Event Notification Report for July 15, 2002
U.S. Nuclear Regulatory Commission
Operations Center
Event Reports For
07/12/2002 - 07/15/2002
** EVENT NUMBERS **
39056 39057 39058
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|Power Reactor |Event Number: 39056 |
+------------------------------------------------------------------------------+
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| FACILITY: SEQUOYAH REGION: 2 |NOTIFICATION DATE: 07/13/2002|
| UNIT: [] [2] [] STATE: TN |NOTIFICATION TIME: 01:45[EDT]|
| RXTYPE: [1] W-4-LP,[2] W-4-LP |EVENT DATE: 07/12/2002|
+------------------------------------------------+EVENT TIME: 22:23[EDT]|
| NRC NOTIFIED BY: TOM RYAN |LAST UPDATE DATE: 07/13/2002|
| HQ OPS OFFICER: FANGIE JONES +-----------------------------+
+------------------------------------------------+PERSON ORGANIZATION |
|EMERGENCY CLASS: NON EMERGENCY |ANNE BOLAND R2 |
|10 CFR SECTION: | |
|ARPS 50.72(b)(2)(iv)(B) RPS ACTUATION - CRITICA| |
|AESF 50.72(b)(3)(iv)(A) VALID SPECIF SYS ACTUAT| |
| | |
| | |
+-----+----------+-------+--------+-----------------+--------+-----------------+
|UNIT |SCRAM CODE|RX CRIT|INIT PWR| INIT RX MODE |CURR PWR| CURR RX MODE
|
+-----+----------+-------+--------+-----------------+--------+-----------------+
| | |
|2 A/R Y 100 Power Operation |0 Hot Standby |
| | |
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EVENT TEXT
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| REACTOR TRIP ON UNDERVOLTAGE ON REACTOR COOLANT PUMP BUSSES
|
| |
| "At approximately 2223 on 07/12/2002, Sequoyah Unit 2 (SQN-2) received an |
| Automatic Reactor Trip on Reactor Coolant Pump Busses undervoltage. The |
| cause of the undervoltage was due to the loss of the Unit 2, 2B and 2D unit |
| boards as a result of a loss of the 2B Start Bus. The 2B and 2D Unit Boards |
| are the 6.9 kV electrical feeds to the 2-2 and 2-4 RCPS, respectively. Plant |
| response as a result of the loss of the Unit Boards was as expected, |
| including the emergency start of all emergency diesel generators and the |
| 2A-A Shutdown board being fed from Its emergency diesel generator. |
| |
| "Plant personnel were in the process of returning the 'B' Common Station |
| Service Transformer (B-CSST) to service at the time of the event. The plant |
| is currently being maintained in Mode 3 at NOT/NOP, 547 degrees F/ 2235 psig |
| respectively, by use of the plant's auxiliary feedwater system and steam |
| dump system. |
| |
| "The cause of the trip of the 25 start bus is unknown at this time and |
| investigation is on going. The Unit 2 Loop 4 atmospheric relief valve |
| (2-PCV-1-30) which opened on the Reactor Trip and did not reclose. Manual |
| operator action was taken to close the affected valve." |
| |
| The licensee notified the NRC Resident Inspector. |
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|Power Reactor |Event Number: 39057 |
+------------------------------------------------------------------------------+
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| FACILITY: HARRIS REGION: 2 |NOTIFICATION DATE: 07/13/2002|
| UNIT: [1] [] [] STATE: NC |NOTIFICATION TIME: 02:57[EDT]|
| RXTYPE: [1] W-3-LP |EVENT DATE: 07/13/2002|
+------------------------------------------------+EVENT TIME: 01:10[EDT]|
| NRC NOTIFIED BY: FRANK JACKSON |LAST UPDATE DATE: 07/13/2002|
| HQ OPS OFFICER: FANGIE JONES +-----------------------------+
+------------------------------------------------+PERSON ORGANIZATION |
|EMERGENCY CLASS: NON EMERGENCY |ANNE BOLAND R2 |
|10 CFR SECTION: | |
|ARPS 50.72(b)(2)(iv)(B) RPS ACTUATION - CRITICA| |
|AESF 50.72(b)(3)(iv)(A) VALID SPECIF SYS ACTUAT| |
| | |
| | |
+-----+----------+-------+--------+-----------------+--------+-----------------+
|UNIT |SCRAM CODE|RX CRIT|INIT PWR| INIT RX MODE |CURR PWR| CURR RX MODE
|
+-----+----------+-------+--------+-----------------+--------+-----------------+
|1 M/R Y 100 Power Operation |0 Hot Standby |
| | |
| | |
+------------------------------------------------------------------------------+
EVENT TEXT
+------------------------------------------------------------------------------+
| MANUAL REACTOR TRIP DUE TO DEH MALFUNCTION |
| |
| "Manual Rx trip due to DEH malfunction during initiation of downpower for |
| scheduled valve testing. Automatic AFW actuation due to low S/G level |
| following trip. 'C' S/G PORV remained open below lift setpoint. Valve shut |
| manually from MCB." |
| |
| The licensee further noted that only the motor driven AFW pump started on a |
| single low level signal as expected. The plant is stable in Mode 3, with |
| normal feedwater and steam dumps to the condenser. An investigation will be |
| completed prior to plant startup. |
| |
| The licensee notified the NRC Resident Inspector. |
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+------------------------------------------------------------------------------+
|Power Reactor |Event Number: 39058 |
+------------------------------------------------------------------------------+
+------------------------------------------------------------------------------+
| FACILITY: WATTS BAR REGION: 2 |NOTIFICATION DATE: 07/13/2002|
| UNIT: [1] [] [] STATE: TN |NOTIFICATION TIME: 18:42[EDT]|
| RXTYPE: [1] W-4-LP,[2] W-4-LP |EVENT DATE: 07/13/2002|
+------------------------------------------------+EVENT TIME: 16:22[EDT]|
| NRC NOTIFIED BY: JOHN RODEN |LAST UPDATE DATE: 07/13/2002|
| HQ OPS OFFICER: LEIGH TROCINE +-----------------------------+
+------------------------------------------------+PERSON ORGANIZATION |
|EMERGENCY CLASS: NON EMERGENCY |ANNE BOLAND R2 |
|10 CFR SECTION: | |
|ARPS 50.72(b)(2)(iv)(B) RPS ACTUATION - CRITICA| |
|AESF 50.72(b)(3)(iv)(A) VALID SPECIF SYS ACTUAT| |
| | |
| | |
+-----+----------+-------+--------+-----------------+--------+-----------------+
|UNIT |SCRAM CODE|RX CRIT|INIT PWR| INIT RX MODE |CURR PWR| CURR RX MODE
|
+-----+----------+-------+--------+-----------------+--------+-----------------+
|1 A/R Y 100 Power Operation |0 Hot Standby |
| | |
| | |
+------------------------------------------------------------------------------+
EVENT TEXT
+------------------------------------------------------------------------------+
| AUTOMATIC TURBINE TRIP/REACTOR TRIP DUE TO ACTUATION OF A MAIN
TRANSFORMER |
| DIFFERENTIAL ELECTRICAL RELAY |
| |
| The following text is a portion of a facsimile received from the licensee: |
| |
| "At 1622 on July 13, 2002, the Unit 1 reactor tripped due to an automatic |
| signal. All plant safety systems were in service at the time of the trip, |
| and all systems responded as designed. All control rods inserted as |
| required, and the Auxiliary Feedwater (AFW) System initiated as expected." |
| |
| "The reactor trip resulted from a turbine trip signal that was generated as |
| a result of a main transformer differential electrical relay actuation. The |
| cause of the differential relay actuation is under investigation at this |
| time." |
| |
| "The plant is currently stable in Mode 3 and will remain in this mode until |
| completion of the investigation." |
| |
| The licensee stated that there were no related maintenance or surveillance |
| activities ongoing at the time of the event but that there were heavy rains |
| in the area earlier in the day. The licensee also stated that normal |
| charging and makeup, pressurizer heaters and sprays, and the reactor coolant |
| pumps are currently being utilized for primary system inventory, pressure |
| and transport control. Secondary system steam is being dumped to the |
| condenser, and the main feedwater pumps are supplying water to the steam |
| generators. The auxiliary feedwater system has been secured, and |
| containment parameters are normal. |
| |
| The licensee notified the NRC resident inspector. |
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Page Last Reviewed/Updated Thursday, March 25, 2021
Page Last Reviewed/Updated Thursday, March 25, 2021