Event Notification Report for December 30, 2025
U.S. Nuclear Regulatory Commission
Operations Center
EVENT REPORTS FOR
12/29/2025 - 12/30/2025
Agreement State
Event Number: 58098
Rep Org: California Radiation Control Prgm
Licensee: Alta CA Geotechnical Inc.
Region: 4
City: Beaumont State: CA
County:
License #: 7824-33
Agreement: Y
Docket:
NRC Notified By: Donald Oesterle
HQ OPS Officer: Adam Koziol
Licensee: Alta CA Geotechnical Inc.
Region: 4
City: Beaumont State: CA
County:
License #: 7824-33
Agreement: Y
Docket:
NRC Notified By: Donald Oesterle
HQ OPS Officer: Adam Koziol
Notification Date: 12/22/2025
Notification Time: 14:15 [ET]
Event Date: 12/22/2025
Event Time: 00:00 [PST]
Last Update Date: 12/22/2025
Notification Time: 14:15 [ET]
Event Date: 12/22/2025
Event Time: 00:00 [PST]
Last Update Date: 12/22/2025
Emergency Class: Non Emergency
10 CFR Section:
Agreement State
10 CFR Section:
Agreement State
Person (Organization):
Warnick, Greg (R4DO)
NMSS_EVENTS_NOTIFICATION (EMAIL)
ILTAB, (EMAIL)
CNSNS (Mexico), - (EMAIL)
Warnick, Greg (R4DO)
NMSS_EVENTS_NOTIFICATION (EMAIL)
ILTAB, (EMAIL)
CNSNS (Mexico), - (EMAIL)
AGREEMENT STATE REPORT - STOLEN MOISTURE DENSITY GAUGE
The following information was provided by the California Department of Public Health, Radiologic Health Branch (RHB) via email:
"The licensee's radiation safety officer (RSO) reported the theft of a CPN moisture density gauge (serial number 70308642). The gauge contains a 10 mCi Cs-137 and a 50 mCi Am-241/Be sealed source. The transit case and the gauge both have the owner's name and contact information taped to them.
"Sometime over the weekend, thieves broke into the company's high security modular storage unit and then cut the lock and cable used to secure the gauge transport case to the mobile unit. The gauge operator confirms that the gauge's trigger lock was engaged after it was last used on Friday, 12/19/2025.
"The licensee reported the theft to the Beaumont Police Department and will contact their gauge service company. The RSO was asked to post an ad in local news for the safe return of the gauge. The RHB will be conducting an investigation."
CA Incident Number: 122225
THIS MATERIAL EVENT CONTAINS A 'Less than Cat 3' LEVEL OF RADIOACTIVE MATERIAL
Sources that are "Less than IAEA Category 3 sources," are either sources that are very unlikely to cause permanent injury to individuals or contain a very small amount of radioactive material that would not cause any permanent injury. Some of these sources, such as moisture density gauges or thickness gauges that are Category 4, the amount of unshielded radioactive material, if not safely managed or securely protected, could possibly - although it is unlikely - temporarily injure someone who handled it or were otherwise in contact with it, or who were close to it for a period of many weeks. For additional information go to http://www-pub.iaea.org/MTCD/publications/PDF/Pub1227_web.pdf
The following information was provided by the California Department of Public Health, Radiologic Health Branch (RHB) via email:
"The licensee's radiation safety officer (RSO) reported the theft of a CPN moisture density gauge (serial number 70308642). The gauge contains a 10 mCi Cs-137 and a 50 mCi Am-241/Be sealed source. The transit case and the gauge both have the owner's name and contact information taped to them.
"Sometime over the weekend, thieves broke into the company's high security modular storage unit and then cut the lock and cable used to secure the gauge transport case to the mobile unit. The gauge operator confirms that the gauge's trigger lock was engaged after it was last used on Friday, 12/19/2025.
"The licensee reported the theft to the Beaumont Police Department and will contact their gauge service company. The RSO was asked to post an ad in local news for the safe return of the gauge. The RHB will be conducting an investigation."
CA Incident Number: 122225
THIS MATERIAL EVENT CONTAINS A 'Less than Cat 3' LEVEL OF RADIOACTIVE MATERIAL
Sources that are "Less than IAEA Category 3 sources," are either sources that are very unlikely to cause permanent injury to individuals or contain a very small amount of radioactive material that would not cause any permanent injury. Some of these sources, such as moisture density gauges or thickness gauges that are Category 4, the amount of unshielded radioactive material, if not safely managed or securely protected, could possibly - although it is unlikely - temporarily injure someone who handled it or were otherwise in contact with it, or who were close to it for a period of many weeks. For additional information go to http://www-pub.iaea.org/MTCD/publications/PDF/Pub1227_web.pdf
Power Reactor
Event Number: 58100
Facility: LaSalle
Region: 3 State: IL
Unit: [1] [] []
RX Type: [1] GE-5,[2] GE-5
NRC Notified By: Brock Pollmann
HQ OPS Officer: Robert A. Thompson
Region: 3 State: IL
Unit: [1] [] []
RX Type: [1] GE-5,[2] GE-5
NRC Notified By: Brock Pollmann
HQ OPS Officer: Robert A. Thompson
Notification Date: 12/28/2025
Notification Time: 20:26 [ET]
Event Date: 12/28/2025
Event Time: 16:06 [CST]
Last Update Date: 12/28/2025
Notification Time: 20:26 [ET]
Event Date: 12/28/2025
Event Time: 16:06 [CST]
Last Update Date: 12/28/2025
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):
Stoedter, Karla (R3DO)
Stoedter, Karla (R3DO)
| Unit | SCRAM Code | RX Crit | Initial PWR | Initial RX Mode | Current PWR | Current RX Mode |
|---|---|---|---|---|---|---|
| 1 | M/R | Y | 93 | Power Operation | 0 | Hot Shutdown |
MANUAL REACTOR SCRAM DUE TO RCS LEAK
The following information was provided by the licensee via phone and email:
"At 1606 CST with Unit 1 in mode 1 at 93 percent power, the reactor was manually tripped due to degrading containment parameters associated with a leak from the 'B' reactor recirculation pump line, which has been isolated. The trip was not complex, however the 'A' reactor recirculation pump tripped to OFF instead of down-shifting to slow speed. Due to the reactor protection system actuation while critical, this event is being reported as a four-hour, non-emergency notification per 10 CFR 50.72(b)(2)(iv)(B).
"Operations responded using emergency operations procedures and stabilized the unit in plant mode 3 (hot shutdown). Decay heat is being removed by discharging steam to the main condenser using the turbine bypass valves. Unit 2 is not affected.
"There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified."
The following information was provided by the licensee via phone and email:
"At 1606 CST with Unit 1 in mode 1 at 93 percent power, the reactor was manually tripped due to degrading containment parameters associated with a leak from the 'B' reactor recirculation pump line, which has been isolated. The trip was not complex, however the 'A' reactor recirculation pump tripped to OFF instead of down-shifting to slow speed. Due to the reactor protection system actuation while critical, this event is being reported as a four-hour, non-emergency notification per 10 CFR 50.72(b)(2)(iv)(B).
"Operations responded using emergency operations procedures and stabilized the unit in plant mode 3 (hot shutdown). Decay heat is being removed by discharging steam to the main condenser using the turbine bypass valves. Unit 2 is not affected.
"There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified."
Power Reactor
Event Number: 58101
Facility: McGuire
Region: 2 State: NC
Unit: [1] [] []
RX Type: [1] W-4-LP,[2] W-4-LP
NRC Notified By: Michael Grembecki
HQ OPS Officer: Robert A. Thompson
Region: 2 State: NC
Unit: [1] [] []
RX Type: [1] W-4-LP,[2] W-4-LP
NRC Notified By: Michael Grembecki
HQ OPS Officer: Robert A. Thompson
Notification Date: 12/29/2025
Notification Time: 16:00 [ET]
Event Date: 12/29/2025
Event Time: 12:29 [EST]
Last Update Date: 12/29/2025
Notification Time: 16:00 [ET]
Event Date: 12/29/2025
Event Time: 12:29 [EST]
Last Update Date: 12/29/2025
Emergency Class: Non Emergency
10 CFR Section:
50.72(b)(2)(iv)(B) - RPS Actuation - Critical 50.72(b)(3)(iv)(A) - Valid Specif Sys Actuation
10 CFR Section:
50.72(b)(2)(iv)(B) - RPS Actuation - Critical 50.72(b)(3)(iv)(A) - Valid Specif Sys Actuation
Person (Organization):
Nielsen, Adam (R2DO)
Nielsen, Adam (R2DO)
| 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 |
EN Revision Imported Date: 12/30/2025
EN Revision Text: AUTOMATIC REACTOR TRIP
The following information was provided by the licensee via phone and email:
"At 1229 EST on 12/29/2025, with Unit 1 in mode 1 at approximately 100 percent power, the reactor automatically tripped due to a lockout of the main generator. The trip was not complex, with all systems responding normally post-trip.
"Operations manually started the motor driven auxiliary feedwater pumps due to anticipation of automatic actuation and has stabilized Unit 1. Decay heat is being removed by the condenser. Unit 2 was not affected.
"Due to the reactor protection system actuation while critical and actuation of the motor driven auxiliary feedwater pumps, this event is being reported as a four-hour, non-emergency notification per 10 CFR 50.72(b)(2)(iv)(B) and an 8-hour non-emergency notification per 10 CFR 50.72(b)(3)(iv)(A).
"There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified."
EN Revision Text: AUTOMATIC REACTOR TRIP
The following information was provided by the licensee via phone and email:
"At 1229 EST on 12/29/2025, with Unit 1 in mode 1 at approximately 100 percent power, the reactor automatically tripped due to a lockout of the main generator. The trip was not complex, with all systems responding normally post-trip.
"Operations manually started the motor driven auxiliary feedwater pumps due to anticipation of automatic actuation and has stabilized Unit 1. Decay heat is being removed by the condenser. Unit 2 was not affected.
"Due to the reactor protection system actuation while critical and actuation of the motor driven auxiliary feedwater pumps, this event is being reported as a four-hour, non-emergency notification per 10 CFR 50.72(b)(2)(iv)(B) and an 8-hour non-emergency notification per 10 CFR 50.72(b)(3)(iv)(A).
"There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified."
Power Reactor
Event Number: 58102
Facility: LaSalle
Region: 3 State: IL
Unit: [1] [] []
RX Type: [1] GE-5,[2] GE-5
NRC Notified By: Brock Pollmann
HQ OPS Officer: Robert A. Thompson
Region: 3 State: IL
Unit: [1] [] []
RX Type: [1] GE-5,[2] GE-5
NRC Notified By: Brock Pollmann
HQ OPS Officer: Robert A. Thompson
Notification Date: 12/29/2025
Notification Time: 21:08 [ET]
Event Date: 12/29/2025
Event Time: 16:00 [CST]
Last Update Date: 12/29/2025
Notification Time: 21:08 [ET]
Event Date: 12/29/2025
Event Time: 16:00 [CST]
Last Update Date: 12/29/2025
Emergency Class: Non Emergency
10 CFR Section:
50.72(b)(3)(ii)(A) - Degraded Condition
10 CFR Section:
50.72(b)(3)(ii)(A) - Degraded Condition
Person (Organization):
Sanchez Santiago, Elba (R3DO)
Sanchez Santiago, Elba (R3DO)
| Unit | SCRAM Code | RX Crit | Initial PWR | Initial RX Mode | Current PWR | Current RX Mode |
|---|---|---|---|---|---|---|
| 1 | N | N | 0 | Cold Shutdown | 0 | Cold Shutdown |
DEGRADED CONDITION
The following information was provided by the licensee via phone and email:
"At 1600 CST on 12/29/2025, it was determined that a through-wall leak identified on a three-quarter inch vent valve off of the bonnet of the Unit 1 'B' reactor recirculation flow control valve qualifies as pressure boundary leakage resulting in a degraded reactor coolant system pressure boundary. Leakage repair will be completed prior to plant startup from the current outage. Therefore, this event is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(ii)(A).
"There was no impact on the health and safety of the public or plant personnel.? The NRC Resident Inspector has been notified. The State of Illinois will be notified."
The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance:
This event is related to EN 58100.
The following information was provided by the licensee via phone and email:
"At 1600 CST on 12/29/2025, it was determined that a through-wall leak identified on a three-quarter inch vent valve off of the bonnet of the Unit 1 'B' reactor recirculation flow control valve qualifies as pressure boundary leakage resulting in a degraded reactor coolant system pressure boundary. Leakage repair will be completed prior to plant startup from the current outage. Therefore, this event is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(ii)(A).
"There was no impact on the health and safety of the public or plant personnel.? The NRC Resident Inspector has been notified. The State of Illinois will be notified."
The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance:
This event is related to EN 58100.