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Event Notification Report for April 15, 2011

U.S. Nuclear Regulatory Commission
Operations Center

Event Reports For
04/14/2011 - 04/15/2011

** EVENT NUMBERS **


46748 46755 46756

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!!!!! THIS EVENT HAS BEEN RETRACTED. THIS EVENT HAS BEEN RETRACTED !!!!!
Power Reactor Event Number: 46748
Facility: COMANCHE PEAK
Region: 4 State: TX
Unit: [ ] [2] [ ]
RX Type: [1] W-4-LP,[2] W-4-LP
NRC Notified By: ED LESSMANN
HQ OPS Officer: BILL HUFFMAN
Notification Date: 04/13/2011
Notification Time: 01:57 [ET]
Event Date: 04/12/2011
Event Time: 22:15 [CDT]
Last Update Date: 04/14/2011
Emergency Class: NON EMERGENCY
10 CFR Section:
50.72(b)(3)(iv)(A) - VALID SPECIF SYS ACTUATION
Person (Organization):
GEOFFREY MILLER (R4DO)

Unit SCRAM Code RX CRIT Initial PWR Initial RX Mode Current PWR Current RX Mode
2 N N 0 Refueling 0 Refueling

Event Text

ESF ACTUATION FOLLOWING LOSS OF A SAFEGUARD BUS DURING EDG TESTING

The following event occurred with the unit in a "No Mode" defueled condition.

"On the 12th of April at 2215 CDT Comanche Peak Nuclear Power Plant Unit 2 had a Train B ESF Actuation (Black Out) reportable per 10CFR50.72(b)(3)(iv) for [the 6.9KV Train B] Emergency AC Electrical power systems including Emergency Diesel Generator (EDG).

"At the time of the event, Unit 2 was in 'No Mode' - the core was off loaded and post maintenance testing was being performed on the 2-02 Emergency Diesel Generator. The scope of the EDG testing was to verify proper operation of the EDG when it was the sole supply to the Unit 2 Train B 6.9KV safeguards buses. Unit 2 Train B 6.9 KV buses have 3 AC sources - XST1 (138KV) preferred source, XST2 (345KV) alternate source and the 2-02 Emergency Diesel Generator.

"The 2-02 EDG was started normally and was operating in parallel with XST1 (preferred AC source) just before the event. The event was triggered when the preferred AC supply breaker to the Train B 6.9KV Safeguard bus was opened per plan. The opening of the preferred feeder breaker resulted in the 2-02 EDG being the sole AC source to the Train B 6.9KV bus. Immediately following this breaker operation, the EDG tripped on an Auto Voltage Regulator failure. This caused the Train B 6.9KV safeguard bus to de-energize which resulted in the automatic closure of the alternate AC (XST2) feeder breaker. This in turn triggered the Train B Solid State Sequencer to sequence on Train B Black Out loads - as designed.

"The Train B Black Out Solid State Sequencer operated as designed. No abnormalities were noted. All available equipment operated as designed.

"The 2-02 EDG is currently tagged out and the problem associated with the [Auto Voltage Regulator] failure is being investigated.

"[The] NRC Resident Inspector has been informed and is currently located on site."

No fuel movement was in progress during this event. Train A safeguard power was unaffected and available throughout. Non-safety related power was also not affected. The only operational impact was the loss of a Train B spent fuel pool cooling pump for approximately 10 minutes. The spent fuel pool temperature increased approximately 1/2 degree during before cooling was restored.

* * * RETRACTION FROM DAVID BUTLER TO HOWIE CROUCH AT 1830 EDT ON 4/14/11 * * *

"Further investigation of this event has determined that the 2-02 Emergency Diesel Generator (EDG) auto voltage regulator functioned as designed. The EDG did not receive an emergency start signal, which was consistent with the design for the plant conditions present. In addition, Unit 2 was defueled and in a 'No Mode' condition, and there was no actuation of any of the systems listed in paragraph 50.72 (b)(3)(iv)(B) by the sequencer operation. Therefore, this event is not reportable because it did not meet the criteria for a system actuation per 50.72(b)(3)(iv)(A) and the guidance in NUREG-1022."

The licensee will be notifying the NRC Resident Inspector. Notified R4DO (Miller).

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Power Reactor Event Number: 46755
Facility: SAN ONOFRE
Region: 4 State: CA
Unit: [ ] [2] [ ]
RX Type: [1] W-3-LP,[2] CE,[3] CE
NRC Notified By: TRAVIS FELDER
HQ OPS Officer: JOHN KNOKE
Notification Date: 04/14/2011
Notification Time: 16:52 [ET]
Event Date: 04/14/2011
Event Time: 12:35 [PDT]
Last Update Date: 04/14/2011
Emergency Class: NON EMERGENCY
10 CFR Section:
50.72(b)(2)(xi) - OFFSITE NOTIFICATION
Person (Organization):
GEOFFREY MILLER (R4DO)

Unit SCRAM Code RX CRIT Initial PWR Initial RX Mode Current PWR Current RX Mode
2 N Y 100 Power Operation 100 Power Operation

Event Text

OFFSITE NOTIFICATION TO STATE OF CALIFORNIA DUE TO HYDROGEN LEAK

"During a scheduled delivery of Hydrogen to Unit 2's active and reserve hydrogen banks, a hydrogen leak was detected at the hydrogen fill connection isolation valve. A notification was made for an uncontrolled release of hazardous material to San Diego Department of Environmental Health at 12:35 PST and California Emergency Management Agency at 12:40 PST. Upon detection, the leak was isolated."

The licensee has notified the NRC Resident Inspector.

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Power Reactor Event Number: 46756
Facility: COOPER
Region: 4 State: NE
Unit: [1] [ ] [ ]
RX Type: [1] GE-4
NRC Notified By: BRIAN STANDER
HQ OPS Officer: JOHN KNOKE
Notification Date: 04/14/2011
Notification Time: 19:54 [ET]
Event Date: 04/14/2011
Event Time: 16:25 [CDT]
Last Update Date: 04/14/2011
Emergency Class: NON EMERGENCY
10 CFR Section:
50.72(b)(2)(xi) - OFFSITE NOTIFICATION
Person (Organization):
GEOFFREY MILLER (R4DO)

Unit SCRAM Code RX CRIT Initial PWR Initial RX Mode Current PWR Current RX Mode
1 N N 0 Refueling 0 Refueling

Event Text

OFFSITE NOTIFICATION TO NEBRASKA DEPARTMENT OF ENVIRONMENTAL QUALITY

"On 4/14/11 at 1625 CDT, NPPD/CNS notified the Nebraska Department of Environmental Quality (NDEQ) of a violation of the National Pollutant Discharge Elimination System (NPDES) requirements during March 2011.

"The NPDES conditions for Total Suspended Solids (TSS) for reverse osmosis (RO) Reject and Boiler Blowdown Waste streams (Outfall 004 - sludge pond), for the month of March exceeded the maximum daily value of 100 mg/L and 30-day average of 30 mg/L. The value of the TSS for the month of March was 190 mg/L. This exceeds the NPDES conditions for TSS during the month of March. The April TSS for NPDES Outfall 004 was verified to be within limits at 6.4 mg/L. This outfall discharges to the Missouri River.

"This is a 4 hour report per 10 CFR 50.72(b)(2)(xi) for any event or situation related to the protection of the environment, for which notification to another government agency has been made."

The licensee has notified the NRC Resident Inspector.

Page Last Reviewed/Updated Thursday, March 29, 2012
Thursday, March 29, 2012