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 |
| | |
+------------------------------------------------------------------------------+
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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Page Last Reviewed/Updated Thursday, March 25, 2021
Page Last Reviewed/Updated Thursday, March 25, 2021