18:15 CDST, the 1A Diesel Generator was made inoperable for a scheduled surveillance. Concurrent with this inoperability, the 0 Diesel Generator received a spurious CO2 actuation signal. This spurious CO2 partial logic actuation did not result in an actual CO2 injection into the 0 Diesel Generator Room. The CO2 system partial actuation however resulted in several ventilation dampers failing closed as designed. With these dampers closed, the ventilation support system for the 0 Diesel Generator became inoperable, the 0 Diesel Generator was declared inoperable at 1923 hours 04/23/03. This condition resulted in both the 1A and 0 Diesel Generators concurrently being inoperable. Actions were taken to terminate the 1A Diesel surveillance and restore the 1A Diesel Generator to an operable status. This was accomplished at 1952 hours 04/23/03. The 1A and 0 Diesel Generators were simultaneously inoperable for 29 minutes. Due to the concurrent Diesel Generator inoperabilities which affect redundant trains required to mitigate the consequences of an accident, it has been determined that this event is reportable as an 8 hour ENS notification.

"Corrective actions have been initiated to address the 0 Diesel Generator CO2 system and restore the ventilation dampers to an operable status. The spurious actuation of the 0 Diesel Generator CO2 system was determined to be due to a Non-Licensed Operator opening the fire detection panel for inspection."

The licensee notified the NRC Resident Inspector.

+------------------------------------------------------------------------------+
|Power Reactor                                    |Event Number:   39789       |
+------------------------------------------------------------------------------+
+------------------------------------------------------------------------------+
| FACILITY: LASALLE                  REGION:  3  |NOTIFICATION DATE: 04/24/2003|
|    UNIT:  [1] [] []                 STATE:  IL |NOTIFICATION TIME: 01:25[EDT]|
|   RXTYPE: [1] GE-5,[2] GE-5                    |EVENT DATE:        04/23/2003|
+------------------------------------------------+EVENT TIME:        19:23[CDT]|
| NRC NOTIFIED BY:  MARK OKOPNY                  |LAST UPDATE DATE:  04/24/2003|
|  HQ OPS OFFICER:  ERIC THOMAS                  +-----------------------------+
+------------------------------------------------+PERSON          ORGANIZATION |
|EMERGENCY CLASS:          NON EMERGENCY         |MONTE PHILLIPS       R3      |
|10 CFR SECTION:                                 |                             |
|AIND 50.72(b)(3)(v)(D)   ACCIDENT MITIGATION    |                             |
|                                                |                             |
|                                                |                             |
|                                                |                             |
+-----+----------+-------+--------+-----------------+--------+-----------------+
|UNIT |SCRAM CODE|RX CRIT|INIT PWR|   INIT RX MODE  |CURR PWR|  CURR RX MODE   |
+-----+----------+-------+--------+-----------------+--------+-----------------+
|1     N          Y       67       Power Operation  |67       Power Operation  |
|                                                   |                          |
|                                                   |                          |
+------------------------------------------------------------------------------+