Forecast and evaluation of performance of on-line radiation exposure management system in nuclear power plants

The computer systems used for nuclear power plants require high reliability and fast response for securing plant safety. Therefore, it is desirable to sufficiently scrutinize and investigate every work in advance by making total system if a computer system is to be introduced. In this paper, the on-line radiation management system, which is the main work of management computer system, is considered with a queuing simulation model, from the standpoint how the congestion at a TLD/ID station which manages the entering into and exiting from a controlled area is reduced. This is meaningful because it handles the major works of the system to be employed and predicts its performance considering the elements other than machine specifications, i.e., human behaviour. Seven conditions are assumed for the model in executing the simulation. The results are briefly as follows: (1) Queue at a TLD/ID station scarcely occurs in normal operation if 6 TLD devices are installed, but if any one device fails, waiting time increases twice or more. (2) Congestion may possibly be reduced without decreasing the whole efficiency if an appropriate management is done according to the degree of congestion. (3) If congestion is more serious, the increase of TLD devices may become necessary, but it is also important to execute the management such as reducing the attendant peak, for example, employing staggered office hours. (Wakatsuki, Y.)