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Event Notification Report for October 17, 2000

                    U.S. Nuclear Regulatory Commission
                              Operations Center

                              Event Reports For
                           10/16/2000 - 10/17/2000

                              ** EVENT NUMBERS **

37432  

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|Power Reactor                                    |Event Number:   37432       |
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| FACILITY: CLINTON                  REGION:  3  |NOTIFICATION DATE: 10/16/2000|
|    UNIT:  [1] [] []                 STATE:  IL |NOTIFICATION TIME: 12:43[EDT]|
|   RXTYPE: [1] GE-6                             |EVENT DATE:        10/16/2000|
+------------------------------------------------+EVENT TIME:        09:21[CDT]|
| NRC NOTIFIED BY:  JIM SCHOTTEL                 |LAST UPDATE DATE:  10/16/2000|
|  HQ OPS OFFICER:  STEVE SANDIN                 +-----------------------------+
+------------------------------------------------+PERSON          ORGANIZATION |
|EMERGENCY CLASS:          N/A                   |ROGER LANKSBURY      R3      |
|10 CFR SECTION:                                 |                             |
|ARPS 50.72(b)(2)(ii)     RPS ACTUATION          |                             |
|                                                |                             |
|                                                |                             |
|                                                |                             |
+-----+----------+-------+--------+-----------------+--------+-----------------+
|UNIT |SCRAM CODE|RX CRIT|INIT PWR|   INIT RX MODE  |CURR PWR|  CURR RX MODE   |
+-----+----------+-------+--------+-----------------+--------+-----------------+
|1     M          N       0        Refueling        |0        Refueling        |
|                                                   |                          |
|                                                   |                          |
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                                   EVENT TEXT                                   
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| MANUAL SCRAM INSERTED PRIOR TO REACHING AUTOMATIC SCRAM SETPOINT FOLLOWING   |
| REPLACEMENT OF ATWS POWER SUPPLIES                                           |
|                                                                              |
| "Clinton Power Station is currently in day 3 of refueling outage RF-7.  At   |
| 09:20 I&C Technicians were performing PMs (PCIMSA017 and PCIMSA019) which    |
| replaced power supplies in the Anticipated Transient Without Scram system    |
| (ATWS).  During reenergization of the ATWS system, the ARI (Alternate Rod    |
| Insertion) initiation alarm occurred. The 'A' RO observed Scram Discharge    |
| Volume Vents and Drains closing and a rising level in the Scram Discharge    |
| Volume (SDV).  At 09:21 a manual scram was inserted at approximately 11      |
| gallons SDV level prior to reaching the automatic scram setpoint of 19.6     |
| gallons Scram Discharge Volume level.                                        |
|                                                                              |
| "Prior to this event Reactor Water Level was at 195 inches. The extra input  |
| of water into the reactor due to this scram caused a level rise to 200       |
| inches. The Reactor Operators raised Reactor Water Cleanup letdown rate from |
| the RPV to bring level back to the preferred range of 190 - 200 inches.      |
|                                                                              |
| "Investigation has revealed that reenergizing the ATWS instrumentation       |
| causes actuation of the ATWS trip system."                                   |
|                                                                              |
| There was no rod motion since all rods were fully inserted prior to the      |
| event.  The licensee informed the NRC resident inspector.                    |
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