A project was conducted to analyze, design, develop, implement, and evaluate an instructional unit intended to improve the diagnostic skills of operating personnel in responding to abnormal and emergency conditions at the High Flux Beam Reactor at Brookhaven National Laboratory. Research was conducted on the occurrence of emergencies at similar plants, and existing instructional materials were obtained. An instructional unit for classroom training was designed using the instructional system design approach. The unit is organized in modules, each of which focuses on a task. Performance objectives, enabling objectives keyed to criterion-referenced measure, handouts, charts, tests, and answers to tests were prepared. The methods used may be useful to others who operate high-risk facilities and conduct emergency procedures training. (Extensive appendices contain the job task analysis, learning objectives, cognitive objectives and test items, class schedule, flipcharts, lesson plan, problem scenarios, question pool, lecture critique, supervisor examination, and a brief bibliography.) (KC)