Human Factors in Incident Investigation

Abstract

The Savannah River Site (SRS), located in South Carolina, is a key Department of Energy production and research facility for nuclear materials. Incident investigations performed at the Savannah River Site showed the cause of approximately 75% of all operating incidents in non-reactor facilities to be human error. The technical incident reporting system in place required the investigator to list the cause of an incident in broad terms (i.e., Personnel Error, Equipment Error) and to categorize it according to subclassifications (i.e., Operator Error, Supervisor Error, Mechanic Error). The reporting system, using these classifications, tended to emphasize “what happened” during an incident and “who was involved”, instead of getting to the details of “why” an incident occurred. The high rate of human error as the cause of incidents indicated that further analysis was in order.

Human factors personnel in the Facility Safety Evaluation Section (FSES - an oversight organization with emphasis on non-reactor facilities) wanted to determine the causes of human error in a way that would identify more precisely why the errors occurred. To satisfy these needs, FSES is implementing a root cause analysis program for SRS. Root cause analysis consists of two parts; the first being Events and Causal Factor (E&CF) Charting; and the second, Root Cause Coding using a Root Cause Tree. The objectives were to provide a systematic method for identifying the root causes of a given incident in order to make detailed recommendations for preventing its recurrence, and to provide a database of incident root causes for identifying problem areas across incidents. Root cause analysis would guide the incident investigator to state “why” an incident occurred using detailed cause codes (e.g., Incomplete Training, Labels Less Than Adequate). Root cause trending would enable FSES to track the causes of human error, recommend solutions, and track corrective actions. FSES developed a one day workshop to train several hundred incident investigators at SRS to perform investigations using the root cause analysis method. This presentation will discuss the development and implementation of the root cause analysis system at SRS by FSES human factors professionals.