Event Notification Report for July 26, 2006
U.S. Nuclear Regulatory Commission
Operations Center
EVENT REPORTS FOR
07/25/2006 - 07/26/2006
Power Reactor
Event Number: 42730
Facility: PALO VERDE
Region: 4 State: AZ
Unit: [] [2] []
RX Type: [1] CE,[2] CE,[3] CE
NRC Notified By: DUANE KANITZ
HQ OPS Officer: PETE SNYDER
Region: 4 State: AZ
Unit: [] [2] []
RX Type: [1] CE,[2] CE,[3] CE
NRC Notified By: DUANE KANITZ
HQ OPS Officer: PETE SNYDER
Notification Date: 07/26/2006
Notification Time: 14:20 [ET]
Event Date: 07/26/2006
Event Time: 07:35 [MST]
Last Update Date: 07/26/2006
Notification Time: 14:20 [ET]
Event Date: 07/26/2006
Event Time: 07:35 [MST]
Last Update Date: 07/26/2006
Emergency Class: NON EMERGENCY
10 CFR Section:
50.72(b)(2)(iv)(B) - RPS ACTUATION - CRITICAL
10 CFR Section:
50.72(b)(2)(iv)(B) - RPS ACTUATION - CRITICAL
Person (Organization):
THOMAS FARNHOLTZ (R4)
JACK FOSTER (NRR)
THOMAS FARNHOLTZ (R4)
JACK FOSTER (NRR)
| Unit | SCRAM Code | RX Crit | Initial PWR | Initial RX Mode | Current PWR | Current RX Mode |
|---|---|---|---|---|---|---|
| 2 | A/R | Y | 90 | Power Operation | 0 | Hot Standby |
VARIABLE OVERPOWER REACTOR TRIP FOLLOWING TURBINE CONTROL VALVE MAINTENANCE
"On July 26, 2006, at approximately 07:34 Mountain Standard Time (MST) Palo Verde Unit 2 experienced an automatic reactor scram on Variable Overpower. Unit 2 was operating at 90% power at normal operating temperature and pressure prior to the event. A main turbine control valve (CV02) was being returned to service following maintenance. CV02 initially started to open which caused reactor power to decrease to approximately 89%. During the evolution, six steam bypass control valve opened (three valves opened 100 percent, one opened 60 percent, and two opened 5 percent). Reactor power rapidly increased to 98% which resulted in an auxiliary Variable Power Trip (VOPT). The VOPT trip set point is 8 percent. The main turbine automatically tripped in response to the reactor trip. All rods inserted, as required. No ESF actuations occurred and none were required.
"No emergency classification was required per the Emergency Plan. Safety related buses remained energized during and following the reactor trip. The Emergency Diesel Generators did not start and were not required. The offsite power grid is stable. No LCOs have been entered as a result of this event. No major equipment was inoperable prior to the event that contributed to the event. The maximum power level during the transient was approximately 98%."
"Unit 2 is stable at normal operating temperature and pressure in Mode 3. The event did not result in any challenges to fission product barriers and there were no adverse safety consequences as a result of this event. The maximum RCS pressure was approximately 2260 psia (normal 2240). The maximum steam generator pressure was approximately 1090 psia (normal 1055). The event did not adversely affect the safe operation of the plant or the health and safety of the public."
The licensee notified the NRC Resident Inspector.
"On July 26, 2006, at approximately 07:34 Mountain Standard Time (MST) Palo Verde Unit 2 experienced an automatic reactor scram on Variable Overpower. Unit 2 was operating at 90% power at normal operating temperature and pressure prior to the event. A main turbine control valve (CV02) was being returned to service following maintenance. CV02 initially started to open which caused reactor power to decrease to approximately 89%. During the evolution, six steam bypass control valve opened (three valves opened 100 percent, one opened 60 percent, and two opened 5 percent). Reactor power rapidly increased to 98% which resulted in an auxiliary Variable Power Trip (VOPT). The VOPT trip set point is 8 percent. The main turbine automatically tripped in response to the reactor trip. All rods inserted, as required. No ESF actuations occurred and none were required.
"No emergency classification was required per the Emergency Plan. Safety related buses remained energized during and following the reactor trip. The Emergency Diesel Generators did not start and were not required. The offsite power grid is stable. No LCOs have been entered as a result of this event. No major equipment was inoperable prior to the event that contributed to the event. The maximum power level during the transient was approximately 98%."
"Unit 2 is stable at normal operating temperature and pressure in Mode 3. The event did not result in any challenges to fission product barriers and there were no adverse safety consequences as a result of this event. The maximum RCS pressure was approximately 2260 psia (normal 2240). The maximum steam generator pressure was approximately 1090 psia (normal 1055). The event did not adversely affect the safe operation of the plant or the health and safety of the public."
The licensee notified the NRC Resident Inspector.
General Information or Other
Event Number: 42731
Rep Org: CALIFORNIA RADIATION CONTROL PRGM
Licensee: LEIGHTON AND ASSOCIATES
Region: 4
City: SANTA PAULA State: CA
County:
License #: 3109-30
Agreement: Y
Docket:
NRC Notified By: ROBERT GREGER
HQ OPS Officer: MARK ABRAMOVITZ
Licensee: LEIGHTON AND ASSOCIATES
Region: 4
City: SANTA PAULA State: CA
County:
License #: 3109-30
Agreement: Y
Docket:
NRC Notified By: ROBERT GREGER
HQ OPS Officer: MARK ABRAMOVITZ
Notification Date: 07/26/2006
Notification Time: 23:50 [ET]
Event Date: 07/26/2006
Event Time: 14:05 [PDT]
Last Update Date: 07/27/2006
Notification Time: 23:50 [ET]
Event Date: 07/26/2006
Event Time: 14:05 [PDT]
Last Update Date: 07/27/2006
Emergency Class: NON EMERGENCY
10 CFR Section:
10 CFR Section:
Person (Organization):
THOMAS FARNHOLTZ (R4)
EDWIN HACKETT (NMSS)
THOMAS FARNHOLTZ (R4)
EDWIN HACKETT (NMSS)
AGREEMENT STATE REPORT - DAMAGED MOISTURE DENSITY GAUGE
The State provided the following information via facsimile:
"At approximately 2 P.M., the licensee called the Department to report that one of their moisture density gauges (CPN model MC3, serial # M39099115) had been run over by a large truck at approximately 12:20 P.M. earlier in the day. This happened when the gauge user had his back turned from the gauge and he was standing approximately 15-20 feet from the gauge. The gauge source rod (Cs-137) was in the shielded position at the time. The housing was severely damaged and the source rod handle was broken off near the weld joint where the source rod attaches to the source capsule. Both the 8 mCi Cs-137 and the 50 mCi Am-241:Be sources remained in their shielded positions as determined by subsequent surveys.
"The incident happened at a Cal Trans job in Santa Paula, CA on Highway 150 at the 28.12 mile marker. The Cal Trans supervisor immediately shut the job down and sent all of the workers home. The area where the gauge was located was secured and roped off until the sources were verified to still be in the gauge.
"The gauge and the broken gauge handle was transported back to the Santa Clarita storage location where a representative from RHB performed the survey to verify that the sources were in the gauge and in their shielded positions. The gauge will be transported to local CPN service representative , Maurer Technical Services in Laguna Hills, where they will do leak tests on the gauge."
The State provided the following information via facsimile:
"At approximately 2 P.M., the licensee called the Department to report that one of their moisture density gauges (CPN model MC3, serial # M39099115) had been run over by a large truck at approximately 12:20 P.M. earlier in the day. This happened when the gauge user had his back turned from the gauge and he was standing approximately 15-20 feet from the gauge. The gauge source rod (Cs-137) was in the shielded position at the time. The housing was severely damaged and the source rod handle was broken off near the weld joint where the source rod attaches to the source capsule. Both the 8 mCi Cs-137 and the 50 mCi Am-241:Be sources remained in their shielded positions as determined by subsequent surveys.
"The incident happened at a Cal Trans job in Santa Paula, CA on Highway 150 at the 28.12 mile marker. The Cal Trans supervisor immediately shut the job down and sent all of the workers home. The area where the gauge was located was secured and roped off until the sources were verified to still be in the gauge.
"The gauge and the broken gauge handle was transported back to the Santa Clarita storage location where a representative from RHB performed the survey to verify that the sources were in the gauge and in their shielded positions. The gauge will be transported to local CPN service representative , Maurer Technical Services in Laguna Hills, where they will do leak tests on the gauge."
!!!!! THIS EVENT HAS BEEN RETRACTED !!!!!
!!!!! THIS EVENT HAS BEEN RETRACTED !!!!!
Power Reactor
Event Number: 42732
Facility: PALO VERDE
Region: 4 State: AZ
Unit: [] [] [3]
RX Type: [1] CE,[2] CE,[3] CE
NRC Notified By: DAVID OAKES
HQ OPS Officer: JOHN KNOKE
Region: 4 State: AZ
Unit: [] [] [3]
RX Type: [1] CE,[2] CE,[3] CE
NRC Notified By: DAVID OAKES
HQ OPS Officer: JOHN KNOKE
Notification Date: 07/27/2006
Notification Time: 03:07 [ET]
Event Date: 07/26/2006
Event Time: 19:00 [MST]
Last Update Date: 08/29/2006
Notification Time: 03:07 [ET]
Event Date: 07/26/2006
Event Time: 19:00 [MST]
Last Update Date: 08/29/2006
Emergency Class: NON EMERGENCY
10 CFR Section:
50.72(b)(3)(ii)(B) - UNANALYZED CONDITION
10 CFR Section:
50.72(b)(3)(ii)(B) - UNANALYZED CONDITION
Person (Organization):
THOMAS FARNHOLTZ (R4)
THOMAS FARNHOLTZ (R4)
| Unit | SCRAM Code | RX Crit | Initial PWR | Initial RX Mode | Current PWR | Current RX Mode |
|---|---|---|---|---|---|---|
| 3 | N | Y | 100 | Power Operation | 100 | Power Operation |
LIMITING CONDITION FOR OPERATION 3.7.4 DEEMED TO BE NONCONSERVATIVE
"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.
"Palo Verde Nuclear Generating Station Technical Specification Limiting Condition for Operation (LCO) 3.7.4 requires only one of two atmospheric dump valves (ADV) per steam generator (SG) to be operable. Palo Verde Unit 3 currently has one ADV inoperable on the #2 SG. All other ADVs in Unit 3 (and all ADVs in Units 1 and 2) are OPERABLE. On July 26, 2006 at approximately 19:00 MST, Palo Verde Engineering personnel determined that this LCO is nonconservative since it does not satisfy the single failure criterion for the safety analyses for the accidents that would render one SG inoperable, specifically steam generator tube rupture (SGTR) with loss of offsite power (LOOP) which utilizes both ADVs on the unaffected SG. In case of one SG inoperable due to the event, and single failure of one ADV fail to open, the plant cannot be brought to safe shutdown condition during those accidents and may result in exceeding the acceptance criteria. This LCO should have required two ADVs per SG to be operable in order to satisfy safety analysis assumptions.
"An administrative control in accordance with NUREG-1432, Standard Technical Specifications will be put in place for immediate compensatory action. NUREG-1432 LCO 3.7.4 Condition A, one required ADV line inoperable requires restoration of the ADV line to OPERABLE status within 7 days. Reperformance of the safety analyses is expected to be the long term solution.
"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 licensee notified the NRC Resident Inspector.
* * * RETRACTION AT 1727 ON 8/29/2006 FROM RAY BUZARD TO ABRAMOVITZ * * *
"The notification is being retracted due to further evaluation by engineering and licensing personnel which has determined that the license basis for Palo Verde Nuclear Generating Station is bounded by a steam generator tube rupture with a stuck open ADV coincident with a loss of offsite power event. The safety analysis for this event relies on one ADV on the unaffected SG which, along with the stuck open ADV on the affected SG, limits the offsite dose consequences to within 10 CFR Part 100 guidelines.
"The safety analysis referred to in the initial ENS notification utilizes 2 ADVs on the intact SG to limit radiological doses to 10 per cent of Part 100 guidelines. However, as noted above, this analysis is not the bounding safety analysis for the SG tube rupture event.
"The administrative control identified in the initial notification will remain in effect until engineering and licensing personnel determine if a Technical Specification change is required to support ADV single failure criteria.
"The Resident Inspector has been notified of this retraction. "
Notified the R4DO (Cain).