Operator Actions Outside the Control Room: A Field Study

Abstract

In the nuclear industry, while there exists a growing body of knowledge on human reliability data for actions inside the main control room, there is a lack of empirical data for field operator tasks. In this paper we present an initial study to verify a new framework for collecting reliability data for actions outside the control room. The study focuses on verifying the applicability and relevance of this framework in real world contexts, specifically regarding performance shaping factors. We have conducted a data collection at the Halden Boiling Water Reactor in Norway with six crews during normal operation. The preparation included: 1) selection of a target scenario where actions outside the control room were relevant; 2) conducting a walkthrough at the site with an experienced operator; 3) performing a task analysis based on the walkthrough; 4) creating a checklist for observation and data collection at the plant; 5) making a questionnaire to assess operators’ perception and understanding of the task; and 6) developing a semi-structured guide for a debriefing interview. During the study the researchers shadowed the two involved operators both in the field and in the control room. The findings confirmed the framework assumptions that performance shaping factors such as communication, background knowledge and situation understanding play a crucial role in actions outside the control room. Other findings from the study highlight the relevance of: a) trust in the team; and b) procedures for standardized task performance, as well as to reduce variability in operators’ actions.