Event Notification Report for October 11, 2009
U.S. Nuclear Regulatory Commission
Operations Center
EVENT REPORTS FOR
10/10/2009 - 10/11/2009
EVENT NUMBERS
45425
!!!!! THIS EVENT HAS BEEN RETRACTED !!!!!
!!!!! THIS EVENT HAS BEEN RETRACTED !!!!!
Power Reactor
Event Number: 45425
Facility: PALO VERDE
Region: 4 State: AZ
Unit: [1] [] []
RX Type: [1] CE,[2] CE,[3] CE
NRC Notified By: JAMES W MORELAND
HQ OPS Officer: CHARLES TEAL
Region: 4 State: AZ
Unit: [1] [] []
RX Type: [1] CE,[2] CE,[3] CE
NRC Notified By: JAMES W MORELAND
HQ OPS Officer: CHARLES TEAL
Notification Date: 10/11/2009
Notification Time: 15:26 [ET]
Event Date: 10/11/2009
Event Time: 04:50 [MST]
Last Update Date: 10/23/2009
Notification Time: 15:26 [ET]
Event Date: 10/11/2009
Event Time: 04:50 [MST]
Last Update Date: 10/23/2009
Emergency Class: NON EMERGENCY
10 CFR Section:
50.72(b)(3)(v)(D) - ACCIDENT MITIGATION 50.72(b)(3)(xiii) - LOSS COMM/ASMT/RESPONSE
10 CFR Section:
50.72(b)(3)(v)(D) - ACCIDENT MITIGATION 50.72(b)(3)(xiii) - LOSS COMM/ASMT/RESPONSE
Person (Organization):
VIVIAN CAMPBELL (R4DO)
VIVIAN CAMPBELL (R4DO)
| Unit | SCRAM Code | RX Crit | Initial PWR | Initial RX Mode | Current PWR | Current RX Mode |
|---|---|---|---|---|---|---|
| 1 | N | Y | 100 | Power Operation | 100 | Power Operation |
REACTOR WATER LEVEL INDICATION INOPERABLE
"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 (Emergency Notification System) or under the reporting requirements of 10CFR50.73.
"On 10/11/2009 at 0450 MST Palo Verde Nuclear Station Unit 1 declared both trains of the Qualified Safety Parameter Display (QSPDS) inoperable due to the discovery that an installed temporary modification (TMOD) impacted the reactor vessel level indication parameter in a non-conservative manner. The modification jumpered failed heater junction thermal connections (HJTC) at the heated and unheated HJTC points. Unit 1 has two failed detectors with TMODs installed. During a design event where these detectors would be needed, these detectors will not alarm at the correct vessel levels.
"The emergency operating procedures use this indication and pressurizer level indications (which are unaffected by this condition) to throttle safety injection flow during certain accidents. With the TMOD providing incorrect indication the operators could throttle flow when full flow should be maintained.
"In addition the QSPDS reactor level indication is used in the Emergency Plan to classify emergencies. The standard Appendix 101 to Palo Verde emergency procedures provides guidance for an alternate method for determining reactor vessel level when RVLMS (Reactor Vessel Level Monitoring System) is out of service. This alternate method determines level by manually determining sub-cooled, saturation or superheated conditions based upon input of reactor vessel pressure and the "raw" QSPDS - RVLMS thermocouple temperature indications. This compensatory measure ensures that classification of events can continue to be completed in a timely manner.
"Unit 1 has entered the LCO (Limiting Condition of Operation) required action for this condition which requires at least one channel be restored to operable status within 7 days. Unit 2 is in a refueling and is not impacted at this time. Unit 3 does not have the TMOD installed. "
According to the licensee Train A TMOD which was installed 2/3/08 and the train B TMOD which was installed 12/12/08. The licensee checked the installation of these TMODs after reviewing operating experience reports from Calvert Cliffs.
The licensee has notified the NRC Resident Inspector.
* * * RETRACTION AT 1916 EDT ON 10/23/09 FROM BUZARD TO HUFFMAN * * *
"On 10/11/2009 at 12:26 MST Palo Verde Nuclear Station Unit 1 reported the inoperability of both trains of the Qualified Safety Parameter Display System (QSPDS) due to the discovery that an installed temporary modification impacted the reactor vessel water level indication parameter in a non-conservative manner. After further Operations and Engineering review it was concluded that the modification, installed due to one inoperable heated junction thermal couple (HJTC) in each train, does not result in the inoperability of either train of QSPDS since the Technical Specification required number of heated junction thermal couples (HJTC) (two each in the upper and lower level indication) remain operable with the temporary modification installed. In addition, the Control Room operators would understand the QSPDS indication and would correctly control the plant per the emergency operating procedures using this indication along with pressurizer level indication to throttle safety injection flow during certain accidents.
"The QSPDS reactor level indication is also used in the Emergency Plan to classify emergencies and the modification would not impact this function.
"Unit 1 has exited the LCO Condition for two inoperable QSPDS reactor vessel water level instrument channels."
The licensee has notified the NRC Resident Inspector. R4DO (Okeefe) notified.
"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 (Emergency Notification System) or under the reporting requirements of 10CFR50.73.
"On 10/11/2009 at 0450 MST Palo Verde Nuclear Station Unit 1 declared both trains of the Qualified Safety Parameter Display (QSPDS) inoperable due to the discovery that an installed temporary modification (TMOD) impacted the reactor vessel level indication parameter in a non-conservative manner. The modification jumpered failed heater junction thermal connections (HJTC) at the heated and unheated HJTC points. Unit 1 has two failed detectors with TMODs installed. During a design event where these detectors would be needed, these detectors will not alarm at the correct vessel levels.
"The emergency operating procedures use this indication and pressurizer level indications (which are unaffected by this condition) to throttle safety injection flow during certain accidents. With the TMOD providing incorrect indication the operators could throttle flow when full flow should be maintained.
"In addition the QSPDS reactor level indication is used in the Emergency Plan to classify emergencies. The standard Appendix 101 to Palo Verde emergency procedures provides guidance for an alternate method for determining reactor vessel level when RVLMS (Reactor Vessel Level Monitoring System) is out of service. This alternate method determines level by manually determining sub-cooled, saturation or superheated conditions based upon input of reactor vessel pressure and the "raw" QSPDS - RVLMS thermocouple temperature indications. This compensatory measure ensures that classification of events can continue to be completed in a timely manner.
"Unit 1 has entered the LCO (Limiting Condition of Operation) required action for this condition which requires at least one channel be restored to operable status within 7 days. Unit 2 is in a refueling and is not impacted at this time. Unit 3 does not have the TMOD installed. "
According to the licensee Train A TMOD which was installed 2/3/08 and the train B TMOD which was installed 12/12/08. The licensee checked the installation of these TMODs after reviewing operating experience reports from Calvert Cliffs.
The licensee has notified the NRC Resident Inspector.
* * * RETRACTION AT 1916 EDT ON 10/23/09 FROM BUZARD TO HUFFMAN * * *
"On 10/11/2009 at 12:26 MST Palo Verde Nuclear Station Unit 1 reported the inoperability of both trains of the Qualified Safety Parameter Display System (QSPDS) due to the discovery that an installed temporary modification impacted the reactor vessel water level indication parameter in a non-conservative manner. After further Operations and Engineering review it was concluded that the modification, installed due to one inoperable heated junction thermal couple (HJTC) in each train, does not result in the inoperability of either train of QSPDS since the Technical Specification required number of heated junction thermal couples (HJTC) (two each in the upper and lower level indication) remain operable with the temporary modification installed. In addition, the Control Room operators would understand the QSPDS indication and would correctly control the plant per the emergency operating procedures using this indication along with pressurizer level indication to throttle safety injection flow during certain accidents.
"The QSPDS reactor level indication is also used in the Emergency Plan to classify emergencies and the modification would not impact this function.
"Unit 1 has exited the LCO Condition for two inoperable QSPDS reactor vessel water level instrument channels."
The licensee has notified the NRC Resident Inspector. R4DO (Okeefe) notified.