On November 13, 2024, the NRC issued a notice of violation (Notice) to BWXT Nuclear Operations Group, Inc. (licensee) for a Severity Level (SL) III violation. The SL III violation involved the licensee’s failure to maintain a monitoring system capable of detecting a criticality in certain process areas of the facility as required in 10 CFR 70.24(a)(1). Specifically, during the conduct of a Nuclear Criticality Safety Process Analysis in October 2023, the licensee determined that initial modeling parameters and assumptions used in October 2012 for the Criticality Accident Alarm System (CAAS) detector placement were incorrect for some areas of the facility. As a result, the CAAS as designed could neither detect the minimum accident of concern nor meet the coverage requirements in 10 CFR 70.24.