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Event Notification Report for June 5, 2003




                    U.S. Nuclear Regulatory Commission

                              Operations Center



                              Event Reports For

                           06/04/2003 - 06/05/2003



                              ** EVENT NUMBERS **



39903  



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|Power Reactor                                    |Event Number:   39903       |

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| FACILITY: OCONEE                   REGION:  2  |NOTIFICATION DATE: 06/04/2003|

|    UNIT:  [1] [2] [3]               STATE:  SC |NOTIFICATION TIME: 19:03[EDT]|

|   RXTYPE: [1] B&W-L-LP,[2] B&W-L-LP,[3] B&W-L-L|EVENT DATE:        06/04/2003|

+------------------------------------------------+EVENT TIME:        11:15[EDT]|

| NRC NOTIFIED BY:  RANDY TODD                   |LAST UPDATE DATE:  06/04/2003|

|  HQ OPS OFFICER:  JOHN MacKINNON               +-----------------------------+

+------------------------------------------------+PERSON          ORGANIZATION |

|EMERGENCY CLASS:          NON EMERGENCY         |KERRY LANDIS         R2      |

|10 CFR SECTION:                                 |                             |

|AUNA 50.72(b)(3)(ii)(B)  UNANALYZED CONDITION   |                             |

|                                                |                             |

|                                                |                             |

|                                                |                             |

+-----+----------+-------+--------+-----------------+--------+-----------------+

|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  |

|3     N          N       0        Cold Shutdown    |0        Cold Shutdown    |

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                                   EVENT TEXT                                   

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| APPENDIX R  ISSUE                                                            |

|                                                                              |

| During an Appendix R design basis review, an Engineer noted that cables      |

| associated with normal operation of components used for one train (Primary   |

| Isolation valves) of Appendix R mitigation were routed through an adjacent   |

| fire zone associated with the other train of Appendix R mitigation.  During  |

| an Appendix R event, control of the affected components is transferred to    |

| the Standby Shutdown Facility, which electrically isolates the subject       |

| cables.                                                                      |

|                                                                              |

| However, the area containing the subject cables does not have fire detection |

| equipment.  The Engineer noted that if a fire occurred and damaged the       |

| cables, it would be theoretically possible for a "smart short" to result in  |

| damage to equipment before action could be taken to transfer control to the  |

| Standby Shutdown Facility.                                                   |

|                                                                              |

|                                                                              |

| Initial Safety Significance:                                                 |

|                                                                              |

| This condition is similar to an example given in NUREG 1022, Section 3.2.4   |

| (fire barrier missing such that the required degree of separation for        |

| redundant safe shutdown trains is lacking).                                  |

|                                                                              |

| In order to result in a loss of safety function, the postulated fire would   |

| have to damage the cable, result in a smart spurious actuation of a          |

| component, damage that component such that it became inoperable (such as by  |

| burning out the motor of a valve), then also spread within the fire zone to  |

| damage the redundant component (for example by burning the power cable or    |

| motor control center).                                                       |

|                                                                              |

| The Oconee license basis is no spurious circuit operations for 10 minutes.   |

| Cable testing sponsored by the NRC, NEI, and EPRI for fire exposure has      |

| demonstrated that armored type cable construction used in this application   |

| is more rugged than other designs and that internal cable failure times      |

| usually extend beyond 30 minutes.                                            |

|                                                                              |

| The area containing the cables is a high traffic area for both personnel and |

| material - including low quantities of transient combustibles, but has no    |

| appreciable fixed fire loads.  Thus the probability of a fire of sufficient  |

| energy to damage the cable is low.  Pending a PRA analysis, it appears       |

| reasonable to credit prompt discovery of a fire and initiation of action to  |

| suppress the fire and/or transfer of control to the Standby Shutdown         |

| Facility prior to cable damage.  Therefore the overall risk impact of this   |

| event is currently considered low.                                           |

|                                                                              |

|                                                                              |

| Corrective Action:                                                           |

|                                                                              |

| The SSF has been declared inoperable pending establishment of a fire watch.  |

|                                                                              |

| The NRC Resident Inspector will be informed of this event by the licensee.   |

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