Event Notification Report for December 06, 2024

AUTOMATIC REACTOR TRIP

The following information was provided by the licensee via phone or email:

"At 1033 EST on December 4, 2024, with Unit 3 in mode 1 at 100% power, the reactor automatically tripped in response to a reactor protection system channel failure while planned maintenance was in progress on a redundant channel. The plant is currently in mode 3. Decay heat is being removed by steam dumps to atmosphere. Unit 4 is unaffected. An actuation of the auxiliary feedwater system occurred and started as designed. An actuation of the emergency core cooling system (ECCS) occurred and started as designed. This event is being reported pursuant to 10 CFR 50.72(b)(2)(iv)(B), and 10 CFR 50.72(b)(3)(iv)(A).

"The NRC Resident Inspector has been notified."

The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance:

The ECCS actuation included safety injection, residual heat removal, and emergency containment cooling. The cause of the trip and the ECCS actuation are under investigation. There are no indications of primary to secondary leakage.

SECONDARY CONTAINMENT INOPERABLE

The following information was provided by the licensee via phone and email:

"At 1640 EST, on December 4, 2024, secondary containment was declared inoperable. This condition is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(v)(C), as an event or condition that could have prevented fulfillment of a safety function.

"Secondary containment was declared inoperable due to a small hole discovered in the service water piping within secondary containment. The effective safety function was restored at 1730 EST by installation of a temporary repair and secondary containment has been restored to operable.

"There was no impact on the health and safety of the public or plant personnel.

"The NRC Resident Inspector has been notified."

Notified R2DO (Suber)

AGREEMENT STATE - SOURCE FAILED TO RETRACT

The following information was provided by the Illinois Emergency Management Agency (the Agency) via email and phone:

"The Agency was contacted on 12/2/24 by radiation oncology staff at Advocate Christ Hospital to advise a 4.3 Ci Ir-192 source for a high dose rate afterloader (HDR) was stuck in the exposed position. The source was extended for daily quality assurance checks and is within a shielded vault. There were no staff or patient exposures. The manufacturer has been contacted to dispatch a service technician to the site and is expected 12/3/24. Agency staff conducted a reactive inspection on 12/2/24 to verify public exposure rates were within limits, verify adequate room security could be maintained, and determine the resources made available by the licensee to prevent any radiation exposures. After investigation, inspectors found the licensee had effectively restricted access by installing a secondary key-pad controlled door outside the vault door. Appropriate signage had been installed and survey readings in all areas were confirmed to be below public exposure limits (max 40 microrem per hour). The fault appears to be electrical and updates will be provided once obtained from Varian staff."

Equipment information:
Device name: Remote afterloader HDR
Model number: GammaMed Plus iX
Serial number: H641313
Manufacturer: Varian

Illinois item number: IL240030

EMERGENCY DIESEL GENERATORS DECLARED INOPERABLE

The following information was provided by the licensee via phone and email:

"At 2358 Eastern Standard Time (EST) on December 5, 2024, emergency diesel generator (EDG) '1' was declared inoperable due to a failure in the standby lube oil temperature control circuit. At this time, EDG '2' was already inoperable due to failure of a relay in the starting air circuity. As a result, both EDGs were simultaneously inoperable; therefore, this condition is being reported as a non-emergency notification per 10 CFR 50.72(b)(3)(v)(D), as an event or condition that could have prevented fulfillment of a safety function.

"Offsite power, EDG '3', and EDG '4' were operable during the entire time period that EDGs '1' and '2' were inoperable. The effective safety function was restored at time 0148 on December 6, 2024, when lube oil temperature was restored and EDG '1' was declared operable. EDG '1' was inoperable concurrently with EDG '2' for approximately 1 hour and 50 minutes.

"There was no impact on the health and safety of the public or plant personnel.

"The NRC Resident Inspector has been notified."

The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance:

The inoperability of two EDGs placed the plant in LCO 3.8.1.