Event Notification Report for March 28, 2025

AGREEMENT STATE REPORT - POTENTIAL OVEREXPOSURE

The following information was received from the New York State Department of Health (NYSDOH) via phone and email:

"New York State Department of Health (NYSDOH) received an email on the morning of 3/20/2025, from the Chief Operating Officer of NRD, LLC to report a potential overexposure of a production worker.

"On 3/7/2025, a production worker had received an acid burn on his forearm resulting in a first-degree burn where the skin was reddened but not visually broken. The chemical agent causing this burn is suspected to be nitric acid with Am-241 contamination used in routine production activities for Am-241 foils. The exact nature of the work being performed, cause of this burn/contamination, and personal protective equipment (PPE) worn by the affected individual is unknown at this time. The initial skin contamination was 8,900 disintegrations per minute (dpm) according to NRD. After 7 hours of decontamination, using water and mild soap, NRD states that they were able to successfully decontaminate some of the areas on the individual's forearm, however, 5,900 dpm remained on the skin. Nasal swabs and whole-body surveys returned as below background levels according to NRD. NRD, LLC stated that only this one worker had been contaminated from this event.

"NRD states that they believed that this contamination was localized to skin contamination with no evidence of internal uptake. However, this individual has been removed from work and a series of bioassays were performed (24-hour composite urine collection) on 3/8/2025, 3/11/2025, and 3/16/2025 and sent to GEL Laboratories for rush analysis. The 3/8/2025 result showed 22.9 picocuries per liter of Am-241, further confirmed via gamma spectroscopy. This preliminary report was provided to NRD on 3/19/2025.

"NRD states that they performed dose reconstruction from this event using the baseline bioassay, last monthly routine bioassay (collected on 3/5/2025), and the singular reactionary bioassay result available from the collection on 3/8/2025 (reported to NRD on 3/19). NRD, LLC used the integrated modules for bioassay (IMBA) using an ingestion-specific intake model, which indicates 5.47 rem committed effective dose equivalent (CEDE) and 128 rem committed dose equivalent (CDE) to the bone surfaces. These doses are not confirmed as official, but estimates provided the information available at this time. Given the nature of intake and the suspected pathways for intake (e.g., dermal absorption), NYSDOH is awaiting clarification for the assumptions and rationale used in estimating this intake as well as seeking additional information on the nasal samples collected/analyzed and the whole-body surveys performed pre-, during and post-decontamination.

"Prior to reporting this event to NYSDOH, NRD, LLC contacted Radiation Emergency Assistance Center/Training Site (REAC/TS) on the evening of 3/19/2025. NRD, LLC informed NYSDOH that REAC/TS was notified and did not recommend any medical intervention. NYSDOH called REAC/TS independently on March 20, 2025, and spoke to the medical team that spoke to NRD. It was noted that REAC/TS did not have enough information at the point of discussion with NRD to determine if any intervention was necessary and requested NRD, LLC to provide additional information on this event. NYSDOH shared information on this event reported by NRD with REAC/TS following this call. NYSDOH immediately recommended to NRD, LLC that they continue timely follow-up with REAC/TS to determine if medical intervention may be necessary per their clinical recommendation, particularly since two additional bioassay samples (3/11/2025 and 3/16/2025; collection dates) were being analyzed and may strengthen the confidence in performing dose reconstruction. If medical intervention is deemed clinically necessary, the timeliness of medical intervention may directly impact the amount of dose received by the affected worker. Because of this, NYSDOH strongly recommended to NRD that they prioritize resolving any information needed for REAC/TS to make this determination.

"NYSDOH has requested a significant amount of additional information and documentation on this event including, but not limited to, the modeled pathways and methods for dose reconstruction, the extent of personnel and area contamination, immediate protective actions, and causes and corrective actions from this event. NYSDOH has also identified several suspected items of noncompliance pertaining to this event and will follow up on these observations.

"It is not suspected that there is any risk to public health or the environment from this event. NYSDOH is monitoring this event and has assigned NYSDOH Incident Number 1523 to internally track this event. NYSDOH will provide an update to this notification once additional information is available."

NMED Event Report ID Number: NY-25-04

PART 21 - SOFTWARE ERROR IN TRANSIENT STABILITY PROGRAM

The following information was provided by Southern Nuclear Operating Company via email:

"This is a non-emergency notification required by 10 CFR 21.21(d)(3)(i). A written report in accordance with 10 CFR 21.21(d)(3)(ii) will be provided within 30 days.

"Based upon the information provided by Operation Technology, Inc. (OTI) in [electrical transient analyzer program] (ETAP) error report ERCA-24-003, revision 1, Southern Nuclear Operating Company (SNC) has determined that a substantial safety hazard could have been created by the error introduced in the transient stability program in the current release of ETAP software utilized at Edwin I. Hatch Nuclear Plant (HNP) and Vogtle Electric Generating Plant Units 1 and 2 (VEGP1-2) were it to go uncorrected. While the nature of the software error detailed by OTI in ETAP error report ERCA-24-003, revision 1 had the potential to impact bus transfers and degrade essential safety-related equipment, SNC has verified that none of the HNP or VEGP1-2 calculations that utilized the transient stability program had false favorable results.

"The NRC Senior Residents at HNP and VEGP1-2 have been notified."

Affected plants:
Hatch Nuclear Plant Units 1 and 2
Vogtle Electric Generating Plant Units 1 and 2