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Event Notification Report for November 16, 1999

                    U.S. Nuclear Regulatory Commission
                              Operations Center

                              Event Reports For
                           11/15/1999 - 11/16/1999

                              ** EVENT NUMBERS **

36438  36439  

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|Power Reactor                                    |Event Number:   36438       |
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| FACILITY: GRAND GULF               REGION:  4  |NOTIFICATION DATE: 11/15/1999|
|    UNIT:  [1] [] []                 STATE:  MS |NOTIFICATION TIME: 11:32[EST]|
|   RXTYPE: [1] GE-6                             |EVENT DATE:        11/15/1999|
+------------------------------------------------+EVENT TIME:        07:30[CST]|
| NRC NOTIFIED BY:  MARTY MCADORY                |LAST UPDATE DATE:  11/15/1999|
|  HQ OPS OFFICER:  FANGIE JONES                 +-----------------------------+
+------------------------------------------------+PERSON          ORGANIZATION |
|EMERGENCY CLASS:          N/A                   |BILL JONES           R4      |
|10 CFR SECTION:                                 |                             |
|AIND 50.72(b)(2)(iii)(D) ACCIDENT MITIGATION    |                             |
|                                                |                             |
|                                                |                             |
|                                                |                             |
+-----+----------+-------+--------+-----------------+--------+-----------------+
|UNIT |SCRAM CODE|RX CRIT|INIT PWR|   INIT RX MODE  |CURR PWR|  CURR RX MODE   |
+-----+----------+-------+--------+-----------------+--------+-----------------+
|1     N          N       0        Cold Shutdown    |0        Cold Shutdown    |
|                                                   |                          |
|                                                   |                          |
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                                   EVENT TEXT                                   
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| DIVISION 1 AND 2 DIESEL GENERATORS DECLARED INOPERABLE                       |
|                                                                              |
| Approximately 20 hours after restoring the Division 1 Diesel Generator (DG)  |
| to service and removing the Division 2 DG from service for outage work, the  |
| Division 1 Load Shedding and Sequencing (LSS) failed.  This resulted in the  |
| Division 1 DG being declared inoperable because of its inability to meet the |
| required surveillance tests.  The Division 1 DG is capable of operating and  |
| supplying the ESF Bus manually.                                              |
|                                                                              |
| The Division 2 DG has test equipment installed to allow ECCS testing.  The   |
| Division 2 DG is considered functional but not operable with the test        |
| equipment installed.  The licensee is reviewing Division 2 equipment status  |
| to determine if Division 2 was fully operable, and if so, this notification  |
| will be retracted.                                                           |
|                                                                              |
| The licensee intends to notify the NRC Resident Inspector.                   |
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|Power Reactor                                    |Event Number:   36439       |
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| FACILITY: DIABLO CANYON            REGION:  4  |NOTIFICATION DATE: 11/15/1999|
|    UNIT:  [1] [2] []                STATE:  CA |NOTIFICATION TIME: 14:20[EST]|
|   RXTYPE: [1] W-4-LP,[2] W-4-LP                |EVENT DATE:        11/15/1999|
+------------------------------------------------+EVENT TIME:        10:50[PST]|
| NRC NOTIFIED BY:  MURRELL EVANS                |LAST UPDATE DATE:  11/15/1999|
|  HQ OPS OFFICER:  STEVE SANDIN                 +-----------------------------+
+------------------------------------------------+PERSON          ORGANIZATION |
|EMERGENCY CLASS:          N/A                   |BILL JONES           R4      |
|10 CFR SECTION:                                 |LEDYARD (TAD) MARSH  NRR     |
|AOUT 50.72(b)(1)(ii)(B)  OUTSIDE DESIGN BASIS   |                             |
|                                                |                             |
|                                                |                             |
|                                                |                             |
+-----+----------+-------+--------+-----------------+--------+-----------------+
|UNIT |SCRAM CODE|RX CRIT|INIT PWR|   INIT RX MODE  |CURR PWR|  CURR RX MODE   |
+-----+----------+-------+--------+-----------------+--------+-----------------+
|1     N          Y       100      Power Operation  |100      Power Operation  |
|2     N          Y       100      Power Operation  |100      Power Operation  |
|                                                   |                          |
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                                   EVENT TEXT                                   
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| LICENSEE IDENTIFIED CONDITION INVOLVING POTENTIAL COMMON MODE FAILURE OF     |
| SEISMICALLY QUALIFIED COMPONENTS                                             |
|                                                                              |
| "In accordance with 10CFR50.72(b)(1)(ii)(B), PG&E is making a 1-hour         |
| non-emergency report of a condition that was outside the design basis for    |
| Units 1 and 2.  PG&E has concluded that, due to a common mode failure        |
| mechanism, multiple degraded indicating lamp sockets in the control room     |
| boards could have caused redundant safety-related equipment to become        |
| inoperable during a postulated seismic event.  The sockets are Westinghouse  |
| EZC Minalite part number 449D187GXX.                                         |
|                                                                              |
| "In September 1999, PG&E identified an adverse trend in the number of broken |
| lamp sockets in the main control board.  An investigation was initiated      |
| where numerous sockets were found broken, in some cases the lamps remained   |
| lit even though the socket was degraded.  The concern with the socket        |
| failures is that the socket can separate during a seismic event and create a |
| short circuit.  This could result in loss of indication and potentially a    |
| loss of control function for the associated component.                       |
|                                                                              |
| "PG&E has identified the cause of socket failures to be tensile stress       |
| placed on the socket during assembly which exceeds the plastic material      |
| yield strength.  The sockets crack and fail over time due to creep.          |
|                                                                              |
| "Sockets which have not been replaced, but may be degraded, have undergone   |
| an inspection and are considered operable."                                  |
|                                                                              |
| The total population of EZC Minalite sockets installed is approximately      |
| 1,300.  Of this number 2-3% have been replaced and <1% remain to be          |
| inspected.  This problem was identified in September 1999.                   |
|                                                                              |
| The licensee plans to inform the NRC resident inspector.                     |
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