A new definition of violation based on accident/failure analyses in nuclear power plants

The objective of this study is to define a violation, a type of human errors, based on a case study in nuclear power plants. Accidents in nuclear power plants are rare-accident of large, complex and high-reliability systems. Since the damage of an accident could be extremely enormous, many efforts have been underway to prevent the human errors. Especially, the violation is a newly emerging type of human errors but its concept is not clearly defined in the nuclear industry. A total of 28 reports related to the human error accidents/failures in the last 10 years were collected from NEED (Nuclear Event Evaluation Database) in KINS-OPIS (Operational Performance Information System). The relationship between causal factors and violations were analyzed by the fault tree analysis (FTA) and the human related event root cause analysis method (HuRAM). As a result, the characteristics of violations were identified and four types of violations (routine, situational, avoidance and optimizing violations) were newly defined. The results of this study can be used to develop proactive countermeasures and implement a supervisory system for preventing violations.