Event Notification Report for January 17, 2025

EN Revision Imported Date: 1/17/2025

EN Revision Text: DEGRADATION OF SAFETY ITEM

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

"At approximately 1030 EST, on 12/12/2024, Nuclear Criticality Safety (NCS) staff were notified that the polyvinyl chloride (PVC) piping of a passive overflow item relied on for safety (IROFS, SGD-147) for Uranium Recovery and Recycle Services (URRS) vessel V-756A was in a deformed condition. V-756A and V-756B are interconnected URRS dissolver product hold tanks. The V-756B redundant passive IROFS overflow (SGD-130) is constructed of steel. NCS staff reviewed the condition of the PVC overflow piping and determined the overflow was deformed into a position that would restrict flow to the point that it could not provide its intended safety function. The safety function of the IROFS is to prevent backflow of uranium bearing material into water and nitric acid systems by providing an overflow path below the height of the water and nitric acid inputs into V-756A/B. The SGD-130 passive overflow was available to perform its intended safety function. The issue was entered as a red-book item in the corrective action program (CAP) as IR-2024-13041.

"Per criticality safety evaluation, CSE-4A, and supporting calculation note, CN-SB-11-031, with the passive overflow IROFS SGD-147 in a failed condition, the overall likelihood index (OLI) for the fault tree scenario increased from -6 to -3 which does not meet the OLI of -4 necessary to meet 10 CFR 70.61 performance requirements. The result is reportable per 10 CFR Part 70 Appendix A(b)(2), 'Loss or degradation of items relied on for safety that results in failure to meet the performance requirements of 10 CFR 70.61.'

"Operations for the dirty dissolver process are down pending further investigation and development of compensatory actions. A causal analysis will be performed and corrective actions to prevent recurrence will be documented in the CAP.

"Further investigation determined that on 12/12/2024, during third shift URRS, while dirty dissolver operations were down, a centrifuge malfunction occurred that necessitated spill clean up of the centrifuge platform area in the ground floor level below the platform. Based on interviews of URRS personnel, it was determined that to clean up the two spill locations, two separate steam-driven eductors with suction wands were utilized to transfer spill solutions to V-756A in roughly the same timeframe. The apparent cause of the PVC overflow piping deformation is excessive steam vapor influx into V-756A from the simultaneous spill cleanup activities.

"A review of the site maintenance database identified one completed maintenance work order for the replacement of V-756A overflow piping for PVC pipe deformation. Additional review of previous maintenance activities for the V-756A will be performed to determine if there were other instances of deformation of the overflow piping for V-756A. This occurrence in September 2024 was not brought to the attention of management or engineering staff to ensure comprehensive follow-up and corrective actions. The occurrence was not captured as red-book CAP item for a degraded or failed IROFS."

"Number and types of controls necessary under normal operating conditions: For scenario 4.3 of CSE-4-A supporting Calculation Note, CN-SB-11-031, two passive overflow IROFS controls (SGD-130 and SGD-147) are necessary under normal operating conditions to prevent a backflow condition into the nitric acid supply.

"Number and types of controls which functioned properly under upset conditions: Passive overflow IROFS (SGD-130) on V-756B is constructed of metal and will not deform when exposed to steam. Criticality safety staff reviewed the SGD-130 overflow for V-756 A/B and determined it could perform its safety function.

"Number and types of controls necessary to restore a safe situation: The PVC overflow IROFS SGD-147 for vessel V-756A was replaced on 12/12/2024. An extent of condition review for process vessels with PVC/plastic pipe passive overflows with potential exposure to excess heat has been initiated.

"Safety significance of events: Passive overflow IROFS SGD-130 remained available and a review of tank level data logging confirmed there was no overflow of V-756 A/B and there was no backflow condition into the deionized water and nitric acid systems.

"Safety equipment status: The passive overflow IROFS control SGD-147 for V-756A/B was replaced on 12/12/2024. The IROFS controls necessary to meet 10 CFR 70.61 performance requirements are in place.

"Status of corrective actions: Operations for the dirty dissolver are down pending further investigation and development of compensatory actions. A causal analysis will be performed and corrective actions to prevent recurrence will be documented in the corrective action program."

* * * RETRACTION ON 01/16/2025 AT 1228 EST FROM STEVE SUBOSITS TO JORDAN WINGATE * * *

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

"Following review of pertinent integrated safety analysis risk assessment information, Westinghouse reevaluated the nuclear criticality safety scenario utilized as the basis for reporting event notification (EN) 57472 on December 13, 2024. The scenario for a backflow condition into the nitric acid header did not consider initiating and enabling conditions in the accident sequence for a potential backflow of uranyl nitrate solution into Uranium Recovery and Recycle Services (URRS) vessels V-756 A/B. The reevaluation determined the overall likelihood index of the scenario with a failure of the SGD-147 passive overflow meets the performance requirements of 10 CFR 70.61.

"Westinghouse is retracting EN 57472 based on the reevaluation of the scenario. 10 CFR 70.61 performance requirements were met to ensure a nuclear criticality remained highly unlikely for the backflow scenario."

Notified R2DO (Suggs), and NMSS Events Notification (email).

AGREEMENT STATE REPORT - MEDICAL EVENT

The following was provided by the Utah Division of Waste Management and Radiation Control (the Department) via email:

At 1000 MST, on 01/10/25, the Utah Cancer Specialists reported a medical event to the Department.

"A Patient was undergoing a Lutathera treatment (contains Lu-177). During treatment, the patient was to receive an amino acid infusion prior to the radiopharmaceutical administration, as per standard protocol. Initially, saline was started; however, the saline line remained clamped, preventing the amino acid infusion from commencing. Fifteen minutes after administering the radiopharmaceutical, it was observed that the amino acids had not been infused. Consequently, the Lutathera treatment was paused, the amino acid infusion was initiated, and subsequently, the Lutathera administration was completed."

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

The prescribed activity was 200 mCi of Lu-177 to the patient. The dose estimate, which is still being evaluated, falls under 10 CFR 35.3045 Subpart M.

Utah Event Report Number: UT250001

A Medical Event may indicate potential problems in a medical facility's use of radioactive materials. It does not necessarily result in harm to the patient.

FITNESS FOR DUTY

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

"At 1302 CST on 1/15/2025, it was determined that a [non-licensed] supervisor tested positive [for a controlled substance] in accordance with the Fitness for Duty (FFD) testing program. The individual's authorization for site access has been terminated.

"The NRC Senior Resident Inspector has been notified."

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

This was determined during random FFD testing. The individual performed no safety related work.

MANUAL TRIP WHILE SHUTDOWN

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

"At 0950 EST, with Unit 2 in mode 3 at 0 percent power, the reactor was manually tripped due to group 2 of control rod bank D failing to withdraw during rod drop testing. The trip was not complex, with all systems responding normally post-trip.

"Operations responded and stabilized the plant. Decay heat is being removed by the auxiliary feedwater and steam dump systems. Unit 1 is not affected.

"At the time of the event, Unit 2 was not critical. Therefore, this event is being reported as an eight-hour, non-emergency notification in accordance with 10 CFR 50.72(b)(3)(iv)(A) as an event that results in a valid actuation of the reactor protection system.

"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:

Four controls rods failed to move on demand. All control rods inserted on the trip.

OFFSITE NOTIFICATION

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

"On January 16, 2025, at 1150 CST, Xcel Energy performed a notification to the State of Minnesota Duty Officer per the National Pollutant Discharge Elimination System (NPDES) Permit (# MN0000868). This notification is being made solely as a four-hour, non-emergency report for notification to other government agency in accordance with 10 CFR 50.72(b)(2)(xi).

"There was no impact to 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 offsite notification is a requirement per the NPDES permit to report any instance of waste water release to the state. There was a release of waste water from a pumping house which was subsequently cleaned up by site personnel.