Event Notification Report for May 26, 2024
U.S. Nuclear Regulatory Commission
Operations Center
EVENT REPORTS FOR
05/25/2024 - 05/26/2024
EVENT NUMBERS
57146
57146
!!!!! THIS EVENT HAS BEEN RETRACTED !!!!!
!!!!! THIS EVENT HAS BEEN RETRACTED !!!!!
Power Reactor
Event Number: 57146
Facility: South Texas
Region: 4 State: TX
Unit: [1] [] []
RX Type: [1] W-4-LP,[2] W-4-LP
NRC Notified By: Randall Maus
HQ OPS Officer: Natalie Starfish
Region: 4 State: TX
Unit: [1] [] []
RX Type: [1] W-4-LP,[2] W-4-LP
NRC Notified By: Randall Maus
HQ OPS Officer: Natalie Starfish
Notification Date: 05/26/2024
Notification Time: 13:52 [ET]
Event Date: 05/26/2024
Event Time: 07:20 [CDT]
Last Update Date: 06/13/2024
Notification Time: 13:52 [ET]
Event Date: 05/26/2024
Event Time: 07:20 [CDT]
Last Update Date: 06/13/2024
Emergency Class: Non Emergency
10 CFR Section:
50.72(b)(3)(v)(D) - Accident Mitigation
10 CFR Section:
50.72(b)(3)(v)(D) - Accident Mitigation
Person (Organization):
Dixon, John (R4DO)
Dixon, John (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 |
EN Revision Imported Date: 6/14/2024
EN Revision Text: TWO OF THREE ESSENTIAL CHILLED WATER TRAINS DECLARED INOPERABLE
The following information was provided by the licensee by phone and email:
"At 0210 CDT 5/24/24, essential chiller 'A' train and cascading equipment was declared inoperable for maintenance to correct a temperature control malfunction.
"At 0720 CDT 5/26/24, essential cooling water 'B' train and cascading equipment (including 'B' train essential chiller) was declared inoperable due to a through wall leak discovered on the essential cooling water return header temperature element thermal well.
"This condition resulted in an inoperable condition on two out of three safety trains for the accident mitigating function, including the train 'A' and train 'B' high head safety injection, low head safety injection, containment spray, electrical auxiliary building heating ventilation and air conditioning (HVAC), and essential chilled water. All 'C' train safety related equipment remains operable.
"This was determined to be reportable within 8 hours as required by 10CFR50.72(b)(3)(v)(D).
"NRC Resident Inspector has been notified."
* * * RETRACTION ON 6/13/24 AT 1552 EDT FROM RAY RULEY TO BILL NYTKO * * *
The following information was provided by the licensee by phone and email:
"This is a communication to retract the 8-hour notification Event Notification (EN) 57146 reported to the NRC pursuant to 10 CFR 50.72(b)(3)(v)(D) on 05/26/2024. Based on a subsequent engineering review of the conditions that existed at the time of discovery, it was determined that:
"1) The maximum postulated leak rate, conservatively estimated, from the 'B' Train essential cooling water return piping thermowell in the mechanical auxiliary building sump room would have been less than the administrative allowable limit for leakage in this room during a design basis accident,
"2) No adjacent safety related components or functions would have been adversely affected, and
"3) the return line leakage represented a negligible impact regarding essential cooling water system inventory and the system ability to cool required components.
"Therefore, it was recommended that the 'B' Train essential cooling water system with the as-found leakage condition be considered operable. Therefore, this event notification is being retracted.
"The NRC Resident Inspector has been notified."
Notified R4DO (Taylor)
EN Revision Text: TWO OF THREE ESSENTIAL CHILLED WATER TRAINS DECLARED INOPERABLE
The following information was provided by the licensee by phone and email:
"At 0210 CDT 5/24/24, essential chiller 'A' train and cascading equipment was declared inoperable for maintenance to correct a temperature control malfunction.
"At 0720 CDT 5/26/24, essential cooling water 'B' train and cascading equipment (including 'B' train essential chiller) was declared inoperable due to a through wall leak discovered on the essential cooling water return header temperature element thermal well.
"This condition resulted in an inoperable condition on two out of three safety trains for the accident mitigating function, including the train 'A' and train 'B' high head safety injection, low head safety injection, containment spray, electrical auxiliary building heating ventilation and air conditioning (HVAC), and essential chilled water. All 'C' train safety related equipment remains operable.
"This was determined to be reportable within 8 hours as required by 10CFR50.72(b)(3)(v)(D).
"NRC Resident Inspector has been notified."
* * * RETRACTION ON 6/13/24 AT 1552 EDT FROM RAY RULEY TO BILL NYTKO * * *
The following information was provided by the licensee by phone and email:
"This is a communication to retract the 8-hour notification Event Notification (EN) 57146 reported to the NRC pursuant to 10 CFR 50.72(b)(3)(v)(D) on 05/26/2024. Based on a subsequent engineering review of the conditions that existed at the time of discovery, it was determined that:
"1) The maximum postulated leak rate, conservatively estimated, from the 'B' Train essential cooling water return piping thermowell in the mechanical auxiliary building sump room would have been less than the administrative allowable limit for leakage in this room during a design basis accident,
"2) No adjacent safety related components or functions would have been adversely affected, and
"3) the return line leakage represented a negligible impact regarding essential cooling water system inventory and the system ability to cool required components.
"Therefore, it was recommended that the 'B' Train essential cooling water system with the as-found leakage condition be considered operable. Therefore, this event notification is being retracted.
"The NRC Resident Inspector has been notified."
Notified R4DO (Taylor)