Using a cause coding tree to identify event root causes

Far too often, when an event occurs in a nuclear plant, only the symptoms of the event are addressed. To do more than address the symptoms, one has to go beyond the first inclination to blame the operator for making a mistake. One has to ask more questions. One has to find the root causes. At Savannah River Plant (SRP) a technique was developed to identify the root causes of operating experience. This paper presents the technique's advantages and compares it to MORT and the Institute for Nuclear Power Operations (INPO's) cause coding.