Event Notification Report for November 08, 2021

EN Revision Imported Date: 11/8/2021

EN Revision Text: FITNESS-FOR-DUTY REPORT

A non-licensed employee had a confirmed positive for alcohol during a random fitness-for-duty test. The employee's access to the plant has been terminated.

The NRC Resident Inspector has been notified.

DOSE TO AN EMBRYO

The following is a summary of a phone call with Community Health Network:

A patient came in to receive a radiotherapy treatment of 148 mCi I-131 on September 30, 2021. The patient received a negative pregnancy test prior to the treatment. At a later date, the patient realized that she was pregnant and estimated the date of conception to be either September 29, 2021 or October 10, 2021. The radiation safety officer estimated the dose to the embryo to be 394 mSv (39.4 rem) based on a conception date of September 29. The estimated dose to the embryo would be 1.7 mSv (0.17 rem) based on a conception date of October 10. The licensee is reporting this event based on the conception date of September 29 because of the potential for higher dose to the embryo.

LOSS OF HIGH RADIATION AUDIBLE ALARM

"On November 5th, 2021, [1207 MDT] it was identified that a portable Area Radiation Monitor (ARM), which was performing the 10 CFR 70.24 safety function of the Criticality Accident Alarm System (CAAS) to energize clearly audible alarm signals if accidental criticality occurs, had been removed from the area in error.

"On July 20th, 2021, during routine CAAS maintenance, UUSA [Urenco USA] staff identified an area in which a CAAS alarm was not clearly audible. UUSA arranged the ARM as a compensatory measure which achieves an equivalent 10 CFR 70.24 safety function in the affected area. UUSA reported this event to the NRC under Event Notification 55480 in accordance with 10 CFR 70.50(b)(2) in which equipment is disabled or fails to function as designed when required by regulation.

"Removal of this ARM resulted in an inability for radiation detectors to energize clearly audible alarm signals if accidental criticality occurs in the affected area. UUSA hereby reports this event in accordance with 10 CFR 70.50(b)(2), in which equipment is disabled or fails to function as designed when required by regulation (10 CFR 70.24)."

The licensee will notify the NRC Region 2 office.

STEAM SUPPLY CHECK FAILURE TO TURBINE DRIVEN AUXILLARY FEEDWATER

"During a Unit 2 refueling outage valve overhaul activity on the steam supply check valve from the number 2 steam generator to the turbine driven auxiliary feedwater pump, 2-MS-4B, the check valve was found with its disc separated from the disc arm. This failure would have resulted in the blowdown of both steam generators during a main steam line break in the steam generator number 2 main steam line upstream of the main steam isolation valves until the operators could isolate the faulted steam generator. On November 6, at approximately 1100 EDT evaluation determined that this condition constituted an unanalyzed condition that could impact containment pressure.

"There has been no radioactive release to the environment. The valve has been repaired. The check valve in the steam supply from the number 1 steam generator to the turbine driven auxiliary feedwater pump was inspected and found to be satisfactory. There has been no impact to Unit 3 which remains at 100% power.

"The Senior Resident has been notified.

"This condition is being reported pursuant to 10 CFR 50.72(b)(3)(ii)(B) as a condition that resulted in the nuclear power plant being in an unanalyzed condition that significantly degrades plant safety."