Jung-Woon Lee

An experimental evaluation of the flowchart type Operating Procedure for Nuclear Power Plants

In Nuclear Power Plants(NPPs), Emergency Operating Procedure(EOP) is used to overcome a undesirable or emergency plant state. Most NPPs are using the two-column type EOP, even though the flowchart type is used in some other NPPs. The flowchart type EOP has inherent characteristics due to its structure and format. In this study, an experimental evaluation was conducted for a flowchart type EOP. For the experimental evaluation, questionnaires were used, observations were made on operators using flowchart type procedures, and ECG based physiological measurements when need were performed. The results of the analysis show that the flowchart type EOP does not have any significant problems when compared with the two-column type as far as the safety of NPPs is concerned. However, we found a few problems, caused by the structure and format of the flowchart type, to be improved.

A proposition of human factors approaches to reduce human errors in nuclear power plants

Human errors in nuclear power plants have been an important subject in the human factors research domain. Although the mechanism of human errors seems not to draw any more interests from reputable researchers, human errors are still occurring in nuclear power plants and efforts to effectively reduce these human errors are still being searched. In this paper, some practices, e.g. HPES, PSR, and HFMP, which are the applications of human factors engineering to Korean nuclear power plants, are discussed. PSR activities are described in detail here since they have brought about many valuable insights into human factors in NPPs. It is also discussed what we should consider in the analyses of human error events. In contrast to this retrospective approach, several prospective approaches are discussed in this paper; work condition analyses for the tasks taken place at locations other than control rooms, the expansion of training opportunities to local operators, the development of an effective know-how transfer system, the establishment of a job management system by considering changes in the morals and cultures in the performance of jobs in NPPs.

Cabinet Module Design and Evaluation

The reactor protection system (RPS) in nuclear power plants plays the roles of generating the reactor trip signal and the engineered safety features (ESF) actuation signal when the monitored plant processes reach the predefined limits. The cabinet of the RPS is used for the RPS integrity testing and monitoring by maintenance operators and is equipped with a flat panel display (FPD) with a touch screen capability as a main user interface for the RPS operation. This paper describes the human factors activities involved in the development process of the RPS: conceptual design, design guidance, and evaluation.

Expert System-Based Implementation of Failure Detection

In light of the need to improve MMIS of NPPs, the advanced I&C research team of KAERI has embarked on developing an Alarm and Diagnosis-Integrated Operator Support System, called ADIOS. ADIOS was composed of two modules such as alarm process module and fault diagnostic module. The alarm process module can offer key alarms to operator using dynamic alarm filtering methods and the fault diagnostic module was able to diagnose the component failure caused by a sensor fault and a hardware fault. ADIOS has been built in an object-oriented AI environment of G2 expert system software tool. In the G2 environment, every alarm and diagnostic component have been treated as an object of class. The attributes of each alarm object include activation status, alarm message, process value, activated time, priority, acknowledgment state, interlocked equipment and caused alarm. If an alarm is activated, its icon color on an overview process mimic diagram changes corresponding to its priority, which can be set initially or determined dynamically by reasoning rules and procedures. The process conditions, such as plant or equipment status and correlated alarms’ states have determined the priority of the activated alarm and the fault diagnostic condition. The knowledge base and the inference engines of ADIOS have been constructed by process analysis of the plant and discussion with operators and nuclear plant experts.