Optimal inspection and replacement periods of the safety system in wolsung nuclear power plant unit 1 with an optimized cost perspective

In this work, a model for detennining the optimal inspection and replacement periods of the safety system in Wolsung nuclear power plant Unit 1 is developed, which is to minimize economic loss caused by inadvertent trip and the system failure. This model uses cost benefit analysis method and the part for optimal inspection period considers the human error, The model is based on three factors as follows: i) The cumulative failure distribution function of the safety system, ii) The probability that the safety system does not operate due to failure of the system or human error when the safety system is needed at an emergency condition and iii) The average probability that the reactor is tripped due to the failure of system components or human error. The model then is applied to evaluate the safety system in Wolsung nuclear power plant Unit I. The optimal replacement periods which are calculated with proposed model differ from those used in Wolsung NPP Unit I by about a few days or months whereas the optimal inspection periods are in about the same range