Event Notification Report for March 31, 2019
U.S. Nuclear Regulatory Commission
Operations Center
EVENT REPORTS FOR
03/30/2019 - 03/31/2019
EVENT NUMBERS
53968
Power Reactor
Event Number: 53968
Facility: PALO VERDE
Region: 4 State: AZ
Unit: [1] [] []
RX Type: [1] CE,[2] CE,[3] CE
NRC Notified By: GEORGE LESTER
HQ OPS Officer: CATY NOLAN
Region: 4 State: AZ
Unit: [1] [] []
RX Type: [1] CE,[2] CE,[3] CE
NRC Notified By: GEORGE LESTER
HQ OPS Officer: CATY NOLAN
Notification Date: 04/01/2019
Notification Time: 06:40 [ET]
Event Date: 03/31/2019
Event Time: 20:06 [MST]
Last Update Date: 05/15/2019
Notification Time: 06:40 [ET]
Event Date: 03/31/2019
Event Time: 20:06 [MST]
Last Update Date: 05/15/2019
Emergency Class: NON EMERGENCY
10 CFR Section:
50.72(b)(3)(ii)(B) - UNANALYZED CONDITION 50.72(b)(3)(v)(C) - POT UNCNTRL RAD REL
10 CFR Section:
50.72(b)(3)(ii)(B) - UNANALYZED CONDITION 50.72(b)(3)(v)(C) - POT UNCNTRL RAD REL
Person (Organization):
MICHAEL VASQUEZ (R4DO)
MICHAEL VASQUEZ (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 |
UNANALYZED CONDITION DUE TO ECCS LEAKAGE
"At 2006 [MST], on 3/31/2019, the Palo Verde Nuclear Generating Station Unit 1 Shift Manager was informed that leakage was measured from the Train A Emergency Core Cooling System (ECCS) piping at approximately 100 ml/minute through a High Pressure Safety Injection (HPSI) A drain valve. This value exceeds the assumed 3000 ml/hour ECCS leakage for a large break loss of coolant accident analysis. At 0230 [MST] on April 1, 2019, the valve was flushed and the leakage reduced to 10 ml/minute (600 ml/hour) and was no longer above the limit of the safety analysis. This condition is being reported as an unanalyzed condition per 10 CFR 50.72(b)3)(ii)(B) and a condition that could have prevented the fulfillment of a safety function to the control the release of radioactive material per 10 CFR
50.72(b)(3)(v)(C). This event did not result in an abnormal release of radioactive material.
"Notification received by Caty Nolan and emailed to HOO.HOC@NRC.GOV
The NRC asked a followup question:
Why was the criterion for Control of Radioactive Material selected?
per the PVNGS Unit 1 Shift Manager, this criterion was selected due to the potential of exceeding offsite dose projections, post recirculation, following a Design Basis Accident."
The resident inspector has been notified.
* * * UPDATE ON 05/15/19 AT 1417 EDT FROM SEAN DORNSEIF TO BETHANY CECERE * * *
"An engineering evaluation concluded that the as-found ECCS leakage would not have degraded the performance of the Pump Room Exhaust Air Cleanup system; therefore, it remained operable.
"The evaluation also concluded that the as-found leakage was within the analysis margins for HPSI pump hydraulic performance and containment flood level following a Large Break Loss of Coolant Accident; therefore, the ECCS also remained operable.
"Based on the above information, the condition identified on March 31, 2019, was an unanalyzed condition per 10 CFR 50.72(b)(3)(ii)(B), but did not prevent the fulfillment of the safety function of the structures or systems that are needed to control the release of radioactive material per 10 CFR 50.72(b)(3)(v)(C).
"The NRC resident inspectors have been informed."
Notified R4DO (Proulx).
"At 2006 [MST], on 3/31/2019, the Palo Verde Nuclear Generating Station Unit 1 Shift Manager was informed that leakage was measured from the Train A Emergency Core Cooling System (ECCS) piping at approximately 100 ml/minute through a High Pressure Safety Injection (HPSI) A drain valve. This value exceeds the assumed 3000 ml/hour ECCS leakage for a large break loss of coolant accident analysis. At 0230 [MST] on April 1, 2019, the valve was flushed and the leakage reduced to 10 ml/minute (600 ml/hour) and was no longer above the limit of the safety analysis. This condition is being reported as an unanalyzed condition per 10 CFR 50.72(b)3)(ii)(B) and a condition that could have prevented the fulfillment of a safety function to the control the release of radioactive material per 10 CFR
50.72(b)(3)(v)(C). This event did not result in an abnormal release of radioactive material.
"Notification received by Caty Nolan and emailed to HOO.HOC@NRC.GOV
The NRC asked a followup question:
Why was the criterion for Control of Radioactive Material selected?
per the PVNGS Unit 1 Shift Manager, this criterion was selected due to the potential of exceeding offsite dose projections, post recirculation, following a Design Basis Accident."
The resident inspector has been notified.
* * * UPDATE ON 05/15/19 AT 1417 EDT FROM SEAN DORNSEIF TO BETHANY CECERE * * *
"An engineering evaluation concluded that the as-found ECCS leakage would not have degraded the performance of the Pump Room Exhaust Air Cleanup system; therefore, it remained operable.
"The evaluation also concluded that the as-found leakage was within the analysis margins for HPSI pump hydraulic performance and containment flood level following a Large Break Loss of Coolant Accident; therefore, the ECCS also remained operable.
"Based on the above information, the condition identified on March 31, 2019, was an unanalyzed condition per 10 CFR 50.72(b)(3)(ii)(B), but did not prevent the fulfillment of the safety function of the structures or systems that are needed to control the release of radioactive material per 10 CFR 50.72(b)(3)(v)(C).
"The NRC resident inspectors have been informed."
Notified R4DO (Proulx).