United States Nuclear Regulatory Commission - Protecting People and the Environment
Home > NRC Library > Document Collections > Reports Associated with Events > Event Notification Reports > 2006 > October 23

Event Notification Report for October 23, 2006

U.S. Nuclear Regulatory Commission
Operations Center

Event Reports For
10/20/2006 - 10/23/2006

** EVENT NUMBERS **


42921 42922 42923 42924 42925 42926

To top of page
Power Reactor Event Number: 42921
Facility: RIVER BEND
Region: 4 State: LA
Unit: [1] [ ] [ ]
RX Type: [1] GE-6
NRC Notified By: DAN WILLIAMSON
HQ OPS Officer: PETE SNYDER
Notification Date: 10/19/2006
Notification Time: 22:35 [ET]
Event Date: 10/19/2006
Event Time: 17:56 [CDT]
Last Update Date: 10/20/2006
Emergency Class: NON EMERGENCY
10 CFR Section:
50.72(b)(2)(iv)(A) - ECCS INJECTION
50.72(b)(2)(iv)(B) - RPS ACTUATION - CRITICAL
50.72(b)(3)(iv)(A) - VALID SPECIF SYS ACTUATION
50.72(b)(3)(v)(D) - ACCIDENT MITIGATION
Person (Organization):
DALE POWERS (R4)
NILESH CHOKSHI (NRR)

Unit SCRAM Code RX CRIT Initial PWR Initial RX Mode Current PWR Current RX Mode
1 A/R Y 100 Power Operation 0 Hot Shutdown

Event Text

AUTOMATIC SCRAM FOLLOWING SPONTANEOUS FEEDWATER VALVE CLOSURE

"At 1756 CDT with the plant operating at 100% power, a reactor scram occurred in response to a reactor water level 3 signal from an apparent loss of feedwater. Both feedwater injection lines isolated when isolation valves were inadvertently closed, The cause of the isolation valve closure is under investigation.

"When reactor water level lowered to level 2, high pressure core spray (HPCS) initiated automatically and recovered water level. The reactor core isolation cooling system (RCIC) was tagged out for maintenance at the time of the event.

"Following the scram, main steam isolation valves isolated on low main steam header pressure. As a result, reactor pressure control was being controlled with the safety relief valves. SRV pressure control in turn led to EOP entry conditions on containment pressure and suppression pool level.

"Both feedwater lines were opened, and normal reactor level control was restored. The MSIV's were opened and pressure control was returned to the turbine bypass valves and the main condenser.

"Initial indications are that all plant equipment functioned as designed with the exception of the 'B' feed pump which experienced an apparent seal failure. The plant is stable in Mode 3. All plant conditions are understood.

"This event is being reported in accordance with 10CRF50.72(b)(2) as an RPS actuation and an injection of HPCS into the reactor vessel, and in accordance with 10CRF50.72(b)(3) as a loss of safety function of HPCS, as it was manually disabled during recovery from the event. The HPCS Injection valve was manually overridden closed for 76 minutes. In addition,' containment isolation valves in multiple systems actuated in response to the RPV level 2 signal."

Reactor vessel water level lowered to below level 2. Decay heat is being removed by normal feedwater to the reactor vessel steaming to the main condenser. Offsite power is available and stable. Emergency Diesel Generators are available.

The licensee notified the NRC Resident Inspector.

* * * UPDATE FROM LICENSEE (D. WILLIAMSON) TO M. RIPLEY 1740 EDT ON 10/20/06 * * *

"The closure signal to the main feedwater header isolation valves occurred when part of a chart recorder above the isolation valve control switches was dropped by an operator. The operator was attempting to adjust the paper drive mechanism in the recorder, and accidentally dropped the paper cartridge, which struck the 'CLOSE' pushbuttons on the isolation valve control switches.

"Following the scram, there was a delay in placing the reactor mode switch in the 'SHUTDOWN' position, which is an immediate action required by procedure. Placing the mode switch to 'SHUTDOWN' bypasses the reactor low steam pressure MSIV Isolation. Reactor steam pressure began dropping after the scram, until it reached the MSIV automatic closure setpoint, and the MSIVs isolated,"

In addition the licensee corrected one of the 10 CFR Section entries from "50.72(b)(3)(v)(A) POT UNABLE TO SAFE SD" to "50.72(b)(3)(v)(D) ACCIDENT MITIGATION." The licensee notified the NRC Resident Inspector.

Notified R4 DO (D. Powers) and NRR EO (N. Chokshi)

To top of page
Power Reactor Event Number: 42922
Facility: HATCH
Region: 2 State: GA
Unit: [1] [2] [ ]
RX Type: [1] GE-4,[2] GE-4
NRC Notified By: P. UNDERWOOD
HQ OPS Officer: JOHN MacKINNON
Notification Date: 10/20/2006
Notification Time: 11:17 [ET]
Event Date: 10/20/2006
Event Time: 09:25 [EDT]
Last Update Date: 10/20/2006
Emergency Class: NON EMERGENCY
10 CFR Section:
50.72(b)(3)(xiii) - LOSS COMM/ASMT/RESPONSE
Person (Organization):
BRIAN BONSER (R2)

Unit SCRAM Code RX CRIT Initial PWR Initial RX Mode Current PWR Current RX Mode
1 N Y 99 Power Operation 99 Power Operation
2 N Y 100 Power Operation 100 Power Operation

Event Text

PLANNED MAINTENANCE FOR HATCH EMERGENCY HVAC HEALTH PHYSICS CONTROL POINT/CHEMISTRY LAB AREA

"On 10/20/2006, the emergency HVAC for the Hatch Nuclear Plant's Health Physics (HP) Control Point /Chemistry Lab area was removed from service for planned corrective maintenance and inspections and testing activities. The HP emergency HVAC is required for functionality of the Operations Support Center (OSC). This area is normally utilized by HP/Chem personnel for analysis of samples during normal as well as emergency conditions. These work activities are planned to be performed and completed within a 12 hour work shift. During the time these activities are being performed, the HP emergency HVAC and filter train will not be available for operation for approximately four (4) hours. As such, the HP emergency HVAC will be rendered non-functional during the performance of this work activity. The OSC working area itself, however, does not lose EP functionality throughout this evolution.

"The HP emergency HVAC provides climate control for Health Physics control point and Chemistry Lab areas. If an emergency condition requiring activation of the OSC occurs during the time these work activities are being performed, then contingency plans call for utilization of the HP Control Point/Chemistry Lab areas as long as radiological conditions allow. Respiratory protection equipment will be utilized as appropriate for emergency responders until the HP emergency HVAC is returned to service. This event is reportable per 10CFR50.72 (b)(3)(xiii) as described in NUREG-1022, Rev. 2 since this work activity affects an emergency response facility for the duration of the evolution."

The NRC Resident Inspector was notified of this event by the licensee.

To top of page
Power Reactor Event Number: 42923
Facility: CALVERT CLIFFS
Region: 1 State: MD
Unit: [1] [ ] [ ]
RX Type: [1] CE,[2] CE
NRC Notified By: M. SECKENS
HQ OPS Officer: BILL HUFFMAN
Notification Date: 10/21/2006
Notification Time: 10:15 [ET]
Event Date: 10/21/2006
Event Time: 07:35 [EDT]
Last Update Date: 10/21/2006
Emergency Class: NON EMERGENCY
10 CFR Section:
50.72(b)(2)(xi) - OFFSITE NOTIFICATION
Person (Organization):
RICHARD BARKLEY (R1)

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

Event Text

NOTIFICATION TO STATE OF CHEMICAL AND SEWAGE RELEASE

"Notification of the State [Maryland Department of the Environment] per the NPDES [National Pollution Discharge Elimination System] permit of the release of a maximum of 20 gallons of sewage and chemicals from a portable toilet to the bay through a storm drain."

A portable toilet was blown-over by high winds at the site.

The licensee notified the NRC Resident Inspector.

To top of page
Power Reactor Event Number: 42924
Facility: SOUTH TEXAS
Region: 4 State: TX
Unit: [1] [2] [ ]
RX Type: [1] W-4-LP,[2] W-4-LP
NRC Notified By: KLAY KLIMPLE
HQ OPS Officer: MIKE RIPLEY
Notification Date: 10/21/2006
Notification Time: 18:26 [ET]
Event Date: 10/21/2006
Event Time: 15:58 [CDT]
Last Update Date: 10/21/2006
Emergency Class: NON EMERGENCY
10 CFR Section:
50.72(b)(3)(xii) - OFFSITE MEDICAL
Person (Organization):
DALE POWERS (R4)

Unit SCRAM Code RX CRIT Initial PWR Initial RX Mode Current PWR Current RX Mode
1 N N 0 Refueling 0 Refueling
2 N Y 100 Power Operation 100 Power Operation

Event Text

OFFSITE MEDICAL TREATMENT OF POTENTIALLY CONTAMINATED CONTRACT EMPLOYEE

"A contract employee experienced heat exhaustion while working in the Reactor Containment Building in a contaminated area and was considered potentially contaminated because the initial survey for radioactive contamination had not been completed prior to transporting the employee offsite for medical treatment."

The licensee notified the NRC Resident Inspector.

* * * UPDATE FROM LICENSEE (B. SCARBOROUGH) TO M. RIPLEY AT 1912 EDT ON 10/21/06 * * *

At 1758 CDT on 10/21/06, the licensee was notified by their Health Physics Dept. that the contract employee was transported to the Matagorda Hospital in Bay City, TX and was found not to be contaminated. Additionally, all instruments and equipment used in the incident were surveyed and no contamination was found.

The licensee notified the NRC Resident Inspector. Notified R4 DO (D. Powers).

To top of page
Power Reactor Event Number: 42925
Facility: PALO VERDE
Region: 4 State: AZ
Unit: [1] [ ] [ ]
RX Type: [1] CE,[2] CE,[3] CE
NRC Notified By: BRAD EKLUND
HQ OPS Officer: MIKE RIPLEY
Notification Date: 10/21/2006
Notification Time: 21:37 [ET]
Event Date: 10/21/2006
Event Time: 15:48 [MST]
Last Update Date: 10/21/2006
Emergency Class: NON EMERGENCY
10 CFR Section:
50.72(b)(2)(iv)(B) - RPS ACTUATION - CRITICAL
Person (Organization):
DALE POWERS (R4)

Unit SCRAM Code RX CRIT Initial PWR Initial RX Mode Current PWR Current RX Mode
1 A/R Y 100 Power Operation 0 Hot Standby

Event Text

AUTOMATIC REACTOR TRIP DUE TO CONTROL ELEMENT ASSEMBLY POSITION TRANSMITTER OUTPUT DEVIATIONS

"The following event description is based on information currently available. If through subsequent reviews of this event, additional information is identified that is pertinent to this event or alters the information being provided at this time, a follow up notification will be made via the ENS or under the reporting requirements of 10CFR50.73.

"On October 21, 2006 at approximately 1549 MST Palo Verde Unit 1 experienced a reactor trip (RPS actuation) from 100% rated thermal power due to low departure from nucleate boiling (DNBR) trips on all four channels of the core protection calculators (CPCs). The unit was at normal temperature and pressure prior to the trip.

"Several minutes prior to the Reactor Trip, RSPT#1 (Reed Switch Position Transmitter) CEA deviation alarms were received for CEA#29 (Shutdown Group B CEA). Operators observed that the magnitude of the deviation was fluctuating erratically. While investigating the alarms CEAC #1 Sensor Fail alarms were received and at 1549 MST, the Reactor automatically tripped on a CPC generated Lo DNBR trips on all 4 channels of CPCs. The apparent cause is presently suspected to be a failure of RSPT#1. An investigation has commenced to determine the root cause of the reactor trip.

"All of the control rods fully inserted into the core. The Steam Bypass Control System operated as designed, directing steam flow to the condenser. No main steam or primary relief valves lifted and none were required. There was no loss of heat removal capability or loss of safety functions associated with the event. Electrical buses transferred to offsite power as designed. The Shift Manager determined this event was an uncomplicated reactor trip. No significant LCOs have been entered as a result of this event. No major equipment was inoperable prior to the event nor contributed to the event.

"Unit 1 is stable at normal operating temperature and pressure in Mode 3. No ESF actuations occurred and none were required. The event did not result in any challenges to the fission product barrier or result in any releases of radioactive materials. There were no adverse safety consequences or implications as a result of this event. The event did not adversely affect the safe operation of the plant or health and safety of the public.

"The NRC Resident was notified at 17:38 MST."

To top of page
Power Reactor Event Number: 42926
Facility: COOPER
Region: 4 State: NE
Unit: [1] [ ] [ ]
RX Type: [1] GE-4
NRC Notified By: JERRY BEBB
HQ OPS Officer: MIKE RIPLEY
Notification Date: 10/21/2006
Notification Time: 23:23 [ET]
Event Date: 10/21/2006
Event Time: 20:12 [CDT]
Last Update Date: 10/21/2006
Emergency Class: NON EMERGENCY
10 CFR Section:
26.73 - FITNESS FOR DUTY
Person (Organization):
DALE POWERS (R4)

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

Event Text

FITNESS FOR DUTY

A contract supervisor tested positive for alcohol during a for-cause test. The supervisor's plant access has been suspended. Contact the Headquarters Operations Officer for additional details.

The NRC Resident Inspector has been notified.

Page Last Reviewed/Updated Friday, March 30, 2012
Friday, March 30, 2012