1. Application control chart concepts of designing a pre-alarm system Sheue-Ling Hwang, Jhih-Tsong Lin, Guo-Feng Liang, Yi-Jan Yau, Tzu-Chung Yenn, Chong-Cheng Hsu Nuclear Engineering and Design 238 (2008) 3522–3527

2. Introduction A well-trained operator in an NPP should possess the abilities not only to monitor the system information, but also to utilize this information to manipulate the system and predict otherwise unforeseen situations. A well-trained operator in an NPP should possess the abilities not only to monitor the system information, but also to utilize this information to manipulate the system and predict otherwise unforeseen situations. There are two approaches among the studies about advanced alarm designs in recent year: improving the alarm system and reducing the frequency of alarms. There are two approaches among the studies about advanced alarm designs in recent year: improving the alarm system and reducing the frequency of alarms.

3. In this study, we implemented a quality control method, which has no complex mathematical model and which has been applied in several industries, to reduce the frequency of alarms in a power plant control room. In this study, we implemented a quality control method, which has no complex mathematical model and which has been applied in several industries, to reduce the frequency of alarms in a power plant control room. In order to evaluate the efficiency of the pre- alarm system, we conducted an experiment to simulate the reactor shutdown and the load- rejection task in a control room to assess task performance. In order to evaluate the efficiency of the pre- alarm system, we conducted an experiment to simulate the reactor shutdown and the load- rejection task in a control room to assess task performance.

5. Quality control chart techniques for fault detection Rule 1: Any one point falls outside the upper control limits (UCL)or lower control limits (LCL). Rule 1: Any one point falls outside the upper control limits (UCL)or lower control limits (LCL). Rule 2: Seven points in a row are continually increasing (or decreasing). Rule 2: Seven points in a row are continually increasing (or decreasing). Rule 3: Cyclical patterns of points occur. Rule 3: Cyclical patterns of points occur. Rule 4: Two out of three consecutive points fall beyond the twosigma limit. Rule 4: Two out of three consecutive points fall beyond the twosigma limit. Rule 5: A run of five points falls beyond the one- sigma limit Rule 5: A run of five points falls beyond the one- sigma limit

7. Method Participants-Twenty-six participants. The ages of participants were 36.5±9.8 years. Participants-Twenty-six participants. The ages of participants were 36.5±9.8 years. Experimental tasks and procedure- Experimental tasks and procedure- The team members in the experiment were a reactor operator (RO), an assistant reactor operator (ARO) and a supervisor. The team members in the experiment were a reactor operator (RO), an assistant reactor operator (ARO) and a supervisor.

8. In the normal state, the system was used to simulate the shutdown of the reactor according to integrated operating procedures. In the normal state, the system was used to simulate the shutdown of the reactor according to integrated operating procedures. In the abnormal state, the procedure of load rejection was used. operators had to find the solutionsfrom the procedure to deal with the events so that all events could be relieved in 10min. In the abnormal state, the procedure of load rejection was used. operators had to find the solutionsfrom the procedure to deal with the events so that all events could be relieved in 10min.

9. During the shutdown and load-rejection procedures, the operators had to monitor six critical parameters of the system. In order to evaluate the effects of the pre- alarm pattern, we set some fault events based on these parameters. During the shutdown and load-rejection procedures, the operators had to monitor six critical parameters of the system. In order to evaluate the effects of the pre- alarm pattern, we set some fault events based on these parameters.

10. The secondary task was based on Hwang et al. ’ s (2007) task of comparing two integers without using any computations. The secondary task was based on Hwang et al. ’ s (2007) task of comparing two integers without using any computations. The subjects used the mouse to choose “ greater than ”, “ equal to ” or “ smaller than ” to respond to the number comparison. The subjects used the mouse to choose “ greater than ”, “ equal to ” or “ smaller than ” to respond to the number comparison.

11. Experimental variables There were two independent variables: alarm type and system state. There were two independent variables: alarm type and system state. The alarm types had three levels – text, graphic pre-alarm and original The alarm types had three levels – text, graphic pre-alarm and original The system state had two levels, the normal and abnormal system states. The system state had two levels, the normal and abnormal system states. Each team operated six trials in the experiment. Each team operated six trials in the experiment.

12. For the dependent variables, task performance, mental workload and team SA were measured. For the dependent variables, task performance, mental workload and team SA were measured. The performance of the primary task was measured by the operation time, the searching time and the frequency of alarm. The performance of the primary task was measured by the operation time, the searching time and the frequency of alarm. The secondary task performance was measured by the rate of correct responses. The secondary task performance was measured by the rate of correct responses.

13. Results-Task performance The result for alarm frequency indicated that the pre-alarm type significantly affected the frequency of alarms (F2,72 = 141.7, P < 0.001). The result for alarm frequency indicated that the pre-alarm type significantly affected the frequency of alarms (F2,72 = 141.7, P < 0.001). Graphics and text were better than the original alarm design, but there was no difference between graphics and text. Graphics and text were better than the original alarm design, but there was no difference between graphics and text.

15. The results indicated that operation times (in seconds) were not significantly different when using different types of pre-alarm systems. The results indicated that operation times (in seconds) were not significantly different when using different types of pre-alarm systems. The results of ANOVA revealed that the main and interaction effects on average searching time were not significant. The results of ANOVA revealed that the main and interaction effects on average searching time were not significant.

17. Results-Mental workload The results of ANOVA indicated that the pre- alarm type was a significant factor (F2,144 = 7.973, P < 0.01) in workload. The results of ANOVA indicated that the pre- alarm type was a significant factor (F2,144 = 7.973, P < 0.01) in workload. The mental workload of either graphics or text was lower than the original, but there was no difference between graphics and text. The mental workload of either graphics or text was lower than the original, but there was no difference between graphics and text. The NASA-TLX mean scores of the normal and abnormal states were 62.24 and 70.47, respectively. The NASA-TLX mean scores of the normal and abnormal states were 62.24 and 70.47, respectively.

18. The ANOVA result indicated that neither the main nor the interaction effect was significant. The ANOVA result indicated that neither the main nor the interaction effect was significant. Results- Team SA

19. Conclusion The results indicated that this system could detect the most common fault symptom in the NPP and that implementing the system could reduce operators ’ mental workload. The results indicated that this system could detect the most common fault symptom in the NPP and that implementing the system could reduce operators ’ mental workload. Future studies could examine whether the pre-alarm system could be expanded to include the operator ’ s physiology indices Future studies could examine whether the pre-alarm system could be expanded to include the operator ’ s physiology indices