CIRCUMVENTION OF SAFETY RELATED EQUIPMENT AT NUCLEAR FUEL SERVICES, INC.

摘要

On June 17,2014, at Nuclear Fuel Services, Inc. (NFS), an employee was observed improperly operating two (2) spring return (i.e., spring closed) valves identified as Safety Related Equipment (SRE). These valves were also identified as Items Relied on for Safety (IROFS). The valves were important for both Nuclear Criticality Safety (NCS) and Chemical Safety purposes. The valves were observed to be "propped" in the open position, thereby circumventing the intended safety function of the valves. The event was reported to the NRC Operations Center on June 18, 2014 (Event #50208); and, NFS' investigation concluded that the cause (of the event) was due to a willful act by a Nuclear Process Operator. In addition, when reviewing the event for NRC reportability, there was an organizational focus on NCS accident sequences with limited consideration of other aspects of the Integrated Safety Analysis (ISA). In other words, when determining reportability, the performance requirements for NCS accident sequences were reviewed and determined to be satisfied; however, the chemical safety accident sequences had not been considered during this review. The initial event and the reportability issues were entered into NFS' Corrective Action Program (CAP) and investigated. The investigation also included human performance and safety culture implications. This paper summarizes the circumstances surrounding the event and discusses the lessons learned as a result of the event investigation and review.